Diagnosis

Extra-articular fracture, simple 

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In diagnosis of a distal femur fracture it must first be determined whether or not there is an articular injury. In order to determine this, traction radiographs and/or CT scans with 3D reconstruction are helpful. In a nonarticular injury, the key challenges will be reduction against deforming forces and fixation of the distal femoral block (particularly in osteoporosis).

Options
1. Avulsions 
2. Oblique or spiral 
3. Transverse 

1. Avulsions 

Avulsions

Avulsions

These fractures can result from medium to moderate injury to the knee. Twisting injuries to the knee may result in major disruptions of the medial collateral, anterior cruciate, or posterior cruciate ligaments. It is most commonly the medial collateral and the anterior cruciate ligament that are injured. Patients with an anterior cruciate ligament injury will sometimes report a popping sensation from the knee at the time of injury. A rapid early hemarthrosis will occur with an anterior cruciate ligament injury. Anterior cruciate ligament injuries most commonly occur in young patients who engage in sporting activities.

Small avulsion fractures may be part of more complex injuries to the knee, such as multiligamentous knee dislocation. MRI can detect associated ligament damage. Consultation with and advice from specialist knee reconstructive surgeons may be needed.

Avulsion of the medial collateral ligament from the femur may result in calcification of this ligament after several years (the so called “Pellegrini-Stieda” lesion).

Avulsion of the lateral collateral ligament from the distal femur is known as the “Segond” fracture. “Segond” fractures may be accompanied by serious ligament injuries to the knee. There may also be peroneal nerve, or meniscal, injuries.

X-ray taken from Orozco R et al, (1998) Atlas of Internal Fixation. Used with kind permission.

2. Oblique or spiral 

Oblique or spiral

Oblique or spiral

These fractures can result from relatively low energy, twisting forces to distal femur. They are often seen in osteoporotic, elderly patients.

Careful inspection of radiographs should be undertaken to ensure that intraarticular extensions are not missed. Traction radiographs, oblique radiographs, or a CT scan may help to elucidate occult articular extensions. Surgeons should always be aware that it may not be until during surgery that an occult intraarticular extension is discovered and that they may need to deal with such a fracture by reducing the articular surface using a lag screw technique.

X-ray taken from Orozco R et al, (1998) Atlas of Internal Fixation. Used with kind permission.

3. Transverse 

Transverse

Transverse

These fractures can result from higher energy injuries in younger patients.

Careful inspection of radiographs should be undertaken to ensure that intraarticular extensions are not missed. Traction radiographs, oblique radiographs, or a CT scan may help to elucidate occult articular extensions. Surgeons should always be aware that it may not be until during surgery that an occult intraarticular extension is discovered and that they may need to deal with such a fracture by reducing the articular surface using a lag screw technique.

X-ray by courtesy of Spital Davos, Switzerland, Dr C Ryf and Dr A Leumann.