[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.