The pathology and management of lesser toe deformities

Overview

This review covers deformities of the second to fifth toes, a common cause of pain, calluses, problems with footwear and difficulty walking. It explains the normal anatomy and mechanics of the toes. The lesser toes share weight with the metatarsal heads, and the plantar fascia and the plantar plate at the base of each toe keep them in contact with the ground during walking. The authors propose treatment algorithms, while noting that the evidence consists mostly of retrospective case series with very few randomised trials.

Types and causes

In a mallet toe the joint nearest the tip bends. A hammer toe bends at the middle joint. A claw toe is overextended at its base and bent at both joints beyond. A crossover toe drifts sideways over its neighbour, most often the second toe. These deformities arise from an imbalance between the tendons and small muscles that bend and straighten the toes. Contributing factors include tight or high-heeled footwear, bunions, inflammatory arthritis, diabetes, neuromuscular disorders and injury. When the plantar plate stretches or tears, the base of the toe becomes unstable, and load shifts onto the metatarsal heads, causing pain in the ball of the foot.

Assessment

The history covers previous injury, diabetes, arthritis, neurological disease, circulation, footwear and the patient's expectations. Examination checks whether each deformity is flexible or fixed, tests the stability of the joint at the base of the toe, and looks for calluses and deformities of the big toe and the rest of the foot. Weight-bearing radiographs are standard, and MRI or ultrasound can show plantar plate tears.

Management

Conservative measures should be tried first: wider shoes with a deep toe box, toe sleeves and padding, off-loading insoles, taping, and an injection for joint inflammation. When surgery is needed, the key principle is to correct and stabilise the joint at the base of the toe before the deformities further along it. Options include soft-tissue releases, tendon transfers, plantar plate repair and metatarsal shortening osteotomies for the base of the toe, and tendon release, joint excision or fusion for the smaller joints. Coexisting deformities such as bunions should be corrected too, to prevent recurrence. Complications include stiffness, recurrence, loss of the toe's gripping function and a floating toe that no longer touches the ground. Crossover toe is the hardest deformity to correct, and in frail elderly patients amputation of the toe may be preferable. Minimally invasive techniques are increasingly used, but good-quality studies are still lacking.