Comparison of Pre and Post-Operative Thoracohumeral Kinematics between Single and Multi-Tendon Rotator Cuff Tears

Research Objectives To conduct a biomechanical evaluation of patients with single and multi-tendon rotator cuff tears to elucidate the changes in thoracohumeral joint motion occurring within the first year of repair as compared to the non-injured arm. Design Longitudinal, prospective. Setting Mobility Lab at the University of Wisconsin-Milwaukee. Participants Ten patients with rotator cuff tears stratified into two groups: supraspinatus tear only n=5 (single) and a supraspinatus tear plus at least one other muscle involved n=5 (multi). Mean age for the single tear group: 63.2 (±7.9 years) and multi tear group: 61.4 (±5.9 years). Mean tear size was 1.2 (±0.2 cm) for the single group and 3.0 (±1.4 cm) for the multi. Participants were evaluated pre-operatively (pre-op) and at approximately 3 months and 6 months post-operatively (post-op). Interventions Not applicable. Main Outcome Measures Peak thoracohumeral (TH) joint external rotation. Results When comparing the post-op average peak TH joint external rotation of the surgical arm to the non-injured arm within each group, both had significantly less external rotation of the surgical arm at 3 months post-op, but only the single tear group had significantly less at 6 months post-op (p = 0.00016). When comparing the average peak TH joint external rotation at each visit between groups, the multi tear group had significantly greater external rotation of the surgical arm at the pre-op (p=0.04) and 6 months post-op (p=0.01) visits. Conclusions The multi tear group had significantly higher motion pre-op and 6 months post-op than the single tear group and normalized to the non-injured arm at 6 months. These results suggest pre-op motion plays a key role in rehabilitation progress, potentially more than the number of muscle tears. Author(s) Disclosures The authors have nothing to disclose.