Showing posts with label Injuries. Show all posts
Showing posts with label Injuries. Show all posts

Tuesday, February 18, 2014

Athletic Foot Injuries

Background

Athletic foot injuries can be difficult to properly diagnose and treat. Bearing the weight of the entire body, the foot is under tremendous stress. In many sports, the foot absorbs tremendous shearing and loading forces, sometimes reaching over 20 times the person's body weight. Physicians who treat these disorders must have a good understanding of the anatomy and kinesiology of the foot.

See the following images.

Select bones of the foot (dorsal and plantar viewsSelect bones of the foot (dorsal and plantar views). Select bones of the foot (superolateral view). Select bones of the foot (superolateral view).

Although foot injuries can occur from a variety of causes, the most common cause is trauma. Other etiologies include (1) rapid or improper warm-up, (2) overuse, (3) intense workouts, (4) improper footwear, and (5) playing on hard surfaces.[1, 2, 3, 4, 5]

Physicians who evaluate and treat common foot problems should have a working knowledge of the individual sports and the injuries that are commonly associated with them. An understanding of the basic treatment approaches for these injuries also is imperative.

For excellent patient education resources, visit eMedicineHealth's First Aid and Injuries Center. Also, see eMedicineHealth's patient education articles Broken Foot and Broken Toe.

NextEpidemiologyFrequencyUnited States

Estimates indicate that 15% of sports-related injuries affect the foot alone.

PreviousNextFunctional AnatomyFoot and ankle

The foot is composed of 26 major bones, which can be divided into 3 regions: the forefoot, midfoot, and hindfoot. The forefoot is comprised of the 5 metatarsals and the 14 phalanges. The 3 cuneiforms (ie, lateral, intermediate, medial), the cuboid, and the navicular represent the midfoot. The hindfoot is composed of the talus and the calcaneus (see image below).

The hindfoot is composed of the talus and the calcThe hindfoot is composed of the talus and the calcaneus. The talus is oriented to transmit forces from the foot through the ankle to the leg.The calcaneus is the largest bone in the foot. The Achilles tendon inserts on the posterior aspect of the calcaneus.The navicular lies anterior to the talus and medial to the cuboid.The cuboid articulates with the calcaneus proximally, with the fourth and fifth metatarsals distally, and with the lateral cuneiform medially (see image below). Select bones of the foot (medial and lateral viewsSelect bones of the foot (medial and lateral views). Each of the cuneiform bones is wedge-shaped. The medial, intermediate, and lateral cuneiform bones articulate with the first 3 metatarsals distally and the navicular proximally. The cuboid articulates with the lateral cuneiform. The 5 metatarsals articulate with the proximal phalanges.The great toe is composed of 2 phalanges, with 3 for each lesser toe.Although variation exists in the number and location of the sesamoid bones, 2 constant sesamoids are present beneath the metatarsal head. The sesamoids are usually present within tendons juxtaposed to articulations.

Select tendons of the foot (see image below)

Select tendons of the foot. Select tendons of the foot. The flexor hallucis longus (FHL) tendon is 1 of 3 structures that lie in the tarsal tunnel. Running behind the medial malleolus, the FHL is the most posterolateral. The FHL runs anterior to insert onto the distal phalanx of the great toe. The FHL acts as a flexor of the great toe, elevates the arch, and assists with plantar flexion of the ankle. The flexor digitorum longus (FDL) tendon passes between the FHL and tibialis posterior tendon. The FDL inserts onto the distal phalanges of the 4 lateral digits and acts to flex the distal phalanges. The tibialis posterior tendon is the most anteromedial of the tarsal tunnel tendons. This tendon inserts on the navicular tuberosity; the 3 cuneiforms; the cuboid; and the second, third, and fourth metatarsals. The tibialis posterior muscle flexes, inverts, and adducts the foot. Laterally, the peroneus longus and peroneus brevis tendons share the common peroneal tunnel running behind and around the lateral malleolus. The peroneus longus plantar flexes the first metatarsal, flexes the ankle, and abducts the foot. The peroneus brevis flexes the ankle and everts the foot. Other important structuresThe plantar aponeurosis or fascia is a deep span of connective tissue extending from the anteromedial tubercle of the calcaneus to the proximal phalanges of each of the toes. Medial and lateral fibrous septa originate from the medial and lateral borders to attach to the first and fifth metatarsal bones. Nerve innervation of the foot runs along the medial and lateral metatarsals and phalanges in a neurovascular bundle. These nerves are vulnerable to compressive forces that, in time, can generate the painful Morton neuroma, which most commonly affects the interspace between the third and fourth metatarsals. Four nerves supply the forefoot: the sural nerve (most lateral), branches of the superficial peroneal nerve, the deep peroneal nerve, and the saphenous nerve. The joint between the forefoot and the midfoot, the tarsometatarsal (TMT) joint or Lisfranc joint, is formed by a mortise of the cuneiform bones surrounding the base of the second metatarsal. This joint is supported by the transverse ligaments, and the Lisfranc ligament joins the medial cuneiform and the base of the second metatarsal. Disruption of this ligament can result in a destabilization of the TMT joint complex of the foot, the result of which can be instability of the arch and the midfoot. PreviousNextSport-Specific Biomechanics

The 3 planes in which the foot and ankle function are the transverse, sagittal, and frontal. Movement is possible in all 3 planes.

Plantar flexion and dorsiflexion occur in the sagittal plane. Plantar flexion involves the foot moving from the anterior leg distally. Dorsiflexion is the opposite motion. Inversion and eversion occur in the frontal plane of motion. Eversion occurs when the bottom of the foot turns away from the midline of the body. Inversion is the opposite action. The 2 transverse plane motions are abduction and adduction. Adduction involves the foot moving toward the midline of the body, whereas abduction is the opposite action. PreviousProceed to Clinical Presentation , Athletic Foot Injuries

Tuesday, February 11, 2014

Meniscus Injuries

Background

Our understanding of the meniscus has changed radically in the last century. In 1887, Sutton described the meniscus as "the functionless remains of a leg muscle."[1] Not until 1948 did Fairbanks appreciate that "meniscectomy is not wholly innocuous," in his classic report of postmeniscectomy radiographic changes.[2] Research and knowledge of the meniscus has continued. The critical importance of the meniscus of the knee joint is now understood.

Note the contrasting images below.

Magnetic resonance imaging scan showing a normal mMagnetic resonance imaging scan showing a normal meniscus. Magnetic resonance imaging scan showing a torn medMagnetic resonance imaging scan showing a torn medial meniscus.

For patient education resources, see the Foot, Ankle, Knee, and Hip Center and Arthritis Center, as well as Knee Pain and Knee Injury.

NextEpidemiologyFrequencyUnited StatesMeniscal injuries may be the most common knee injury. The prevalence of acute meniscal tears is 61 cases per 100,000 persons.The overall male-to-female incidence is approximately 2.5:1. The peak incidence of meniscal injury for males is in those aged 31-40 years. For females, the peak incidence is in those aged 11-20 years. In patients older than 65 years, the rate of degenerative meniscal tears is 60%. Surgical procedures of the meniscus are performed on an estimated 850,000 patients each year.[3] International

Estimates indicate that at least twice the number of meniscus procedures in the United States are performed worldwide.

PreviousNextFunctional Anatomy

The menisci are 2 semilunar wedges in the knee joint positioned between the tibia and the femur. They are essentially extensions of the tibia that act to deepen the articular surfaces of the otherwise relatively flat tibial plateau to accommodate the relatively round femoral condyles. The superior surfaces are concave and in contact with the femoral condyles; the inferior surfaces are flat and conform to the tibial plateaus. The peripheral, convex borders of the menisci are thick and attach to the joint capsule; the opposite border tapers inward to a thin, free edge centrally. Therefore, menisci have a triangular shape in cross section. Each covers approximately two thirds of the corresponding articular surface of the tibia. The medial and lateral menisci each have distinct, individual anatomic characteristics.[4, 5, 6]

The medial meniscus is semicircular or C-shaped and approximately 3.5 cm in length from anterior to posterior. It is asymmetric with a considerably wider posterior horn than anterior horn. Peripherally, the medial meniscus is continuously attached to the joint capsule, with the middle portion being more firmly attached via connection with fibers of the deep medial collateral ligament. It is anchored to the tibia by the coronary (meniscotibial) ligaments.

The posterior horn of the medial meniscus inserts in the posterior intercondylar fossa directly anterior to the posterior cruciate ligament. The anterior horn attachment is more variable, distributed in a 6- to 8-mm area anterior to the anterior cruciate ligament (ACL) tibial attachment in the anterior intercondylar fossa. Some anterior fibers attach over the anterior periphery of the tibial articular surface, and some posterior fibers of the anterior horn merge with the transverse meniscal ligament that connects to the lateral meniscus.

The lateral meniscus is more nearly circular or O-shaped and covers a larger portion of the tibial plateau surface than the medial meniscus. Its length from anterior to posterior is slightly less than the medial meniscus, and it has an almost uniform width. There is attachment to the joint capsule peripherally, except in the region of the middle one third, where there is no attachment but rather a hiatus for the popliteal tendon.

Unlike the medial meniscus, there is no attachment of the lateral meniscus to the lateral collateral ligament, but the lateral meniscus is anchored to the tibia via coronary (meniscotibial) ligaments. Posteriorly, the lateral meniscus is uniquely attached to the medial femoral condyle by meniscofemoral ligaments. These ligaments are highly variable and pass anterior (ligament of Humphrey) and/or posterior (ligament of Wrisberg) to the posterior cruciate ligament. The posterior attachment to the tibia is just anterior to the medial meniscus attachment in the posterior intercondylar fossa. The anterior horn inserts anterior to the lateral tibial spine and in close proximity to the ACL tibial insertion. Some fibers actually may blend into the ACL.

Despite their attachments, both menisci have mobility. The medial meniscus, with excursion of approximately 5 mm, is half as mobile as the lateral meniscus, whose mobility may exceed 10 mm. The anterior horns are more mobile than the posterior horns. This mobility allows for improved conformity of the tibiofemoral joint. Because the posterior horn of the medial meniscus has the least movement, it is at greatest risk for disruption.

The microanatomy of the meniscus is dense fibrocartilage composed of cells and an extracellular matrix of collagen fibers in network. The cells are termed fibrochondrocytes because they appear to be a mixture of fibroblasts and chondrocytes. These cells are responsible for the synthesis and maintenance of the extracellular fibrocartilaginous matrix.

The most abundant component of the menisci is collagen (75%)—mainly type I collagen (>90%) but it also contains types II, III, V, and VI. Collagen fibers are arranged mostly along a longitudinal or circumferential direction, with some interwoven radial and oblique fibers. The circumferential fibers are related directly to the menisci's functional ability to dissipate compressive loads. The other fibers act primarily as ties to enhance structural rigidity and to help prevent longitudinal splitting. The extracellular matrix also includes proteoglycans, glycoproteins, and elastin.

