Patellar Resurfacing: Does It Affect Outcomes of Distal Femoral Replacement After Distal Femoral Resection?

BACKGROUND: Patellar resurfacing after routine arthroplasty remains controversial. Few studies have specifically examined the effect of patellar resurfacing on outcomes after resection of the distal part of the femur and reconstruction with a megaprosthesis. Our objective was to compare the outcomes of megaprosthesis reconstructions of the distal part of the femur with and without patellar resurfacing after resection of a distal femoral tumor. METHODS: We retrospectively reviewed the clinical records of patients with a femoral tumor who underwent resection of the distal part of the femur and endoprosthetic reconstruction between 1993 and 2013. We excluded patients who had had extra-articular knee resection, patellectomy, revision, reconstruction with an expandable prosthesis, or a proximal tibial replacement associated with the distal femoral replacement. We compared demographic characteristics, surgical variables, anterior knee pain, range of motion, extensor lag, Insall-Salvati ratio, Insall-Salvati patellar tendon insertion ratio, impingement, patellar degenerative disease, additional patellar procedures, complications, and Musculoskeletal Tumor Society (MSTS) score between the patellar resurfacing and nonresurfacing groups. RESULTS: One hundred and eight patients--sixty without patellar resurfacing and forty-eight with patellar resurfacing--were included in the study. The mean age was 33.9 years (range, twelve to seventy-five years). There were fifty-four men and fifty-four women. The mean duration of follow-up was 4.5 years (range, 0.7 to twenty years). There was no significant difference in anterior knee pain between the groups (p = 0.51). Anterior knee pain did not significantly affect the range of motion, extensor lag, or reoperation or complication rate. Patellar degenerative disease occurred in 48% of the nonresurfaced knees but was not associated with focal pain. Complication rates were similar in the two groups, although peripatellar calcifications were significantly more common in the resurfacing group (19% versus 2%; p = 0.005). There was no significant difference in the mean MSTS score between the nonresurfacing (81%) and resurfacing (71%) groups (p = 0.34). CONCLUSIONS: There were no differences in anterior knee pain, range of motion, extensor lag, or MSTS score between the patients with and those without patellar resurfacing. There were no cases of patellar component loosening or revision. In light of the similar outcomes in the two groups, the decision to resurface should be left up to the individual surgeon, who should take into account preoperative peripatellar pain and the status of the patella at the time of resection. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Patellar Height Decreasing After Distal Femur Endoprosthesis Reconstruction Does Not Affect Functional Outcome.

INTRODUCTION: The patellar height can influence extensor mechanism and the knee function. Thus, during knee arthroplasty, the surgeon seeks to maintain the correct patellar height. However, it is more difficult to define and maintain the correct patella height in megaprosthesis reconstructions after tumor resections. The objective of this study was to evaluate patellar height after distal femur endoprosthesis reconstruction and its association to knee function. METHODS: This retrospective analysis included 108 patients who underwent distal femur resections and endoprosthesis reconstruction. The minimum follow-up was 1 year or until the patients underwent patellar resurfacing or endoprosthesis revision. Patellar height was calculated using Insall-Salvati ratio (ISR) and Insall-Salvati patellar tendon insertion ratio (PTR) at 2 different times: postoperatively and at the final follow-up. The postoperative ratio was calculated using the best postoperative radiograph taken at least 1 month after the procedure. The final measures were based on the radiograph available at the last follow-up consultation. The ISR and PTR were associated to anterior knee pain (AKP), range of motion (ROM), and extension lag (EXL). RESULTS: The average follow-up was 4.5years. The mean postoperative ISR was 1.02, and the mean ISR at final follow-up was 0.95 (P<.0001). The mean postoperative PTR was 1.45, and the mean PTR at final follow-up was 1.40 (P=.016). There was no association between patellar height and AKP, ROM, and EXL. Patellar height decreases significantly after distal femur resections but does not affect AKP, ROM, and EXL.