Medial Synovial Plica Irritation

Background

Medial synovial plicae are embryological structures that form within the knee. They are normal anatomical structures found within the joint capsule of the knee, appearing as thin, soft, and flexible structures that move with the knee during flexion and extension. Impingement of the plicae during motion of the knee can cause inflammation, resulting in medial knee pain. The medial suprapatellar plica of the knee is an intra-articular synovial fold on the medial aspect of the knee. This plica is one of the most common sources of knee pain in patients; however, a proper rehabilitation program allows most patients to recover from the symptoms associated with irritation of this structure.[1]

NextEpidemiologyFrequencyUnited States

No exact numbers on the incidence of patients with an irritated synovial plica are available; however, it is estimated that approximately 50% of patients who present with knee pain to a physician's office have some irritation of their patellofemoral joint. In this group of patients, most of them have some amount of suprapatellar plical irritation. Medial plica syndrome is seen in both young and old patients with a wide variety of activity levels.

PreviousNextFunctional Anatomy

The suprapatellar plica is an intra-articular synovial fold, which has its main component on the medial aspect of the knee. When the knee is in full extension, the suprapatellar plica commonly forms a shelf, which can be palpated by an examiner. Proximally, the plica is attached to the articularis genu muscle. Distally, it is attached to the anterior horn of the medial meniscus and the medial edge of the retropatellar fat pad. In some patients, this plical shelf can become fibrotic and may impinge on the medial edge of the medial femoral condyle. The distal synovial fold of the medial plicae is in close proximity with the tendon sheath of the gracilis, which could potentially explain gait abnormalities seen with plicae irritation.

PreviousNextSport-Specific Biomechanics

The quadriceps muscles and the articularis genu muscle dynamically control the medial suprapatellar plica. Good quadriceps tone seems to result in normal motion of this plica, whereas patients with poor quadriceps tone or tight hamstring muscles (antagonists of the quadriceps) commonly have irritation of their synovial plica.

PreviousProceed to Clinical Presentation , Medial Synovial Plica Irritation

Read More

Medial Collateral Knee Ligament Injury

Background

Medial collateral ligament (MCL) injuries of the knee are very common sports-related injuries. The MCL is the most commonly injured knee ligament. Injuries to the MCL occur in almost all sports and in all age groups.

NextEpidemiologyFrequencyUnited States

The incidence of MCL injuries is impossible to determine because of the wide spectrum of injury severity. Many MCL injuries are minor and may never be evaluated by a physician.[1]

PreviousNextFunctional Anatomy

The medial aspect of the knee has been divided into 3 distinct layers based on cadaver dissection. The first layer is the deep fascia, which consists of the sartorius fascia anteriorly and a thin fascial layer posteriorly. The thin posterior fascia covers the popliteal fossa and the heads of the gastrocnemius muscle. The second layer includes the superficial MCL, also known as the tibial collateral ligament. This ligament attaches proximally to the medial femoral epicondyle and to the tibia distally, approximately 4-5 cm distal to the joint line. The parapatellar retinaculum and patellofemoral ligament are within this layer.

The third layer is the knee joint capsule, which attaches proximally and distally at the articular margins. The capsule is divided into thirds from anterior to posterior. The anterior third of the capsule is the thinnest portion. It is attached to the anterior horn of the medial meniscus and is reinforced by the medial retinaculum. The middle third of the capsule consists of the deep medial collateral ligament. It is firmly attached to the mid body of the medial meniscus. Proximal to the meniscal attachment, it is termed the meniscofemoral ligament. Distal to its meniscal attachment, it is termed the meniscotibial ligament. The posterior third of the capsule includes the posterior oblique ligament (POL) and the oblique popliteal ligament. The POL has 3 arms, the superficial, tibial, and capsular.

See the figure below.

The medial and lateral collateral ligaments of the knee. Courtesy of Randale Sechrest, MD, CEO, Medical Multimedia Group PreviousNextSport Specific Biomechanics

The superficial MCL has been shown through serial cutting studies to provide the primary restraint to valgus loads at all degrees of flexion. It is also an important restraint to anterior tibial translation when the anterior cruciate ligament is injured. The superficial MCL acts as a primary restraint to external rotation of the tibia.

