Clinical Features And Evaluation

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Internal impingement is a pathologic condition typically seen in overhead throwing athletes. Baseball pitchers are most commonly afflicted, although athletes participating in other sports requiring repetitive shoulder abduction and external rotation such as tennis, volleyball, javelin throwing, and swimming are at risk.1-6 Patients typically present with complaints of posterior shoulder pain when the arm is abducted and maximally externally rotated (late cocking and acceleration phases of throwing). Symptoms may be vague and reported by the athlete only as a gradual onset of loss of velocity or control during competition, often known as dead arm syndrome (Box 23-1). Other common complaints are feeling tight and uncomfortable while throwing, along with difficulty warming up.7 The majority of athletes do not recall a single acute event, but many report an acute exacerbation of previous lesser symptoms as the impetus for seeking medical attention. Concomitant labral injury is not uncommon and may be identified by mechanical catching or popping during the follow-through phase of throwing if an unstable lesion is present (superior labrum anterior and posterior, or SLAP). Tennis players often report pain with the overhead serve, but no difficulty with ground strokes. Athletes occasionally acknowledge a recent episode of overuse and should specifically be asked about changes in throwing habits, training, or mechanics prior to the onset of symptoms. Knowing the duration of symptoms, precise anatomic location of pain, and any previous treatment, including periods of rest, is beneficial.

Once the history is completed, a thorough physical examination is carried out as noted in Chapter 16. Specific physical examination testing for internal impingement involves eliciting pain attributed to the infraspinatus tendon and posterior superior labrum. Active range of motion of both shoulders should be carefully measured and documented, along with measures of passive internal rotation and external rotation with the shoulder in abduction and the scapula stabilized in order to mimic the position the arm reaches during the late cocking phase. Most throwers have significantly increased external rotation and concomitant decreased internal rotation in the dominant throwing shoulder due to skeletal and soft-tissue adaptations that develop over time.6,8,9 It is not uncommon for external rotation with the shoulder abducted 90 degrees to reach 130 to 155 degrees, with limited internal rotation in the range of 40 to 55 degrees. However, the total arc of motion (external rotation + internal rotation) should be equal in both shoulders.8,10 Asymmetrical total motion may be caused by pathologic decrease in internal rotation due to posterior capsular contracture, which Burkhart et al11 believe is the primary underlying pathologic process driving this entity. In addition, posterior musculature contrac-

Figure 23-1 Schematic representation of posterosuperior glenoid impingement: The posterior edge of the glenoid and the deep surface of the supraspinatus and infraspinatus are directly in contact with one another. (From Walch G, Boileau P, Noel E, et al: Impingement of the deep surface of the supraspinatus tendon on the posterosuperior glenoid rim: An arthroscopic study. J Shoulder Elbow Surg 1992;1:238-245.)

Rights were not granted to include this figure in electronic media Please refer to the printed publication.

ture due to the eccentric forces driving deceleration can contribute to the loss of motion.

If the patient experiences posterior pain with maximal external rotation at 90 to 110 degrees of abduction, the posterior impingement test is considered positive (Fig. 23-2).3,12,13 Tenderness to palpation is usually located at the infraspinatus insertion on the humeral head, just inferior to the posterolateral acromial margin. This can best be elicited by having the patient lie prone with the arm hanging free over the edge of the examination table, and then palpating the posterior joint line.

Testing for labral pathology should be performed due to the strong association between internal impingement and SLAP lesions. A multitude of tests have been reported with varying degrees of sensitivity and specificity.14 We use several including the active compression (O'Brien's), Meyer's, Mimori's, and Clunk tests, but caution the reader that no single test is adequately sensitive or specific to make the diagnosis with a high degree of certainty.14,15 Resisted testing of the supraspinatus, infraspinatus, and subscapularis should be performed to document any side-to-side differences, although a strength deficit of at least 20% must be present to be appreciated by manual muscle testing.16 Affected athletes often have weakness and pain with external rotation strength testing, particularly at 90 degrees

Box 23-1 Internal Impingement: Signs and Symptoms

• Vague shoulder pain that later localizes posteriorly

• Stiffness and difficulty warming up to throw

• "Dead arm" or decreased throwing velocity, control, and effectiveness

• Pain in late cocking and early acceleration

• Positive posterior impingement sign

• Excessive external rotation

• Mild anterior instability and rotational instability

• Glenohumeral internal rotation deficit without corresponding increase in external rotation of abduction. Stability testing should be performed to assess not only the amount of translation in the glenohumeral joint, but also the endpoint of that translation. It is not uncommon for a thrower to have symmetrical, natural increases in posterior translation in both shoulders; however, most throwers do not have significant inferior translation (negative sulcus sign). Scapular motion should also be assessed by a sitting lift-off test or a wall push-up. Weakened scapular retractors and elevators can contribute to internal impingement by leading to increased compression between the posterior glenoid and humeral structures in the cocking phase.17,18

Figure 23-2 The posterior impingement test is performed with the shoulder abducted 90 to 110 degrees and in maximal external rotation. Posterosuperior shoulder pain in this position indicates a positive test.1923

Figure 23-3 Arthrographic magnetic resonance image demonstrating a SLAP (superior labrum anterior to posterior) lesion. Less well visualized is an articular side partial-thickness rotator cuff tear.

Box 23-2 Internal Impingement: Anatomic Lesions

Figure 23-3 Arthrographic magnetic resonance image demonstrating a SLAP (superior labrum anterior to posterior) lesion. Less well visualized is an articular side partial-thickness rotator cuff tear.

Plain radiographs of the shoulder may show cystic changes at the insertion of the infraspinatus tendon on the humeral head, but are usually unremarkable. Our radiographic series includes four views: a Stryker notch view, an anteroposterior view in external rotation, a West Point view, and a glenoid view (Neer anteroposterior). Radiographs should be obtained to exclude other pathology, especially a posterior glenoid exostosis or Bennett's lesion, which can be a marker of internal impingement.19 Arthrographic magnetic resonance imaging (MRI) is the best diagnostic test to evaluate potential changes associated with internal impingement. Findings on MRI most often include articular-side rotator cuff (infraspinatus) injury, posterior and superior labral injury or detachment, and cystic changes in the humeral head (Fig. 23-3).20 Labral pathology is often subtle and difficult to diagnose accurately by nonarthrographic MRI evaluation. Special MRI sequences, especially in shoulder abduction-external rotation (ABER) views, may be useful to demonstrate common pathology. MRI results must be interpreted with caution and correlated with clinical findings because as many as 40% of asymptomatic throwers will have pathologic changes noted on MRI.21

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Cure Tennis Elbow Without Surgery

Cure Tennis Elbow Without Surgery

Everything you wanted to know about. How To Cure Tennis Elbow. Are you an athlete who suffers from tennis elbow? Contrary to popular opinion, most people who suffer from tennis elbow do not even play tennis. They get this condition, which is a torn tendon in the elbow, from the strain of using the same motions with the arm, repeatedly. If you have tennis elbow, you understand how the pain can disrupt your day.

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