Incidence of Axillary Nerve Injury After Arthroscopic Shoulder Stabilization.

PURPOSE

To investigate the incidence of axillary nerve palsy after arthroscopic shoulder stabilization and to measure the distance between the nerve and capsule in shoulders with a capsular lesion.

METHODS

This retrospective study included 2,027 shoulders (1,909 patients; 1,433 male and 476 female patients; mean age, 32 years [age range, 13-81 years]) subjected to arthroscopic soft-tissue stabilization for recurrent shoulder instability from 2005 to 2017. The exclusion criteria were bone grafting or transfer and preoperative axillary nerve symptoms. We retrospectively reviewed patient records and investigated the incidence and clinical features of axillary nerve palsy. We measured the closest distance between the axillary nerve and capsule on preoperative magnetic resonance images.

RESULTS

Postoperative axillary nerve palsy occurred in 4 shoulders (0.2% of all arthroscopic stabilizations). Capsular repair was performed in 2 shoulders (1.2% of 160 capsular repairs); humeral avulsion of the glenohumeral ligament (HAGL) repair, 1 shoulder (2% of 47 HAGL repairs); and isolated Bankart repair, 1 shoulder (0.05% of 1,941 Bankart repairs). The closest distance between the nerve and capsule was 3.4 ± 3.2 mm in shoulders with capsular or HAGL lesions and less than 1 mm in the 3 shoulders with palsy. The common symptoms in axillary nerve palsy cases were shoulder discomfort, delayed recovery of range of motion, and deltoid weakness and atrophy. A definitive diagnosis was made with electromyography in all cases. Nerve injury by a suture was confirmed during revision surgery in 3 shoulders subjected to capsular or HAGL repair during the initial operation. The palsy was transient and fully recovered in 1 shoulder with isolated Bankart repair.

CONCLUSIONS

The incidence of axillary nerve palsy after arthroscopic soft-tissue shoulder stabilization was low but higher in shoulders subjected to capsular or HAGL repair. We should always consider the possibility of axillary nerve palsy in shoulders that require capsular or HAGL repair.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.