Open Antegrade Muscle Advancement Reduces Retear Rates Compared to Arthroscopic Repair With Intra‐articular Release in Subscapularis Tears With Advanced Fatty Infiltration

PURPOSE: To compare arthroscopic repair without muscle advancement and open repair with muscle advancement in subscapularis tendon tears with fatty infiltration of Goutallier grade III or IV. METHODS: This study retrospectively investigated patients with subscapularis tears and advanced fatty infiltration of Goutallier grade III or IV between March 2009 and October 2022. Inclusion criteria were pre- and postoperative radiologic evaluation and a minimum of 2-year follow-up. Exclusion criteria included partial repair, double-row suture bridge repair, and advanced glenohumeral osteoarthritis. Patients who underwent arthroscopic subscapularis repair were compared with those who underwent open subscapularis repair with antegrade muscle advancement based on clinical scores (visual analog scale pain score, subjective shoulder value, American Shoulder and Elbow Surgeons shoulder score, and the University of California, Los Angeles shoulder score), range of motion (forward flexion, external and internal rotation), internal rotation strength (modified belly-press test), and retear rate assessed by magnetic resonance arthrography. A subgroup analysis was performed in patients with isolated subscapularis tears, comparing clinical scores and retear rates between the two groups. Continuous variables were compared using t-tests, and categorical variables were compared using chi-square or Fisher's exact tests; Welch's t-test was used for subgroup analyses. RESULTS: The study included 170 patients; 112 patients underwent arthroscopic repair and 58 patients underwent open repair. Baseline characteristics were not different between the groups. The clinical scores did not differ between the groups preoperatively or at 2 years postoperatively. The proportion of patients achieving the minimal clinically important difference for American Shoulder and Elbow Surgeons was similar between groups (91.4% open vs. 88.4% arthroscopic, P = .549). Patient acceptable symptom state achievement did not differ significantly (72.4% open vs. 62.5% arthroscopic, P = .196). The modified belly-press test score and the range of motion for internal rotation were both significantly better in the open repair group compared to the arthroscopic repair group at 2 years after surgery (P = .011 and P = .021, respectively), whereas no difference was observed preoperatively. The retear rate was lower for open repair than for arthroscopic repair (51.7% vs. 76.8%, respectively; P < .001). In the subgroup of isolated subscapularis tears (n = 49; 33 arthroscopic and 16 open repairs), the clinical scores did not differ between the groups preoperatively or at 2 years postoperatively. The modified belly-press test score and the range of motion for internal rotation were both significantly better in the open repair group (P < .001 and P = .007, respectively). The retear rate was lower with open repair than with arthroscopic repair (37.5% vs. 75.8%, P = .009). CONCLUSIONS: For subscapularis tendon tears with advanced fatty infiltration, open repair with antegrade muscle advancement may be a superior alternative to arthroscopic repair without muscle advancement, potentially resulting in lower retear rates and improved clinical outcomes. However, patient-reported outcomes did not significantly differ between the 2 approaches. LEVEL OF EVIDENCE: Level III, retrospective comparative study.