Radiologic Evaluation of Change of Ankle Joint after Total Knee Arthroplasty

인공 슬관절 치환술 후 족관절 변화에 대한 방사선학적 연구

Purpose: To evaluate the incidence and describe radiologic pattern of ankle arthritis following change of mechanical loading axis by total knee arthroplasty. Materials and Methods: We reviewed radiographs of 419 cases, 243 patients underwent total knee arthroplasy from January 2002 to October 2006 retrospectively. We described radiologic parameters around the ankle joint and measured the amount of change of knee varus or valgus angle by comparing preoperative and postoperative anteroposterior standing lower extremities AP X-rays. We divided cases into two groups, one with radiologically arthritic change of the ankle joint and the other one without any radiologic change after surgery. We compared two groups in each parameters and analyzed statistically (SPSS v13.0). Results: Three hundred eighty one cases were divided into varus group and 38 cases in valgus group. 125 cases were divided into ankle arthritic change-positive subgroup among the varus group and 251 cases were in negative subgroup. The amount of varus angle correction by total knee arthroplasty showed significant difference between two subgroups. There was no significant difference in each parameters between subgroups within 38 valgus cases. Conclusion: Ankle arthritis can be aggravated after total knee arthroplasty because of the change of mechanical loading axis onto the ankle joint. Therefore it may be needed to evaluate symptoms and function of ankle joints before performing total knee arthroplasties especially in patients with huge varus deformities of knee joints.