Copyright 2009
Definition
There are many different types of fractures which can occur about the knee. Fractures of the femur include femoral condyle fractures involving one or both of the condyles. These fractures can split the condyles and then extend trnasversely so there is a T-type fracture with the condyles both free floating from the shaft of the femur. Splits in the coronal plane of the condyle are termed “Hoffa” fractures. Fractures of the patella are common with car accidents when the flexed knee hits the dashboard. These fractures are typically transverse or comminuted. Fractures of the proximal tibia are termed plateau fractures and are classified by the location and involvement of the bone. These fractures most commonly involve the lateral tibial plateau but can also involve the medial plateau in isolation or in conjunction with the lateral plateau.
Most fractures about the knee are accompanyied by significant swelling of the knee. Fractures that involve the knee often are seen in conjunction with soft tissue injury to the surrounding ligaments, meniscus, or cartilagemous surface of the tibial plateau or femoral condyles.
Knee fractures are often the result of high energy injuries which placed the neurovascular structures at risk. This means that a careful examination must be performed on each patient to ensure that accompanying injuries are not missed.
Many times fractures about the knee are complicated by arthritic changes in the future since the joint surface was disrupted with concommitant injury to the cartilage.
Diagnosis is suspected clinically by swelling, pain, and deformity. A careful history of the mechanism of injury can often clue the examiner into accompanying injuries.
Imaging includes plain x-rays, MRI, and cat scan (CT). Plain x-rays are a quick and inexpensive way to look at the bony injury and should always be performed. MRI and CT are often used to assess soft tissue disruption (MRI) and to gain a better appreciation of the bony injury (CT) but aren’t necessary in all fractures. CT should always be performed when the congruity of the joint line is in question. CT will give a better idea of comminution and joint line irregularity which is important to restore in surgery in order to prevent arthritic changes in the future.
Treatment options depend on the fracture type, but many of these fractures require surgical reduction and fixation with plates and screws. Surgical intervention is necessary when the articulating surface of the femur and tibia is more then 2-3mm displaced in most cases. Any irregularities of the joint surface that is not reduced will lead to increased pressure points of the joint which eventually causes breakdown of the cartilage.
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