Most meniscal tissue is avascular and depends on passive diffusion and mechanical pumping to provide nutrition to the fibrocytes within the meniscal substance. Arnoczky and Warren demonstrated the important vascular anatomy of the menisci.[7, 8] The limited peripheral blood supply originates from the medial and lateral inferior and superior geniculate arteries. Branches from these vessels give rise to a perimeniscal capillary plexus within the synovium and joint capsule, which, in turn, supplies the meniscus periphery.

Studies have shown that 10-30% of the periphery of the medial meniscus and 10-25% of the lateral meniscus receives a vascular supply; the remainder receives its nutrition from the synovial fluid from passive diffusion and mechanical pumping. A few terminal branches of these vessels, along with the middle geniculate artery through the synovial covering of the anterior and posterior horn attachments, supply increased vascularity to the meniscal horns. The potential for vascular ingrowth is essential for successful meniscal healing and surgical repair. Various zones of the meniscus are described based on the blood supply; the red zone is the well-vascularized periphery, the red-white zone is the middle portion with vascularity peripherally but not centrally, and the white zone is the central avascular portion.

The neuroanatomy of the meniscus is not well described. However, the distribution of neural elements has been demonstrated in essentially the same anatomic distribution as the vascular supply. The anterior and posterior horns are the most richly innervated, and the body innervation follows the pattern along the periphery. Although not entirely clear, these nerve endings are believed to play a role in sensory feedback and proprioception. The greater innervation of the horns of the meniscus reflects the need for feedback at the extremes of flexion and extension, when the meniscal horns are compressed and neural elements are activated.[4, 5, 6]

The meniscus has unique anatomic properties. An understanding of this anatomy is essential to comprehending its important functions, which include load bearing, load and force distribution, joint stability, joint lubrication, and proprioception.[4, 5, 9] One of the primary functions is to provide load bearing across the knee joint. Fifty percent of the compressive load in the knee is transferred by the menisci in extension, whereas up to 85% of the load is transferred at 90° of flexion. The collagen orientation makes this load bearing possible by converting the compressive forces to tensile forces.

Load and forces are distributed across a much larger surface area because of the menisci, which (1) decrease focal contact pressure by increasing the contact area and (2) protect the underlying articular cartilage. Resection of 15-34% of a meniscus may increase contact pressure by more than 350%. Normal knees have 20% better shock-absorbing capacity than meniscectomized knees.

Joint stability is increased because of meniscal structure, which allows increased congruence and conformity between the femoral condyles and tibial plateaus.[4, 5] The wedge-shaped meniscus attached to the tibia serves as a secondary stabilizer. For example, the posterior horn acts as a shim to resist anterior tibial translation relative to the femur. Meniscectomy alone may not increase knee laxity, but it has been shown that in association with ACL deficiency, anterior laxity is increased. Meniscal lubrication occurs by fluid exudation across the surface, much like articular cartilage.

The classification of meniscal tears provides a description of pathoanatomy. The types of meniscus tears are (1) longitudinal tears that may take the shape of a bucket handle if displaced, (2) radial tears, (3) parrot-beak or oblique flap tears, (4) horizontal tears, and (5) complex tears that combine variants of the above.

PreviousProceed to Clinical Presentation , Meniscus Injuries

Thursday, February 6, 2014

Cervical Disc Injuries

Background

Acute cervical spine injury has been associated with sports such as football, gymnastics, rugby, ice hockey, and diving. Athletes with cervical disc injury may present with neck pain, radicular pain, quadriparesis, or quadriplegia secondary to myelopathy.

Cervical disc injury includes 2 entities. The more common form involves annular tears with herniation of the nucleus pulposus (ie, soft disc herniation). The second type of disc injury is an annular tear without herniation of the nucleus pulposus (ie, internal disc disruption).

When considering the term cervical disc injury, it is important to recognize the natural history of cervical degenerative disease. It is this process that may insidiously predispose one to cervical disc injury of either an acute or chronic nature. Cervical disc injuries can be treated conservatively or by surgery, depending on the clinical presentation.

Return to play is an important but controversial issue following successful treatment of cervical disc injury. No accepted universal guidelines regarding return to play exist.

This article intends to outline the etiopathology, evaluation, and treatment of cervical disc disease. Available guidelines for return to play following cervical disc injury are also presented.

NextEpidemiologyFrequencyUnited States

In a study of asymptomatic individuals younger than 40 years, the incidence of cervical disc herniation was 10%, the incidence of disc degeneration was 25%, and the incidence of foraminal stenosis was 4%.[1] In another study, the incidence of cervical focal disc protrusions in asymptomatic volunteers was 50% and of annular tears at one or more levels was 37%.[2]

PreviousNextFunctional Anatomy

Seven cervical vertebrae articulate with one another anteriorly via the interbody joint with an intervening intervertebral disc and 2 uncovertebral joints. Laterally, they articulate via the paired posterolaterally placed zygapophyseal (facet) joints.

Each cervical vertebra forms a ring with the vertebral body anteriorly, the pedicles laterally, and the laminae posteriorly. The ring is known as the spinal or neural canal. As the vertebrae stack upon one another, the connection of the spinal foramina is known as the spinal canal. Through the spinal canal runs the spinal cord, nerve roots, vessels, and meninges (membranous covering of the spinal cord and nerve roots).

The cervical spinal nerves take origin from the spinal cord as the anterior and posterior rootlets. The posterior rootlet has a segmental brain that lies on its most lateral extent at the inner portion of the intervertebral foramen. The posterior and anterior rootlets join to form a spinal nerve, which is only approximately 2 cm long and lies within the intervertebral foramen. The spinal nerve divides into a posterior and anterior ramus at the outlet of the intervertebral foramen. The spinal nerves exit the intervertebral foramen above the numbered cervical vertebrae, and the thoracic and lumbar nerves exit the intervertebral below the numbered vertebra. Consequently, the eighth cervical nerve exits between the C7 and T1 segment

The symptoms related to pathology at each of the intervertebral disc segments have been well described and are not elaborated on in this article. Note that during dynamic range of motion (ROM), the intervertebral foramen, which houses the exiting cervical nerves, becomes very dynamic. In flexion, the intervertebral foramen enlarges in patency, and it decreases with extension. In rotation, the ipsilateral side becomes smaller, and the contralateral side becomes larger. The extreme changes of the foramina are magnified when motions are coupled with flexion and extension.

Distinctiveness of the cervical disc

The predominance of literature has addressed the lumbar spine; much of the lumbar spine literature has been extrapolated and applied to the cervical spine. Bogduk, using microdissection, systematically evaluated 59 human cadaveric intervertebral discs.[3] The orientation, location, and attachments of each strip bundle of collagen were recorded photographically and in sketches. He concluded that the cervical annular fibrosus did not consist of concentric laminae of collagen fibers, as noted in lumbar discs. Rather, the annulus forms a crescentic mass. The primary thickness is anterior and tapers laterally toward the uncinate processes. Posterolaterally, it is essentially deficient; posteriorly, it is represented by a thin layer of paramedian vertically oriented fibers. The anterior crescentic mass is likened to an interosseus ligament more so than a ring of concentric fibers surrounding the nucleus pulposus.[4]

PreviousNextSport Specific Biomechanics

Cervical spine injury is commonly associated with axial loading with the neck in flexion. In flexion of the neck to 30°, the normal lordosis of the cervical spine is obliterated and axial loading of the head is dissipated through a straight spine.[5] Examples of axial loading in players include a football player striking his opponent with the crown of his helmet, an ice hockey player striking his head on the board while doing a push or check, a diver striking the ground with his head after diving in shallow water, and a gymnast accidentally landing head down while performing a somersault on a trampoline.

The effects of axial loading of the cervical spine include fracture of vertebrae, cervical disc herniations, ligament rupture, facet fracture, and dislocations. The neurologic deficits are greater in athletes with congenital spinal stenosis.[6, 7]

New guidelines in athletic sports have decreased the incidence of spinal cord injury. For example, permanent cervical quadriplegia has decreased significantly in high school and college level football, secondary to changes in the rules involving tackling. The Guidelines of NCCA Football rules committee banned spear tackling in football.[8] In 1977, The American Academy of Pediatrics published a statement banning the use of trampolines in schools because of the high incidence of quadriplegia associated with this apparatus.[9] The Canadian Committee on the prevention of spinal injury due to hockey recommends rules against boarding and crosschecking and on education to avoid spearing and impact with boards.[10] Similar guidelines for diving prohibit diving in water that is less shallow than twice one's height.[5]

Disc herniation resorption

Absorption of a cervical herniated disc has been appreciated. Mochida followed the regression of cervical disc herniation by using MRI. He noted that acutely, active resorption of herniated material occurred. The MRI findings did suggest that part of the resorbed material may have consisted of hemorrhagic substance. Mochida noted that extruded material exposed to the epidural space was resorbed more quickly than subligamentous herniation probably because of increased exposure to the immune system.[11]

Resorption of herniated disc material should not be confused with repair. Injured or degenerative disc material does not repair itself to a significant extent. In review of intervertebral segment physiology and metabolic turnover, Nachemson drew some remarkable conclusions.[12] He cited that diffusion of solutes can take place through the central portion of the endplates, as well as through the annulus fibrosus. There are also vascular contacts between the marrow spaces, the vertebral body, and the hyaline cartilaginous endplates. These vascular contacts are significantly less in discs that show advanced degenerative changes. He also cited that the area between the nucleus and annulus posteriorly is proportionally less than the area of the anterior margins, lending itself to possible nutrient deficiency and hastened fibrotic infiltration.

The surface area for diffusion is smaller posteriorly. Combining the relative diffusion limitations posteriorly and the mechanics of posterolateral disc herniation, it becomes rather apparent why a possible pattern of failure exists in this region.[12]

PreviousProceed to Clinical Presentation , Cervical Disc Injuries

Saturday, February 1, 2014

Thoracic Disc Injuries

Background

Thoracic disc injury, first described in 1838, is an uncommon site of injury owing to the stabilizing effect of the rib cage.[1] The similarity of symptoms to lumbar disc herniation makes the diagnosis of a thoracic disc injury difficult,[2, 3, 4, 5, 6] but the process tends to be self-limiting and rarely requires surgical intervention.[4]

(See also the articles Disk Herniation and Thoracic Spine, Trauma [in the Radiology section], Thoracic Discogenic Pain Syndrome [in the Sports Medicine section], Lumbar Disc Disease [in the Neurosurgery section], and Herniated Nucleus Pulposus [in the Orthopedic Surgery section], as well as Return to Contact Sports After Spinal Surgery and Thoracoscopic Spine Surgery for Decompression and Stabilization of the Anterolateral Thoracic and Lumbar Spine on Medscape.)

For patient education resources, see the Bone Health Center, Back, Ribs, Neck, and Head Center, Back, Neck, and Head Injury Center, and Muscle Disorders Center, as well as Back Pain and Chronic Pain.

NextEpidemiologyFrequencyUnited States

The incidence of thoracic disc injuries is 1 in 1 million persons per year, and these injuries account for 0.25-0.75% of all disc herniations.[7]

PreviousNextFunctional Anatomy

The thoracic discs are unusually stable compared with the cervical and lumbar discs. The stability of the thoracic discs is secondary to the surrounding rib cage, with the stabilizing effect of the rib articulations. However, the blood supply of the thoracic spine is more tenuous than the cervical and lumbar spine, especially at the T4-T9 watershed area, which is more prone to ischemic injury.

