RECURRENT ANTERIOR SHOULDER INSTABILITY

Dear Editor,

Hill-Sachs lesion or posterolateral indentation fracture of the humeral head is caused by compression of the humeral head during dislocation and is pathognomonic for Glenohumeral instability [1]. Here I am reporting 2 cases of anterior shoulder instability with Hill-Sachs lesion, one of a recurrent anterior subluxation and other recurrent anterior dislocation.

First patient was a 24 year old services wrestler who was member of the national team. He reported with complaints of pain in the right shoulder, numbness in the right arm following throwing movements and feeling of something slipping inside the shoulder when arm got into a particular position. Patient had sustained an injury to the right shoulder during a wrestling bout two years ago and thereafter continued to be symptomatic on resumption of wrestling following a period of rest. Patient continued to be treated with NSAIDs and intermittent rest in spite of deterioration in sports performance and recurrence of symptoms. Following complaints of numbness in the arm, patient was evaluated for cervical spondylosis. However, cervical radiograph was reported to be normal. Positive findings on physical examination included, loss of external rotation in the abducted position and positive anterior apprehension manoeuvre and stress testing in supine position. On radiographic evaluation with an instability series, the West Point modified axillary view (Fig-1) and Stryker notch view demonstrated the Hill-Sachs lesion. Despite classical symptoms and examination findings, diagnosis of recurrent anterior shoulder subluxation was never entertained.

Fig. 1.

West Point modified axillary radiograph performed on patient with recurrent anterior subluxation. Postero-lateral portion of the humeral lead (arrow) has a Hill-Sachs deformity

Second patient was a 33 year old dental officer who had represented Karnataka schools in the National Basketball championship. Between 1995 to 2000, patient suffered several episodes of injury to right shoulder during games and on two occasions had anterior shoulder dislocation. (?Acute subluxation or dislocation with spontaneous relocation on other occasions). Patient was treated with NSAIDs and rest ranging from six weeks with no attempt at muscle rehabilitation programmes. On radiographic evaluation, all three views in the instability series i.e. AP in internal rotation, modified West Point axillary view and Stryker notch view (Fig-2) showed Hill-Sachs lesion.

Fig. 2.

Stryker notch radiograph performed on patient with recurrent anterior dislocation. Postero-lateral portion of the humeral head (arrow) has a Hill-Sachs deformity.

Recurring Glenohumeral instability is the most common complication of Glenohumeral dislocation as well as acute traumatic subluxation. The risk of recurring dislocation depends on the patient's age at the time of initial dislocation. The re-dislocation rate in patients younger than 20 years is greater than 90%, whereas, after the age of 40, the rate falls below 25% and after the age of 70, it is extremely low [2]. Because of this risk, two potentially important elements of post reduction treatment are protection and muscle rehabilitation. Several authors have suggested that Hill-Sachs lesion plays a role in initiating instability by engaging the anterior lip of the Glenoid [1].

Through this letter I intend to highlight the fact that the basic principles of post reduction treatment i.e. protection and muscle rehabilitation were ignored in both the cases, thus predisposing them to recurrent instability, and also to suggest the possible role of Hill-Sachs lesion in recurrent instability. A proper rehabilitation program and early identification of Hill-Sachs lesion and consideration of surgical treatment of this defect, in the event of failure of conservative treatment, in the form of filling the defect with bone graft or with infraspinatus tendon or rotational osteotomy of the humerus [3], could have enabled these patients to lead a normal active life style. Some authors however feel that presence of Hill Sachs lesion or its size should not be of concern if anterior soft tissue repair is performed adequately [4].