Lesser tuberosity osteotomy and subscapularis tenotomy repair techniques during total shoulder arthroplasty: A meta-analysis of cadaveric studies.

BACKGROUND: Numerous techniques have been used to mobilize and repair the subscapularis tendon during total shoulder arthroplasty. The purpose of this study is to perform a detailed comparison of subscapularis tenotomy and lesser tuberosity osteotomy repairs during total shoulder arthroplasty.

METHODS: Two independent reviewers searched two databases (PubMed and the Cochrane Library) to find cadaveric studies comparing the biomechanical strength of various subscapularis repair techniques following total shoulder arthroplasty. Articles that compared at least two repair techniques with similar biomechanical methods were included.

FINDINGS: An initial literature search resulted in 145 studies. A title and abstract review resulted in five studies which analyzed outcomes of subscapularis tenotomy (total n=29) or lesser tuberosity osteotomy using a single- or dual-row suture technique (total n=46). Load to failure was significantly higher in the lesser tuberosity osteotomy group (M 443, SD 231N) than the tenotomy group (M 350, SD 113N) (p=0.047). Tenotomy (n=19) and lesser tuberosity osteotomy (n=31) had average cyclic displacements of 1.7mm (SD 1.3) and 2.1mm (SD 1.6), respectively (p=0.34). Mode of failure was significantly different between the two groups (p<0.0001), with soft tissue failure accounting for most tenotomy repairs (97%) and bone failure accounting for the majority of lesser tuberosity osteotomy repairs (72%).

INTERPRETATION: Based on current biomechanical data, lesser tuberosity osteotomy is a stronger repair than a subscapularis tenotomy at "time-zero" in terms of load to failure. However, cyclic displacement did not differ statistically between the two techniques.