PreviousNextSport-Specific Biomechanics

The facet orientation in the thoracic spine is vertical, with a slight medial angulation. This orientation allows for easier lateral bending and rotation versus pure bending. Biomechanical studies have shown that intervertebral discs are at the highest risk of injury when combined with bending and torsional forces. Therefore, the thoracic spine discs are at a decreased risk of injury because of the decreased bending potential in this segment of the spine.

The spinal cord-to-canal ratio (the ratio of the cross-sectional area of the cord to the cross-sectional area of the spinal canal) is 40% in the thoracic spine versus 25% in the cervical spine. The thoracic spine is also naturally kyphotic. These 2 facts make the thoracic spine more sensitive to cord compression from disc herniation.

PreviousProceed to Clinical Presentation , Thoracic Disc Injuries

Wednesday, January 29, 2014

Sports-Related Facial Soft Tissue Injuries

Overview

Sports-related facial soft tissue injuries are not uncommon.[1, 2, 3, 4, 5, 6, 7] The position and anatomy of the face make it particularly vulnerable to trauma. In addition, few sports mandate the use of protective equipment, leaving the face susceptible to injury.

The mechanism of facial soft tissue injuries is often a direct impact from an external source (eg, sporting equipment, another participant, environment/playing surface). The forces exerted by the impact can lead to friction, shear, compression, and/or traction of the soft tissue and underlying structures. Injury patterns vary widely by sport, based on various factors (eg, rules, equipment).[8, 9, 10]

Although most such injuries are minor in nature, they should be evaluated promptly with a focused history and thorough examination. In addition, facial injuries should be treated early to reduce the likelihood of possible adverse outcomes (ie, infection, loss of function, poor cosmesis). In this article, common sports-related soft tissue facial injuries are discussed, with an emphasis on the initial evaluation, diagnosis, and treatment.

Prevention

The use of protective equipment, such as helmets and headgear, face masks, eye protection (shields or goggles), and mouthpieces are useful in preventing some types of facial soft tissue injuries. Importantly, make sure the rules of the sport allow for the use of such protective equipment before recommending or providing the protective equipment.

NextHistory and Physical Examination

A focused and thorough history should be obtained from the injured athlete, including his or her pertinent medical history, the mechanism of injury (if not witnessed by the medical staff), and the source of pain. If the patient is unable to report history information, family members can provide such information. The presence of symptoms such as visual changes or altered sensorium should also be ascertained at this time.

Physical examination

As with any head and neck injury, examination of an individual with trauma to the face must start with an evaluation of the patient's airway, breathing, and circulation (ABCs). Cervical spine injury should also be considered based on the mechanism of injury, and appropriate precautions should be taken. The physical examination should be focused on the specific injury site.

The face is extremely vascular, and even minor injuries may result in profuse bleeding. Copious irrigation should be used to clean and accurately assess the injury. Visual inspection and palpation should be used to systematically examine the face for symmetry. Start superiorly, with the scalp and frontal bones, and proceed inferiorly and laterally. Examine the oral cavity for any disrupted dentition or lacerations. During inspection, pay particular attention to any areas of swelling because this may indicate a more significant underlying injury.

Note the location, size, shape, and depth of any lacerations, and explore wounds for foreign bodies. Palpate for areas of crepitus or bony step-off. Gross asymmetry may signify underlying nerve damage. Assess neurologic function by evaluating sensation and motor function.

PreviousNextLaceration

As with the physical examination, a systematic approach to facial laceration repair ensures the best chance at an optimum outcome.[11] A summary of one methodologic approach follows.

Wound assessment

Familiarity with the pertinent anatomic aspects of the face is important. Clear anatomic boundaries are present that must be respected and carefully realigned to avoid obvious deformity. Cosmetic results are better when minimal tension is placed on the wound edges at the time of repair. Therefore, wounds with the long axis parallel to the natural skin tension lines have much better cosmetic outcomes. The degree of tension on the wound edges can be estimated by measuring the distance that the wound edges retract away from the center of the lesion. Marked retraction (>5 mm) indicates strong skin tension. With such wounds, placement of dermal sutures in a 2-layer closure should be considered.

Anesthesia

Anesthesia can be provided by topical, local, or regional block. An advantage of using regional block in the face is that the wound edges are not distorted from the local anesthetic. The areas for regional block injection are shown in the image below. Amide anesthetics (eg, lidocaine, bupivacaine, mepivacaine) are used most commonly. Allergic reactions are uncommon. When using anesthetics containing epinephrine, care should be used to avoid areas with end arteries (ie, the nose).

Distribution of nerves for regional anesthesia of Distribution of nerves for regional anesthesia of the face.

The regional block and the area of anesthesia are as follows:

Supraorbital and supratrochlear blocks – Forehead, anterior one third of the scalpInfraorbital block – Lower lid, upper lip, and lateral aspect of the noseMental nerve block – Lower lip and chinWound cleaning and irrigation

All areas should be thoroughly explored, copiously irrigated, cleaned, and débrided of devitalized tissue before closure. Irrigation lessens the risk of infection. Interestingly, regardless of irrigation, noncontaminated wounds repaired within 6 hours of injury rarely develop infection, and the overall rate of infection of repaired scalp and facial wounds is 1%.

After irrigation, gentle cleansing of the wound should be performed with a dilute povidone-iodine solution (Betadine; Purdue Pharma, LP, Stamford, Conn) or iodine solution. The wound edge (1-2 mm) can be safely removed to rid the area of devitalized tissue. Attempts should be made to make the wound edges perpendicular with the skin surface because this results in a smoother, less noticeable scar. (See the image below).

Top: Improper repair of an angled laceration. BottTop: Improper repair of an angled laceration. Bottom: Proper repair of an angled laceration, with creation of perpendicular edges for a flush repair. Repair

Deep wounds should be repaired in layers. Unrepaired muscle layers are much more likely to produce noticeable scarring. When performing a 2-layer closure, the deep layers should be closed with absorbable suture. Importantly, use the minimum amount of subcutaneous suture necessary because the risk of infection is related to the amount of suture used. Nonabsorbable, monofilament suture should be used for skin closure. Monofilament suture is associated with a lower risk of infection compared with a polyfilament suture. (See the image below.)

Steps to repair lip laceration. A 3-layered approaSteps to repair lip laceration. A 3-layered approach is needed, as depicted.

The suture technique should be selected based on the site of the wound and the amount of tension on the wound edges. A simple interrupted technique can be used in areas of low tension or in wounds in which the tension has been reduced with a layer of subcutaneous sutures. This technique is also useful for realigning wounds with irregular wound edges. Areas of high tension are best closed using a vertical mattress technique. All facial wounds should be repaired in less then 24 hours to decrease the risk of infection and achieve the best cosmetic result. If a delay in closure is necessary, wounds should be covered with saline-moistened gauze until the repair can be made.

Dermal adhesives, such as 2-octyl cyanoacrylate, have been shown to be equivalent to sutures for the repair of simple, clean wounds in areas of low tension.[12] The adhesives are applied topically to the wound edges. Advantages of adhesives include shorter repair time, fewer supplies, less pain during repair, and elimination of the need to remove sutures or staples at a follow-up visit. Note that dermal adhesives should not be used on the lips or mucous membranes; avoid their use in patients with poor circulation or who have a propensity to form keloids.

Staples are good alternatives to sutures in the repair of scalp lesions. Stapling involves shorter repair time and less cost compared with suture repairs. Rates of infection and inflammatory response are not higher than those associated with suture repair. During the staple application, an assistant helps to evert and approximate the wound edges, while the primary operator uses the stapler. Disadvantages include the inability to accurately align the wound edges in irregular wounds and an increased likelihood of visible scarring, thus limiting the use of stapling to the scalp.

Follow-up

The athlete should be given instructions for proper wound care, including the normal healing process and signs that might indicate the presence of complications. Anticipate any complication (eg, infection, swelling, bleeding, dehiscence) and give precise instructions for early return. The following is a list of laceration sites and recommendations on suture size and typical time to removal:

Scalp - 4-0 suture or staple, with removal in 7-14 daysForehead - 5-0/6-0 sutures, with removal in 5 daysEyebrow - 5-0/6-0 sutures, with removal in 3-5 daysFace - 6-0 suture, with removal in 5 daysEyelid - 6-0/7-0 sutures, with removal in 3 daysNose - 5-0 sutures, with removal in 3-5 daysEars - 6-0 sutures, with removal in 10-14 daysLips - 6-0 sutures, with removal in 3-5 daysPreviousNextOther InjuriesContusion

Contusions are the most common facial soft tissue injury seen by a sports medicine team. They are usually the result of blunt trauma to the face. Ice should be applied for 10-20 minutes to minimize the immediate inflammatory response. This treatment should continue for the next 48-72 hours. Over-the-counter (OTC) nonsteroidal anti-inflammatory drugs (NSAIDs) are good for symptom relief. Complications are uncommon

Abrasion

Abrasions are partial-thickness disruptions of the epidermis as a result of sudden, forcible friction. These wounds should be gently cleansed of all debris. Failure to remove all debris can lead to "tattooing" of the skin and a poor cosmetic result. Local or regional anesthetic may be required to keep the patient comfortable and achieve adequate cleaning. Lubrication of the wound using an antibiotic ointment and covering with a sterile bandage may encourage healing.

Corneal abrasion

Corneal abrasions result from loss of the surface epithelium. Disruption near the central visual axis interferes with visual acuity. Such abrasions should be treated with a course of ophthalmic topical antibiotics. Topical analgesics may be used initially, but avoid prescribing them to the athlete for home use because this may delay reepithelialization and suppress the normal blink reflex.

Emergent consultation with an ophthalmologist is warranted for suspected retained intraocular foreign bodies, and urgent consultation is needed for suspected corneal ulcerations (microbial keratitis). These injuries require close follow-up. Referral to an ophthalmologist should also be made for any athlete with continued pain after 48 hours or inadequate healing by 72 hours.

Epistaxis

Epistaxis typically does not require invasive treatment. Most often, bleeding can be controlled by maintaining continuous pressure for 10 minutes. This is achieved by asking the athlete to grasp and pinch his or her nose. While this task is performed, have the athlete tilt the head forward to avoid bleeding into the pharynx, which can lead to aspiration. Pressure should be maintained for at least 5 minutes and for up to 20 minutes. If this is unsuccessful, a second attempt should be made.

Packing the affected nostril with gauze soaked in topical decongestant may be necessary to achieve hemostasis. If the bleeding site is clearly observed, chemical cautery can be attempted using silver nitrate directly at the site. If bleeding is not controlled despite these measures, the nasal cavity should be packed from posterior to anterior with ribbon gauze impregnated with petroleum jelly. Nasal tampons may also be helpful. For particularly resistant cases, referral to an otolaryngologist may be required.

