Operative versus nonoperative treatment after primary traumatic anterior glenohumeral dislocation

Bony Versus Soft Tissue Reconstruction for Anterior Shoulder Instability: An Expected Value Decision Analysis

Background:

One complication of anteroinferior glenohumeral shoulder dislocation is a critical bone defect that requires surgical repair to prevent recurrent instability. However, controversy exists regarding the surgical management because both open and arthroscopic surgeries have respective advantages and disadvantages. Moreover, it is difficult to determine the patient’s preferred treatment, as factors that influence treatment choice include recurrence rates, morbidity of the procedures, and patient preferences.

Hypothesis:

Patients who have a higher probability of recurrent instability after arthroscopic surgery will select open surgery whereas patients with a lower probability of recurrent instability after arthroscopic surgery will favor arthroscopy.

Study Design:

Economic and decision analysis; Level of evidence, 2.

Methods:

A decision tree was constructed to model each hypothetical outcome after open or arthroscopic surgery for glenohumeral instability in patients with bone defects. A literature review was performed to determine the probability of occurrence for each node while utility values for each outcome were obtained via patient-administered surveys given to 50 patients without prior history of shoulder injury or dislocation. Fold-back analysis was then performed to show the optimal treatment strategy. Finally, sensitivity analysis established the thresholds at which open treatment becomes the optimal treatment.

Results:

The ultimate expected value—the objective evaluation of all potential outcomes after choosing either open or arthroscopic surgery—was found to be greater for arthroscopic surgery than for open surgery (87.17 vs 81.64), indicating it to be the preferred treatment. Results of sensitivity analysis indicated that open surgery becomes the preferred treatment when probability of recurrence after arthroscopic treatment is ≥23.8%, although varying the utility, defined as an aggregate patient preference for a particular outcome, has no effect on the model. When the rate of no complication after open surgery is 97.6%, open surgery becomes the patient’s preferred treatment.

Conclusion:

Arthroscopic surgery is an acceptable treatment if recurrent instability occurs consistently at ≤23.8%. This has important implications given the technical difficulty of successfully performing arthroscopic fixation to resolve recurrent anteroinferior glenohumeral dislocations associated with critical osseous defects. However, due to a lack of clinical outcomes studies, more research is needed to better predict the optimal operative treatment.

Anterior shoulder dislocation increases the propensity for recurrence: a cadaveric study of the number of dislocations and type of capsulolabral lesion

BACKGROUND

The number of anterior shoulder dislocations that predispose to recurrence is unknown; some clinicians recommend surgical repair after the initial episode and others after multiple recurrences. The purpose of this study was to quantify the forces during successive anterior dislocations of cadaveric shoulders and to inspect the capsule and labrum afterwards, in order to assess the propensity for recurrence.

MATERIALS AND METHODS

Twenty-two human cadaveric shoulders were tested using a custom cadaveric shoulder dislocation device with simulated muscle loading. Each was positioned in the apprehension position and the humerus was moved in horizontal abduction until the shoulder dislocated. The joint reaction force was measured, as was the force that developed passively in the pectoralis major muscle. Following 3 successive dislocations, each was inspected for anterior capsulolabral lesions.

RESULTS

There was a significant decrease in force after the second dislocation. In 11, there was no labral avulsion and a significant decrease in force after the first dislocation. In the other 11, there was a labral avulsion and a significant decrease in force after the second dislocation.

CONCLUSION

Two successive anterior shoulder dislocations may increase propensity for recurrence; but this is influenced by the type of capsulolabral lesion that occurs. No labral avulsion, likely a result of capsular stretching, may be a worse prognostic finding than labral avulsion after the initial episode.