Distal Femur Fracture
Synonyms: Supracondylar femur fracture, distal femur fracture
Distal Femur Fx ICD-9
Distal Femur Fx Etiology / Epidemiology / Natural History
- High-energy (MVA, Falls from height) in young patients, fragility fracture in elderly patients, periprosthetic fracture.
Distal Femur Fx Anatomy
- Hoffa Fragment = coronal (frontal) plane fragment associated with comminution in the intercondylar notch. Present in @1/3 of Type C fractures.
Distal Femur Fx Clinical Evaluation
- ATLS resuscitation. These can be high enegery injuries, assessment should begin with the A,B,C's.
- Obvious deformity of knee/thigh often with limb shortening
- Document neurovascular exam before and after any treatment.
Distal Femur Fx Xray
- A/P and lateral views of the knee.
- CT: Ct scan is nearly always indicated for pre-operative planning as there is a high association with coronal plane fractures which are difficult to see on plane films. (Nork SE, JBJS Am 2005;87:564-569)
Distal Femur Fx Classification/Treatment
- AO Classification
- Type A=extraarticular
-Treatment = retrograde IM nail or ORIF usually via minimal lateral approach
- Type B=unicondylar fractures
-Treatment = percutaneous lag screw fixation +/- plating
- Type C=intrarticular fractures
-Treatment = ORIF via modifed lateral parapatellar arthrotomy (Starr AJ, JOT 1999;13:138). Generally articular reduction and submuscular locked plate positioning via a small incision with spanning of metaphyseal comminution.
- Periprosthetic distal femur fracture
-Treatment = Lateral locked plating with indirect reduction (Ricci WM, JOT 2006;20:190).
- Consider primary TKA with tumor prosthesis for elderly osteoporotic patients with severe comminution. The linea aspera is the key to rotational alignment during surgery. Drape out normal leg and ensure femoral head can be visualized with c-ram.
- AO Classification
Distal Femur Fx Associated Injuries / Differential Diagnosis
- Multiply injured patient
- Meniscal tear
- Knee ligmanetous injury: ACL / MCL / LCL / PCL / PLC.
Distal Femur Fx Complications
Distal Femur Fx Follow up care
Distal Femur Fx References
- 100% union, 5% valgus malunion, 9% external rotation of 10°-15°. 14% required implant removal. Average knee ROM = 5°-114° for locked plating. (Weight M, JOT 2004;18:503).