PreviousNextReturn to Play

Return to play should be based on the location and severity of the injury, sport and position requirements, and risk of the injury causing a concomitant injury. Most athletes are able to return to play immediately after treatment on the sideline or in the training room. When making return-to-play decisions, attention should be given to whether the area in question can be protected from further injury.

Previous, Sports-Related Facial Soft Tissue Injuries

Friday, January 24, 2014

Meniscus Injuries

Background

Our understanding of the meniscus has changed radically in the last century. In 1887, Sutton described the meniscus as "the functionless remains of a leg muscle."[1] Not until 1948 did Fairbanks appreciate that "meniscectomy is not wholly innocuous," in his classic report of postmeniscectomy radiographic changes.[2] Research and knowledge of the meniscus has continued. The critical importance of the meniscus of the knee joint is now understood.

Note the contrasting images below.

Magnetic resonance imaging scan showing a normal mMagnetic resonance imaging scan showing a normal meniscus. Magnetic resonance imaging scan showing a torn medMagnetic resonance imaging scan showing a torn medial meniscus.

For patient education resources, see the Foot, Ankle, Knee, and Hip Center and Arthritis Center, as well as Knee Pain and Knee Injury.

NextEpidemiologyFrequencyUnited StatesMeniscal injuries may be the most common knee injury. The prevalence of acute meniscal tears is 61 cases per 100,000 persons.The overall male-to-female incidence is approximately 2.5:1. The peak incidence of meniscal injury for males is in those aged 31-40 years. For females, the peak incidence is in those aged 11-20 years. In patients older than 65 years, the rate of degenerative meniscal tears is 60%. Surgical procedures of the meniscus are performed on an estimated 850,000 patients each year.[3] International

Estimates indicate that at least twice the number of meniscus procedures in the United States are performed worldwide.

PreviousNextFunctional Anatomy

The menisci are 2 semilunar wedges in the knee joint positioned between the tibia and the femur. They are essentially extensions of the tibia that act to deepen the articular surfaces of the otherwise relatively flat tibial plateau to accommodate the relatively round femoral condyles. The superior surfaces are concave and in contact with the femoral condyles; the inferior surfaces are flat and conform to the tibial plateaus. The peripheral, convex borders of the menisci are thick and attach to the joint capsule; the opposite border tapers inward to a thin, free edge centrally. Therefore, menisci have a triangular shape in cross section. Each covers approximately two thirds of the corresponding articular surface of the tibia. The medial and lateral menisci each have distinct, individual anatomic characteristics.[4, 5, 6]

The medial meniscus is semicircular or C-shaped and approximately 3.5 cm in length from anterior to posterior. It is asymmetric with a considerably wider posterior horn than anterior horn. Peripherally, the medial meniscus is continuously attached to the joint capsule, with the middle portion being more firmly attached via connection with fibers of the deep medial collateral ligament. It is anchored to the tibia by the coronary (meniscotibial) ligaments.

The posterior horn of the medial meniscus inserts in the posterior intercondylar fossa directly anterior to the posterior cruciate ligament. The anterior horn attachment is more variable, distributed in a 6- to 8-mm area anterior to the anterior cruciate ligament (ACL) tibial attachment in the anterior intercondylar fossa. Some anterior fibers attach over the anterior periphery of the tibial articular surface, and some posterior fibers of the anterior horn merge with the transverse meniscal ligament that connects to the lateral meniscus.

The lateral meniscus is more nearly circular or O-shaped and covers a larger portion of the tibial plateau surface than the medial meniscus. Its length from anterior to posterior is slightly less than the medial meniscus, and it has an almost uniform width. There is attachment to the joint capsule peripherally, except in the region of the middle one third, where there is no attachment but rather a hiatus for the popliteal tendon.

Unlike the medial meniscus, there is no attachment of the lateral meniscus to the lateral collateral ligament, but the lateral meniscus is anchored to the tibia via coronary (meniscotibial) ligaments. Posteriorly, the lateral meniscus is uniquely attached to the medial femoral condyle by meniscofemoral ligaments. These ligaments are highly variable and pass anterior (ligament of Humphrey) and/or posterior (ligament of Wrisberg) to the posterior cruciate ligament. The posterior attachment to the tibia is just anterior to the medial meniscus attachment in the posterior intercondylar fossa. The anterior horn inserts anterior to the lateral tibial spine and in close proximity to the ACL tibial insertion. Some fibers actually may blend into the ACL.

Despite their attachments, both menisci have mobility. The medial meniscus, with excursion of approximately 5 mm, is half as mobile as the lateral meniscus, whose mobility may exceed 10 mm. The anterior horns are more mobile than the posterior horns. This mobility allows for improved conformity of the tibiofemoral joint. Because the posterior horn of the medial meniscus has the least movement, it is at greatest risk for disruption.

The microanatomy of the meniscus is dense fibrocartilage composed of cells and an extracellular matrix of collagen fibers in network. The cells are termed fibrochondrocytes because they appear to be a mixture of fibroblasts and chondrocytes. These cells are responsible for the synthesis and maintenance of the extracellular fibrocartilaginous matrix.

The most abundant component of the menisci is collagen (75%)—mainly type I collagen (>90%) but it also contains types II, III, V, and VI. Collagen fibers are arranged mostly along a longitudinal or circumferential direction, with some interwoven radial and oblique fibers. The circumferential fibers are related directly to the menisci's functional ability to dissipate compressive loads. The other fibers act primarily as ties to enhance structural rigidity and to help prevent longitudinal splitting. The extracellular matrix also includes proteoglycans, glycoproteins, and elastin.

Most meniscal tissue is avascular and depends on passive diffusion and mechanical pumping to provide nutrition to the fibrocytes within the meniscal substance. Arnoczky and Warren demonstrated the important vascular anatomy of the menisci.[7, 8] The limited peripheral blood supply originates from the medial and lateral inferior and superior geniculate arteries. Branches from these vessels give rise to a perimeniscal capillary plexus within the synovium and joint capsule, which, in turn, supplies the meniscus periphery.

Studies have shown that 10-30% of the periphery of the medial meniscus and 10-25% of the lateral meniscus receives a vascular supply; the remainder receives its nutrition from the synovial fluid from passive diffusion and mechanical pumping. A few terminal branches of these vessels, along with the middle geniculate artery through the synovial covering of the anterior and posterior horn attachments, supply increased vascularity to the meniscal horns. The potential for vascular ingrowth is essential for successful meniscal healing and surgical repair. Various zones of the meniscus are described based on the blood supply; the red zone is the well-vascularized periphery, the red-white zone is the middle portion with vascularity peripherally but not centrally, and the white zone is the central avascular portion.

The neuroanatomy of the meniscus is not well described. However, the distribution of neural elements has been demonstrated in essentially the same anatomic distribution as the vascular supply. The anterior and posterior horns are the most richly innervated, and the body innervation follows the pattern along the periphery. Although not entirely clear, these nerve endings are believed to play a role in sensory feedback and proprioception. The greater innervation of the horns of the meniscus reflects the need for feedback at the extremes of flexion and extension, when the meniscal horns are compressed and neural elements are activated.[4, 5, 6]

The meniscus has unique anatomic properties. An understanding of this anatomy is essential to comprehending its important functions, which include load bearing, load and force distribution, joint stability, joint lubrication, and proprioception.[4, 5, 9] One of the primary functions is to provide load bearing across the knee joint. Fifty percent of the compressive load in the knee is transferred by the menisci in extension, whereas up to 85% of the load is transferred at 90° of flexion. The collagen orientation makes this load bearing possible by converting the compressive forces to tensile forces.

Load and forces are distributed across a much larger surface area because of the menisci, which (1) decrease focal contact pressure by increasing the contact area and (2) protect the underlying articular cartilage. Resection of 15-34% of a meniscus may increase contact pressure by more than 350%. Normal knees have 20% better shock-absorbing capacity than meniscectomized knees.

Joint stability is increased because of meniscal structure, which allows increased congruence and conformity between the femoral condyles and tibial plateaus.[4, 5] The wedge-shaped meniscus attached to the tibia serves as a secondary stabilizer. For example, the posterior horn acts as a shim to resist anterior tibial translation relative to the femur. Meniscectomy alone may not increase knee laxity, but it has been shown that in association with ACL deficiency, anterior laxity is increased. Meniscal lubrication occurs by fluid exudation across the surface, much like articular cartilage.

The classification of meniscal tears provides a description of pathoanatomy. The types of meniscus tears are (1) longitudinal tears that may take the shape of a bucket handle if displaced, (2) radial tears, (3) parrot-beak or oblique flap tears, (4) horizontal tears, and (5) complex tears that combine variants of the above.

PreviousProceed to Clinical Presentation , Meniscus Injuries

Saturday, January 18, 2014

Lumbosacral Spine Acute Bony Injuries

Background

Injuries to the lumbar spine have received only a small amount of attention compared with other athletic injuries. This can be explained by a number of reasons. Spinal fractures are relatively uncommon in sports participation compared with other types of injuries; most injuries to the lumbar spine are relatively minor and fit into the category of soft-tissue injuries. These soft-tissue injuries are usually self-limited and resolve without coming to the attention of healthcare professionals.

The mechanisms and severity of sports-related lumbar spinal injuries reflect a competitive and risk-taking culture.[1, 2, 3, 4, 5, 6] Lumbar spine bony injuries are often limited to specific sports, most frequently seen in sports such as automobile or motorcycle racing,[7, 8, 9] skydiving[10] (see the image below), power weight lifting,[11, 12] wrestling,[13] gymnastics,[14, 15, 16] football,[17, 18, 19, 20, 21, 22] hockey,[23] rowing,[24] horseback riding,[25, 26] and high-speed snow sports.[27, 28, 29, 30, 31] This article reviews the diagnosis and management of acute lumbar vertebral fractures.

Sagittal computed tomography scan reconstruction oSagittal computed tomography scan reconstruction of a young female who had a skydiving accident. The parachute deployed, but the patient landed on concrete and sustained a lower-extremity fracture and a fracture of L1. She was neurologically intact but required an open reduction with a fusion and instrumental fixation of the fracture.

For excellent patient education resources, see eMedicineHealth's patient education articles Vertebral Compression Fracture and Low Back Pain.

Related Medscape Reference topics:

Lumbar Disk Problems in the Athlete

Lumbar Spine Fractures and Dislocations

Lumbar Spine Trauma Imaging

Lumbosacral Disc Injuries

Lumbosacral Discogenic Pain Syndrome

Related Medscape resources:

Resource Center Exercise and Sports Medicine

Resource Center Joint Disorders

Resource Center Spinal Disorders

CME/CE Back Pain in a 39-Year-Old Man from Guatemala

CME Early Surgery for Severe Sciatica Relieves Pain Faster Than Conservative Treatment

CME/CE Low Back Pain: Evaluating Presenting Symptoms in Elderly Patients

NextEpidemiologyFrequencyUnited States

The epidemiology of thoracic and lumbar spine injuries in athletes is very difficult to document. Most epidemiologic studies on lumbar spine injuries in athletes lack prospective data. The thoracolumbar junction and lumbar spine are common sites for fractures due to the high mobility of the lumbar spine compared with the more rigid thoracic spine. Injury to the cord or cauda equina occurs in approximately 10-38% of adult thoracolumbar fractures and in as many as 50-60% of fracture dislocations. The rate of bony injury without neurologic consequence is undoubtedly higher.

