gms | German Medical Science

Pain in the anterior knee remains an unsolved problem in knee endoprosthetics. The question of a necessary patellar replacement is subject to very controversial discussion. The objective of this prospective study was to compare medium-term results of three different methods of patellar resurfacing during bicondylar resurfacing and to determine their possible advantages or disadvantages.

Bicondylar resurfacing was performed in 225 patients over a period from May 1998 to December 2002. The implantation was always performed in the same operation technique using the knee prosthesis system Natural-Knee Type-II. 3 patient groups of 75 patients each were formed, whereby patellar dorsal resurfacing was performed intraoperative in Group A. Patella osteophytes were removed in patients of Group B, the dorsal patellar surface smoothed with an oscillating saw and thus cartilage largely removed. The patellae of Group C were freed of marginal osteophytes, where present, otherwise they were left completely untouched. Evaluation was made using the Knee Society Clinical Rating Scores and a Patella Score. In addition, the extent of movement, position of the patella and patient satisfaction were determined.

In the early follow-up period, the patients in Groups A and B had better results than those in Group C. Later (2-year follow-up), the divergence narrowed and there were no longer significant differences in the scores, in the extent of movement or in patient satisfaction among the three groups. There was a tendency to better knee function in the patients without dorsal resurfacing after a longer period had elapsed since operation. The patella-related complication rate was low in all three groups.

No advantage which could justify the primary replacement of the patellar joint surface was seen in the medium-term course. There was also no increase in implantation-related complication rate, but the long-term results are not yet available. Compared to the two groups without dorsal resurfacing, the results of patients in whom cartilage was removed from the joint surface and modelled were more convincing in the early postoperative period. Rehabilitation advantages could result from this finding.