[Dwyer osteotomy : Lateral sliding osteotomy of calcaneus]

To correct the underlying inframalleolar varus deformity and to restore physiologic biomechanics of the hindfoot.

Neurologic, posttraumatic, congenital, and idiopathic cavovarus deformity. In patients with end-stage ankle osteoarthritis with varus heel malposition as additional single-stage procedure complementing total ankle replacement. Severe peroneal tendinopathy with concomitant cavovarus deformity.

General surgical or anesthesiological risks, infections, critical soft tissue conditions, nonmanageable hindfoot instability, neurovascular impairment of the lower extremity, neuroarthropathy (e. g., Charcot arthropathy), end-stage osteoarthritis of the subtalar joint, severely reduced bone quality, high age, insulin-dependent diabetes mellitus, smoking.

The lateral calcaneus cortex is exposed using a lateral incision. The osteotomy is performed through an oscillating saw. The posterior osteotomy fragment is manually mobilized and shifted laterally. If needed, a laterally based wedge can be removed and/or the osteotomy fragment can be translated cranially. The osteotomy is stabilized with two cannulated screws, followed by wound closure.

A soft wound dressing is used. Thromboprophylaxis is recommended. Patient mobilization starts on postoperative day 1 with 15 kg partial weight bearing using a stabilizing walking boot or cast for 6 weeks. Following clinical and radiographic follow-up at 6 weeks, full weight bearing is initiated step by step.

Between January 2009 and June 2013, a Dwyer osteotomy was performed in 31 patients with a mean age of 45.7 ± 16.3 years (range 21.5-77.4 years). All patients had a substantial inframalleolar cavovarus deformity with preoperative moment arm of the calcaneus of -17.9 ± 3.3 mm (range -22.5 to -10.5 mm), which has been improved significantly to 1.6 ± 5.9 mm (range -16.9 to 9.9 mm). Significant pain relief from 6.3 ± 1.9 (range 4-10) to 1.1 ± 1.1 (range 0-4) using the visual analogue scale was observed. The American Orthopaedic Foot and Ankle Society score significantly improved from 33.1 ± 14.2 (range 10-60) to 78.0 ± 10.5 (range 55-95).