IMPORTANCE:
Repair of the subscapularis can be effective in the setting of reverse total shoulder arthroplasty (rTSA). However, there has yet to be a consensus on an optimal repair technique.

OBJECTIVES:
The purpose of this systematic review is to consolidate current high-quality studies comparing outcomes after rTSA with different subscapularis repair techniques.

EVIDENCE REVIEW:
A comprehensive literature review was conducted according to the preferred reporting items for systematic reviews and meta-Analyses using the PubMed, Embase, Scopus and Cochrane databases for original, English-language studies observing outcomes of rTSA after subscapularis repair published between January 1, 2000 and December 31, 2020. Subscapularis management techniques were repair to (1) tendon (tendon-tendon), (2) prosthetic stem, (3) lesser tuberosity (bone tunnels) or (4) a subscapularis-preserving approach (intact). The repair technique was recorded for included studies, and clinical and functional subjective scores were extracted from text, tables and figures. Forest plots were created to allow for qualitative comparison of the outcomes of interest between subscapularis repair techniques.

FINDINGS:
Seven comprehensive studies were identified, which included 367 patients. The mean age of patient at the time of surgery was 71.1 ± 2.8 years (range = 47-87 years). Overall, 259 patients underwent tendon-tendon repair, 48 patients underwent repair to prosthetic stem, 40 patients underwent repair with bone tunnels and 20 patients' subscapularis remained intact. Significant improvement was seen in most studies for Single Assessment Numeric Evaluation (range, Δ 42.6-Δ 46.0 out of 3), American Shoulder and Elbow Surgeons (range, Δ44.2-Δ43.6 out of 3) and Visual Analogue Scale pain scores (range Δ 4.2-Δ 6 out of 5). Active forward elevation (range Δ 40.4°-Δ 57.3° out of 4) and active external rotation (range Δ 2.9°-Δ 16.0° out of 4) significantly improved, but forward elevation varied by nearly 17° (Δ16.94°), while external rotation varied by 13° (Δ13.16°) among repair techniques. Complications were reported in only one study, which used a tendon-tendon technique.

CONCLUSIONS AND RELEVANCE:
This study summarizes the current evidence regarding subscapularis repair techniques after rTSA including functional and subjective clinical outcome scores. Several different subscapularis repair techniques during rTSA appear to lend to sufficient improvement in clinical and subjective outcomes. This information can help guide future studies in this area and highlights the need for high quality studies comparing different subscapularis repair techniques.

LEVEL OF EVIDENCE:
III.





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