The kneecap (patella) is a flat, rounded, triangular bone at the front of the knee joint. As the body’s largest sesamoid bone, it is embedded within a tendon. It protects the knee and enhances quadriceps leverage for leg straightening. Despite its strength, the kneecap can fracture, significantly affecting leg function.
How Kneecap Fractures Occur
Kneecap fractures typically result from specific forces. Direct trauma, such as a fall directly onto the knee, a direct blow during sports, or a car accident impact, is a common cause. These impacts often lead to fractures where the bone breaks into multiple pieces.
Indirect trauma involves a sudden, powerful quadriceps contraction. For example, if the foot is planted during a fall, the muscle can pull the kneecap apart. This indirect force commonly results in a transverse fracture, a break across the kneecap. Both direct and indirect mechanisms can damage the extensor mechanism, affecting the ability to straighten the leg.
Signs and Symptoms of a Fractured Kneecap
A fractured kneecap often presents with immediate indicators. Severe pain around the kneecap is typically experienced right after the injury. Swelling and bruising around the knee are common, often due to blood accumulation (hemarthrosis) within the joint.
Difficulty or inability to straighten the leg, especially when trying to lift it against gravity, indicates damage to the knee’s extensor mechanism. Walking or bearing weight on the injured leg is challenging due to pain and instability. A visible gap or abnormal kneecap shape may be felt through the skin, indicating a displaced fracture.
What to Do and How It’s Diagnosed
If a kneecap fracture is suspected, protect the injured knee and seek medical attention. Avoid putting weight on the leg and keep the knee still. Applying ice, elevating the leg, and taking over-the-counter pain medication can help manage swelling and discomfort. Prompt medical evaluation is important for proper diagnosis and treatment.
A doctor will conduct a physical examination, checking for swelling, tenderness, and kneecap deformities. They will also assess the ability to straighten or bend the knee. X-rays are usually the first diagnostic step to confirm a fracture and determine its nature. For complex fractures or soft tissue damage, a CT scan or MRI may provide detailed images.
Treatment Options for a Fractured Kneecap
Treatment for a fractured kneecap depends on its severity and pattern. Non-surgical treatment is an option for fractures with minimal displacement or an intact extensor mechanism. This approach involves immobilizing the leg with a cast or brace to allow healing. Weight-bearing may be restricted for several weeks, and pain management with medication is also part of conservative care.
Surgical intervention is necessary for severe fractures, such as displaced bone fragments, open fractures, or a disrupted extensor mechanism. The goal of surgery is to realign the bone pieces and restore the knee’s function. Techniques include using screws, pins, and wires to hold fragments together, particularly for transverse fractures. If the kneecap is severely shattered, some fragments might be too small to reattach and may need to be removed.
Path to Recovery and Rehabilitation
The journey to recovery after a kneecap fracture involves distinct phases. Initial bone healing typically takes 6 to 12 weeks, though full recovery can extend for several months. During this period, the leg is often immobilized to allow the fracture to mend.
Physical therapy plays a significant part in regaining strength, flexibility, and range of motion in the knee. Exercises focus on strengthening the quadriceps muscles, improving knee bending, and restoring a normal walking pattern. Weight-bearing activities are gradually increased as healing progresses. Returning to daily activities, work, and sports is a phased process, progressing as strength and mobility improve. Potential complications during recovery can include knee stiffness, muscle weakness, and the development of post-traumatic arthritis.