Supraspinatus Tendonitis

Background

Supraspinatus tendonitis is often associated with shoulder impingement syndrome. The common belief is that impingement of the supraspinatus tendon leads to supraspinatus tendonitis (inflammation of the supraspinatus/rotator cuff tendon and/or the contiguous peritendinous soft tissues), which is a known stage of shoulder impingement syndrome (stage II) as described originally by Neer in 1972.[1]

The causes of supraspinatus tendonitis can be broken down into extrinsic and intrinsic factors.[2, 3] Extrinsic factors are further broken down into primary impingement, which is a result of increased subacromial loading, and secondary impingement, which is a result of rotator cuff overload and muscle imbalance. In athletes whose sport involves stressful repetitive overhead motions, a combination of causes may be found.

Recent studies

Lewis et al demonstrated the presence of neovascularity in individuals with a clinical diagnosis of rotator cuff tendinopathy and, to a lesser extent, in asymptomatic shoulders. Twenty patients (mean age, 50.2 y; range 32-69 y) with a clinical diagnosis of unilateral rotator cuff tendinopathy received a clinical examination then underwent bilateral grey scale and color Doppler ultrasound assessment.

Neovascularity was found in the symptomatic shoulder in 13 of 20 patients (35%) as well as in the asymptomatic shoulder in 5 of the 20 patients (25%).[4] Of 6 other patients who withdrew from the study before entering the trial, 1 withdrew due to cessation of symptoms and did not have neovascularity in either shoulder; 5 withdrew due to bilateral symptoms, of whom 2 had signs of bilateral neovascularity, 1 had unilateral neovascularity, and the remaining 2 did not have neovascularity in either shoulder.[4] No association was identified between the presence of neovascularity and pain, duration of symptoms, and neovascularity and shoulder function. The investigators noted more research is needed to evaluate the relevance of their findings.

In another study, Millar et al suggested proinflammatory cytokines may have a role in supraspinatus tendinopathy.[5] The investigators used custom micro-arrays to assess rat supraspinatus tendinopathy produced by running overuse. In addition, samples of torn supraspinatus tendon and matched intact subscapularis tendon from patients undergoing shoulder surgery for rotator cuff tears, as well as control samples of subscapularis tendon from 10 individuals with normal rotator cuffs undergoing arthroscopic shoulder stabilization, were collected and examined with semiquantitative reverse transcription polymerase chain-reaction (RT-PCR) and immunohistochemistry.[5] The presence of significant upregulation of proinflammatory cytokines and apoptotic genes was found in the rat samples (P = 0.005) as well as in the supraspinatus and subscapularis tendons obtained from the patients with rotator cuff tears (P = 0.0008).

NextEpidemiologyFrequencyUnited States

Supraspinatus tendonitis is a common cause of shoulder pain in athletes whose sports involve throwing and overhead motions.

PreviousNextFunctional Anatomy

The shoulder consists of 2 bones (ie, humerus, scapula), 2 joints (ie, glenohumeral, acromioclavicular), and 2 articulations (ie, scapulothoracic, acromiohumeral). Several interconnecting ligaments and layers of muscles join these bones. The relative lack of bony stability in the shoulder permits a wide range of motion. Soft tissue structures are the major glenohumeral stabilizers.

The static stabilizers consist of the articular anatomy, glenoid labrum, joint capsule, glenohumeral ligaments, and inherent negative pressure in the joint. The dynamic stabilizers include the rotator cuff muscles, long head of the biceps tendon, scapulothoracic motion, and other shoulder girdle muscles such as the pectoralis major, latissimus dorsi, and serratus anterior.

The rotator cuff consists of 4 muscles, which control 3 basic motions: abduction, internal rotation, and external rotation. The supraspinatus muscle is responsible for initiating abduction, the infraspinatus and teres minor for controlling external rotation, and the subscapularis for controlling internal rotation. The rotator cuff muscles provide dynamic stabilization to the humeral head on the glenoid fossa, forming a force couple with the deltoid to allow elevation of the arm. It is responsible for 45% of abduction strength and 90% of external rotation strength.

