The tibial plateau is a crucial structure within the knee joint, forming the top part of the shin bone, or tibia. This broad, flattened region serves as the main weight-bearing surface for the lower limb. Its integrity is fundamental for everyday movements like walking, running, and jumping, supporting overall mobility and lower body function.
Location and Key Features
The tibial plateau is located at the upper, proximal end of the tibia, articulating with the thigh bone (femur) to form the tibiofemoral joint. This surface is composed of two distinct areas: the medial and lateral condyles, which are rounded projections. A raised bony structure, the intercondylar eminence, separates these two condyles along the midline.
Both the medial and lateral condyles are covered by articular cartilage, a smooth tissue that reduces friction and allows fluid movement within the joint. The medial condyle is typically more oval, while the lateral condyle is generally more circular. This articular cartilage can be up to 4.5 millimeters thick, contributing to the joint’s cushioning. Crescent-shaped cartilage pads called menisci also rest on the tibial plateau’s margins, enhancing joint congruence and stability.
Its Role in Knee Function
The tibial plateau supports the body’s weight and distributes forces across the joint during movement. It forms the foundation of the knee joint, enabling the femur to articulate smoothly for actions like bending and straightening the leg. This surface helps absorb the impact of daily activities, ensuring stress is evenly spread between the tibia and femur.
The shape of the tibial plateau, along with the menisci, contributes to knee stability and its ability to glide and pivot. Ligaments and tendons also attach to the plateau, providing structural support and facilitating controlled motion. Specifically, the medial tibial condyle bears approximately 60% of the knee’s weight, underscoring its role in load bearing.
Types of Tibial Plateau Injuries
Injuries to the tibial plateau primarily involve fractures, which are breaks in the upper shin bone extending into the knee joint. These fractures often result from high-impact trauma, such as motor vehicle accidents, sports injuries, or falls, especially in younger individuals. Less severe forces, like simple falls, can cause these fractures in older individuals, particularly if they have weakened bones due to conditions like osteoporosis.
Tibial plateau fractures can vary in severity and type, ranging from simple cracks to complex breaks with multiple bone fragments or depression of the joint surface. They can affect the lateral (outer), medial (inner), or both (bicondylar) sides of the plateau. Common symptoms include severe pain directly below the knee, swelling, and an inability to bear weight on the affected leg. Other signs may include bruising, a limited range of knee motion, or numbness or a “pins and needles” sensation in the foot if nerves are affected. If a tibial plateau injury is suspected, prompt medical evaluation is necessary for diagnosis and management.