How should I fixate the subscapularis in total shoulder arthroplasty? A systematic review of pertinent subscapularis repair biomechanics

Abstract

Background The present study aimed to review the biomechanical outcomes of subscapularis repair techniques during total shoulder arthroplasty (TSA) to assist in clinical decision making. Methods A systematic review of multiple databases was performed by searching PubMed, Scopus, Cochrane Library, Google Scholar, and all databases within EBSCOhost to find biomechanical studies of subscapularis repair techniques in cadaveric models of TSA. Results Nine studies met the inclusion criteria. In the majority of studies, lesser tuberosity osteotomy (LTO) techniques had greater load to failure and less cyclic displacement compared to subscapularis tenotomy or peel methods. LTO repairs with sutures wrapped around the humeral stem demonstrated superior biomechanical outcomes compared to techniques using only a tension band. In terms of load to failure, the strongest repair of any study was a dual-row fleck LTO using four sutures wrapped around the stem. Conclusions Several cadaveric studies have shown superior biomechanical outcomes with LTO techniques compared to tenotomy. In the majority of studies, the strongest subscapularis repair technique in terms of biomechanical outcomes is a compression LTO. Using three or more sutures wrapped around the implant and the addition of a tension suture may increase the biomechanical strength of the LTO repair.