Primary Total Knee Arthroplasty for Distal Femur Fractures: A Systematic Review of Indications, Implants, Techniques, and Results.

Distal femur fractures (DFFs) in elderly patients historically were difficult to treat because of osteoporotic bone, comminution, and intra-articular involvement. Current surgical treatment options, including intramedullary nailing, internal fixation, and external fixation, are complicated by prolonged immobility, malunion, and nonunion. Furthermore, fixation increases the complexity of subsequent arthroplasty. Primary total knee arthroplasty (TKA) is a rarely used treatment for acute DFF but may be of benefit in select patients. For a systematic review of the reported indications, techniques, implants, outcomes, and complications of TKA for DFF, we searched the major databases Medline, EMBASE (Excerpta Medica dataBASE), and the Cochrane Library. Few studies of this technique have been reported, and the majority of published studies have been level III and level IV, with heterogeneous results and outcomes. Many of the patients in these studies achieved early weight-bearing with primary TKA. Complication rates varied and may be higher for older patients with more comorbidities, but whether these rates are higher than those of patients treated with internal fixation is unclear. Modular constrained implants may be appropriate for comminuted intra-articular fractures, whereas extra-articular fractures may be sufficiently managed with unconstrained implants supplemented with fracture fixation.