Abstract
Introduction
The goal of arthrodesis around the ankle or of triple (hind foot) arthrodesis is a painless, plantigrade, and stable foot. Stress fracture is a differential diagnosis for pain following an ankle/subtalar arthrodesis. Management of stress fractures following sound ankle/subtalar fusion is extremely difficult as the entire movement tends to occur at the fracture site, hence hampering healing.
Methods and materials
33 patients underwent ankle/subtalar arthrodesis at our institute from 2000-2008. The average age of the patients was 69 years and the male: female ratio was 2:1. The minimum follow-up was for one year. Although there were some variations in technique, all the arthrodesis were performed by removal of articular cartilage, bone grafting of any defects and rigid internal fixation.
Results
2/33 patients developed a stress fracture of the distal tibia following successful ankle/subtalar fusion. An angle of ankle/subtalar fusion showed an average of 0 degrees +/− 3 degrees in the sagital plane, except for the two cases that developed the stress fracture. The angles in these cases were 13 and 11 degrees. The stress fractures occurred proximal to the level of the previous arthrodesis internal fixation devices (arthrodesis nail/cancellous screws). Intramedullary and extramedullary devices were utilised to obtain union across the stress fracture sites, without success.
Discussion
Equinus of more than 10 degrees following ankle/subtalar arthrodesis is a high risk factor for developing a stress fracture of the distal tibia following ankle/subtalar arthrodesis. Stress fracture following successful ankle/subtalar arthrodesis causes severe morbidity. They are extremely difficult to treat, hence are best avoided if possible.
