Background: Children with unresolved brachial plexus palsy frequently develop a disabling internal rotation contracture of the shoulder. Several surgical options, including soft tissue procedures such as muscle releases and/or transfers, and bone operations such as humeral osteotomy are available to correct this deformity.
Objective: To evaluate the results obtained with arthroscopic release of subscapularis tendon in treatment of adduction internal rotation contracture of the shoulder joint secondary to obstetric brachial plexus paralysis.
Patients and methods: This was a prospective study which had been conducted at Orthopedic Surgery Department, Al-Azhar University Hospitals (Al-Hussein and Sayed Galal Hospitals),  the study included 10 patients with shoulder contracture secondary to obstetric brachial plexus palsy,from January 2020 to August 2021, Follow up, scheduled at immediately after operation, 2 weeks, 4 weeks, 2 months and 6 months post operatively.
Result: The mean passive external rotation (ER) was 72.3° (40° - 90°) and the mean active ER was 72.9° (20° - 90°) at the end of follow up. The mean global Mallet score improved from 11.6 ± 1.07 SD (range from 10 to 13) preoperatively to 17.5 ± 2.22 SD (from 13 to 20) postoperatively. There were statistically significant differences between passive ER and Mallet score pre and post operatively. Passive ER, active ER and mallet score were higher among group with partial injury than complete injury but with no significant differences. There have been no intraoperative or postoperative complications.
Conclusion: Isolated subscapularis tendon release was an easy, efficient and safe procedure in young children with shoulder adduction–internal rotation contracture due to obstetric brachial plexus palsy. It improved abduction and external rotation, but has no statistically significant influence on internal rotation.