[Treatment of Morton neuroma by neurectomy. Apropos of 43 cases].

PURPOSE OF THE STUDY: Morton's neuroma is a frequent cause of metatarsalgia. Its diagnosis is clinical but progress in medical imaging: ultrasound, evoked potentials and above all MRI allows an improvement of para-clinical diagnosis.

MATERIAL AND METHODS: 48 neuromas were treated surgically between 1979 and 1990. That represents 46 feet in 43 patients. Female predominance was clear with an average age of 53 years. The follow-up period was 6 years and 10 months. 3 patients had multiple injuries. Medical treatment had been prescribed prior to surgery in 24 patients (15 had injections, 9 orthopedic shoe inserts and 5 both injections and inserts). The interval between the first symptoms and surgery was long since it was on average of 3 years and 6 months. The neuroma was located 36 times in the third interdigital space. The initial incision was plantar 11 times dorsal 32 times. Only neurectomies were performed. The neuroma was very large 9 times. 10 patients had treatment for other affections in the same operative time.

RESULTS: At review, 41 feet were completely painless. Shoe wear was normal for 32 patients. 12 pulpar hypoesthesia and 7 commissural and pulpary hypoesthesia were noted. 3 of 11 patients operated by the plantar approach had a painful hyperkeratosic scar.

DISCUSSION: None of our cases had preoperative MRI because our most recent case has 4 years of evaluation. At the present time the MRI could contribute to diagnosis owing to good tissular differentiation. The neurectomy led to a total disappearance of pain but hypoesthesia was frequent. The dorsal approach induces cutaneous complication. Neurolysis induces a sensitive postoperative deficit but recurrence occurs in 77 per cent of cases after neurolysis.

CONCLUSION: Morton's neuroma is located essentially in the third interdigital space. Neurectomy is a simple operation that often leads to recovery.