Availability of Patella Resurfacing in Primary Total Knee Arthroplasty Through Evaluation and Analysis of the Patella in Revision Total Knee Arthroplasty

Noh, Young Min; Nam, Kyung Mo; Kang, Dae Myung; Kim, Dong Heon

Abstract

PURPOSE
The aim of this study was to discuss about availability of patella resurfacing in primary total knee arthroplasty through evaluation and analysis of the patella in revision total knee arthroplasty.
MATERIALS AND METHODS
The study was performed for 27 patients who could be followed up more than 12 months after having the revision TKA from March, 2004 to July 2008 among 105 patients (145 knees) who could be followed up more than 5 years after having primary TKA due to degenerative arthritis from 1989 to 1997. There were Group A (15 knees) which had patella resurfacing in revision TKA without patella resurfacing in primary TKA, Group B (12 knees) which had patella resurfacing in primary TKA, but didn't have patella resurfacing in revision TKA. There was difference of mean 11.2 years (6~15 years) between the time that the patients had primary TKA and the time that the patients had revision TKA. The patients consisted of 3 males and 24 females. The average age of the patients who had revision TKA was 76.2 years old (68~87). The Feller's patella score was used as clinical evaluation system after primary TKA, before and after revision TKA, and last follow-up. Ahlback's score was used by for the radiological evaluation of preoperative and postoperative outcome. And Outerbridge classification was used for the evaluation of group A which about wear of articular surface of patellofemoral joint in primary TKA and revision TKA, and positions of wear were classified.
RESULTS
The Feller's patella score of group A, The outcome before revision TKA, 14.5 points, after 3 months TKA, 22.6 points, and 12 months follow-up, 24.2 points. The Feller's patella score of group B, The outcome before revision TKA, 24.2 points, after 3 months TKA, 24.3 points, and 12 months 24.8 points. The Ahlback score of group A decreased from 3.4 to 1.7 points, group B decreased from 1.6 to 1.5 points and group C decreased from 3.8 to 1.7 points. The Outerbridge classification of group A was mean 1.9 grade in primary TKA, and mean 3.6 grade in revision TKA. The wear of patella mainly occurred at medial facet.
CONCLUSION
The patella resurfacing in primary TKA is considered as a useful treatment on the basis of these clinic and radiologic evaluation.