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Objectives and questions: Pectoralis minor hyperactivity is associated with scapular dyskinesis and related shoulder symptoms. Arthroscopic pectoralis minor release (APMR) has been reported as a treatment option. The aim of this study was to evaluate postoperative scapular kinematics and patient-reported outcome measures, including a scapula-inclusive PROM. To our knowledge, this represents the largest reported arthroscopic series of pectoralis minor release with a comprehensive set of documented outcome measures and objective scapular kinematic analysis.

Material and methods: A monocentric APMR registry between 2023 and 2025 was used to prospectively collect PROMs and to analyze postoperative scapular kinematics. Fifty-five patients were included (50 female, follow-up 6–29 months). Ten patients underwent concomitant acromioplasty with rotator cuff repair, while 45 patients underwent isolated APMR. Clinical assessment included the Subjective Shoulder Value (SSV), isometric strength testing, Constant score (all pre– and postoperatively), and postoperatively the Oxford Shoulder Score, EQ-5D-5L, as well as FS ASAP–22 score, a recently developed scapula-inclusive PROM. Responders were defined as patients with a ≥10–point improvement in the Constant score. Postoperative scapular kinematics were assessed using ShowMotion 3D tracking (active shoulder flexion and abduction compared with the contralateral shoulder).

Results: All primary outcome measures improved significantly (mean SSV from 45.2±19.2% to 73.3±20.7%, p<0.001; isometric strength from 9.71±3.92 lbs to 12.89±5.38 lbs, p<0.001; Constant score from 51.2±13.8 to 72.2±17.5, p<0.001). The mean postoperative FS ASAP-22 score was 64.8±21.8% of the maximum achievable score, with a scapula subscore of 63.3±23.3%. FS ASAP-22 correlated strongly with the postoperative Constant score (ρ=0.74, p<0.001). Forty-four patients (80%) were classified as responders. Among non-responders, two patients (4%) showed clinical deterioration, while nine patients (16%) improved below the responder threshold. No major surgical complications were observed. Scapular upward rotation increased during abduction at 30° (95% CI 0.2–2.2, p = 0.023), 60° (95% CI 0.7–4.0, p=0.006), and 90° (95%CI 0.4–4.9, p=0.021), and during flexion at 60° (95% CI 0.3–3.6, p=0.023) and 90° (95% CI 0.5–4.3, p=0.015), with no differences at higher elevation angles. Non-responders more frequently presented with psychological comorbidities (27% vs. 0%), connective tissue disorders (27% vs. 0%), or pain sensitization (45% vs. 9%).

Discussion and conclusions: APMR demonstrates acceptable short-term safety and is associated with meaningful functional improvement and increased scapular upward rotation. Psychosocial comorbidities and connective tissue disorders appear to negatively influence outcomes and should be carefully considered during patient selection and preoperative counseling.