Background Pattellofemoral complications are one of the most common problems aftter total knee arthroplasty. No widely accepted view or criteria currently exist concerning whether or not patellar resurfacing should accompany total knee arthroplasty for osteoarthritis of theknee.
Objectives We recently devised our own criteria for application of patellar resurfacing and performed selective patellar resurfacing in accordance with this set of criteria. The clinical outcome was analyzed.
Methods The study involved 230 knees on which total knee arthroplasty was performed between 2005 and 2011 because of osteoarthritis of the knee. The mean age at operation was 74, and the mean postoperative follow-up period was 58 months. Our criteria for application of patellar resurfacing are given below. Criterion A pertains to evaluation of preoperative clinical symptoms related to the patellofemoral joint: (a) interview regarding presence/absence of pain around the patella, (b) cracking or pain heard or felt when standing up from a low chair, (c) pain when going upstairs/downstairs. Because it is difficult for individual patients to identify the origin of pain (patellofemoral joint or femorotibial joint), the examiner advised each patient about the location of the patellofemoral joint when checking for these symptoms. Criterion B pertains to intense narrowing or disappearance of the patellofemoral joint space on preoperative X-ray of the knee. Criterion C pertains to the intraoperatively assessed extent of patellar cartilage degeneration corresponding to class 4 of the Outerbridge classification. Patellar resurfacing was applied to cases satisfying at least one of these sets of criteria (A-a,-b,-c, B and C). Postoperatively, pain of the patellofemoral joint was evaluated again at the time of the last observation, using Criterion A-a,-b,-c.
Results Patellar resurfacing was applied to 25 knees in accordance with the criteria mentioned above. There were 23 knees satisfying at least one of the Criterion sets A-a,-b,-c, 18 knees satisfying Criterion B and 15 knees satisfying Criterion C. (Some knees satisfied 2 or 3 of Criteria A, B and C). When the pain originating from patellofemoral joint (Criterion A) was clinically assessed at the time of last observation, pain was not seen in any knee of the resurfacing group and the non- resurfacing group.
Conclusions Whether or not patellar resurfacing is needed should be determined on the basis of the symptoms or findings related to the patellofemoral joint, and we see no necessity of patellar resurfacing in cases free of such symptoms/findings. When surgery was performed in accordance with the criteria on patellar resurfacing as devised by us, the clinical outcome of the operated patellofemoral joint was favorable, although the follow-up period was not long. Although further follow-up is needed, the results obtained indicate that selective patellar resurfacing yields favorable outcome if applied to cases judged indicated with appropriate criteria.
References Rodriguez-M, et al. The Outerbridge classification predicts the need for patellar resurfacing in TKA. Cliin Orthop Relat Res. 2010 May; 468(5):1254-7.
Helmy N, et al. To resurface or not to resurface the patella in total knee arthroplasty. Cliin Orthop Relat Res. 2008 Nov; 466(11):2775-83.
Shin HN, et al. Long-term changes of the nonresurfaced patella after total knee arthroplasty. J Bone Joint Surg Am. 2004 May; 86-A(5): 935-9
Disclosure of Interest None Declared