What is the significance of a Schatzker type four tibial plateau fracture in terms of knee joint instability?

From the Guidelines

A Schatzker type four tibial plateau fracture is equivalent to a knee dislocation in terms of knee joint instability due to the involvement of the medial tibial plateau and potential damage to surrounding ligaments, such as the medial collateral ligament (MCL) complex. This fracture type directly affects the medial compartment of the knee, crucial for valgus stability, and can lead to articular incongruity, abnormal load distribution, and accelerated post-traumatic arthritis if not properly addressed 1. The significance of a Schatzker type four tibial plateau fracture lies in its potential to cause significant knee joint instability, often requiring surgical intervention with open reduction and internal fixation to restore articular congruity and joint stability 1. Key considerations in the management of such fractures include:

• Early definitive osteosynthesis within the first 24 hours to reduce local and systemic complications, unless severe visceral injury, circulatory shock, or respiratory failure are present 1
• Temporary stabilization with an external fixator or osseous traction may be necessary in cases of severe trauma or instability, followed by delayed definitive osteosynthesis once the clinical status is stabilized 1
• The quality of reduction is crucial in preventing long-term instability and arthritis, with anatomic restoration of the joint surface being essential 1. In terms of specific muscles or ligaments involved, the MCL complex is often compromised, further compromising knee stability 1. The biomechanics of a Schatzker type four tibial plateau fracture involve a split or depression fracture pattern of the medial tibial plateau, leading to valgus instability and potential articular incongruity 1. Overall, the management of a Schatzker type four tibial plateau fracture requires careful consideration of the fracture severity, surrounding ligamentous injuries, and overall clinical status to optimize outcomes and prevent long-term morbidity and mortality 1.

From the Research

Biomechanics and Muscles/Ligaments Involved

• A Schatzker type four tibial plateau fracture is considered equivalent to a knee dislocation due to the involvement of multiple ligaments and the complexity of the fracture pattern 2, 3.
• The fracture typically involves the lateral tibial plateau and can be associated with injuries to the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and medial collateral ligament (MCL) 3, 4.
• The mechanism of injury for a Schatzker type four tibial plateau fracture is often a varus or valgus force, which can lead to comminution of the lateral tibial plateau and bone contusion of the lateral femoral condyle 3.
• The injury can also involve rotation forces, which can contribute to the complexity of the fracture pattern and the associated ligamentous injuries 3, 4.

Knee Joint Instability

• A Schatzker type four tibial plateau fracture can lead to significant knee joint instability due to the disruption of multiple ligaments and the articular surface of the tibia 5, 6.
• The fracture can be associated with a high risk of ACL avulsion, particularly when the knee is in a flexed position at the time of injury 4.
• The flexion-valgus pattern of injury is a common mechanism for Schatzker type four tibial plateau fractures associated with ACL avulsions 4.
• The treatment of a Schatzker type four tibial plateau fracture often requires individualized planning and may involve a combination of surgical approaches and fixation techniques to achieve stable fixation and restore knee joint function 2, 5.

Treatment and Outcomes

• The treatment of complex Schatzker type IV tibial plateau fractures requires careful planning and may involve a combination of surgical approaches, including medial and lateral approaches, and the use of external fixators or internal fixation devices 2, 5.
• The outcomes of treatment for Schatzker type four tibial plateau fractures can be satisfactory, with patients achieving full range of motion and stable knee joints, but the treatment can be challenging and requires careful attention to the individual fracture pattern and associated injuries 2, 5.