Hindfoot equinus secondary to the relative overpull of the gastrosoleus complex is common and may respond to Achilles lengthening. For the fixed varus hindfoot deformity without arthritic changes, realignment is achieved by a calcaneal osteotomy. Formal hindfoot correction may also be useful if the ankle is unstable, to minimise varus forces on the ankle.
Calcaneal osteotomy was introduced to correct a varus deformity of the hindfoot with some equinus. Calcaneal osteotomies are generally performed through a lateral approach which can be extended if an ankle stabilisation procedure is required.
Dwyer (1975) popularised the wedge osteotomy describing a closing lateral wedge osteotomy to correct hindfoot varus. With subtalar inversion, the Achilles tendon becomes an active secondary inverter, and the forefoot is adducted and pulled closer to the heel as the patient walks on the lateral border of the foot. The medial forefoot has limited weight bearing and the plantar fascia is not stretched. Therefore he recommeded division of the plantar fascia.
This was taken further by Gould (1984) who achieved satisfactory results by combining calcaneal osteotomy and greenstick osteotomies of the metatarsal bases. Sammarco (2001) reported combined calcaneal and first metatarsal osteotomies in 21 feet, with an improvement in the mean AOFAS ankle-hindfoot score from 46 to 89 and in the midfoot score from 41 to 89 at a mean follow-up of 4 years. There were 3 non-unions of metatarsal osteotomies.
Samilson (1985) attempted to restore the architecture of the foot whilst preserving joint motion by performing a sliding crescenteric osteotomy combined with plantar fasciotomy. This obtained a similar displacement as the Dwyer, backward and upward. The Samilson osteotomy is particularly useful in calcaneocavus.