Clinical Outcomes and Tendon Healing After Arthroscopic Isolated Subscapularis Tendon Repair: Results at Midterm Follow-up

Background: Few studies have reported clinical outcomes and tendon healing rates after arthroscopic isolated subscapularis (SSC) repair (AISR). Purpose/Hypothesis: The primary purpose of this study was to evaluate clinical outcomes and tendon healing after AISR. It was hypothesized that AISR would result in satisfactory clinical outcomes along with a high rate of tendon healing at the midterm follow-up. The secondary purpose was to assess the influence of tear size and muscle atrophy on SSC tendon healing and patient-reported outcomes. It was hypothesized that both would be negatively correlated with healing but would have no effect on clinical outcomes . Study Design: Case series; Level of evidence, 4. Methods: A retrospective analysis was conducted on prospectively collected data for 77 patients who underwent primary AISR between 2011 and 2021 at a single institution, with a minimum 2-year postoperative follow-up for all patients. Functional outcomes were assessed using the American Shoulder and Elbow Surgeons (ASES) score, the Subjective Shoulder Value (SSV), and the visual analog scale for pain. Repair techniques and concomitant procedures were also collected. SSC tendon healing was evaluated via ultrasound at the final follow-up. Linear regression analysis was performed to determine factors affecting SSC healing. Results: The mean follow-up was 58.1 ± 3.3 months. ASES scores significantly improved from 41.5 to 81.6, and the SSV improved from 38.2 to 80.5 ( P < .01 for both). Among the 40 patients (51.9%) who underwent postoperative ultrasound, 87.5% showed complete tendon healing. There were no significant differences in outcome scores between healed and unhealed tendons. Increased muscle atrophy and larger tears were correlated with failure of SSC healing (β = −0.285 [ P = .015] and β = −0.157 [ P = .045], respectively). Conclusion: Improved clinical outcomes and an overall high rate of tendon healing were seen at the midterm follow-up after AISR. Smaller tear sizes with less muscle atrophy were correlated with improved tendon healing. However, even when the tendon incompletely healed, the procedure improved functional outcomes.