Should megaprosthesis implants be a viable option in elderly patients after distal femur and periprosthetic distal femur fractures?-a retrospective cohort study

Background: Distal femur fractures (DFF) and periprosthetic distal femur fractures (PDFF) in elderly patients are challenging to manage, often requiring the use of distal femur replacement (DFR) implants to manage severe bone loss and comminution. The study's main purpose was to analyze outcomes and complications of DFR implant after DFF or PDFF at our institution to understand the feasibility and reliability of this treatment considering a review of the current literature. Methods: Fourteen consecutive patients undergoing total knee replacement with megaprosthesis implant from January 1st, 2017 to January 1st, 2021, at our institution were retrospectively analyzed. Inclusion criteria were age =65 years and DFF or PDFF after primary total knee arthroplasties (TKA) implantation. Patient-reported outcome measures (PROMs) such as Knee Society Score (KSS) and Oxford Knee Score (OKS) were analyzed, as well as radiographic pre- and post-operative imaging. Complications were recorded from the early postoperative period to the last follow-up. Results: Nine patients were diagnosed with PDFF and five with DFF. At a mean follow-up of 30.7 months (range, 12 to 69 months), the mean KSS knee score was 79.5 +/- 11.2; the mean KSS function score was 69.0 +/- 17.9. The mean OKS was 31.6 +/- 8.9. The mean age at intervention was 82.1 +/- 7.6 years. Two delayed wound closures and one chronic prosthetic joint infection (PJI) were observed. No death was observed at the last follow-up. Conclusions: Megaprosthesis implants could be a suitable option in elderly, arthritic patients diagnosed with complicated DFFs and PDFFs, allowing joint function preservation and a rapid return to daily activities. DFR remains an intervention burdened by devastating complications that must be considered in the treatment choice.