Background The inferior glenohumeral ligament (IGHL) plays an important role in maintaining shoulder joint stability. However, no systematic studies on shoulder stability and function of patients with FS after IGHL release exist. This study assessed the functional and clinical outcomes of IGHL release for FS.Methods Forty-seven patients underwent arthroscopic capsule and IGHL release with the same postoperative rehabilitation procedure. Five functional parameters were measured postoperatively at 4, 8, 12 and 28 weeks: the apprehension test result, American Shoulder and Elbow Surgeons Score (ASES), Constant score, visual analog scale (VAS) score and active range of motion (ROM).Results All patients improved in the aforementioned evaluations. At 28 weeks, the ASES, Constant score and VAS score improved from 31.30±6.41 to 92.43±3.89, 30.15±6.85 to 90.71±4.27 and 6.73±0.72 to 0.60±0.74, respectively (p<0.05). Forward flexion (FF) and abduction (ABD) improved from 73.85±14.94 to 166.70±7.23 and from 69.65±12.74 to 165.03±6.36, respectively (p<0.05). External rotation (ER) and internal rotation (IR) also significantly improved. In total, 95% of the patients were able to perform full elevation, and 97.5% of the patients could place the dorsum of their hands between their shoulder blades. All patients had negative apprehension tests, and no dislocations occurred. No other serious postoperative complications were observed.Conclusions Arthroscopic capsule and IGHL release was effective and could improve the active ROM and relieve pain in patients with FS. This surgical procedure did not cause instability or dislocations in the shoulder joint.