The clinical presentation is consistent with lateral epicondylitis, which is caused from pathologic changes at the origin of the extensor carpi radialis brevis (ECRB).
Physical exam findings consistent with lateral epicondylitis include tenderness over the lateral epicondyle at the origin of the ECRB, and pain that is reproduced with gripping, resisted long finger extension, resisted wrist extension while the elbow is fully extended, and maximum passive wrist flexion. This should be distinguished with the pain with resisted supination with the arm and wrist in extension characteristically seen with radial tunnel syndrome.
Nirschl et al looked at their surgical cohort of patients with lateral epidondylitis that were treated with surgery. They found the lesion that was consistently identified at surgery was immature fibroblastic and vascular infiltration of the origin of the extensor carpi radialis brevis (ECRB). There was an over-all improvement rate of per cent, and per cent of the patients returned to full activity including rigorous sports following surgical treatment.
Morris et al used indwelling EMG to look at muscle activity about the elbow during tennis strokes in nine professional and collegiate level players. They concluded the predominant activity of the wrist extensors in all strokes may be one explanation for predisposition to injury.
Tendonitis, more properly termed tendinosis, results from acute or chronic stress of the rotator cuff tendons. Rotator cuff impingement results from repeated irritation of the rotator cuff beneath the acromial arch. 20 Repetitive overhead reaching and weight training are frequent precipitants of rotator cuff tendinosis and impingement. Rotator cuff tendinosis is diagnosed by eliciting pain or weakness with stress testing of the rotator cuff muscles. There are two common tests used for diagnosis of impingement. The Hawkins' test elicits pain with the shoulder passively flexed to 90 degrees and internally rotated. 21 The Neer's test elicits pain with passive abduction of the shoulder to 180 degrees. 22 Radiographs, if obtained, may show calcific deposits in the subacromial space or at the insertion of the supraspinatus tendon to the greater tuberosity. In cases of impingement, curvature of the acromion process may be seen.
The humerus, glenoid, scapula, acromion, clavicle and surrounding soft tissues make up the shoulder. There are three significant articulations: the sternoclavicular joint, the acromioclavicular joint and the glenohumeral joint. The glenohumeral joint is the most commonly dislocated major joint in the body.
Ligaments and surrounding musculature, including the rotator cuff muscles, contribute to shoulder joint stability. The rotator cuff is composed of the four muscles: supraspinatus, infraspinatus, teres minor and subscapularis that interlock to function as one unit. These muscles help with internal and external rotation of the shoulder and importantly depress the humeral head against the glenoid as the arm is elevated. The tendons join together to form one tendon, the rotator cuff tendon. This passes through the subacromial space. The subacromial bursa, which has a large number of pain sensors, fills the space between the acromion and the rotator cuff tendon. [ 1 ]