There are numerous causes of cavovarus feet, the most common of which are the hereditary motor and sensory peripheral neuropathies. Regardless of the underlying aetiology, cavovarus feet are caused by muscle imbalance. Often the imbalance is between a relatively strong tibialis posterior acting against a weaker peroneus brevis, and a relatively weak tibialis anterior being over powered by peroneus longus. Intrinsic muscle weakness and gastro-soleal tightness is common.

After the failure of non-operative management, flexible deformity can be corrected with a combination of tendon transfers and osteotomies. Frequently surgical management of cavovarus feet involves a combination of calcaneal and first metatarsal osteotomies, peroneus longus to brevis transfer, transfer of tibialis posterior through the interosseous membrane to the dorsum of the foot, tendo-Achilles and plantar fascia lengthening and correction of toe deformities.

The post-operative recovery is slow, but most patients achieve good functional results and report improvements in their activities of daily living.

Introduction and Aims: Despite being a relatively common condition in childhood, there is little information in the world literature documenting the foot deformities seen in the Hereditary Motor and Sensory Neuropathies (HMSN). The aim of this paper was to thoroughly investigate the foot deformities seen in children with HMSN.

Method: We reviewed 104 feet from 52 children with HMSN seen for the first time in clinics at the Central Remedial Clinic, Dublin and The Children’s Hospital at Westmead, Sydney between January 1996 and June 2003. All patients were reviewed by a consultant neurologist and orthopaedic surgeon. The data we collected included: HMSN type, sex, age at first presentation, type of foot deformity, bilaterality of deformity, symmetricality of deformity, whether surgery had been required, age at surgery and the details of the surgery performed. We divided surgery types into soft tissue procedures alone and combined soft tissue and bony procedures.

Results: Sixty-nine feet had a cavovarus deformity, 23 feet had a planovalgus deformity and 12 feet had no significant deformity. All cases with deformity had bilateral involvement, and of those with deformity, only 45% had symmetrical involvement. In HMSN I, III, IV, V and X linked HMSN, cavovarus was the most common deformity. However, in HMSN II, 55% of feet had a planovalgus deformity, 36% had a cavovarus deformity and 9% no deformity. Forty-three feet required surgery of some type. Thirty-four feet with a cavovarus deformity had surgery, 17 required soft tissue surgery and 17 combined bony and soft tissue surgery. Nine feet with a planovalgus deformity had surgery, seven required soft tissue surgery alone, and two had combined surgery.

Conclusion: Cavovarus is the most common foot deformity seen in patients with HMSN. However, a planovalgus deformity is not uncommon, and in HMSN II, planovalgus is seen more frequently than cavovarus. Surgical intervention was required in just under half of the feet with deformity. Surgery, and in particularly combined soft tissue and bony surgery, is required more often to treat feet with a cavovarus deformity than with a planovalgus deformity.