The supraspinatus outlet is a space formed by the acromion, coracoacromial arch, and acromioclavicular joint on the upper rim and the humeral head and glenoid below. It accommodates passage and excursion of the supraspinatus tendon. Abnormalities of the supraspinatus outlet have been identified as a cause of impingement syndrome and rotator cuff tendonitis.

Impingement implies extrinsic compression of the rotator cuff in the supraspinatus outlet space. Bigliani and associates discovered and described that variations in acromial size and shape can contribute to impingement. From cadaveric studies, 3 different variations in the morphology of the acromion are described. Type I is flat, type II is curved, and type III is anteriorly hooked. Although the curved configuration is the most common (43% prevalence, compared with 17% for flat and 40% for hooked), the hooked configuration is associated most strongly with rotator cuff pathology.

Other sites of impingement in the supraspinatus outlet space include the coracoacromial ligament, where thickening can occur, and the undersurface of the acromioclavicular joint, where osteophytes can form. Only rarely is the medial coracoid involved. These impingement sites in the supraspinatus outlet are compressed further when the humerus is placed in the forward flexed and internally rotated position, forcing the greater tuberosity of the humerus into the undersurface of the acromion and coracoacromial arch.

Nonoutlet impingement can also occur. The causes may be loss of normal humeral head depression either from a large rotator cuff tear or weakness of the rotator cuff muscles from a C5/C6 neural segmental lesion or a suprascapular mononeuropathy. Another way this may occur is with thickening or hypertrophy of the subacromial bursa and rotator cuff tendons.

PreviousNextSport-Specific Biomechanics

Overuse or repetitive microtrauma sustained in the overhead position may contribute to impingement and rotator cuff tendonitis. Shoulder pain and rotator cuff tendonitis are common in athletes involved in sports requiring repetitive overhead arm motion (eg, swimming, baseball, tennis).

Secondary impingement

Supraspinatus tendonitis is often attributed to impingement, which is seldom mechanical in athletes. Rotator cuff tendonitis in this population may be related to subtle instability and therefore may be secondary to such factors as eccentric overload, muscle imbalance, and glenohumeral instability or labral lesions. This has led to the concept of secondary impingement, which is defined as rotator cuff impingement that occurs secondary to a functional decrease in the supraspinatus outlet space due to underlying instability of the glenohumeral joint.

Secondary impingement may be the most common cause in young athletes who use overhead motions and who frequently place repetitive large stresses on the static and dynamic glenohumeral stabilizers, resulting in microtrauma and attenuation of the glenohumeral ligamentous structures and leading to subclinical glenohumeral instability. Such instability places increased stress on the dynamic stabilizers of the glenohumeral joint, including the rotator cuff tendon. These increased demands may lead to rotator cuff pathology such as partial tearing or tendonitis, and, as the rotator cuff muscles fatigue, the humeral head translates anteriorly and superiorly, impinging on the coracoacromial arch, which leads to rotator cuff inflammation. In these patients, treatment should be directed at the underlying instability.

Glenoid impingement

Recently, the concept of glenoid impingement has been suggested as an explanation for partial-thickness rotator cuff tears in throwing athletes, particularly those tears involving the articular surface of the rotator cuff tendon. Such tears might occur in the presence of instability due to increased tensile stresses on the rotator cuff tendon either from abnormal motion of the glenohumeral joint or from increased forces on the rotator cuff necessary to stabilize the shoulder.

Arthroscopic studies of these patients have noted impingement between the posterior superior edge of the glenoid and the insertion of the rotator cuff tendon with the arm placed in the throwing position, abducted and externally rotated. Lesions are noted along the area of impingement at the posterior aspect of the glenoid labrum and articular surface of the rotator cuff. This concept is believed to occur most commonly in throwing athletes and must be considered when assessing for impingement and rotator cuff tendonitis.

