Neuromuscular ultrasound for the differential diagnosis of radial tunnel syndrome and lateral epicondylitis.

BACKGROUND AND PURPOSE: Lateral elbow pain is quite common in everyday life. Lateral epicondylitis and radial tunnel syndrome are the most common causes of lateral elbow pain. The aim of this study was to evaluate the sensitivity and specificity of neuromuscular ultrasound examination in the diagnosis of lateral epicondylitis versus radial tunnel syndrome.

METHODS

This was a prospective double-blinded pilot study of 68 elbows in 34 patients with lateral elbow pain. Patients underwent clinical examination and standardized neuromuscular ultrasound evaluation in the first 15 days after the initiation of symptoms. Statistical significance was set at p < .001. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated.

RESULTS

Sixty-eight radial nerves were examined in 34 healthy controls (16 males; mean age 48.1 ± 8.2 years). Pain with palpation over the radial tunnel was found in 25 of 48 elbows (52.1%) compared to the pain over the lateral epicondyle found in 10 of 48 elbows (20.8%). Τhe sensitivity of palpation in differentiating radial tunnel syndrome from lateral epicondylitis was 75.7%, while the specificity was 50% (PPV 71.4%, NPV 51.5%). The sensitivity of neuromuscular ultrasound in differentiating radial tunnel syndrome from lateral epicondylitis was 92.6%, while the specificity was 80% (PPV 92.6%, NPV 80.0%). In most of the patients (25/31), fibrous bands anterior to the radio-capitellar joint were responsible for the nerve entrapment.

CONCLUSIONS

The present study highlights the importance of the neuromuscular ultrasound's diagnostic role in differentiating radial tunnel syndrome from lateral epicondylitis in the clinical scenario of lateral elbow pain.