Comprehensively Evaluate the Function of Shoulder Posterior Instability.

Dear Editor-in-Chief: We appreciated reading the article by Lee et al1 entitled “Nonoperative Management of Posterior Shoulder Instability: What Are the Long-Term Clinical Outcomes?” The main purpose of this study was to compare long-term outcomes after operative versus nonoperative treatment of posterior shoulder instability. We congratulate the authors for their excellent work. However, the study has several shortcomings requiring discussion. The first shortcoming is that the patient-reported outcomes were incomprehensive. Only the degree of pain at the follow-up was assessed in this study. In a review of shoulder-rating scales published in 2010, at least 26 different shoulder outcome scores were available to choose from to track patient outcomes.2 Overall, despite the lack of standardized methodology, the most prevalent functional outcome measure used by investigators is the American Shoulder and Elbow Surgeons (ASES) scoring system. The ASES was developed in 1994 to be a general shoulder functional score that could be widely applied to all patients regardless of the diagnosis. The self-assessment section has 3 domains that includes a single, numeric-based visual analog scale and a 10 question activities of daily living scale.2 The “pain scale” is only one of subcategories of ASES. Therefore, we recommend a more comprehensive assessment could be made in this study. A further shortcoming is that the results of this study are limited to recurrent instability rate and did not include objective physical examinations, such as the posterior load-shift maneuver, the posterior drawer, and jerk test. These deficiencies prevalent among the study lead to difficulties in comparing results between operative and nonoperative treatment. Besides that, return to sport after shoulder anterior instability has been extensively reported in the literature. Zaremski et al3 performed a meta-analysis of 17 studies and found that return to play was 44% for nonoperatively treated patients and 95% for those treated operatively. In this study, 48.6% (18 of 37) patients in the nonoperative group and 60.3% (47 of 78) patients in the operative group participated in a sports.1 However, the authors did not assess the rate of return to sport and recurrent instability based on the type of treatment (nonoperative vs surgical management). Therefore, the proportion of patients returning to their sport or preinjury competition level or the mean time to return to sport or preinjury competition should be assessed at the follow-up. These results are of great significance to the decision making of clinical treatment of posterior shoulder instability. For all of the aforementioned, we firmly believe that the study's weaknesses undermine its conclusions.