Treatment for ulnar neuropathy at the elbow.

Background: Ulnar neuropathy at the elbow (UNE) is the second most common entrapment neuropathy after carpal tunnel syndrome. Treatment may be conservative or surgical, but optimal management remains controversial. This is an update of a review first published in 2011 and previously updated in 2012 and 2016.

Objectives: To determine the effectiveness and safety of conservative and surgical treatment for ulnar neuropathy at the elbow (UNE). We intended to test whether: - surgical treatment is effective in reducing symptoms and signs and in increasing nerve function; - conservative treatment is effective in reducing symptoms and signs and in increasing nerve function; - it is possible to identify the best treatment on the basis of clinical, neurophysiological, or nerve imaging assessment.

Search methods: We searched the Cochrane Neuromuscular Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, four other databases, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform to July 2022.

Selection criteria: The review included only randomised controlled clinical trials (RCTs) or quasi-RCTs evaluating people with clinical symptoms suggesting the presence of UNE. We included trials evaluating all forms of surgical and conservative treatments. We considered studies regarding therapy of UNE with or without neurophysiological evidence of entrapment.

Data collection and analysis: Two review authors independently reviewed titles and abstracts of references retrieved from the searches and selected all potentially relevant studies. The review authors independently extracted data from included trials and assessed risk of bias. We contacted trial investigators for any missing information. The primary outcome was clinically relevant improvement in function compared to baseline. The secondary outcomes of interest were change in neurological impairment, change from baseline of the motor nerve conduction velocity across the elbow, change from baseline in the nerve diameter/cross-sectional area at the elbow, evaluated by ultrasound or MRI, change in quality of life and adverse events. We used GRADE methodology to assess the certainty of evidence.

Main results: We included 15 RCTs (970 participants), of which six studies were new for this update. Sequence generation was inadequate in one study and not described in six studies; other studies had a low risk of selection bias. We evaluated the clinical outcomes (3 trials, 261 participants) and neurophysiological outcomes (2 trials, 101 participants) of simple decompression versus decompression with submuscular or subcutaneous transposition. Moreover, we evaluated the clinical outcomes of endoscopic versus open decompression surgery (2 trials, 99 participants). We found there was probably little to no difference in clinical improvement in function for simple decompression versus subcutaneous transposition (risk ratio (RR) 0.92, 95% confidence interval (CI) 0.74 to 1.14; 1 study, 147 participants) and simple decompression versus submuscular transposition (RR 0.95, 95% CI 0.77 to 1.17; 2 studies, 114 participants). Compared to simple decompression, we found little to no difference in wound infections for subcutaneous transposition (RR 0.29, 95% CI 0.06 to 1.35; 1 study, 147 participants) and submuscular transposition (RR 0.35, 95% CI 0.10 to 1.21; 2 studies, 114 participants). We found no difference between endoscopic and open decompression in terms of postoperative clinical improvement measured by the Bishop score (RR 0.98, 95% CI 0.84 to 1.14; 2 studies, 99 participants). Among surgical treatments, further single trials investigated postsurgical electrical stimulation after open decompression, nerve decompression and transposition with supercharged end-to-side anterior interosseous nerve-to-ulnar motor nerve transfer. Among conservative treatments for mild or moderate UNE, single trials explored the efficacy of participants' education, night splinting, nerve gliding exercises, corticosteroid and dextrose perineural injection.

Authors' conclusions: Low- to moderate-certainty evidence indicates that there is little to no difference in terms of improvement in function or surgical complications between simple decompression and decompression with subcutaneous or submuscular transposition in idiopathic UNE, including when the nerve impairment is severe. Moderate-certainty evidence indicates that there is little to no difference between endoscopic and open decompression in improving clinical function and in terms of procedural complications. Very low-certainty evidence indicates that it is unclear if steroid injections have an effect on clinical improvement, compared to placebo, and if written instructions have an effect on clinical improvement, compared to surgical decompression. Findings from a small RCT on conservative treatment showed that in mild cases, information on movements or positions to avoid may reduce subjective discomfort. One RCT showed that dextrose injection might reduce pain at either short-term (four months) or long-term follow-up (12 months), compared to placebo. Another RCT did not show differences in clinically relevant improvement between dextrose and corticosteroid injection. In clinically severe UNE, findings from a small RCT showed that postsurgical electrical stimulation improves intrinsic muscle reinnervation and strength at 12 months' follow-up.