The knee is recognized as the largest and most complex joint structure in the human body, serving a fundamental function in weight-bearing, standing, and overall mobility. This pivotal joint allows for the necessary bending and straightening motions required for walking, running, and climbing. A fractured knee refers to a break in one or more of the bones that form this joint, which can severely compromise a person’s ability to move and support their body weight.
The Knee Joint and Fracture Definition
The knee joint is composed of the articulation between three specific bones: the distal end of the femur, which is the thigh bone; the proximal end of the tibia, which is the shin bone; and the patella, commonly known as the kneecap. A knee fracture is officially defined as a break occurring in any of these three bones, particularly those fractures that involve or are adjacent to the joint line. This type of injury can result from a sudden, powerful force, often described as high-impact trauma, such as a motor vehicle collision or a fall from a significant height.
Identifying Common Fracture Signs
Following a fracture, the body exhibits signs of a serious injury to the joint. The most immediate symptom is severe, intense pain at the site of the break, which worsens when any pressure or movement is attempted. This pain is quickly followed by rapid and noticeable swelling around the knee, frequently accompanied by bruising.
A person with a fractured knee is typically unable to bear weight on the affected leg. In more severe cases, the knee may display a visible deformity, appearing misshapen or “out of place,” which suggests significant displacement of the bone fragments. Furthermore, a fracture of the kneecap can prevent the person from actively straightening their leg due to the disruption of the extensor mechanism.
Types of Knee Fractures
Knee fractures are categorized by the specific bone that is broken and the characteristics of the break itself. The patella, or kneecap, is the most commonly fractured bone in the knee, often breaking into two or more pieces from a direct blow. Tibial Plateau fractures involve the top surface of the tibia where it meets the femur, and these injuries are frequently associated with damage to the underlying cartilage.
Distal Femur fractures occur in the lower portion of the thigh bone, just above the knee joint, and these can be supracondylar or intracondylar depending on whether the joint surface is involved. Beyond the location, medical professionals also use descriptive terms like non-displaced, where the bone fragments remain aligned. Conversely, a displaced fracture means the broken pieces have shifted out of correct alignment, making surgical intervention more likely. An open fracture, also termed compound, is the most severe, involving a break in which the bone pierces the skin, which carries a high risk of infection.
Initial Diagnosis and Treatment Approaches
The confirmation of a suspected knee fracture begins with a thorough physical examination, where the doctor assesses the deformity, swelling, and the patient’s ability to move the leg. Imaging studies are then ordered, with plain X-rays being the primary tool used to visualize the broken bone and determine the fracture pattern. For complex breaks, such as those involving the joint surface like the tibial plateau, a computed tomography (CT) scan or magnetic resonance imaging (MRI) may be used to gain a more detailed view of the bone fragments and associated soft tissue damage.
Treatment for a knee fracture follows two main paths, depending on the stability and type of the break. Non-surgical management is reserved for stable, non-displaced fractures, involving the use of a cast or brace to immobilize the joint and allow the bone to heal in proper alignment. Patients are instructed to limit or completely avoid putting weight on the injured leg during the initial healing period.
Unstable, significantly displaced, or comminuted fractures, where the bone is shattered into multiple fragments, require surgical intervention. During surgery, the orthopedic surgeon realigns the bone fragments and secures them using various hardware, such as screws, pins, plates, or wires, to ensure stability. Following either non-surgical or surgical treatment, physical therapy is initiated to help the patient restore strength, regain range of motion, and reduce the long-term stiffness that can result from the injury.