Artikel
Ten Year Survivorship Analysis After Cemented And Uncemented Medial Unicompartmental Knee Arthroplasty. A Prospective, Long-Term Follow-Up Study
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Veröffentlicht: | 18. Oktober 2011 |
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Gliederung
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Questionnaire: In the recent past, unicompartmental knee arthroplasty (UKA) is seen as a good alternative to total knee replacement (TKR) and therefore the interest in UKA for patients with unicompartmental tibiofemoral non-inflammatory disease appears to be increasing. The following prospective study describes the clinical outcome and the 10 years survival rates in a series of 242 cemented and uncemented medial Unicompartmental Knee Arthroplasty (UKA) cases performed in 236 patients for medial osteoarthritis.
Methods: Details from patients treated by the senior author (GB) with unicompartmental knee arthroplasty were recorded and updated on an annually base from 1991 up to the present. The following study currently covers data until 1999. Early outcomes were reported and published in 2004 and 2010. Patients were assessed by an independent clinical observer using the Knee Society Rating System as a validated outcome measure. Kaplan-Meier analysis was used to calculate the 10 year survival rates using the endpoint of revision for any cause.
Results and Conclusions: The cemented femur (tibia) device was used in 161 (155) and the uncemented femur (tibia) device in 81 (87) cases. There was one lost of follow-up. The mean elapsed time since the day of surgery was 10.4 years (maximum 18.7 years). There were no failures due to progression of lateral osteoarthritis, aseptic loosening of the femur component or due to polyethylene wear. Two (0.99%) traumatic and 4 (1.99%) non-traumatic bearing luxation occurred and there were three revisions due to aseptic loosening of the tibia component (1.49%). Two revisions were caused by traumatic loosening (0.99%), one was caused by an infection (0.49%) and one was based on misplacement of the components (0.49%). There had been thirteen surgeries for revision because of failures for any reason and 41 patients had been withdrawn because they had died, giving an all over cumulative survival rate at ten years (knees at risk=201) of 94.07%. The Knee Society Rating System (KSRS) showed a significant improvement. The knee (function) score showed an increase from pre 33.5 (54.7) to post operative 94 (83.6) Points. The Range of Motion gained in average from 106.8 to 122.3 degrees. Remarkably there was no revision surgery neither for aseptic loosening, nor based on infection for the uncemented device and we could not detect a significant difference in the ten year survival rate of patients with a BMI <30 (95.59%), BMI from 30 to 36 (92.39%) and a BMI>36 (100%). It is widely accepted that UKA has a lower morbidity with a lower risk of serious complications, including infection, and is significantly less expensive. Given strict indication criteria's and appropriate surgical expertise, UKA has a high survival rate comparable to TKA and shows a significant improvement in knee and function scores. The results indicate that there is no relationship between BMI and 10 year survival rate in this cohort.