In the United States, Keene reported an overall rate of 7% for sport-related lumbar injuries in the athlete population.[30] Most of these injuries occurred during practice or preseason conditioning, and only 6% occurred during actual competition. Lumbar spine injuries were significantly more common in football[17, 18, 19, 20] and gymnastics.[14, 15, 16]

Statistics from the US Air Force Academy indicated that 9% of all athletic injuries affect the spinal column. In an analysis of injuries in a professional football team, Ryan et al reported a 6% rate of spinal injuries.[9] Snook reviewed all musculoskeletal injuries sustained by college wrestlers and female gymnasts and found a rate of thoracolumbar spine injuries of 2% for the wrestlers[13] and 13% for the female gymnasts.[32]

Related Medscape Reference topics:

Cauda Equina and Conus Medullaris Syndromes

Lumbosacral Facet Syndrome

Lumbosacral Radiculopathy

Lumbosacral Spondylolisthesis

Lumbosacral Spondylolysis

Related Medscape resources:

Resource Center Exercise and Sports Medicine

Resource Center Osteoporosis

Specialty Site Orthopaedics

International

Information on the incidence of sports-related spinal injuries in other countries is also limited and difficult to determine due to differences in data collection and reporting among countries. In England, Williams estimated that spinal injuries accounted for 15% of all injuries sustained in sports.[10] Furthermore, injuries to the thoracic and lumbar spine seemed to be more frequent in automobile racing, horseback riding, parachuting, mountain climbing, and weightlifting.

PreviousNextFunctional Anatomy

The lumbar spine consists of a mobile segment of 5 vertebrae, located between the relatively immobile segments of the thoracic and sacral segments at either end. The thoracic spine is stabilized by the attached rib cage and intercostal musculature, whereas the sacral segments are fused, providing a stable articulation with the ilium. The lumbar vertebrae are particularly large and heavy compared with the cervical and thoracic vertebrae. The bodies are wider, the pedicles are shorter and heavier, and the transverse processes project somewhat more laterally and ventrally when compared with other spinal segments. The laminae are shorter vertically than the bodies and are bridged by strong ligaments. Finally, the spinal processes are broader and stronger than those in the thoracic and cervical spine.[33]

The lumbar spine must transmit compressive, bending, and twisting forces that are generated between the upper and lower body. Consequently, as one moves more caudally into the lumbar spine, the muscle groups and ligaments become larger and stronger.

The intervertebral discs consist of 2 components, the annulus fibrosus and the nucleus pulposus. The annulus is a dense fibrous ring located at the periphery of the disc, which has strong attachments to the vertebrae and serves to confine the nucleus pulposus. The lumbar spine is surrounded by powerful musculature and ligaments, which dynamically stabilize the spine.

Related Medscape Reference topic:

Topographic and Functional Anatomy of the Spinal Cord

PreviousNextSport-Specific Biomechanics

The lumbar spine is a complex, 3-dimensional (3-D) structure that is capable of flexion, extension, lateral bending, and rotation. In the spine, the total range of motion is the result of a summation of the limited movements that occur between the individual vertebrae. Strong muscles and ligaments are crucial for supporting the bony structures and for initiating and controlling movement.

The most common movement of the lumbar spine is flexion. During flexion, anterior compression of the intervertebral disc and widening of the spinal canal occurs along with some sliding movement of the articular process in the zygapophyseal joint. This movement is limited by the posterior ligamentous complex and the dorsal muscles. Extension of the lumbar spine is more limited, producing posterior compression on the disc, narrowing of the spinal canal, and a sliding motion of the zygapophyseal joint. The anterior longitudinal ligament, ventral muscles, lamina, and spinous processes limit the extension of the lumbar spine.

Lateral bending involves lateral compression of the intervertebral disc, along with sliding separation of the zygapophyseal joint on the convex side. An overriding of the zygapophyseal joint occurs on the concave side. The intertransverse ligaments limit the lateral bending of the spine. Rotation of the lumbar spine involves compression of the annulus fibrosus fibers. It is limited by the geometry of the facet joints and the iliolumbar ligaments. The motion of the lumbar spine cannot be considered without evaluating the synchronous movements of the cervical and thoracic spine. The entire spinal column moves as one unit in all planes of motion. Each region of the spine has its own characteristic curvature. These curves allow an upright posture while maintaining the center of gravity over the pelvis and lower limbs. Although most rotation is accomplished at the cervical spine, flexion and lateral bending are primarily cervical and lumbar functions.

Spinous process fractures may occur as a result of direct trauma to the posterior spine or as a result of forcible flexion and rotation. These injuries are usually not associated with neurologic deficits. Violent muscular contraction or direct trauma can cause fractures of the transverse processes. For example, a football helmet blow to the back can cause fractures of either the spinous or transverse processes. Burst fractures (see the images below) are usually associated with axial loading and compression of the spine. Acute traumatic spondylolisthesis is usually associated with major trauma and extreme hyperextension of the spine.

Sagittal T1-weighted magnetic resonance imaging stSagittal T1-weighted magnetic resonance imaging study of a professional driver who was in a rollover motor vehicle accident while racing his car. This figure shows a T-10 unstable burst fracture producing severe kyphotic deformity of the spine. The abnormal signal on the vertebral body and the extradural defect represents a subacute hematoma producing spinal cord compression. The patient had severe paraparesis and underwent an emergency operation. The procedure involved an anterolateral retroperitoneal approach with a corpectomy and vertebral reconstruction. Postoperative plain x-ray film of a professional dPostoperative plain x-ray film of a professional driver who experienced a burst fracture in a rollover motor vehicle accident while racing his car. This image shows a vertebral reconstruction with the use of a titanium cage filled with bone and the arthrodesis with a Z plate. Sagittal computed tomography scan reconstruction oSagittal computed tomography scan reconstruction of an athlete who had a burst fracture.

The intervertebral discs are thick and strong. The annulus fibrosus receives most of the forces that are transmitted from one vertebral body to another, and it is designed to resist tension and shearing forces. The nucleus pulposus is designed to resist compression forces; it receives primarily vertical forces from the vertebral bodies and redistributes them in a radial fashion to the horizontal plane. This structure allows the intervertebral discs to dissipate the axial loading.

Related Medscape Reference topics:

Disk Herniation Imaging

Herniated Nucleus Pulposus

Lumbar Compression Fracture

Lumbosacral Spine Sprain/Strain Injuries

Lumbosacral Spondylolisthesis

Lumbosacral Spondylolysis

Related Medscape resources:

Resource Center Spinal Disorders

Specialty Site Neurology & Neurosurgery

Specialty Site Orthopaedics

PreviousProceed to Clinical Presentation , Lumbosacral Spine Acute Bony Injuries

Wednesday, January 15, 2014

Elbow and Forearm Overuse Injuries

Background

Overuse injuries of the elbow and forearm are very common in athletes.[1, 2] Any sport that subjects an athlete to repetitive elbow flexion-extension or wrist motion can cause these syndromes. A simple way to approach these syndromes is to divide them into the different pathologies. Athletes can have tendinopathies of the triceps or biceps tendons.

Although lateral epicondylitis and medial epicondylitis are both overuse injuries, they are covered individually in other articles within this journal. Pronator syndrome is covered as a distinct entity of median nerve entrapment. Radial nerve injury is also in another article.[3] This article includes injuries to the elbow capsule and olecranon area.

Overuse injuries to the forearm and elbow are very common in throwing and racquet sports.[4, 5, 6, 7, 8, 9, 10] Any activity that entails repetitive flexion-extension of the elbow or pronation-supination of the wrist can lead to overuse injuries. As the number of recreational athletes increases, the incidence of these injuries increases.[11] The physician must obtain a very comprehensive history when dealing with these injuries because a subtle finding often can determine the proper diagnosis.[7, 8, 10, 12, 13] Obtaining a vocational history is also very important because many skilled laborers or assembly line workers perform the same offending motion at work.

For excellent patient education resources, visit eMedicineHealth's First Aid and Injuries Center. Also, see eMedicineHealth's patient education articles Repetitive Motion Injuries, Sprains and Strains, and Tennis Elbow.

Related Medscape Reference topics:

Biceps Tendinopathy

Little League Elbow Syndrome

Nerve Entrapment Syndromes

Related Medscape resources:

Resource Center Exercise and Sports Medicine

Resource Center Trauma

NextEpidemiologyFrequencyUnited States

The frequency of elbow and forearm overuse injuries is difficult to determine because of the multiple comorbid states and diagnoses that are possible (see Differentials and Other Problems to Be Considered). Some of these are covered in this article.

PreviousNextFunctional Anatomy

The elbow is a complex joint that consists of 3 true joints that function as 1 joint.[1, 2] The humeroulnar joint is a modified hinge joint and allows flexion and extension. The humeroradial joint functions not only as a hinge joint to allow flexion and extension, but also as a pivot joint that allows rotation of the radial head on the capitellum. The proximal radioulnar joint allows supination and pronation to occur. The combined motion of these joints allows a range of motion from 5-150º of flexion-extension and 75º of pronation to 80º of supination. Remember that the olecranon process of the ulna sits in the humeral olecranon fossa in 20º or less of flexion.

The ligamentous structures can be divided into the lateral and medial structures.[1, 2] These ligaments are better described as thickenings of the capsule, rather than true ligaments. Of the 3 medial structures, the anterior medial collateral ligament (AMCL) is the most important, providing approximately 70% of the valgus stability of the elbow. On the lateral side, the lateral ulnar collateral ligament (LUCL) is the strongest of the 4 branches, providing varus support.

The annular ligament maintains the radial head position in the radial notch of the humerus. Dynamic stability is provided by 4 muscle groups that transverse the elbow. The biceps brachii, brachioradialis, and brachialis muscles are the major flexors of the elbow joint. The triceps and anconeus muscles achieve extension. The supinator and biceps brachii muscles provide supination. Pronation is achieved through the pronator quadratus, pronator teres, and flexor carpi radialis muscles.

Understanding where the 3 major nerves cross the elbow is also very important. Overuse injuries or direct trauma can affect these nerves. The median nerve crosses the joint medially between the 2 heads of the pronator muscle and consists of fibers from the C5-T1 spinal nerves. The ulnar nerve travels posterior to the medial epicondyle in the cubital tunnel, down the posterior medial side of the forearm and crosses the wrist in the Guyon canal. This nerve is composed of fibers from C8 and T1 spinal nerves.[14] The radial nerve crosses the elbow laterally and branches into the superficial (sensory) and posterior interosseous nerve, which is purely motor in innervation. This branch goes deep through the arcade of Frohse, which is a common site of entrapment. The radial nerve is made up of branches from the C5-C7 spinal nerves.

