Mid-Term Follow Up Results of Subtalar Distraction Arthrodesis Using a Double Bone-Block for Calcaneal Malunion

PURPOSE: This study was designed to evaluate the mid-term results and efficacy of subtalar distraction double bone-block arthrodesis for calcaneal malunion. MATERIALS AND METHODS: From January 2004 to June 2007, we operated on 6 patients (10 cases). There were 5 males (9 cases) and 1 female (1 case), four of which presented with bilateral calcaneal malunion. Seven cases were operated on initially. The period between initial injury and arthrodesis was 23 months, and the average follow up period was 58 months. In operation, we applied an extensile lateral approach and arthrodesis was performed through a tricortical double bone-block and cannulated screws. The American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scale was used for clinical evaluation. In radiologic analysis, plain X-ray and CT were examined to assess union and various parameters. RESULTS: The mean age of the patients was 41 years. All cases achieved radiologic union at the final follow-up. The mean AOFAS Ankle-Hindfoot scale (maximum of 94 points) increased from 43.3 points preoperatively to 85.4 points at the final follow-up. The radiologic analysis of the pre- and postoperative standing lateral radiographs showed improvements of 5.6 mm in talo-calcaneal height, 1.8° in talocalcaneal angle, 5.1° in talar declination angle and 5.3° in talo-first metatarsal angle. CONCLUSION: Subtalar distraction two bone-block arthrodesis provides overall good results not only in the short term but also the mid-term with significant improvement in clinical and radiologic outcomes. This procedure warrants consideration for managing calcaneal malunion with loss of height and subtalar arthritis.