Periprosthetic Distal Femur Fractures: Review of Current Treatment Options

The geriatric population in general and specifically recipients of total knee arthroplasty (TKA) have increasing functional demands along with an increasing life expectancy. Certain intraoperative aspects of the index procedure, revision TKA, or the patient’s physiology (i.e.- osteoporosis, rheumatoid arthritis, neurologic disease) predispose the patient to post-operative periprosthetic distal femur fractures (PDFF). This review describes the epidemiology, classification, examination, and treatment options of PDFF. Osteoporosis and intraoperative anterior femoral cortex notching are primary patient and surgeon specific factors, respectively. The two most commonly used classification systems were described by Rorabeck and Kim and should be used to guide the surgeon’s choice of treatment.  The non-operative treatment of PDFF is rare, requires close radiographic follow up, and delayed union is common. Open reduction with internal fixation (ORIF) is best accomplished with minimally invasive techniques and distal locking screws. Retrograde, intra-medullary nail fixation is technically difficult, but provides earlier weight bearing and comparable time to union as ORIF.  Revision TKA is indicated in patients with adequate bone stock, a simple fracture pattern without ligamentous instability, and a loose or malaligned femoral component.  Allograft-prosthetic composite (APC) or distal femoral replacement (DFR) is indicated for patients presenting with a PDFF about poor or deficient bone stock.  Patients with PDFF present a challenge to the arthroplasty surgeon in regards to choice of treatment and increased morbidity and mortality post-operatively. Close follow up is required and fracture union is often delayed.