PreviousNextSport-Specific Biomechanics

Repetitive elbow flexion can cause biceps tendinosis or anterior capsule strain. Activity that involves forceful elbow extension can cause triceps tendinosis or posterior impingement syndrome. In addition, any activity that causes increased valgus stress on the elbow can also cause ulnar nerve injury, posterior impingement syndrome, or olecranon stress fractures. These injuries are common in throwing sports and overhead racquet sports. Sports that require a great deal of wrist flexion-extension or pronation-supination can lead to pronator syndrome or radial tunnel syndrome. Posterolateral rotatory instability is seen only after a posterior elbow dislocation.

Related Medscape Reference topics:

Biceps Tendinopathy

Imaging of Elbow Fractures and Dislocations in Adults

Little League Elbow Syndrome

Nerve Entrapment Syndromes

Ulnar Nerve Entrapment

Related Medscape resources:

Resource Center Exercise and Sports Medicine

Resource Center Trauma

PreviousProceed to Clinical Presentation , Elbow and Forearm Overuse Injuries

Tuesday, January 14, 2014

Carpal Bone Injuries

Background

The carpus, or wrist, is a complex joint that provides abduction and adduction in the frontal plane of the upper extremity, extension and flexion for hand movements, and supination and pronation in the coronal plane.

In the early 1800s, Colles was the first to differentiate between wrist fractures and wrist dislocations.

NextEpidemiologyFrequencyUnited States

The frequency of carpal bone injuries cannot be specifically determined because they encompass a range and variety of injuries near and around the wrist joint. Additionally, retrospective analysis by diagnosis category grossly underestimates the number of incidents.

The author's perspective is from a personal observation made one weekend day during a 12-hour shift several years ago in Wildomar, California. Seven fractures or fracture-dislocations of the wrist presented to the emergency department; all were related to roller blades, and all involved children aged 5-16 years.

The rate of chronic overuse injuries and other sports-specific injuries approaches 35-50% of all carpal injuries in the sports world. Fractures of the distal radius account for one sixth of all fractures seen and treated in the emergency department. These injuries are most common in patients aged 6-10 years and those aged 60-69 years.

International

International rates approximate the US rate.

PreviousNextFunctional Anatomy

The wrist joint, or carpus, is a complex arrangement between the forearm and the carpal bones, stabilized by strong, ligamentous attachments.[1, 2] The average wrist movement is 80º in flexion, 70º in extension, 30º in ulnar deviation, and 20º in radial deviation. Pronation and supination occur at the radioulnar articulation in the forearm, not at the wrist. The majority of injuries to the wrist occur with the wrist in the flexed position.

The muscles of the hand originate primarily in the forearm and pass over the wrist; the flexor carpi ulnaris inserts into the pisiform bone and is the only muscle that inserts into the wrist. The second and third metacarpals are fixed at the base and are immobile.

Carpal bones

The 8 carpal bones are arranged in 2 rows and are cuboid, with 6 surfaces. Of these 6 carpal surfaces, 4 are covered with cartilage to articulate with the adjacent bones, and 2 are roughened for ligament attachments. The proximal row, which contains the scaphoid, lunate, triquetrum, and pisiform, articulates with the radius and triangular cartilage to form the carpus. The distal row contains the trapezium, trapezoid, capitate, and hamate.

The ulnar nerve runs deep to the flexor carpus ulnaris tendon through the canal of Guyon. The median nerve lies between the flexor carpus radialis and the palmaris longus tendon in the carpal tunnel. Blood is supplied via the radial and ulnar arteries, which form the dorsal palmar arch. The scaphoid bone receives its blood supply from the distal part of this arch, which is prone to injury.

Anatomic considerations

The carpus is composed of the interval between the distal end of the radius and ulna and the proximal end of the metacarpal bones. A complex system of articulations works in unison to provide a global range of motion for the wrist joint. As noted above (see Functional Anatomy, Carpal bones), 8 carpi are arranged in 2 rows to form a compact, powerful unit. The distal row articulates with the proximal surface of the metacarpal bones. The proximal row articulates with the distal end of the radius and the fibrocartilaginous end of the ulna. The ulna does not articulate with the carpus.

The wrist has 5 large joint cavities in addition to the intercarpal joint spaces: (1) radiocarpal joint, (2) distal radioulnar joint, (3) midcarpal joint, (4) large carpometacarpal joint (between the carpus and the second, third, fourth, and fifth metacarpals), and (5) small carpometacarpal joint (between the first metacarpal and trapezium).

Motion at the wrist joint occurs between the radius and carpal bones. The size, position, and relation to the radius and surrounding carpal bones render the wrist joint vulnerable to injury. With dorsiflexion and radial deviation of the wrist, the joint is impinged by the radius; because of its narrow mid portion, the wrist joint is predisposed to injury. Healing depends on blood supply to the area; at this joint, blood enters the bone along the dorsal surface near its mid portion. Thus, the scaphoid is prone to avascular necrosis.

PreviousNextSport-Specific Biomechanics

Sport-specific biomechanics focus on the unique characteristics that place the carpal bones at risk for injury during a sporting activity. This can be as obvious as a fall onto an outstretched hand during a roller sport to the hand plant that is involved in a gymnastics move.

Chronic use and movements in racquet sports, golf, and baseball require the carpus to resist torque stress. Depending on the strength of the weakest link, acute or chronic injury can ensue, which can be especially true in the hyperpronation-supination activity that is involved in the modern golf swing. The key to wrist injury prevention is to improve strength and flexibility in all planes of motion.

PreviousProceed to Clinical Presentation , Carpal Bone Injuries

Sunday, January 5, 2014

Facial Soft Tissue Injuries

Background

Facial soft-tissue injuries are not uncommon in athletics.[1, 2, 3, 4, 5, 6, 7] The position and anatomy of the face make it particularly vulnerable to trauma. In addition, few sports mandate the use of protective equipment, leaving the face susceptible to injury. Although most such injuries are minor in nature, they should be evaluated promptly with a focused history and thorough examination (see image below). In addition, facial injuries should be treated early to reduce the likelihood of possible adverse outcomes (ie, infection, loss of function, poor cosmesis). In this article, common sports-related soft-tissue facial injuries are discussed, with an emphasis on the initial evaluation, diagnosis, and treatment.

Location of the parotid gland and duct system. Location of the parotid gland and duct system.

For excellent patient education resources, visit eMedicineHealth's First Aid and Injuries Center and Eye and Vision Center. Also, see eMedicineHealth's patient education articles Facial Fracture, Black Eye, Nosebleeds, Bicycle and Motorcycle Helmets, and Bicycle Safety.

NextEpidemiologyFrequencyInternational

The exact frequency of facial soft-tissue injuries related to sports participation is unknown. This is, in part, due to the minor nature of many injuries, which can lead to underreporting. It may also be due to the wide variation that is seen between demographic groups and between specific sports.

Previous reports estimate sports participation to account for 3-29% of all facial injuries.[5] In terms of overall sports-related injury, facial trauma accounts for 11-40% of injuries attended to by medical professionals. Most injuries are reported in males, particularly those aged 10-29 years. Sports that mandate the use of helmets and face masks tend to have fewer soft-tissue injuries compared with sports that do not mandate the use of such equipment.

PreviousNextSport-Specific Biomechanics

The mechanism of facial soft-tissue injuries is often a direct impact from an external source (eg, sporting equipment, another participant, environment/playing surface). The forces exerted by the impact can lead to friction, shear, compression, and/or traction of the soft tissue and underlying structures. Injury patterns vary widely by sport, based on various factors (eg, rules, equipment).[8, 9, 10]

PreviousProceed to Clinical Presentation , Facial Soft Tissue Injuries

Monday, December 30, 2013

Femur Injuries and Fractures

Background

The spectrum of femoral shaft fractures is wide and ranges from nondisplaced femoral stress fractures to fractures associated with severe comminution and significant soft-tissue injury. Femoral shaft (see image below) fractures are generally caused by high-energy forces and are often associated with multisystem trauma. Isolated injuries can occur with repetitive stress and may occur in the presence metabolic bone diseases, metastatic disease, or primary bone tumors.[1, 2]

An example of an isolated, short, oblique midshaftAn example of an isolated, short, oblique midshaft femoral fracture, which is very amenable to intramedullary nailing. Although not seen in this x-ray film, radiographic visualization of both the proximal and distal joints should be performed for all diaphyseal fractures.

Most femoral diaphyseal fractures are treated surgically with intramedullary nails or plate fixation. The goal of treatment is reliable anatomic stabilization, allowing mobilization as soon as possible. Surgical stabilization is also important for early extremity function, allowing both hip and knee motion and strengthening. Injuries and fractures of the femoral shaft may have significant short- and long-term effects on the hip and knee joints if alignment is not restored.

Treatment of femoral shaft fractures has undergone significant evolution over the past century. Until the recent past, the definitive method for treating femoral shaft fractures was traction or splinting. Before the evolution of modern aggressive fracture treatment and techniques, these injuries were often disabling or fatal. Traction as a treatment option has many drawbacks, including poor control of the length and alignment of the fractured bone, development of pulmonary insufficiency, deep vein thrombosis, and joint stiffness due to supine positioning.

The femur is very vascular and fractures can result in significant blood loss into the thigh. Up to 40% of isolated fractures may require transfusion, as such injuries can result in loss of up to 3 units of blood.[3] This factor is significant, especially in elderly patients who have less cardiac reserve.

Femoral fracture patterns vary according to the direction of the force applied and the quantity of force absorbed. A perpendicular force results in a transverse fracture pattern, an axial force may injure the hip or knee, and rotational forces may cause spiral or oblique fracture patterns. The amount of comminution present increases with the amount of energy absorbed by the femur at the time of fracture.[1, 2, 4, 5]

For excellent patient education resources, visit eMedicineHealth's First Aid and Injuries Center. Also, see eMedicineHealth's patient education article Broken Leg.

Related Medscape Reference topics:

Femoral Neck Stress and Insufficiency Fractures [in the Orthopedic Surgery section]

Femoral Neck Stress Fracture

Femur Fracture [in the Emergency Medicine section]

Related Medscape resources:

Resource Center Exercise and Sports Medicine

Specialty Site Emergency Medicine

Specialty Site Orthopaedics

CME A 49-Year-Old Man With a Femur Fracture and Hyperdense Bones

CME Vitamin D and Musculoskeletal Health

NextEpidemiologyFrequencyUnited StatesThe incidence of femoral fractures is reported as 1-1.33 fractures per 10,000 population per year (1 case per 10,000 population). In individuals younger than 25 years and those older than 65 years, the rate of femoral fractures is 3 fractures per 10,000 population annually. These injuries are most common in males younger than 30 years. Causes may include automobile, motorcycle, or recreational vehicle accidents or gunshot wounds. The average number of days lost from work or school from femoral fractures is 30.The average number of days of restricted activity due to femoral fractures is 107.The incidence of femoral injuries and fractures increases in elderly patients.PreviousNextFunctional Anatomy

The femur is the strongest, longest, and heaviest bone in the body and is essential for normal ambulation. It consists of 3 parts (ie, femoral shaft or diaphysis, proximal metaphysis, distal metaphysis). The femoral shaft is tubular with a slight anterior bow, extending from the lesser trochanter to the flare of the femoral condyles. During weight bearing, the anterior bow produces compression forces on the medial side and tensile forces on the lateral side. The femur is a structure for standing and walking, and it is subject to many forces during walking, including axial loading, bending, and torsional forces. During contraction, the large muscles surrounding the femur account for most of the applied forces.[1, 2, 4, 5]

Several large muscles attach to the femur. Proximally, the gluteus medius and minimus attach to the greater trochanter, resulting in abduction of the femur with fracture. The iliopsoas attaches to the lesser trochanter, resulting in internal rotation and external rotation with fractures. The linea aspera (rough line on the posterior shaft of the femur) reinforces the strength and is an attachment for the gluteus maximus, adductor magnus, adductor brevis, vastus lateralis, vastus medialis, vastus intermedius, and short head of the biceps. Distally, the large adductor muscle mass attaches medially, resulting in an apex lateral deformity with fractures. The medial and lateral heads of the gastrocnemius attach over the posterior femoral condyles, resulting in flexion deformity in distal-third fractures.