Stability of the medial side of the knee is provided by dynamic and static restraints. The static restraints are the superficial MCL and the joint capsule, including the deep MCL and the POL. The semimembranosus muscle, the pes anserine muscles, and the vastus medialis muscle provide dynamic stability. The muscles of the pes include the sartorius, gracilis, and semitendinosus. These muscles flex and internally rotate the tibia. The semimembranosus has 4 attachments: direct, tibial, inferior, and capsular.[2, 3]

PreviousProceed to Clinical Presentation , Medial Collateral Knee Ligament Injury

Read More

Medial Condylar Fracture of the Elbow

Background

Medial condylar fractures of the elbow, demonstrated in the images below, are rare in adults and children; prompt recognition of these sometimes elusive injuries is imperative so that complications can be averted.

Milch classification of condylar fractures. NextEpidemiologyFrequencyUnited States

Trauma to the elbow has a high potential for complications and residual functional disability. Luckily, fractures of the humeral condyles are uncommon in adults. Medial condylar fractures are less common than fractures of the lateral condyle. Together, these injuries account for approximately 5% of all distal humerus fractures in adults.

During adolescence, the distal humerus is the second most common site of physeal injury (second only to the distal radius). Supracondylar fractures account for approximately two thirds of distal humeral injuries in children. In children with elbow fractures, isolated medial condyle fractures are uncommon and account for approximately 1-2% of all distal humerus fractures. In children, medial condyle fractures occur at a peak age of 8-12 years.

Fracture of the medial epicondyle of the elbow, as seen in the image below, is common and occurs in approximately 10% of pediatric elbow fractures. Most of these injuries occur in males aged 10-14 years.

Medial epicondylar fracture PreviousNextFunctional Anatomy

The elbow joint is composed of the bony articulation between the humerus, ulna, and radius. The distal end of the humerus can be divided into the medial and lateral condyles. The articular portion of the medial condyle is the trochlea, and the articular portion of the lateral condyle is the capitulum. The epicondyle is considered part of the nonarticular portion of the condyle. The dividing point for the distal humerus, separating the medial and lateral condyles, is the capitulotrochlear sulcus.

Distinguishing between the articular and nonarticular surface of the condyles is important in the diagnosis and management of condylar fractures. By definition, fractures that involve only the intra-articular surface have no muscular attachments and can only be repositioned by pressure of the opposing articular surface or by open reduction and internal fixation. Fractures that extend beyond the joint capsule have attached muscle and ligaments. The position of the fracture fragment is often influenced by its muscular attachment.

The stability of the elbow is enhanced by its surrounding ligamentous structures. The medial collateral ligament and the lateral collateral ligament (ie, ulnar collateral ligament, radial collateral ligament) provide further stability of the elbow. The radiocapitellar joint is supported by the radial collateral and annular ligaments.

Collectively, the forearm musculature originates from the bony epicondyle prominences. The wrist flexors originate from the medial epicondyle, and the wrist extensors originate from the lateral epicondyle. Because the forearm musculature traverses the elbow joint, some inherent stability to the joint is conferred by muscular contraction.

The structures of the upper arm and elbow are located in either the anterior or posterior compartments. The anterior compartment contains the biceps brachii, brachialis, and coracobrachialis muscles. The anterior compartment also contains the brachial artery, median nerve, musculocutaneous nerve, and ulnar nerve. The ulnar nerve passes behind the medial condyle as it enters the forearm. Because of its location and relatively tight tethering to the epicondyle, the ulnar nerve can be injured when the medial humeral condyle is fractured. The posterior compartment contains the triceps brachii muscle and the radial nerve.

The bony anatomy of the elbow in the pediatric population deserves special mention. Many of the challenges encountered in diagnosing elbow fractures in pediatric patients involve proper knowledge of the ossification centers of the elbow. In general, ossification of the growth centers begins at an earlier age in girls than in boys. Although variation exists, ossification of the growth centers of the elbow occurs at the following times:

Capitellum - 11 monthsMedial epicondyle - 4-6 yearsRadial head - 5-6 yearsOlecranon - 6-8 yearsTrochlea - 9-10 yearsLateral epicondyle - 10-12 yearsPreviousNextSport Specific Biomechanics

By definition, the elbow is a true hinge joint that is very stable to all motions except varus and valgus stress. The articulation of the trochlea of the humerus and the olecranon of the ulna defines the plane of flexion and extension at the elbow. The elbow also allows for pronation and supination at the radiocapitellar articulation. The radiocapitellar joint does provide some stability against valgus stress by acting as a buttress to prevent medial elbow opening. Stability is further enhanced by the strength of the ulnar collateral ligament, the principal stabilizing ligament of the elbow that resists valgus stress.

