Key message
• People had similar results in symptom scores and surgical complications whether the nerve was simply released (simple decompression) or released and moved to a new position under the skin or muscle (subcutaneous or submuscular transposition). We also found no major differences in terms of symptom scores and surgical complications between surgery done with a larger cut (open decompression) and surgery done using a small camera (endoscopic decompression).
• It is unclear if only giving written instructions helps to improve symptoms of ulnar neuropathy at the elbow (UNE), compared to surgical decompression.
• Written information alone improved people's work activities and reduced pain at night as much as when people also used splints or did exercises.
• There was no evidence that corticosteroid injections improved symptoms of UNE, whereas dextrose injections seemed to reduce pain when measured four or 12 months later.
What is ulnar neuropathy?
UNE (when the ulnar nerve is pinched at the elbow) is the second most common condition caused by pressure on a nerve (nerve compression syndrome) by the nearest anatomical structures, after carpal tunnel syndrome. The ulnar nerve travels down the side of the elbow and is important for hand movements and the touch sensation. Symptoms of UNE are tingling of the fourth and fifth fingers at night, pain in the elbow, and a change in sense of touch if the elbow is bent for a long time. When UNE is severe, some hand muscles can become weak and smaller or thinner. Treatment of UNE can be surgical or nonsurgical (e.g. splints, physical therapy, and rehabilitation).
What did we want to find out?
Doctors are not sure of the best way to treat UNE. We wanted to find out which treatments help improve symptoms, nerve functioning, quality of life or have any unwanted effects. We also wanted to find out whether one type of treatment is better than another.
What did we do?
We searched for studies that looked at treatments for UNE.
We compared and summarised the results of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
We included 15 studies involving 970 people. Six of these were new for this update.
Eight studies compared different types of surgery for ulnar nerve entrapment at the elbow: simple nerve release (decompression), moving the nerve to a new position under the muscle or under the skin (called submuscular or subcutaneous transposition), removing part of the inner elbow bone (medial epicondylectomy), moving the nerve to the front of the elbow (anterior transposition). Traditional open surgery was also compared with a newer method using a small camera (endoscopic decompression). One study compared surgery (decompression) with no surgery (conservative treatment). Another study tested surgery that included nerve decompression plus moving the nerve under a tissue layer (subfascial transposition), with or without an extra nerve connection to support hand muscles (a special nerve transfer technique used in severe cases). One small study looked at whether electrical stimulation after surgery could help the small muscles in the hand recover.
Four studies tested nonsurgical treatments. One compared three approaches in people with mild to moderate symptoms: advice alone, advice plus wearing a night splint, advice plus nerve-gliding exercises.
Other studies compared different types of injections: corticosteroid vs fake (sham) injection, corticosteroid vs dextrose, dextrose vs sham.
Main results
We combined results from three studies that compared two surgical techniques: simple decompression and transposition of the ulnar nerve (subcutaneous or submuscular). We found probably little to no difference in symptom scores and surgical complications between the techniques. When we combined two trials that compared endoscopic and open decompression, we found that there may be little to no difference between the two techniques in terms of improving clinical function and surgical complications. Researchers found no clinical differences between surgical techniques in the other surgical trials.
In clinically mild/moderate UNE, written information alone may be as effective in improving work activities and reducing pain at night as when participants also used splints or did exercises. Dextrose injection may reduce pain when measured four or 12 months later. Researchers found no evidence that corticosteroid injection improved symptoms of UNE.
What are the limitations of the evidence?
In general, our confidence in the evidence was limited by problems with how the studies were carried out, and because they did not include many people. We are moderately confident in the evidence regarding the comparison between open and endoscopic surgery, while we have little confidence in the comparison between simple compression and transposition.
How up to date is this evidence?
This review updates our previous review. The evidence is up to date to 18 July 2022.
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.
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.
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.
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.
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.
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.
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.