PreviousProceed to Clinical Presentation , Supraspinatus Tendonitis

Read More

Bicipital Tendonitis

Background

Bicipital tendinitis, or biceps tendinitis, is an inflammatory process of the long head of the biceps tendon and is a common cause of shoulder pain due to its position and function.[1, 2, 3, 4, 5] The tendon is exposed on the anterior shoulder as it passes through the humeral bicipital groove and inserts onto the superior aspect of the labrum of the glenohumeral joint. Disorders of the biceps tendon can result from impingement or as an isolated inflammatory injury. Other causes are secondary to compensation for rotator cuff disorders, labral tears, and intra-articular pathology.

For patient education resources, see the Arthritis Center and Sports Injury Center, as well as Tendinitis, Rotator Cuff Injury, and Repetitive Motion Injuries.

NextEpidemiologyFrequencyUnited States

Bicipital tendinitis is frequently diagnosed in association with rotator cuff disease as a component of the impingement syndrome or secondary to intra-articular pathology, such as labral tears.[6]

PreviousNextFunctional Anatomy

As its name implies, the biceps has 2 proximal heads with a common distal insertion onto the radius. The long head of the biceps merges with the short head of the biceps to form the body of the biceps brachii muscle. This muscle is a powerful supinator and flexor of the forearm.

The long head biceps tendon lies in the bicipital groove of the humerus between the greater and lesser tuberosities and angles 90° inward at the upper end of the groove, crossing the humeral head to insert at the upper edge of the glenoid labrum and supraglenoid tubercle. The long head of the biceps tendon helps to stabilize the humeral head, especially during abduction and external rotation.

See the image below.

Biceps muscle and tendons. PreviousNextSport-Specific Biomechanics

Bicipital tendinitis frequently occurs from overuse syndromes of the shoulder,[7] which are fairly common in overhead athletes such as baseball pitchers, swimmers, gymnasts, racquet sport enthusiasts (eg, tennis players), and rowing/kayak athletes.[8, 9, 10, 11] Trauma may occur because of direct injury to the biceps tendon when the arm is passed into excessive abduction and external rotation. This pattern of shoulder injury can also occur in the left shoulder of right-handed golfers. Many overuse injuries coexist with some degree of bicipital tendinitis and rotator cuff tendinitis.

The athletic shoulder differs qualitatively from the biomechanics of the shoulder in daily life because of the higher energies and repetitive motions that are involved in athletic activities. Sports activities that require repetitive overhead motion with inadequate reparative time may cause the biceps tendon to break down.

PreviousProceed to Clinical Presentation , Bicipital Tendonitis

Read More

Hip Tendonitis and Bursitis

Background

Hip overuse injuries such as tendinitis and bursitis occur commonly in active individuals who participate in running, cycling, and cutting sports such as football, hockey, soccer, etc.[1, 2, 3, 4, 5, 6, 7, 8] These injuries can occur after an acute injury, such as an adductor strain from soccer, or present as a chronic pain, such as a hamstring tendinopathy from repetitive activities such as running. Training errors, biomechanical issues, and sudden increases in activity levels are also risk factors. In the adolescent age group, traction injuries such as avulsion fracture and apophysitis can occur and cause difficulties with training and performance.[9, 10]

The investigation into the cause and treatment of hip overuse injuries can often be frustrating for clinicians and patients alike. Many musculoskeletal injuries can cause referred pain into the hip area, but so can intra-abdominal, gynecologic, urologic, and spinal disorders.[1, 3, 4, 5, 6, 7, 8, 11]

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

NextEpidemiologyFrequencyUnited States

Hip overuse syndrome is a relatively common condition, particularly in people who are physically active.

PreviousNextFunctional Anatomy

The hip joint can be imagined as a ball and socket. The ball, called the femoral head, is seated within the acetabulum of the pelvic bone (the socket). Both of these bones are covered by articular cartilage, a lubricating and cushioning layer that helps to prevent damage to the underlying bones. Likewise, the labrum is a cushion of fibrocartilage deep within the socket that helps to aid articulation and provide further cushioning.