The radial-collateral ligament protects the joint from posterolateral rotary instability and is usually injured during elbow dislocation. The wrist extensor tendons that originate on the lateral intermuscular septum of the arm and the lateral epicondyle provide the elbow with stabilization against varus stress.

PreviousProceed to Clinical Presentation , Medial Condylar Fracture of the Elbow

Read More

Medial Gastrocnemius Strain

Background

A medial calf injury is a musculotendinous disruption of varying degrees in the medial head of the gastrocnemius muscle that results from an acute, forceful push-off with the foot.[1, 2, 3, 4, 5, 6] This injury occurs commonly in sports activities (eg, hill running, jumping, tennis), but it can occur in any activity. A medial calf injury is often seen in the intermittently active athlete, often referred to as the "weekend warrior.

This condition has been termed "tennis leg" because of its prevalence in this particular sport, but medial calf injury can happen in a variety of sports or other activities. One mechanism that occurs is on the back leg during a lunging shot, in which the knee is extended while the foot is dorsiflexed. This action puts maximal tension on the gastrocnemius muscle as the lengthened muscle is contracted at the "push off," resulting in a medial calf injury. (See also the Medscape Reference article Calf Augmentation.)

An unusual presentation of a medial gastrocnemius injury during namaz praying was reported by Yilmaz et al, who performed a retrospective study of the sonographic and magnetic resonance image (MRI) findings of patients referred over 7 years with leg pain and swelling.[7] Of 543 patients, 14 had a final diagnosis of medial gastrocnemius rupture that occurred during namaz praying. Nine of 14 (64.2%) patients had incomplete tears at the musculotendinous junction, and 5 of 14 (35.8%) patients had partial tears.

The diagnosis in 4 of 14 (28.6%) patients was misattributed to deep vein thrombosis due to clinical findings and presentation, associated fluid collection between the gastrocnemius and soleus muscles was found in 11 of 14 (78.5%) patients, and isolated fluid collection between the gastrocnemius and soleus muscles was seen in 1 patient.[7] The investigators suggested ultrasonography and MRI can be used to correctly diagnose patients with medial gastrocnemius injuries.

For excellent patient education resources, visit eMedicineHealth's First Aid and Injuries Center. Also, see eMedicineHealth's patient education articles Muscle Strain and Sprains and Strains.

NextEpidemiologyFrequencyInternational

Medial calf injuries occur more commonly in men than in women, and these injuries usually afflict athletes and others in the fourth to sixth decade of life. Medial calf injuries are most commonly seen acutely, but up to 20% of affected patients report a prodrome of calf tightness several days before the injury, thus suggesting a potential chronic predisposition.

PreviousNextFunctional Anatomy

The medial head of the gastrocnemius muscle originates from the posterior aspect of the medial femoral condyle, and as it courses distally, the medial head merges with the lateral head of the gastrocnemius. Further distally, the joined heads of the gastrocnemius merge with the soleus muscle-tendon complex to form the Achilles tendon. The main function of the gastrocnemius muscle is to plantar flex the ankle, but it also provides some knee flexion, as well as contributes to the posterior stability of the knee and partially to the motion of the menisci with flexion/extension of the knee. Throughout the belly of the muscle, the medial gastrocnemius has several origins of tendinous formation. Most strains occur at this musculotendinous junction.

PreviousNextSport-Specific Biomechanics

The medial calf injury usually occurs when an eccentric force is applied to the gastrocnemius muscle, which usually happens when the knee is extended, the ankle is dorsiflexed, and the gastrocnemius attempts to contract in the already lengthened state.[1, 2, 3, 4, 5, 6] This is the common position of the back leg in a tennis stroke, and it results in the greatest force to the muscle unit; but medial calf injuries can also occur during a typical contraction of ankle plantar flexion, especially if the athlete is pushing or lifting a large weight or force.

PreviousProceed to Clinical Presentation , Medial Gastrocnemius Strain

Read More