The blood supply enters the femur through metaphyseal arteries and branches of the profunda femoris artery, penetrating the diaphysis and forming medullary arteries extending proximally and distally. With intramedullary nailing, the blood supply is disrupted and progressively reestablishes itself over 6-8 weeks. Healing of the fracture is enhanced by the surrounding soft tissue and local recruitment of blood supply around the callus. The femoral artery courses down the medial aspect of the thigh to the adductor hiatus, at which time it becomes the popliteal artery. Injuries to the artery occur at the level of the adductor hiatus, where soft-tissue attachments may cause tethering. Uncommonly, the sciatic nerve is injured in femoral shaft fractures; however, it may become injured in proximal or distal femoral injuries.

Related Medscape Reference topics:

Nerve Entrapment Syndromes [in the Neurosurgery section]

Nerve Entrapment Syndromes of the Lower Extremity [in the Orthopedic Surgery section]

PreviousNextSport-Specific Biomechanics

Trauma-induced fractures of the femur occur with contact and during high-speed sports. A significant amount of energy is transferred to the limb in a femur fracture, such as might be generated in skiing, football, hockey, rodeo, and motor sports.

Stress fracture

A femoral stress fracture is the result of cyclic overloading of the bone or a dramatic increase in the muscular forces across their insertion, causing microfracture. These repetitive stresses overcome the ability of the bone to heal the microtrauma. The area most susceptible to stress fracture is the medial junction of the proximal and middle third of the femur, which occurs as a result of the compression forces on the medial femur.

Stress fractures can also occur on the lateral aspect of the femoral neck in areas of distraction and are less likely to heal nonoperatively than compression-side stress fractures. Stress fractures occur most often in repetitive overload sports such as in runners and in baseball and basketball players. For more information, refer to the Medscape Reference article Femoral Neck Stress Fracture.

PreviousProceed to Clinical Presentation , Femur Injuries and Fractures

Monday, December 23, 2013

Clavicular Injuries

Practice Essentials

Although clavicle fractures are common and usually heal regardless of the selected treatment, complications are possible, warranting careful attention to these injuries. Multiple attempts have been made to devise a classification scheme for clavicle fractures. The most common system is the following one, created by Allman, in which the clavicle is divided into thirds[1] :

Group I fractures: Middle third injuriesGroup II fractures: Distal third injuriesGroup III fractures: Medial (proximal) third injuriesSigns and symptoms

Clinical signs and symptoms of clavicle fracture include the following:

The patient may cradle the injured extremity with the uninjured armThe shoulder may appear shortened relative to the opposite side and may droopSwelling, ecchymosis, and tenderness may be noted over the clavicleAbrasion over the clavicle may be noted, suggesting that the fracture was from a direct mechanismCrepitus from the fracture ends rubbing against each other may be noted with gentle manipulationDifficulty breathing or diminished breath sounds on the affected side may indicate a pulmonary injury, such as a pneumothoraxPalpation of the scapula and ribs may reveal a concomitant injuryTenting and blanching of the skin at the fracture site may indicate an impending open fracture, which most often requires surgical stabilization Nonuse of the arm on the affected side is a neonatal presentationAssociated distal nerve dysfunction indicates a brachial plexus injuryDecreased pulses may indicate a subclavian artery injuryVenous stasis, discoloration, and swelling indicate a subclavian venous injury[2, 3]

See Clinical Presentation for more detail.

Diagnosis

Laboratory studies

Complete blood count (CBC): If a vascular injury is suspected, to check the hemoglobin and hematocrit valuesArterial blood gas (ABG): If a pulmonary injury is suspected or identified

Imaging studies

Chest radiography: Obtain an expiration posteroanterior (PA) chest film (along with the above-mentioned ABG test) if a pulmonary injury is suspected or identified Radiography of the clavicle and shoulderComputed tomography (CT) scanning with 3-dimensional (3-D) reconstruction: To help evaluate displaced fracturesArteriography: If a vascular injury is suspectedUltrasonography

See Workup for more detail.

Management

The vast majority of clavicle fractures heal with nonoperative management, which includes the use of a figure-of-eight brace or a simple shoulder sling.

Surgical indications include the following:

Complete fracture displacement[4] Severe displacement causing tenting of the skin with the risk of punctureFractures with 2 cm of shorteningComminuted fractures with a displaced transverse "zed" (or Z-shaped) fragment[4] Neurovascular compromiseDisplaced medial clavicular fractures with mediastinal structures at risk[5] Polytrauma (with multiple fractures): To expedite rehabilitationOpen fracturesAn inability to tolerate closed treatmentFractures with interposed muscleEstablished, symptomatic nonunionConcomitant glenoid neck fracture (floating shoulder)

When a midshaft clavicle fracture requires surgical fixation, the commonly performed procedure involves open reduction of the fracture, followed by either insertion of an intramedullary device or fixation with a plate and screws.[6, 7, 8, 9]

In a distal clavicle fracture, stable fixation can be achieved in many ways, including through combinations of a coracoclavicular screw, Dacron or Mersilene tape, tension banding, a Kirschner wire (K-wire), and clavicular plates. Regardless of the exact technique used, the general principles of fracture reduction and fixation and stabilization of the coracoclavicular interval apply.

See Treatment and Medication for more detail.

Image libraryA posterior view demonstrating a closed clavicle fA posterior view demonstrating a closed clavicle fracture tenting the skin (arrow), which can potentially lead to an open fracture. NextBackground

Clavicle fractures are common and easily recognized because of their subcutaneous position, as shown in the images below. Fracture union usually progresses regardless of the treatment initiated. Despite the innocuous appearance of clavicle fractures, however, potential treatment difficulties and possible complications warrant careful attention to these injuries. (See Prognosis, Treatment, and Medication.)

A posterior view demonstrating a closed clavicle fA posterior view demonstrating a closed clavicle fracture tenting the skin (arrow), which can potentially lead to an open fracture. Comparison of both clavicles, with the left tentinComparison of both clavicles, with the left tenting the skin (wide arrow). Close-up view of clavicle tenting the skin (arrow)Close-up view of clavicle tenting the skin (arrow).

The clavicle is the first bone in the body to ossify, beginning at the fifth week of gestation.[2] Through age 5 years, the growth is primarily through intramembranous ossification. The medial epiphysis ossifies late, beginning at age 12-19 years, and may not completely fuse until age 22-25 years. Physial injuries around this area may be mistaken for fractures, and care should be taken in evaluating injuries. (For patients aged 22-25 years, the Salter-Harris classification for physial injuries can be used, and nonoperative treatment can often be initiated.) (See Anatomy, Clinical Presentation, DDx, and Workup.)

Historically, clavicle fractures have been considered best treated nonoperatively, with good outcomes. Management typically included the use of either a shoulder sling or a figure-of-eight brace. The vast majority of these fractures healed, with variable amounts of cosmetic deformity.

Studies have examined the different patterns of displacement and clinical outcomes of clavicle fractures according to their location. The medical literature has focused predominantly on fractures of the middle and distal clavicle but is still lacking concerning the management of medial clavicle fractures; the literature does, however, indicate that medial clavicle fractures respond well to nonoperative management. Controversy remains concerning operative versus nonoperative treatment of middle and distal clavicle fractures.[10, 11, 12, 13] (See Treatment and Medication.)

Fracture classification

Multiple attempts have been made to devise a classification scheme for clavicle fractures. The most common system is the following one, created by Allman, in which the clavicle is divided into thirds[1] :

Group I fractures: Middle third injuriesGroup II fractures: Distal third injuriesGroup III fractures: Medial (proximal) third injuries

Neer made a significant revision to the Allman classification scheme. Group II (distal clavicle) fractures were further divided into 3 types, based on the location of the clavicle fracture in relation to the coracoclavicular ligaments. The reason for this modification was that distal clavicle fractures behave differently depending on the exact location of the injury. The designations are as follows (see Clinical Presentation and Workup)[14] :

Type I fractures: Minimally displaced and occur lateral to an intact coracoclavicular ligament complex; these fractures may be treated nonoperatively and symptomatically (see the image below) Type II fractures: Occur when the medial fragment is separated from the coracoclavicular ligament complex; the medial fragment is displaced cephalad by the pull of the sternocleidomastoid muscle, and the distal fragment is displaced caudally by the weight of the upper extremity, with the intact coracoclavicular ligament complex; the resulting deformity leads to marked displacement of the fracture ends, predisposing this fracture type to a higher prevalence (up to 30%) of nonunion Type III injuries: Minimally displaced or nondisplaced and extend into the acromioclavicular (AC) joint; as with type I fractures, these injuries can be treated symptomatically; the development of late AC degenerative changes can be treated with distal clavicular excision Type I fracture of the distal clavicle (group II).Type I fracture of the distal clavicle (group II). The intact ligaments hold the fragments in place. A type II distal clavicle fracture. In type IIA, bA type II distal clavicle fracture. In type IIA, both conoid and trapezoid ligaments are on the distal segment, while the proximal segment, without ligamentous attachments, is displaced. A type IIB fracture of the distal clavicle. The coA type IIB fracture of the distal clavicle. The conoid ligament is ruptured, while the trapezoid ligament remains attached to the distal segment. The proximal fragment is displaced.

The Neer type II fracture was later divided into types IIA and IIB, as follows (see the images below):

Type IIA - Displaced due to fracture medial to the coracoclavicular ligaments; the conoid and trapezoid remain attached to the distal fragment Type IIB - Displaced due to fracture medial to the coracoclavicular ligaments; either the conoid is torn or, more rarely, both the conoid and trapezoid are torn Anatomy of the clavicle indicating potential fractAnatomy of the clavicle indicating potential fracture sites. PreviousNextAnatomy

The clavicle is an S-shaped bone that acts as a strut between the sternum and the glenohumeral joint. Another function of the clavicle is to help protect the neurovascular bundle that runs behind it. The junction of the middle and distal thirds of the clavicle is a common site of fracture because this is the thinnest part of the bone, and there is relatively little protection by muscular attachments.

