Long-term subscapularis strength assessment after Bristow-Latarjet procedure: isometric study

Background: The subscapularis is the strongest rotator cuff muscle. Bristow-Latarjet procedure may impair subscapularis function. The aim of the study is to describe the difference in isometric subscapularis (SSC) strength after L-shape tenotomy versus muscle split in patients who underwent to Bristow-Latarjet procedure. Materials and methods: From 2000 to 2006, we enrolled 376 patients for Bristow-Latarjet procedures. We identified 2 groups according to the subscapularis approach. Group A included 264 subjects with subscapularis L shape tenotomy; group B included 112 subjects with subscapularis muscle split. The subscapularis function was assessed with lift-off and belly-press tests. Isometric strength of rotator cuff muscle was assessed at an average follow-up of 45 months in group A and 42 months in group B, recording the maximum isometric peak torque (PT) (N), maximum isometric couple (Nm), relative strength index (N/Kg), strength, couple and external/internal rotator ratio. Constant and Rowe were used as scores. Results: Subscapularis assessment in the overall population showed 33 cases (8.8%) with a positive Liftoff test and 30 cases (8%) with a positive belly-press test. Rowe and Constant scores increased in both groups (P < .01). The mean PT in group A was lower of 24,8 Nw than group B (P < .01); similarly, the max PT values of group A were lower of 26.1 Nw than group B (P < .01). Conclusion: L-shaped tenotomy in Bristow-Latarjet procedure has a weakening effect on the subscapularis and for these reasons we strongly recommend the muscle split approach for an optimal subscapularis function recovery. Level of evidence: Level III, Retrospective Case Control Study, Treatment Study. (C) 2012 Journal of Shoulder and Elbow Surgery Board of Trustees.