Evaluation of ankle joint function after subtalar arthrodesis

Objective To evaluate the postoperative efficacy and to analysis the changes of ankle joint function of patients with isolated subtalar arthrodesis.Methods The data of patients who were treated by subtalar arthrodesis between January1996and August 2011 was retrospectively analyzed.According to the 36-item short-form(SF-36)health survey and American Orthopaedic Foot and Ankle Society(AOFAS)ankle-hindfoot score,the symptoms were assessed.To evaluate ankle function,bilateral ankle activities on sagittal and coronal planes were analyzed and ankle degeneration signs on weight-bearing X-rays were observed.The obtained data were analyzed with t-test and Pearson linear correlation.Results Thirty-seven patients(27 males,10females)with an average age of 42.6(range,13to74)years were followed up.The average follow up period was 9.2(range,2to 17)years.The average of SF-36 score had increased from34.26±11.02 preoperatively to 77.59±12.57 postoperatively(P0.01).The average of AOFAS ankle-hindfoot score had increased from50.32±12.39 preoperatively to 73.14±15.44postoperatively with statistical significance(P0.01).Dorsiflexional and plantarflexional ankleactivities of 34 patients got obviously limited to 45.6%,which were related to decreased talar inclination,reduced hindfoot height and ankle degeneration.Both medial and lateral stability of the ankle joint stayed good after subtalar fusion,and there was no much compensatory activity on coronal plane.Conclusions Subtalar arthrodesis is indeed an effective procedure to treat subtalar diseases,although it changed ankle joint function to some extent.Postoperatively91.9%patients got ankle motion limited significantly,but the ankle joint had no obvious compensatory varus or valgus activities after subtalar fusion and its medial and lateral stability stayed fine.