Ankle arthrodesis is a common operation with published fusion rates ranging from 62–100%. The literature documents the difficulties of obtaining arthrodesis in certain patients for example with neuroarthropathy, but the risk of non union related to deformity, bone quality, bone defects and systemic disease has not previously been reported. Between 2002 and 2006 we performed an ankle arthrodesis in 154 patients, and analyzed these patients retrospectively to delineate categories of risk factors for achieving arthrodesis. From this analysis we devised a preoperative radiographic scoring system to grade complexity of pre-operative ankle arthrodesis. The scoring system is based upon 5 categories; size and plane of deformity, presence and size of bone defects, presence and area of avascular necrosis, site of previous fracture in post-traumatic arthritis and predisposing condition causing the arthritis. Each category has potential scores of 1–5, apart from the latter which is scored up to 6, with higher scores being more severe. The grade of complexity is derived from a cumulative score from all 5 categories. Statistical analysis revealed good intra and inter- observer correlation. Multivariate regression analysis demonstrated that this scoring system correlates with the techniques used for arthrodesis as well as outcome. This study demonstrated that if the method of arthrodesis is altered according to the relative risk of non –union then there is no significant difference in outcome between patients of high and low risk for non-union We present a new scoring system for severity of pre-operative condition in ankle arthrodesis patients and introduce an algorithm for surgical correction based upon this pre-operative scoring system. The surgical techniques for the arthrodesis are presented, ranging from simple screw fixation to more complex bone grafting techniques, bone stimulation and alternative methods of fixation.
We present our experience with a medial approach for triple arthrodesis for correction of severe rigid hindfoot deformity in patients who were at risk for wound complications with a standard lateral approach. Between 1995 and 2002, we treated 17 patients with a rigid hindfoot valgus deformity, and for whom a triple arthrodesis was planned, using a single medial incision. The indication for surgery was pain refractory to shoe wear, orthotic and brace modifications. The severity of the hindfoot deformity itself was not sufficient an indication for this procedure, since during the same time period, 157 triple arthrodesis procedures were performed using a two incision technique, many of which were associated with severe hindfoot varus or valgus deformities. The medial incision was indicated specifically for patients who were at risk for wound complications following correction of the hindfoot valgus deformity due to stretching of the lateral skin. There were 15 patients with rheumatoid arthritis (RA), and two patients who had deformity of the hind-foot following a crush injury associated with scarring of the lateral skin over the sinus tarsi. In addition to standard weight bearing radiographs of the foot and ankle, non-invasive vascular studies were performed in 5/17 patients pre-operatively who on clinical examination were considered to have peripheral vascular disease. Immunosuppressant medication(s) were not discontinued prior to surgery for the patients with RA, and were renewed once wound healing occurred. The surgery was performed in a standard manner for each patient, with an extensile medial incision, the use of a laminar spreader to facilitate exposure and joint debridement, and removal of appropriate bone wedges to improve correction. Cannulated partially threaded 5.0 mm (for the talonavicular and calcaneocuboid joints) and 6.5 mm (for the subtalar joint) screws were used in each patient. All 17 patients were examined a mean of 4.5 years following surgery (range 2.5–8), and the examination focused on the success of arthrodesis, the presence of ankle arthritis, as well as hindfoot deformity. Other outcome parameters were not specifically examined since these patients had multiple additional lower limb deformities, as well as arthritides of the foot and ankle unrelated to the performance of the triple arthrodesis. The correction obtained was compared with preoperative radiographs. There were no wound healing complications in any patient. Arthrodesis was obtained in 16/17 patients. In one patient with RA, a non-union of the calcaneocuboid joint was noted radiographically, but had been present for 6 years, and was asymptomatic. There was no loss of correction, however hindfoot valgus was present in three patients, caused by arthritis of the ankle associated with valgus tibiotalar deformity. Two additional patients had since undergone a total ankle replacement for correction of arthritis not associated with deformity, and one had undergone an ankle arthrodesis 2 years following the triple arthrodesis for correction of severe arthritis as well as tibiotalar deformity. On the anteroposterior foot radiograph, the talus-first metatarsal angle improved from a mean of 26 degrees (range 15–45), to a mean of 5 degrees (range 0–15). The talocalcaneal angle was not measured, since reproducible preoperative measurements could not be obtained. The axial talocalcaneal angle was not measured. The medial approach to triple arthrodesis is a reliable procedure, and can be used with a predictable outcome in patients who are at risk for wound healing complications for correction of hindfoot valgus deformity.
