Functional Outcome of Patients with Malignant Tumors around the Knee Treated by Modular Endoprosthesis: A Comparative Study between Patellar Resurfacing and Nonresurfacing

Abstract

Patellar resurfacing with knee arthroplasty has always been controversial. The literature contains data that support both resurfacing and not resurfacing the patella. However, the literature does not review a lot of studies that address the impact of patellar resurfacing on the functional outcome following resection of distal femur tumors and limb salvage using modular prosthesis. Is patellar resurfacing better than nonresurfacing as regards functional outcome of modular prosthesis used for the treatment of tumors around the knee? Two groups of patients; both were subjected to wide excision of tumors around the knee and limb salvage using modular prosthesis. The first group underwent reconstruction with patellar resurfacing, while the second underwent reconstruction without patellar resurfacing. The age of these groups of patients ranged from 11 to 71 years. The patients were 17 males and 19 females. We evaluated patients using the musculoskeletal tumor society scoring system (MSTS), knee society final score, knee society function score, and anterior knee pain score. We found that MSTS functional score, knee society final score and knee society function score, and anterior knee pain score were all better in patients who underwent patellar resurfacing compared to nonresurfacing patients. However, only the difference in anterior knee pain score was statistically significant (P = 0.030). Differences in other scores between these two groups were all statistically insignificant (P value of the MSTS difference = 0.103, P value of the knee society final score difference = 0.423, and P value of the knee society function score difference = 0.337). Patellar resurfacing could be helpful in decreasing anterior knee pain and the necessity to future surgeries addressing patellofemoral pain, especially in revision cases, patients with patellofemoral problems, and patients with extensor mechanism weakness and those with anterior knee pain. Since Anterior Knee Pain Scale was the only scoring system, among all scoring systems used, that confirmed a significant impact of patellar resurfacing on the outcome following resections and reconstructions; we cannot give an explicit strong recommendation favoring the routine patellar resurfacing in all cases undergoing resections and reconstructions using modular prosthesis. We recommend patellar resurfacing in older patients, based on our results, which show possible benefit of patellar resurfacing in older patients. We think that old age and the preexisting knee arthritis could be relative indications for patellar resurfacing.