Numerous muscular and ligamentous forces act on the clavicle, and knowledge of these differing forces is necessary to understand the nature of displacement of clavicle fractures and why certain fracture patterns tend to cause problems if not reduced and surgically stabilized. (See the image below.)

Anatomy of the clavicle indicating potential fractAnatomy of the clavicle indicating potential fracture sites.

The clavicle articulates with the sternum at the sternoclavicular (SC) joint and with the acromion at the AC joint. Many ligamentous structures attach to the clavicle and provide stability for the articulations with the sternum and the acromion. The primary stabilizers of the SC joint are the anterior and posterior capsules. Other ligamentous structures attaching here are the interclavicular ligament and the costoclavicular ligament. Stability of the SC joint in the anterior-posterior plane is derived predominantly from the posterior capsule, with additional stability conferred by the anterior capsule. The interclavicular and costoclavicular ligaments have little effect on stability of the joint.

At the level of the AC joint, the coracoclavicular and AC ligaments provide stability for the joint. The coracoclavicular ligament is actually 2 separate ligaments, the conoid and the trapezoid, which both attach from the coracoid to the inferior surface of the distal clavicle. Debski et al have delineated the different functions of the conoid and trapezoid in resistance to applied loads to the AC joint.[15] The conoid is the predominant restraint to anterior and superior loading, while the trapezoid is the major restraint to posterior loading at the AC joint. The AC ligament is at the superior-lateral aspect of the clavicle and overlies the AC joint.

Three muscles originate on the clavicle, and 3 muscles insert on it. The muscles that take their origin from the clavicle are as follows:

SternohyoidPectoralis majorDeltoid

The muscles that insert on the clavicle are as follows:

SternocleidomastoidSubclaviusTrapezius

These 6 muscles may become deforming forces on the clavicle in the presence of a fracture, with the displacement of fracture fragments depending on the location of the fracture in relation to the muscular and ligamentous attachments.

Many other important structures are in extremely close contact with the clavicle and are thus subject to injury in the context of clavicle fractures. The subclavian artery (which becomes the axillary artery as it passes anteriorly to the first rib) and vein are both in close proximity to the middle portion of the clavicle. Additionally, the brachial plexus also passes behind the clavicle posterolateral to the subclavian vessels and is at risk with displaced fractures of the middle clavicle.

The subclavius muscle lies between the clavicle and these neurovascular structures, and, though small, it is believed to prevent more frequent damage to these structures. Reports also exist of injuries to the apices of the lung, most commonly with displaced middle third clavicle fractures.

PreviousNextPathophysiology

Because of its subcutaneous position, the clavicle may be fractured easily, with the fracture often being an isolated injury. However, clavicle fractures are also common in the context of high-energy injury or multiple traumatic injuries. In these situations, it is important to examine the patient for other associated injuries, such as rib fractures, scapula fractures, other fractures about the shoulder girdle, pulmonary contusion, pneumothorax, hemothorax, and closed head injuries. (See the image below.)

Clavicle fracture with rib fractures. Remember to Clavicle fracture with rib fractures. Remember to look for associated injuries.

The frequency with which the 3 groups of fractures occur is as follows:

Group I (middle third) - Approximately 80%Group II (distal third) - 12-15%Group III (medial third) - Less than 5%Group I fractures

Most group I fractures occur medial to the coracoclavicular ligament, at the junction of the middle and outer third of the clavicle. The proximal fragment is typically displaced upward because of the pull of the sternocleidomastoid muscle. The usual mechanism of injury involves a direct force applied to the lateral aspect of the shoulder as a result of a fall, sporting injury, or motor vehicle accident. Group I fractures are shown in the images below

Nondisplaced middle clavicle fracture. Nondisplaced middle clavicle fracture. Displaced fracture of middle clavicle. Displaced fracture of middle clavicle. Displaced middle clavicle fracture. Displaced middle clavicle fracture. Group II fractures

Fractures of the distal third of the clavicle result from a direct blow to the top of the shoulder. They occur distal to the coracoclavicular ligament.[16]

Group III fractures

Fractures of the medial third of the clavicle occur as a result of a direct blow to the anterior chest. A diligent search for associated injuries should accompany group III fractures because considerably strong forces are required to fracture this area of the clavicle.

Greenstick or buckle-type fractures are common in children. Most of these fractures are nondisplaced and heal uneventfully.

PreviousNextEtiology

Clavicle fractures may be caused by direct or indirect trauma. The most common mechanism is an indirect one, involving a fall directly onto the lateral shoulder.[17, 18, 19] Examples of a direct mechanism would be a blow from a hockey stick or a direct fall onto the clavicle. At-risk athletes include those in football, hockey, and soccer and those at risk for falling during roller skating, skiing, bicycling, or horseback riding.

A less common mechanism for clavicle fractures is a fall onto an outstretched hand (ie, a FOOSH injury). The radiographs below depict clavicle fracture in a hockey player.

Comminuted fracture in a hockey player. Note the mComminuted fracture in a hockey player. Note the medial fragment tenting the skin. Additional view of fracture displacement and commiAdditional view of fracture displacement and comminution in a hockey player. The sternocleidomastoid is the deforming force of the medial fragment. Radiographs after open reduction and internal fixaRadiographs after open reduction and internal fixation of a comminuted fracture in a hockey player. PreviousNextEpidemiologyOccurrence in the United States

The clavicle is the most frequently fractured bone in the body in childhood, accounting for 10-16% of all fractures in this age group.

In adults, clavicle fractures account for 2.6-5% of all fractures and 44% of all shoulder girdle injuries.[20, 21, 22] Middle third (group I) fractures account for 69-82% of all fractures of the clavicle, whereas distal third (group II) fractures account for 12%, and medial third (group III) fractures occur in 6% of cases.[20, 21]

Clavicular injuries affect 1 in 1000 people per year. Bimodal incidence occurs in men younger than 25 years and older than 55 years. Pneumothorax occurs in 3% of patients.

International occurrence

The annual incidence rate of clavicular fractures is estimated to be between 30 and 60 cases per 100,000 population.[12]

Sex- and age-related demographics

Clavicular injuries occur 2.5 times more commonly in males than in females, reflecting a greater involvement of males in contact and violent sports and motor vehicle accidents (MVAs).

Clavicle fractures, the most common of all pediatric fractures, can present even in the newborn period, especially following a difficult delivery. A large peak incidence occurs in males younger than 30 years due to sports injuries. A smaller peak occurs in elderly patients, who tend to sustain clavicle fractures (in association with osteoporosis) during low-energy falls.[12]

PreviousNextPrognosis

Most clavicle fractures treated nonoperatively heal, although with variable amounts of cosmetic deformity. Younger children generally require shorter periods of immobilization (2-4 wk) than do adolescents and adults (4-8 wk).

Complications

Nonunion

Nonunion is a failure to show clinical or radiographic progression of healing after 4-6 months. The following are risk factors for nonunion:

Fracture comminutionSignificant fracture displacement or shorteningType 2 fractures of the distal third of the clavicleRefractureFemale sexAdvanced ageFractures with more than 2 cm of shortening

The nonunion rate for all midclavicle fractures treated nonoperatively is 6%; the rate is 15% for displaced midclavicle fractures treated nonoperatively.[23] Symptoms of nonunion can be pain, motion, or loss of function. Note, however, that many nonunions are asymptomatic and require no treatment. Refer patients with symptomatic nonunion to an orthopedic surgeon to discuss surgical options. In some situations, a bone stimulator to help promote bone healing can be tried before surgery.

Murray et al reported that smoking was the greatest risk factor for nonunion among patients treated nonoperatively for diaphysial clavicle fractures. In a study, the investigators followed the healing course of 941 patients with such fractures and, using multivariate analysis, found that, along with smoking, both comminution and fracture displacement were particularly significant factors in nonunion.

The investigators determined that by using known risk factors, a statistical model can be used to estimate the probability of nonunion in a specific patient and can therefore help to determine whether he or she should be treated surgically. The investigators also concluded that smoking cessation needs to be included in the treatment of diaphysial clavicle fractures.[24]

Malunion

Malunion is when the fracture heals with significant angulation, shortening, and a poor appearance. Mild malunion is common after clavicle fractures, but it is usually not clinically significant. Occasionally, the patient can have pain or a mild limitation in motion or strength. Symptoms from nerve impingement may occur but are uncommon. Surgeries for malunion attempt to restore the clavicular length and correct any angular deformity of the clavicle.

Neurovascular injuries

Group I fractures (middle third of the clavicle) have been associated with injuries to the neurovascular bundle and the pleural dome.

Neurovascular compromise can develop from exuberant callus formation or from malunion. The medial cord and ulnar nerve are affected most often; treatment is surgical in nature. Brachial plexus compression resulting from hypertrophic callus formation may cause peripheral neuropathy.

Intrathoracic injuries

These include the following:

PneumothoraxSubclavian artery and vein injuryInternal jugular vein injuryAxillary artery injury

Other

A spike of bone can form subcutaneously after angulated fractures heal. This can be symptomatic for athletes who wear shoulder pads or for backpackers. If a donut pad is not sufficient to relieve symptoms, surgical excision can be considered. Posttraumatic arthritis can develop if a clavicle fracture enters the AC or SC joints.

Complications after group III fractures (medial third of the clavicle) resemble those associated with posterior sternoclavicular dislocations, including pneumothorax and compression or laceration of the great vessels, trachea, or esophagus.

Mortality

While the overwhelming majority of clavicle fractures are benign, there is a possibility of associated, life-threatening intrathoracic injuries.

Kendall et al reported a fatality from an isolated clavicle fracture from transection of the subclavian artery,[25] the first such report in the literature. The fatality may have been due to the fact that the fall was not witnessed and the patient lay unassisted for an unknown period of time. The patient never regained spontaneous circulation, and the injury to the subclavian artery was diagnosed at autopsy. The postmortem examination revealed a midclavicular fracture with transection of the subclavian artery. A 2.6-L hemothorax and damage to parietal and apical pleura were noted, but no other injuries were present.

Although this case is unique, it does emphasize the need to be aware of the potentially catastrophic complications of damage to the vascular structures in close proximity to the clavicle.

PreviousNextPatient Education

At the initial visit, discuss the following with the patient who has a clavicular injury:

A visible prominence may remain at the fracture site after it heals; this may be more evident in thin individualsFracture nonunion is possible, and surgery may be necessaryRefracture is a possibility if the patient engages in contact sports, particularly if he or she returns to play before the bone healing is solid

Educate patients about proper placement and adjustment techniques for a figure-of-eight bandage (clavicle strap) and inform them that paresthesias or edema in the hands or fingers indicate that the strap is too tight and should be removed.

Neonatal clavicle fracture

Advise parents to minimize pressure and movement of the ipsilateral arm during handling of a neonate with a clavicle fracture. The parent may try to pin the shirt sleeve of the affected arm to the front of the child’s shirt to minimize movement.

For patient education information, see the First Aid and Injuries Center, as well as Broken Collarbone (Broken Clavicle) and Shoulder Dislocation.

PreviousProceed to Clinical Presentation , Clavicular Injuries