The Subscapularis Healing Index: A New Scoring System for Predicting Subscapularis Healing After Arthroscopic Repair

Background: Previous research has emphasized the effect of prognostic factors on arthroscopic rotator cuff repair (ARCR) success, but a specific focus on subscapularis (SSC) tendon repair healing is lacking. Purpose: To identify prognostic factors for SSC healing after ARCR and develop the Subscapularis Healing Index (SSC-HI) by incorporating these factors. Study Design: Case-control study; Level of evidence, 3. Methods: This was a retrospective study using prospectively maintained data collected from patients with isolated or combined SSC tears who underwent ARCR between 2011 and 2021 at a single institution with a minimum 2-year follow-up. Functional outcomes were assessed using the American Shoulder and Elbow Surgeons (ASES) score, Subjective Shoulder Value (SSV), and visual analog scale (VAS) pain scale. SSC tendon healing was evaluated via ultrasound at the final follow-up. Multivariate logistic regression analysis was performed to determine the factors affecting SSC healing, and based on these factors, the SSC-HI, which ranges from 0 to 15 points, was developed using odds ratios (ORs). Results: Among 1018 ARCR patients, 931 met the inclusion criteria; 279 returned voluntarily for postoperative SSC ultrasound assessment. The overall healing failure rate was 10.8% (30/279). Risk factors for healing failure included female sex ( P = .008; OR, 3.119), body mass index (BMI) ≥30 ( P = .053; OR, 2.323), supraspinatus fatty infiltration ≥3 ( P = .033; OR, 3.211), lower SSC fatty infiltration ≥2 ( P = .037; OR, 3.608), and Lafosse classification ≥3 ( P = .007; OR, 3.224). A 15-point scoring system comprised the following: 3 points for female sex, 2 points for BMI ≥30, 3 points for supraspinatus fatty infiltration ≥3, 4 points for lower SSC fatty infiltration ≥2, and 3 points for Lafosse classification ≥3. Patients with ≤4 points had a 4% healing failure rate, while those with ≥9 points had a 55% rate of healing failure. Patients with a healed SSC reported significantly higher ASES (healed SSC: ΔASES, 44.7; unhealed SSC: ΔASES, 29; P < .01) and SSV (healed SSC: ΔSSV, 52.9; unhealed SSC: ΔSSV, 27.5; P < .01) and lower VAS (healed SSC: ΔVAS, –4.2; unhealed SSC: ΔVAS, –3; P < .01) scores compared with those with an unhealed SSC. Conclusion: The SSC-HI scoring system integrates clinical and radiological factors to predict SSC healing after surgical repair. Successful SSC healing was found to be associated with enhanced functional outcomes, underscoring the clinical relevance of SSC healing prediction in the management of these tears.