The hip joint is subject to strong forces (which can be multiple times the body weight) with all weight-bearing activities, from walking to running, as well as jumping and cutting sports. This is due to the long, lever-arm mechanism of the lower extremity, with the hip joint being the fulcrum. Thus, the hip joint is often the location of degenerative arthritis as people age.

The capsular ligaments of the hip joint, which act like ropes, are formed from thickened portions of the joint capsule, helping to keep the 2 bones together and aid in articulation. These ligaments provide stability and tension to the joint with movement.

Anteriorly, the rectus femoris, iliopsoas, gracilis, and sartorius muscles connect the pelvic bone to the femur and help aid in flexion of the femur, bringing the leg up toward the body. These muscles, along with the rest of the quadriceps muscles, which extend the knee, are the largest and most powerful muscles in the body, responsible for producing large concentric, isometric, and eccentric forces. Because of this, these muscles are subject to traumatic injuries and tears from sudden starts (concentric contraction), stops (eccentric contractions), and direct trauma, as well as overuse injuries from repetitive activities (microtrauma).

Medially, the set of 3 adductor muscles and the pectineus connect the inner aspect of the femur to the front and inferior aspect of the pelvis; contracting these muscles adducts the femur back to midline and across the body (ie, crossing the legs). From the outside, the tensor fasciae latae and biceps femoris (toward the back) aid in abduction, moving the legs outward from the body. Posteriorly, the semitendinous and semimembranous muscles (the hamstrings), the biceps femoris, and the large gluteus maximus extend the leg backward from the body.

The gluteus medius, another posterior muscle of the hip and buttocks, aids in internal rotation and abduction of the thigh. The piriformis, quadratus, and superior and inferior gemelli work in tandem to perform external rotation of the hip.

PreviousNextSport-Specific Biomechanics

All of the previously mentioned muscle groups are subject to increased loads in athletic and recreational activity (see Functional Anatomy). Tendons, which attach muscle directly into bone, are structures that are subject to high tensile strength, meaning they must stretch as the muscles shortens, but they do not provide strength. Inflammation of a tendon from injury or repetitive stress is called tendinitis.

Several tendons are cushioned from the underlying bone by a lubricating and cushioning sac called a bursa. The largest bursa in the hip joint is between the iliopsoas muscle and the pelvic brim and is called the iliopsoas bursa. Between the tensor fasciae latae and gluteus medius muscles and the greater trochanter of the femur, a portion of bone that juts out laterally from the proximal femur, lies the greater trochanteric bursa. Any bursa within the body can be inflamed from repetitive stress of the overlying muscles, direct trauma, or a spreading infection.

The tendinous portion of the muscle has poor blood flow, so injury or stress at the attachment of the tendon onto the bone can lead to degeneration of the area. This degeneration is associated with the disorientation of collagen fibers, increased cellularity, and angiofibroblastic degeneration. Pathology examination of these tendons fails to reveal inflammatory cells or increased blood supply to the area. These "scars" within the tendon are difficult to treat because of decreased blood flow into the injured area.

In the pelvic bones of children, adolescents, and young adults, the tendons attach onto a secondary growing portion of bone. This connection between the larger pelvic bone and smaller secondary growth area is called the apophysis, and in this age group it is the weakest link from the musculature to the bone. Consequently, the apophysis can be the direct source of pain from irritation (apophysitis), or it can be broken apart by a strong force on the tendon and pulled away from the larger pelvic bone (avulsion fracture).

Avulsion fractures around the pelvis occur in prepubertal athletes as the result of an actively contracting muscle encountering abrupt resistance such as a misstep, rapid acceleration, or eccentric movements. The treatment of most smaller avulsion fractures is similar to the treatment of strains of the muscle-tendon unit.

PreviousProceed to Clinical Presentation , Hip Tendonitis and Bursitis

Read More