Effects of arthroscopic rotator cuff repair on isokinetic muscle function 6-months following surgery: influence of tear type, tear size and tendon retraction.

BACKGROUND: Rotator cuff tears are a common musculoskeletal condition which can lead to functional limitations and impairments in quality of life. The purpose of the present study was to investigate the effects of arthroscopic repair surgery on isokinetic muscle function before and 6-months after surgery. Additionally, the mediating effects of tear type, tear size and tendon retraction were examined.

METHODS: Data from n = 67 patients (56 ± 9 years) with full-thickness rotator cuff tears were analyzed. Before and 6-months after surgery, isokinetic muscle function in external/internal rotation and abduction/adduction movements was assessed. Further, tear size, tear type (Collin classification) and tendon retraction (Patte classification) were analyzed using magnetic resonance imaging (MRI).

RESULTS: After statistical analysis, a significant increase in limb symmetry index (LSI) of external (p < 0.001), internal rotation (p < 0.01), abduction (p < 0.001) and adduction (p < 0.001) were observed from pre- to post-surgery. The results revealed that tear size and tendon tear type significantly mediated the functional outcome, with no significant effect of tendon retraction.

CONCLUSION: The present findings point towards the notion that the functional outcome following rotator cuff repair was significantly dependent on tear type and tear size but not tendon retraction. Patients with larger sized tears presented pronounced deficits following 6-months indicating that rehabilitation times need to be adjusted accordingly.