RÉSUMÉ
BACKGROUND:Studies have shown that there are significant differences in the geometric morphology of the distal femur of different races and genders,and there are more short female patients in southern China,so the phenomenon of overhanging or insufficient coverage of imported knee prostheses often occurs during surgery. OBJECTIVE:To investigate the characteristics of distal femur bones in southern Chinese women and compare them with imported joint prostheses by simulating the three-dimensional reconstruction of the distal femur bone and matching the femoral side after osteotomy with common imported joint prostheses. METHODS:From January to December 2021,120 female volunteers underwent a CT scan of knee joints.The images were imported into Mimics 20.0 software in Dicom format for three-dimensional reconstruction and then imported into Magic 22.0 software to simulate osteotomy by posterior cruciate ligament preserved total knee arthroplasty and to conduct a matching study with a normal imported joint prosthesis. RESULTS AND CONCLUSION:(1)The functional anteroposterior dimension(fAP)of the distal femur and Persona matched prosthesis had a total overhang rate of 25%(30/120).The fAP≤47 mm group had an overhang than the other groups(P<0.05).The poor coverage rate of Triathlon prosthesis was 12.5%(15/120),and poor coverage was more likely in fAP>53 mm group than in fAP≤53 mm group(P<0.05).(2)The total poor coverage rate of femoral intercondylar width matching with Triathlon prosthesis was 27.5%(33/120).Therefore,the poor coverage rate of bone surface in the central region of the distal femur was more likely in the fAP≤47 mm group than in other groups(P<0.05).The overhang rate of Journey II was 21.6%(26/120),and the overhang rate was higher in the fAP>53 mm group than in the fAP≤53 mm group(P<0.05).(3)Journey II CR prosthesis had the largest difference with the length of the anterior mediolateral diameter of the femur,which was easy to hang out on the anterolateral side of the femoral prosthesis.The Persona CR prosthesis has the largest difference with the length of the posterior mediolateral diameter of the femur,which is easy to be poorly covered in the posterior medial part of the prosthesis.It is recommended to increase the femoral prosthesis with reduced mediolateral diameter in the fAP≤47 mm group and add wider and narrower sizes than the conventional size of intercondylar width,and optimize the anterolateral angular arc design of the femoral prosthesis to improve the matching of posterior cruciate ligament reserved knee prosthesis.
RÉSUMÉ
PURPOSE: The result of cementless total knee arthroplasty with posterior cruciate ligament retention in rheumatoid arthritis patients was evaluated. MATERIALS AND METHODS: Thirty patients (fifty knees) followed up after cementless total knee arthroplasty with posterior cruciate ligament retention was evaluated clinically and radiologically. Average follow up was 9.2 years(5.1~14.3). RESULTS: The mean HSS knee score improved from 47.4 preoperatively to 81.8 postoperatively, and the mean range of motion of 89.7 degrees preoperatively to 101.2 degrees postoperatively. The mean tibiofemoral angle was 4.9 degrees valgus. Posterior instability was observed in 1 case(2%) at the most recent follow up. Radiolucent line was observed in 41 cases(82%), and osteolysis was observed around tibial component in 13 cases(26%), and around femoral component in 4 cases(8%). Eight cases(16%) of revision was due to 1 case of aseptic loosening and osteolysis each, and the other due to polyethylene wear of patellar or tibial component. CONCLUSION: Although there are osteopenia in rheumatoid arthritis compared to osteoarthritis, cementless total knee replacement with posterior cruciate retention showed stable fixation. However, the new method for initial fixation of tibial component is needed because osteolysis around tibial component tended to start around cancellous screws.