Return to Sport as Outcome Measure for Shoulder Instability: Surprising Findings in Non-Operative Management in a High School Athlete Population

OBJECTIVES: Recurrence rates have traditionally been used as a proxy for “failure” when comparing conservatively vs. operatively managed patients with anterior shoulder instability. Return to sport has been evaluated as an outcome proxy after surgical intervention, but no study has compared conservative vs. operative management using sustained return to sport as the main outcome measure. The purpose of this study was to compare the results between conservatively and operatively treated patients as to their ability to return a patient to uninterrupted sport in a subsequent season after an anterior instability event. METHODS: We identified and followed 179 scholastic athletes who were treated for a confirmed diagnosis of anterior shoulder instability. 97 were treated initially with conservative management, and 32 were managed surgically. Patients were excluded if they did not have remaining eligibility to play a subsequent season of athletics (high school seniors), or if they were treated with benign neglect (neither conservative nor operative treatment). “Ultimate success” was defined as return and completion of the subsequent season without time loss due to any shoulder related diagnosis. We substratified by age, sport, and type of instability event (subluxation vs. dislocation) using ANOVA and binary logistic regression. RESULTS: In the conservatively managed group, 85% met the definition of ultimate success by returning to play a subsequent season of scholastic athletics in the same sport without any time loss due to a shoulder condition. In the surgical group, 72% were able to achieve this status (p<0.05). Age did not differ between the two groups. Patients were 5x less likely to return to sport if they had sustained a dislocation requiring reduction compared to a subluxation confirmed as an anterior instability event (OR: 4.96, 95%CI= 1.2-9.6). CONCLUSION: Patients who were treated conservatively for an anterior shoulder instability event were far more likely to have a “successful” outcome than published results if the definition of outcome is changed from no recurrence to completion of a subsequent season in their same sport. Patients sustaining a subluxation were nearly uniformly successful in doing so. While surgical success using this definition was quite lower, there was likely a selection bias in the decision making process due to bone loss, surgeon preference or other factor. Nevertheless, this data would suggest that if a patient’s goal is to return to the same level of sport and “next season”, conservative management is highly effective. Further study to determine whether these results hold out with longer term follow up are warranted, but the routine fixation of the first time dislocator based on better outcomes, is called into question depending on what one’s definition of success is.