Total knee replacement is one of the most common orthopedic procedures with more than 700,000 performed each year in the United States.1 Fractures that occur around a total knee replacement, such as periprosthetic distal femur fractures, are devastating injuries that can be challenging to treat. Supracondylar fractures that occur above a femoral prosthesis have adequate bone distally for fixation with a lateral plate and screws or a femoral nail. A distal femoral replacement may be necessary in patients who have poor bone stock distally or if the fracture occurs in close proximity to the femoral prosthesis. Distal femoral replacements have also been performed in patients with significant comminution of the distal femur and osteopenia. Distal femoral replacements are especially beneficial in elderly patients who can bear weight as tolerated immediately postoperatively. Rapid mobilization decreases morbidity and prevents the 8-week period of immobilization that is required with open reduction and internal fixation or intramedullary nailing.1,2

The first step in a distal femoral replacement is to cut the distal femur down to viable bone. The femoral and tibial sides are then prepped to accept their corresponding prostheses, which are usually cemented stemmed components. The femoral and tibial components are most commonly joined together with a hinge to provide more stability to the knee. Distal femoral replacements have demonstrated high survivorship as well as relatively good function in the appropriate population.2,3

Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).

References

  1. Williams SN, Wolford ML, Bercovitz A. Hospitalization for total knee replacement among inpatients aged 45 and over: United States, 2000-2010. NCHS Data Brief No. 210; August 2015.
  2. Jassim SS, McNamara I, Hopgood P. Distal femoral replacement in periprosthetic fracture around total knee arthroplasty. Injury. 2014;45(3):550-553.
  3. Appleton P, Moran M, Houshian S, Robinson CM. Distal femoral fractures treated by hinged total knee replacement in elderly patients. J Bone Joint Surg Br. 2006;88(8):1065-1070.
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