The digital nerve stretch test: A sensitive indicator of Morton's neuroma and neuritis

Abstract 

We describe a physical sign not previously reported, which adds a sensitive and specific tool to assist the clinical diagnosis of interdigital neuralgia in the foot including Morton's entrapment neuropathy.

A prospective record was kept of symptoms and signs in patients treated for Morton's neuroma or neuritis, including the web space pressure test, metatarsal approximation, Mulder's click and the digital nerve stretch test.

Twenty-two consecutive patients underwent surgery for Morton's metatarsalgia. At surgery, 16 patients had a neuroma; four had an abnormally thickened, inflamed nerve, and one had evidence of neuritis, and underwent neurolysis. One patient had an epidermal cyst.

Our digital nerve stretch test showed 100% sensitivity, with a 95% positive predictive value for Morton's neuroma and neuritis. However, it was also positive in the patient with an epidermal cyst.

Although demonstrated in a small group, we believe this sign to be of value in the diagnosis of this condition, and worthy of further study and evaluation.

Keywords: Morton's neuroma, Interdigital neuritis, Clinical signs