PCA Type Total Joint Arthroplasty of the Knee

Abstract

During the period from July 1984 until December 1986, we performed total knee replacement (TKR) using porous coated anatomical (PCA) knee prostheses in a total of 38 cases (50 joints) at Nagoya City University and affiliated institutions. By disease, these cases comprised 24 cases (29 joints) of osteoarthritis (OA) and 14 cases (21 joints) of rheumatoid arthritis (RA). The age of the patients at the time of surgery ranged from 63 to 81 years (average 62.9 years) for OA and from 37 to 73 years (average 58.3 years) for RA. In all cases, bone cement was used for fixation of the femur and tibia as well as the patella. The tibial components used were mostly small (7 mm thick). Prior to surgery, flexion contracture above 31° was found in six joints, and a range of motion with a contracture of less than 60° was noted in eight joints. In addition, six joints required compensation for bone loss in the medial condyle of the tibia. The post-operative observation period ranged from 2 months to 2 years 8 months. In OA, the 100-point score ranged from 41.6 points before surgery to 80.6 points after surgery, and range of motion (ROM) from 116.6° pre-operatively to 89.6° post-operatively. The values for RA were 36.2–79.8 points and 77.3° –101.6°, respectively. Adequate ROM was achieved for knees with flexion contracture and knees with contracture. The results in cases involving compensation for bone loss were also satisfactory. A comparison of our results with those obtained at Chiba University where TKR using PCA without cement (resurfacing type) was carried out on 47 cases (58 joints; 18 cases, 25 joints, of OA and 22 cases, 30 joints, of RA) led us to conclude that the use of bone cement had no bearing on the clinical evaluation. The postoperative femorotibial angle was in most cases satisfactory. The setting position of both the femoral component and the tibial component showed good alignment in the frontal plane but large variations in the sagittal plane. In cases of knees with flexion contracture, the total extent of bone resection was substantial.