Summary

The progression to glenohumeral arthritis after anterior stabilization surgery occurred in 8% of a young and high demand patient population.

Abstract

Introduction

Shoulder instability is a common cause of shoulder pain and dysfunction, particularly in young and active individuals. While arthroscopic stabilization for anterior glenohumeral instability has shown excellent success preventing recurrent instability and allowing return to sport, eventual progression to glenohumeral arthritis remains a concern in these patients. Older age, higher number of anchors used, and greater capsular shrinkage have been previously established as risk factors for progression to glenohumeral arthritis in patients who underwent arthroscopic anterior stabilization. However, the rate of and risk factors for arthritis post-surgery in young and high demand populations have not been well characterized and may be important in guiding decision making when treating the young patient with first time shoulder instability. The purpose of this study was to evaluate the rate of progression to glenohumeral arthritis and identify potential risk factors after arthroscopic anterior stabilization in a young and high demand population.

Methods

This study included 287 active duty servicemembers identified in the Military Heath System (MHS) with anterior shoulder instability who underwent primary arthroscopic surgical stabilization and had postoperative imaging or medical records available over a 12-year period between January 2004 and September 2016. All procedures were performed at a single institution. Patients were excluded if they had previously undergone a stabilization procedure on the shoulder of interest, if no preoperative imaging was available, if they did not have a minimum follow up of four years, or if operative information regarding the number of anchors used was unavailable. Presence of arthritis (yes/no) was defined over follow up using radiographic parameters as described by Samielson and Prieto identifying patients with at least mild arthritis. Kaplan-Meier survival curves were estimated for development of arthritis and compared by patient characteristics using log-rank tests. Cox proportional hazard models were used to calculate Hazard Ratios (HR) with 95% confidence intervals (95% CI) associated with patient characteristics as predictors of the development of glenohumeral arthritis, adjusted for confounders identified in univariate analyses.

Results

Among the 287 patients with anterior shoulder instability requiring surgical fixation, 8% (23/287) developed glenohumeral arthritis. The mean age of all patients was 22.7 years (SD 5.26). The median time to diagnosis of arthritis was 8 years and the median follow-up time was 9 years (IQR 6;11). Kaplan-Meier curves showed differences in time to arthritis among patient groups stratified by age, index surgery anchor number, and revision (yes/no), (log rank p for each <0.05). Adjusted for potential confounders in a multivariable Cox regression model, risk factors for the development of glenohumeral arthritis included age (HR=1.85, 95% CI, 1.34 to 2.55), index surgery anchor number (HR=1.54, 95% CI, 1.11 to 2.14), and revision before diagnosis with glenohumeral arthritis (HR=2.83, 95% CI=1.15 to 6.95).

Conclusion

This is the largest series looking at glenohumeral arthritis after arthroscopic surgical stabilization for anterior shoulder instability. The progression to glenohumeral arthritis after anterior stabilization surgery occurred in 8% of a young and high demand patient population. Patient age and number of anchors used are statistically significant risk factors for progression to arthritis. Additionally, revision surgery was found to be a risk factor, which has not been previously reported in the literature. These results demonstrate decreased rates of arthritis when compared to older populations, which may advocate for early surgical intervention for a young patient presenting with shoulder instability.