Abstract
Objectives:
The decision to return to sport (RTS) following shoulder stabilization surgery is primarily driven by time since surgery, recovery of upper limb range of motion and the patient’s ability to perform sport-specific activities without any restrictions. However, there is limited and conflicting knowledge about recovery of shoulder function after stabilization surgery, and determinants of the readiness of a patient’s return to sport. The primary objective of this study was to evaluate strength and functional performance in patients at 4 to 6 months following shoulder stabilization surgery prior to their return to sport. We also sought to investigate the association between post-operative rehabilitation and strength, functional performance, and self-reported function and readiness to RTS.
Methods:
A prospective study of patients undergoing shoulder stabilization surgery between 2019 and 2023 for traumatic, anterior glenohumeral dislocation and injury was undertaken. Patients, following consent, were referred for evaluation which consisted of maximal isometric internal and external rotator strength, together with two commonly used functional performance tests the closed kinetic chain upper extremity stability (CKCUES) test and Y balance test-upper quarter (YBT-UQ). Patient-reported surveys including the Western Ontario shoulder instability index (WOSI) and Shoulder Instability Return to Sport Index (SIRSI) were employed to assess perceived function and psychological readiness to RTS, respectively. A categorical scoring tool assessing the frequency, duration and intensity of post-operative rehabilitation was also employed. Paired samples t-tests were performed to assess between-limb differences in strength and functional performance, with Cohens d effect sizes calculated to interpret the magnitude of any differences. Spearman’s correlation coefficients were undertaken to assess the relationship between the intensity of post-operative rehabilitation and strength, functional performance, and the WOSI and SIRSI, while linear regression analyses investigated pertinent patient factors and their ability to predict outcomes in performance-based functional tests.
Results:
Sixty-seven patients (92% male, mean age = 21.4 ± 4.3 years) were evaluated at a mean of 4.4 ± 0.7 months post-surgery. Significant between-limb differences of moderate effect were observed for maximal internal rotator strength (mean difference = 16.3 N; 95% CI: 9.4 to 23.2; d= 0.61, p≤0.001), external rotator strength (mean difference = 16.1 N; 95% CI: 9.8 to 22.4; d= 0.66, p≤0.001) and YBT-QT composite score (mean difference = 0.04; 95% CI: 0.03 to 0.05; d= 0.74, p≤0.001). CKCUES power score was moderately, and significantly correlated with maximal internal (r=0.50, p≤0.001) and external rotator strength (r=0.41, p≤0.001), as was the normalised score of the YBT-UQ of the operated arm (IR, r=0.36, p=0.004; ER r=0.42, p<0.001). YBT-UQ scores of the operated arm were both significantly correlated with the WOSI (r=-0.26, p=0.031) and the SIRSI (r=0.27, p=0.026). The level and intensity of patient reported post-operative rehabilitation was the most significant predictor of performance in the YBT-UQ test (β=0.280, p=0.043).
Conclusions:
This study demonstrates that significant between-limb differences exist in both internal and external rotator strength and functional performance at 4 to 6 months following shoulder stabilization surgery. Functional performance, as measured by the CKCUES and YBT-UQ tests, is moderately correlated with maximal rotator strength. Post-operative rehabilitation intensity emerged as a significant predictor of YBT-UQ performance, underscoring the important role of good, thorough rehabilitation in optimising post-operative physical function and readiness prior to RTS.