A tibial plateau fracture is a break of the upper part of the tibia (shinbone) that involves the knee joint. This could involve the medial, lateral, central, or bicondylar (medial and lateral). Symptoms include pain, swelling, and a decreased ability to move the knee. People are generally unable to walk. Complication may include injury to the artery or nerve, arthritis, and compartment syndrome. The cause is typically trauma such as a fall or motor vehicle collision. Risk factors include osteoporosis and certain sports such as skiing. Diagnosis is typically suspected based on symptoms and confirmed with X-rays and a CT scan. Some fractures may not be seen on plain X-rays. Pain may be managed with NSAIDs, opioids, and splinting. In those who are otherwise healthy, treatment is generally by surgery. Occasionally, if the bones are well aligned and the ligaments of the knee are intact, people may be treated without surgery. They represent about 1% of broken bones. They occur most commonly in middle aged males and older females. In the 1920s they were called a "bumper fracture" due to their association with people being hit by a motor vehicle while walking.
Signs and symptoms Tibial plateau fractures typically presents with knee effusion, swelling of the knee or fragmentation of the tibia which leads to loss of its normal structural appearance. Blood in the soft tissues and knee joint (hemarthrosis) may lead to bruising and a doughy feel of the knee joint. Due to the tibial plateau's proximity to important vascular (i.e. arteries, veins) and neurological (i.e. nerves such as peroneal and tibial) structures, injuries to these may occur upon fracture. A careful examination of the neurovascular systems is imperative. A serious complication of tibial plateau fractures is compartment syndrome in which swelling causes compression of the nerves and blood vessels inside the leg and may ultimately lead to necrosis or cell death of the leg tissues.
Cause Tibial plateau fractures may be divided into low energy or high energy fractures. Low energy fractures are commonly seen in older females due to osteoporotic bone changes and are typically depressed fractures. High energy fractures are commonly the result of motor vehicle accidents, falls or sports related injuries. These causes constitute the majority of tibial plateau fractures in young individuals.
Mechanism Fractures of the tibial plateau are caused by a varus (inwardly angulating) or valgus (outwardly angulating) force combined with axial loading or weight bearing on knee. The classically described situation in which this occurs is from a car striking a pedestrian's fixed knee (bumper fracture). A bumper fracture is usually a fracture of the lateral tibial plateau, caused by a forced valgus movement. This causes the lateral part of the distal femur and the lateral tibial plateau to come into contact, compressing the tibial plateau and causing the tibia to fracture. The name of the injury is because it was described as being caused by the impact of a car bumper on the lateral side of the knee while the foot is planted on the ground, although this mechanism is only seen in about 25% of tibial plateau fractures. The term "bumper fracture" was coined in 1929 by Cotton and Berg. Fracture of the neck of the fibula may also be found, and associated injury to the medial collateral ligament or cruciate ligaments occurs in about 10% of cases. However, most of these fractures occur from motor vehicle accidents or falls. Injury can be due to a fall from height in which knee forced into valgus or varus. The tibial condyle is crushed or split by the opposing femoral condyle, which remains intact. The knee anatomy provides insight into predicting why certain fracture patterns occur more often than others. The medial plateau is larger and significantly stronger than the lateral plateau. Also, there is a natural valgus or outward angulation alignment to the limb which coupled with the often valgus or outwardly angulating force on impact will injure the lateral side. This explains how 60% of plateau fractures involve the lateral plateau, 15% medial plateau, 25% bicondylar lesions. Partial or complete ligamentous ruptures occur in 15-45%, meniscal lesions in about 5-37% of all tibial plateau fractures.
Diagnosis In all injuries to the tibial plateau radiographs (commonly called x-rays) are imperative. Computed tomography scans are not always necessary but are sometimes critical for evaluating degree of fracture and determining a treatment plan that would not be possible with plain radiographs. Magnetic Resonance images are the diagnostic modality of choice when meniscal, ligamentous and soft tissue injuries are suspected. CT angiography should be considered if there is alteration of the distal pulses or concern about arterial injury.
Classification Physicians use classification types to assess the degree of injury, treatment plan and predict prognosis. Multiple classifications of tibial plateau fractures have been developed. Currently, the Schatzker classification system is the most widely accepted and used. It is composed of six condyle fracture types classified by fracture pattern and fragment anatomy. Each increasing numeric fracture type denotes increasing severity. The severity correlates with the amount of energy imparted to the bone at the time of injury and prognosis. Schatzker classification for tibial plateau fracture:
Type I = Lateral Tibial plateau fracture without depression. This is a wedge-shaped pure cleavage fracture and involves a vertical split of the lateral tibial plateau. It is usually the result of a low energy injury in young individuals with normal mineralization. May be caused by a valgus force combined with axial loading that leads to the lateral femoral condyle being driven into the articular surface of the tibial plateau. Represent 6% of all tibial plateau fractures.
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