Arthroscopic management of shoulder instabilities: anterior, posterior, and multidirectional

Arthroscopy is considered a relatively new technique for the surgical repair of an unstable shoulder. Shoulder arthroscopy has grown in popularity and is considered the gold standard for treating carefully selected patients. Despite its increasing popularity, the procedure has a significant learning curve and has resulted in early higher recurrence rates when compared with patients treated with open techniques. With the addition of newer instrumentation, the refinement of techniques, and additional capsular plication and tensioning, outcomes for patients treated with shoulder arthroscopy should continue to improve. A major distinguishing feature in selecting appropriate candidates for shoulder arthroscopy is whether there have been significant bone changes resulting from dislocation recurrence. Recurrent anterior dislocation may create an anterior glenoid rim fracture, erosion loss from multiple recurrences, and an impression defect on the posterior aspect of the humeral head. The loss of contact area between the "ball and cup" may compromise the results of techniques that restore the anatomic restraints of soft tissues. Early intervention is becoming recognized as an important factor in patient selection for arthroscopic treatment. Imaging studies after traumatic injuries include radiographs, CT scans, possible articular contrast studies, and MRIs. These studies can identify and quantify rim fractures and the remaining articular contact in patients with recurrent subluxations, allowing for earlier appropriate intervention. Patients with significant bone loss may be best treated with an open procedure that allows grafting of the deficiency. Arthroscopic techniques to repair fractures or graft deficiencies continue to evolve. Rim fractures can be anatomically repaired with a suture anchor technique when recognized early. Rim erosion from chronic recurrent dislocations may require a combination of soft-tissue reattachment and coracoid grafting. Humeral head defects may require either soft-tissue or bone grafting to avoid engagement with the anterior edge of the glenoid. These techniques require arthroscopic skill and experience and are currently being performed as open procedures. In the future, it is likely that arthroscopy will be involved in the entire spectrum of treatment for shoulder instability.