Surgical treatment for knee osteoarthritis subsequent to previous femur fractures

Objective To investigate the indications and clinical outcomes of total knee arthroplasty or osteotomy for knee osteoarthritis subsequent to previous femur fractures. Methods Six patients (three male and three female) with knee osteoarthritis subsequent to previous femur fractures were analyzed retrospectively between February 2006 and February 2017. The average age of patients was 58.2±10.3 years old, ranged from 51 to 79 years. Four patients underwent total joint replacement and two underwent osteotomy. The average age of patients in joint replacement group was 60.5±12.3 years old. The age of the two patients in the osteotomy group was 51 and 55 years old, respectively. The extra-articular deformity angle of the coronal plane of the femur, lateral distal femur angle of mechanical axis, hip-knee-ankle angle (HKA) of preoperative and postoperative were determined on long-standing radiography. The mean angle of the extra-articular deformity in the joint replacement group was 17.0±7.7 degrees. The angle of the extra-articular deformity in the osteotomy group was 34 and 20 degrees. Lateral distal femur angle of mechanical axis in the joint replacement group was within the range of 87±7 degrees. Lateral distal femur angle of mechanical axis in the osteotomy group was out of the range of 87±7 degrees. The mean preoperative HKA of the joint replacement group was 161.8±8.0 degrees. The preoperative HKA of the osteotomy group was 155 and 160 degrees, respectively. Knee function was estimated according to knee range of motion and Knee Society Score (KSS). The results of postoperative hip-knee-ankle angle, knee range of motion (ROM) and knee society score were compared between the two groups. Results The mean HKA of the joint replacement group reached 176.0±2.8 degrees at one year postoperatively. The HKA of the osteotomy group improved to 177 and to 175 degrees at one year postoperatively. The average preoperative knee ROM improved significantly from 71±16 degrees preoperatively to 113±5 degrees postoperatively. The mean knee ROM of the joint replacement group was 113.0±6.8 degrees. The knee ROM of two patients in the osteotomy group was 110 and 115 degrees, respectively. The average preoperative KSS score improved significantly from 46±3 preoperatively to 88±3 postoperatively. The mean KSS of the joint replacement group was 88.8±3.0, while the KSS of the osteotomy group was 85 and 82. No bone nonunion was observed in the two patients in osteotomy group. Conclusion For patients with knee osteoarthritis subsequent to previous femur fractures, satisfactory short-term clinical outcomes could be obtained by total knee arthroplasty or osteotomy with the strict selection of proper operative indications. Key words: Femoral fractures; Osteoarthritis; Arthroplasty, replacement, knee