An appreciation of posterior instability of the shoulder.

Fortunately, posterior instability of the shoulder is a relatively uncommon occurrence in the athlete. Acute traumatic posterior dislocations can be readily managed by conservative measures. Recurrent posterior subluxation, however, represents a more challenging problem for the orthopedic surgeon. As has been discussed, most patients with this disorder respond to nonsurgical treatment including physical therapy and modification of the offending activities. Should these modalities fail, operative treatment may be necessary. Careful assessment of the patient to rule out the associated presence of excessive ligamentous laxity or a voluntary component to the instability is mandatory. Pain is clearly the principal indicator for surgical treatment. Painless subluxation, either voluntary or involuntary, should first be treated conservatively. The surgical options discussed in this article range from simple soft-tissue repair to more complex osteotomies with combined capsular plication. It is important that the procedure be appropriate to the pathology. We do not believe that one technique alone can address all variants of posterior instability. Most instances of recurrent posterior subluxation represent unidirectional instability in patients with otherwise normal bony morphology. In these patients, a posterior capsulorrhaphy combined with appropriate immobilization should be effective. In select instances, when either excessive glenoid retroversion or deficiency is encountered, a glenoid osteotomy and posterior capsulorrhaphy have proved successful. This technique, more than any other, carries a number of potential technical pitfalls and should be employed cautiously. Multidirectional posterior instability, now a well-recognized entity, requires a different surgical approach--the capsular shift. Designed to address the inferior redundancy, as well as posterior laxity, this procedure is applicable to the multidirectional posterior subluxator. In conclusion, posterior instability of the athlete's shoulder is an increasingly recognized entity. Most instances are amenable to nonsurgical care. Should surgical treatment be necessary, optimal results may be achieved by careful attention to patient assessment, instability categorization, determination of the presence of ligamentous laxity, and appropriate surgical technique.