Comparison of Survivorship of Distal Femoral Replacements by the Fixation Method.

BACKGROUND

Distal femoral replacements (DFRs) are utilized in primary and revision total knee arthroplasty in the setting of segmental femoral bone loss, but they are known to have high failure rates. This study aimed to examine DFR survival by fixation method to determine if the use of cemented fixation or a femoral cone may decrease the risk of aseptic loosening and all-cause revision.

METHODS

This study was a retrospective, single-institution cohort study of patients who underwent DFR for revision total knee arthroplasty or native distal femoral fracture. Patient demographic and surgical data were collected via chart review, and the fixation method was determined using operative notes and radiographs. Patients were divided into cohorts by DFR fixation method: cemented, cementless, and cemented with a femoral cone. Outcomes of interest included revision rates, revision causes, and DFR survival by fixation method. We identified 243 DFRs for study inclusion: 187 cemented, 30 cementless, and 26 cemented with femoral cone. No significant differences were seen among groups for indication of primary DFR (P = 0.54).

RESULTS

By the last follow-up, 55 (29.4%) cemented, four (13.3%) cementless, and six (23.1%) cemented with femoral cone DFRs had required revision (P = 0.16). Causes of revision, including aseptic loosening, periprosthetic joint infection, periprosthetic fracture, and soft tissue failure, were not significantly different among groups (P = 0.97). Femoral loosening was the primary cause of revision in eight (14.5%) cemented, one (25.0%) uncemented, and one (16.7%) cemented with femoral cone revised DFRs (P = 0.62). The 5-year survival rates for cemented, uncemented, and cemented with femoral cone were 72, 87, and 77%, respectively.

CONCLUSIONS

In our retrospective cohort, the method of DFR fixation did not significantly affect rates or causes of revision. This study represents a larger sample of DFRs than comparable analyses.