MR neurography findings of brachial plexopathy following total shoulder arthroplasty.

Abstract

Objectives: To characterize nerve injury patterns following total shoulder arthroplasty (TSA).

Methods: This retrospective study reviewed brachial plexus MR neurography (MRN) in patients with brachial plexopathy within 180 days post TSA from 2016 to 2023. Patients with pre-existing neurologic symptoms or without available electrodiagnostic testing (EDX) data were excluded. MRN findings were extracted from the original report and independently reviewed by a second, musculoskeletal fellowship trained radiologist.

Results: A total of 27 patients (15F/12 M, mean age 67) were included. MRN and EDX-confirmed nerve injury localization matched in 13 patients, with nerve hyperintensity and/or enlargement identified in 7 cases at the plexus proper and 6 cases at the branch nerve level (suprascapular, axillary, radial, median). Nerve impingement by screw (n = 3) or extruded cement (n = 1) and mass effects including soft tissue edema (n = 1), hematoma (n = 2), or joint effusion (n = 2) were identified. MRN detected muscle denervation in 8 of 19 patients with EMG abnormalities, with a median TSA-to-MRN interval of 62.5 days (range, 19-95) versus 3 days (range, 2-155) in those without denervation on MRN (p = 0.003). Inter-rater reliability demonstrated substantial to almost perfect agreement for MRN assessments, except for cord hyperintensity. All patients were clinically followed up: 3 had complete symptomatic resolution and 21/27 reported partial improvement at a mean follow-up time of 25.5 months.

Conclusions: MRN findings closely correlated with EDX-confirmed clinical diagnoses in cases with MRN abnormalities. Additionally, MRN identified secondary findings, such as local mass effect on nerve segments, that can guide management.