Jesse Wolfstadt MD MSc FRCSC1 and Aaron Nauth MD MSc FRCSC2 1Division of Orthopaedic Surgery, Department of Surgery, McMaster University, Hamilton, ON, Canada 2Division of Orthopaedic Surgery, Department of Surgery, University of Toronto, Toronto, ON, Canada The management of periprosthetic distal femur fractures can be challenging and is often complicated by poor bone quality or bone stock. The ideal management strategy to achieve the best short‐term (morbidity, rehabilitation) and long‐term (knee function, implant survivorship, union rates, complications) outcomes remains unclear. Most patients with distal femur periprosthetic fractures are low‐demand, medically complex patients. Careful assessment should be performed preoperatively to assess the quality and amount of bone stock, stability of components, and integrity of the collateral ligaments. Stable components with adequate bone stock are often treated with ORIF with either an RIMN or periarticular locked plating. In patients with unstable components or inadequate bone stock or quality, a revision TKA with either revision components or a distal femoral replacement (DFR) may be indicated. Figure 56.1 Preoperative radiographs of a 78‐year‐old female patient demonstrating a distal femur periprosthetic fracture above a previously well‐functioning TKA (A and B). Nine‐month postoperative radiographs demonstrating healing following treatment with locked plating (C–E). PubMed, Ovid MEDLINE, and Cochrane databases were searched with the following terms: periprosthetic femur fracture, distal femoral replacement, periarticular plate, locked plate, open reduction internal fixation, intramedullary nail, and reamed intramedullary nail. The quality of evidence available to answer the question is limited to four retrospective studies of level III evidence. While there are many studies investigating the outcomes of ORIF of distal femur periprosthetic fractures,1,2 there is a lack of studies investigating revision to a DFR for these fracture types.3,4 There were only four level III studies that directly compared the outcomes of ORIF and DFR.5–8 Thirty‐nine patients treated with ORIF using either a conventional or locked plating were retrospectively compared to 29 patients treated by revision to a DFR.5 Treatment selection with regard to ORIF versus DFR was selected at the discretion of the surgeon based on the fracture pattern. All non‐ or minimally displaced fractures were treated with ORIF and all fractures with femoral component loosening were treated with DFR. Displaced fractures with a stable femoral component were treated with both techniques (33 with ORIF and 12 with DFR). There was no statistically significant difference between ORIF and DFR regarding clinical outcome (p = 0.3), survivorship (0.729, hazard ratio [HR] = 1.19; 95% confidence interval [CI]: (046–3.09)), and infection (1.000). The only significant difference found was the occurrence of nonunion (15.4% with ORIF group vs 0% with DFR, p = 0.03). Five of the six cases of nonunion eventually underwent conversion to DFR. Three patients (10.3%) in the DFR group required repeat surgery for patellar maltracking. Ruder et al. performed a retrospective review to assess the functional outcomes of 23 patients treated with DFR and 35 patients treated with ORIF for a distal femur periprosthetic fracture (PPF).6 The only significant difference found preoperatively was in patient age, with older patients being more likely to receive a DFR (78 in ORIF vs 83 in DFR, p = 0.008). There was no difference in total complications (p = 0.46), hospital length of stay (p = 0.51), ambulatory status (p = 0.08), or mortality. The authors suggested that age is the predominant factor predicting ambulatory status and functional outcomes following distal femur PPF, irrespective of treatment modality. A recent retrospective study by Hoellwarth et al. reviewed 87 patients treated with locked plating and 53 treated with DFR.8 There was no significant difference between locked plating and DFR for 90‐day mortality (9% vs 4%, p = 1.0), one‐year mortality (22% vs 10%, p = 0.41), revision surgery at one year (9% vs 3%, p = 0.36), and maintaining ambulation (77% vs 81%, p = 0.30). The final study was a retrospective review of 35 patients (36 knees) who underwent primary DFR for periprosthetic fractures and 13 patients with failed ORIF who were converted to a DFR.7 Thirteen of 141 patients (9.2%) had failed primary ORIF for distal femur periprosthetic fracture, requiring conversion to DFR. The most common causes for failure include nonunion, infection, and refracture. There was a trend toward greater postoperative complications for patients who failed ORIF and were converted to DFR compared with primary DFR (38.5% vs 16.7%, p = 0.09). The optimal choice of implant for ORIF of periprosthetic distal femur fractures with stable components remains unclear.
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Periprosthetic Fractures: Knee
Clinical scenario
Top three questions
Question 1: In elderly patients with displaced periprosthetic distal femur fractures, are outcomes improved with open reduction and internal fixation (ORIF) compared to revision TKA?
Rationale
Clinical comment
Available literature and quality of the evidence
Findings
Resolution of clinical scenario
Question 2: In elderly patients with displaced periprosthetic distal femur fractures, are outcomes improved with retrograde intramedullary nailing (RIMN) compared to periarticular locked plating?
Rationale
Clinical comment
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