BACKGROUND: The indications for glenohumeral arthrodesis are severe lesions of the supra-clavicular brachial plexus. This is a demanding surgery with numerous complications. To reduce morbidity, a few rare arthroscopic techniques have been developed. We compared arthroscopic shoulder arthrodesis with open arthrodesis. Our hypothesis is that the results of arthroscopic arthrodesis would be at least as good as open arthrodesis in terms of strength and mobility, and better in terms of complications. METHODS: Sixteen patients underwent arthrodesis for sequelae of complete brachial plexus palsy between 2008 and 2022. The procedures were performed in our university hospital by experienced surgeons. Six patients underwent open arthrodesis, and 10 arthroscopically. Data were collected retrospectively. A clinical assessment was carried out preoperative and monthly until bone fusion. Clinical examination included measurement of flexion, abduction and rotation amplitudes. Strength was assessed. Secondary endpoints included pain assessment, operative time, American Shoulder and Elbow Surgeons index, Disabilities of the Arm, Shoulder and Hand score and Simple Shoulder Test. Radiographs were analyzed at each consultation until bone fusion was acquired. RESULTS: The average age of the patients was 28 years. Mean follow-up time after arthrodesis was 49.38 months. There was no statistically significant difference between the two groups on preoperative data. The vast majority of brachial plexus palsies were due to road traffic accidents. Patients underwent arthrodesis an average of 29 months after the accident. There was a statistically significant difference (p = 0.034) in the postoperative complication rate in favor of the arthroscopic group. There was no significant difference in mobility or strength. There were no significant differences in pain levels or scores, either pre- or postoperatively. CONCLUSION: The results of arthroscopic shoulder arthrodesis are at least as good as open arthrodesis in terms of strength and mobility, and better in terms of complications. The most frequent complications are pseudarthrodesis, humeral fractures, infection and pain. It would be interesting to carry out a multicenter, prospective study to confirm our results.