Study: Outcomes Similar With or Without Patellar Resurfacing in Oncologic Limb-Salvage Surgery

A study comparing the outcomes of megaprosthesis reconstruction of the distal femur with or without patellar resurfacing after resection of femoral tumors found no statistical difference in anterior knee pain, range of motion, extension lag, or ISOLS/MSTS score.

In light of these results, based on findings in 108 patients from the MD Anderson Cancer Center database, “the decision to resurface the patella in the oncologic patient who will undergo limb salvage surgery with rotating hinge prosthesis should be performed on a case-by-case basis and should depend on the status/appearance of the patella,” said Mauricio Etchebehere, MD, PhD, who presented the study in Poster 551.

Valerae O. Lewis, MD, the senior author for the study, noted that patients who receive endoprostheses are generally younger than those who receive total knee arthroplasties. “In the orthopaedic oncologic community, there are two different trains of thought regarding patella resurfacing,” she said. “One is that in this younger population the lack of resurfacing can lead to anterior knee pain. Another is that resurfacing of the patella simply adds another component in the reconstruction of these young patients that can fail and lead to additional revision/operations.

Abstract
Introduction:
The necessity for patellar resurfacing after arthroplasty remains controversial. To date, few studies have specifically examined the effect of patellar resurfacing on outcomes after resection and megaprosthesis reconstruction of the distal femoral tumor resection. Objectives were to compare the outcomes of megaprosthesis reconstructions of the distal femur with or without patellar resurfacing after resection of femoral tumors.

Methods: An internal review board–approved retrospective review of the tumor registry and orthopaedic oncology database was performed. The clinical records of patients who underwent distal femur resection and endoprosthetic reconstruction for femoral tumors between 1993 and 2013 at our institution were identified. We excluded patients who had extra-articular knee resection, patellectomy, revisions, expandable prostheses, and proximal tibia replacement associated with the distal femur replacement. We compared demographic characteristics; surgical variables, including the use or not of patellar resurfacing, type of implant, amount of femur resected, surgical approach; and functional outcomes, including anterior knee pain (AKP), range of motion (ROM), extension lag (EXL), feeling of instability, patellar subluxation/dislocation, Insall-Salvati ratio, Insall-Salvati patellar tendon insertion ratio, impingement, patellar degenerative disease, additional patellar procedures, prosthesis complications, and ISOLS/MSTS score.

Results: One-hundred-eight patients were included in the study, 60 without patellar resurfacing and 48 with patellar resurfacing. Mean age was 33.9 years (range, 12 to 75 years.), with 54 men and 54 women, with a mean follow up of 4.5 years (range, 0.7 to 20 years). There was no significant difference in incidence of AKP between groups (P = 0.51). AKP did not significantly affect ROM, EXL, or complication rates. Patellar degenerative disease occurred in 48% of the nonresurfacing group but was not associated with pain (P = 0.35). Complication rates were similar in both groups, although patellar calcification was significantly more common in the resurfacing group (19% vs. 2%; P = 0.005). Six additional patellar procedures were done in the nonresurfacing group and three in the resurfacing group (P = 0.72), including three patellar resurfacings in the nonresurfacing group. No patient from the resurfacing group underwent patellar component revision. The ISOLS/MSTS scores from 62 patients were 81% in the nonresurfacing group and 71% in the resurfacing group (P = 0.34).

Conclusions: We observed no statistical difference in AKP, ROM, EXL, or ISOLS/MSTS score between patients undergoing distal femur replacement with or without patellar resurfacing. There were no incidences of patella loosening or revision. Thus, we feel that in light of the similar outcomes in both groups, the decision to resurface should be left up to the individual surgeon, taking into account the status of the patella at time of resection.  

Details of the authors’ disclosures as submitted to the Orthopaedic Disclosure Program can be found in the Final Program; the most current disclosure information may be accessed electronically at www.aaos.org/disclosure

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