Reviewing Patellar Resurfacing in Total Knee Replacement

Looking at the results of many studies can offer answers to a single question. In this study the question of interest was: Should the kneecap (patella) be replaced during a total knee replacement (TKR)? Looking at studies one at a time can't always give the information needed to answer the question.

Researchers reviewed the results of 15 studies done between 1996 and 2003. The studies were all randomized control trials (RCT). This means patients were put in one of two groups randomly: the experimental group and the control group. RCT allows scientists to tell when the results are directly from the experiment. A blinded RCT means no one (subjects or researchers) knows which group the subjects are in.

All patients had arthritis, either osteoarthritis or rheumatoid arthritis. Half the group had the patella replaced. Ten different types of joint implants were used. This is called patellar resurfacing. The other half didn't have the patella replaced (nonresurfaced). For patients who kept their own patella, the surgeon smoothed any rough edges and removed any torn cartilage or bone spurs.

More patients with nonresurfaced patellas had problems later. Reoperation was much higher for this group. The nonresurfaced group also had more knee pain and especially pain when climbing stairs. Overall results seemed to point to patellar resurfacing as the better way to go when replacing the knee joint.

The authors say that this is just a general opinion. Follow-up in most studies wasn't long enough to give a complete picture of results. The broad range of implant types and level of surgeon experience were factors in the outcome. The type of patient and the methods of operating affect results too.



References: R. S. Nizard, MD, PhD, et al. A Meta-analysis of Patellar Replacement in Total Knee Arthroplasty. In Clinical Orthopaedics and Related Research. March 2005. Vol. 432. Pp. 196-203.