Outcomes of periprosthetic distal femur fractures following total knee arthroplasty: Intramedullary nailing versus plating.

BACKGROUND

Periprosthetic distal femur fractures (PPDFFs) present a challenge in terms of optimizing fixation in patients with poor bone quality and limited bone stock. The main treatment options include laterally based plating and intramedullary nailing. We hypothesized that treatment of PPDFFs with intramedullary nails would result in improved union rate, fewer complications, and an equivalent rate of malalignment compared to plating.

MATERIALS AND

METHODS

Cases of PPDFFs were identified through a query of our institutional trauma database between 2011-2018. Adult patients (>18 years) were included if they sustained a fracture of the distal femur around a total knee arthroplasty (TKA) that was not initially treated at another institution. The anatomic lateral distal femoral angle (aLDFA) and the anatomic posterior distal femoral angle (aPDFA) were measured on the follow-up radiographs.

RESULTS

Ninety-seven PPDFFs in 97 patients, with a mean age of 76 years and 74% female were identified. Plating was used in 74 patients (76%) and 23 patients (24%) were treated with intramedullary nailing. Extension deformity in the sagittal plane was more common following intramedullary nailing compared to plating (10/23 nailing versus 10/74 plating) (p=0.002). There were 12 reoperations (12/75, 16%), and the method of fixation was not associated with rate of reoperation (p=0.9).

CONCLUSION

Intramedullary nailing was associated with an increased risk of malalignment, most commonly an extension deformity, in this series. However, malalignment was not associated with worse outcomes.