Changes in ulnar and median nerve conduction velocity after reverse total shoulder arthroplasty: Correlation with distalization and lateralization

Abstract

Purpose: The purpose of this study was to assess ulnar and median nerve injury after reverse total shoulder arthroplasty (RSA) by measuring the sensory nerve conduction velocity (SCV). The secondary objective was to evaluate the impact of lateralization and/or distalization on SCV changes. Methods: Twenty consecutive cases were prospectively included and retrospectively reviewed. SCV of the ulnar and median nerves as well as humeral lateralization/distalization quantified by plain radiography were evaluated pre-operatively and at 1 week post-operatively. Changes in SCV were tested using the paired t-test, and correlations between humeral lateralization/distalization and SCV changes were tested using Kendall's rank correlation coefficient and maximal information coefficient (MIC). Results: The SCV of the ulnar nerve was delayed from 55.4 ​m/s pre-operatively to 53.0 ​m/s post-operatively (p ​= ​0.021), whereas there was no significant change in the median nerve (p ​= ​0.17). There was a weak to moderate correlation between ulnar nerve SCV delay and lateralization (τ ​= ​−0.38; p ​= ​0.021; MIC ​= ​0.70) but no significant correlation with distalization (p ​= ​0.65; MIC ​= ​0.56). Conclusions: Following RSA, a small but significant delay in SCV of the ulnar nerve was observed. A negative correlation was found between lateralization and SCV delay of the ulnar nerve.

Keywords

• Reverse shoulder arthroplasty
• Nerve injury
• Sensory nerve conduction velocity
• Humeral lateralization
• Ulnar nerve
• Median nerve