ABSTRACT
We retrospectively reviewed the experience of a large international multi-centre study of primary total knee arthroplasty with mobile bearing design and modifications of the tibial component to allow for bicruciate preservation, posterior cruciate retention, or sacrifice. Twenty-seven surgeons performed 4,743 total knee replacements between 1981 and 1997. Implants inserted were 324 that retained both cruciate ligaments, 2,165 that retained the posterior cruciate, and 2,254 that sacrificed both cruciates. The patella was resurfaced in 2,838 and unresurfaced in 1,905. With failure defined as revision or reoperation for any reason, the overall survivorship was 79% at 16 years' follow-up. Revision occurred in 259 (5.4%) knees out of the entire cohort. The risk adjusted rates of failure were higher in females, younger patients, osteoarthritis, post-traumatic arthritis, and in patients who had a meniscal bearing prosthesis or patellar resurfacing. The most common cause of revision was bearing-related issues including chronic instability, bearing subluxation, bearing dislocation, or bearing wear in 2.3%.
Subject(s)
Arthroplasty, Replacement, Knee/mortality , Arthroplasty, Replacement, Knee/methods , Cohort Studies , Female , Follow-Up Studies , Humans , Knee Prosthesis , Male , Polyethylene/chemistry , Proportional Hazards Models , Prosthesis Failure , Retrospective Studies , Risk , Survival Rate , Tibia/pathology , Time Factors , Treatment OutcomeABSTRACT
BACKGROUND: Mobile-bearing knee designs represent an alternative to conventional fixed-bearing total knee arthroplasty. We present the results of a prospective, intermediate-term clinical follow-up study of the bicruciate ligament-sacrificing porous-coated Low Contact Stress rotating-platform total knee design. METHODS: Between February 1984 and January 1994, 528 uncemented primary knee replacements were performed in 421 patients. All patellae were resurfaced with use of the Low Contact Stress rotating patellar component. The average age of the patients at the time of the index procedure was sixty-nine years. The study group included 261 women and 160 men. Patients were evaluated at three months, six months, and yearly thereafter with use of the 100-point New Jersey Orthopaedic Hospital knee-scoring system. In addition, a radiographic analysis of the tibial, femoral, and patellar components was performed at each interval. RESULTS: There were twenty-nine failures that resulted in revision. The Kaplan-Meier estimate of implant survival at twelve years was 89.5% (95% confidence interval, 83.4% to 95.6%). The total clinical scores improved significantly compared with the preoperative scores for the first twelve months postoperatively and then plateaued. Three hundred and twenty-one knees had adequate radiographic follow-up (average, 8.1 years; range, five to twelve years). Zonal radiographic analysis revealed ninety-three instances of radiolucent lines (eighty-two of which measured <1 mm in width), with the greatest number of radiolucent lines (thirty-nine) being located around the tibial tray stem. None of these lines were deemed to be progressive, and no knee with a radiolucent line that measured >2 mm was revised because of failure. CONCLUSIONS: This first-generation uncemented, mobile-bearing, bicruciate ligament-sacrificing knee replacement was associated with a good survival rate and demonstrated clinical efficacy during the five to twelve-year follow-up interval. .
Subject(s)
Arthroplasty, Replacement, Knee/methods , Knee Prosthesis , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Postoperative Complications/epidemiology , Prospective Studies , Prosthesis Failure , Reoperation/statistics & numerical data , Survival AnalysisABSTRACT
Two hundred fifty-six primary cementless meniscal-bearing total knee arthroplasties were performed between May 1985 and January 1989. All knees were replaced with a low contact stress metal-backed anatomic mobile patella. The average patient follow-up was 11.5 years. No patellae were revised for failure of fixation and no dislocations or subluxations were reported. One patella was revised for polyethylene wear, and one well-functioning component was removed at the time of revision to facilitate range of motion and wound closure. The survival estimate at 12 years was 99.5%. Compared to the high incidence of failure of metal-backed fixed-bearing patellae components, the anatomic rotating patella provides durable long-term results with a low incidence of complications.
