BACKGROUND: Periprosthetic distal femoral fractures (PDFF) are challenging injuries, as mostly geriatric patients with serious comorbidities are affected. Revision to a distal femoral replacement (DFR) is often the best option in very distal fractures, poor bone stock and/or loose total knee replacement. Data on outcome after these surgeries is limited.

OBJECTIVES: This study was initiated to analyze the outcome after distal femoral replacement for periprosthetic distal femoral fractures.

MATERIALS AND METHODS: Data of the German Arthroplasty Registry (EPRD) were analyzed. From a total of 43,945 revision knee replacement surgeries in the registry, 629 patients could be identified with a PDFF in which a DFR was used for revision. The mean age was 79.1 years, and 84.1% were female. Revisions and mortality were analyzed and compared with patient groups with a similar procedure (revision total knee arthroplasty) or similar general condition (fracture hip replacement). To make the groups more comparable, matched-pair-analyses were performed that included age, gender, BMI and comorbidities as matching parameters.

RESULTS: Within 1 year after surgery 17.1% of the patients died and 10.4% were revised. Within 4 years 35.5% died and 22.3% were revised. Revision rates were lower in elective knee revisions (1 year 6.0%, 4 years 16.8%). Periprosthetic joint infection (PJI) accounted for 50% of all revisions, resulting a PJI rate of 7.3%. Mortality after DFR was similarly high as after fracture hip arthroplasty.

CONCLUSION: After DFR for PDFF every third patient died, and every fifth patient needed revision within 4 years after surgery, which demonstrates the severity of this injury. Efforts should be undertaken to provide optimal treatment to these high-risk patients to reduce unfavorable outcomes. Surgeries should be well prepared and performed as early as possible in hospitals with adequate experience.