The purpose of this study was to evaluate long-term clinical and radiological results as well as survival rates of the NexGen® CR posterior cruciate retaining prosthesis.
We evaluated a consecutive series of 761 total knee replacements performed on 716 patients from 1999 to 2001 at our institution. All patients had been recorded prospectively in our in-house arthroplasty register. Follow-up data were available for 379 patients at 10 years postoperatively. Functional outcome was evaluated using the Knee Society score. An additional radiographic evaluation was performed on 224 patients at 10 years. The mean age of the patients at the time of surgery was 71 years. 75 % of the patients were female, 25 % were male. Mean BMI of the patients was 29.2 kg/m(2). The preoperative diagnosis was osteoarthritis in 91 %, rheumatoid arthritis in 5,5 % and posttraumatic osteoarthritis in 2 %. Patella resurfacing was performed in 4 %. All components were cemented.
Mean Knee Society clinical score improved from 26.7 points preoperatively to 88.5 points at the time of the latest follow-up, and mean Knee Society function score improved from 48.3 to 55.2 points. Flexion improved from a mean of 106.7° preoperatively to 111.4° at 10 years. Patellofemoral pain was indicated by 66 % of the patients before surgery and 4 % at the latest follow-up. 96 % were satisfied with the result of the surgery at 10 years. Radiographic evaluation was performed on 224 patients at the time of the latest follow-up. 203 patients (91 %) had normal radiographic findings, 21 patients (9 %) showed pathological findings. Radiolucencies were seen in 18 patients on the AP view of the tibia, 1 patient had an additional femoral radiolucency. There was an osteolysis located in the lateral tibia seen in 1 patient and an occurrence of heterotopic ossification in another patient. One knee showed a patella subluxation. No patient had radiographic evidence of loosening. 17 knees had required revision surgery with exchange of at least one of the components up to 10 years after the index procedure. 5 of the patients had revision for a deep infection, 2 for periprosthetic fractures of the distal femur with loosening of the prosthesis, 1 for fracture of the proximal tibia due to osteoporosis, 4 for aseptic loosening, 3 for instability and 2 for severe pain. Kaplan-Meier survival of all components using revision for any reason as the end point was 97.8 % at 10 years.
The good clinical and radiological long-term results as well as the satisfactory survival rate after total knee replacement with the NexGen CR® prosthesis are comparable with the results of other long-term studies using the NexGen CR® and assimilable prosthesis. Our results demonstrate that quality of life was improved by the implantation of the NexGen CR® prosthesis even a long time after the index procedure despite old age and comorbidity of the patients.