[Dwyer osteotomy : Lateral sliding osteotomy of calcaneus].

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

INDICATIONS: 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.

CONTRAINDICATIONS: 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.

SURGICAL TECHNIQUE: 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.

POSTOPERATIVE MANAGEMENT: 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.

RESULTS: 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).