Patellar / Quadriceps Tendon Rupture

• The patellar tendon connects the patella (kneecap) to the tibia (shinbone).
• Rupture of this tendon can be caused by injury or trauma. It may occur from a fall or a direct blow to the knee. It can also occur when the knee is bent, and the foot planted such as when landing from a jump. Other causes include anabolic steroid use, recent fluroquinolone antibiotics, and chronic or longstanding tendinopathy which may put individuals at higher risk for tendon rupture.
• Symptoms of a patellar tendon rupture include hearing a pop or the sensation of the knee giving way, sudden and severe pain, the inability to straighten the knee or walk, swelling and bruising, a palpable gap in the tendon below the kneecap, and sagging or drooping of the kneecap.

• The quadriceps tendon connects the quadriceps muscle group on the front of the thigh to the patella. When one straightens the knee, the quadriceps tendon pulls on the patella, which then pulls on the patellar tendon. This coordinated action allows you to straighten your leg at the knee, which is essential for many everyday activities like walking, running, and standing up.
• Similar to the patellar tendon, a quadriceps tendon rupture can be caused by trauma or injury, steroid use, certain antibiotics, and risk may be higher in those with pre-existing tendon issues. These injuries typically occur in middle-aged individuals who play running and jumping sports. Injury often occurs when there is heavy load on the leg with the foot planted and the knee partially bent such as an awkward landing. Falls and direct force to the front of the knee can also cause quadriceps tendon ruptures.
• Symptoms include pain and swelling at the front of the knee, the inability to extend the knee or maintain an extended position, a palpable gap above the patella, and difficulty walking or a feeling of knee instability. The patella will appear to sit higher with a quadriceps tendon injury.

Your UCSF Women’s Sports Medicine physician will inquire about the circumstances of your injury, your symptoms, and review your medical history to evaluate underlying risk factors.

The diagnosis of either injury begins with a clinical examination where your physician looks for bruising, swelling, and feels for palpable gaps in the tendon, and assesses the ability to straighten the leg against gravity including testing range of motion and muscle strength.

Imaging studies will be ordered including X-rays to show the position of the patella which is often lower in a patellar tendon rupture (called patella baja) or higher in a quadriceps tendon rupture (called patella alta). An MRI will provide detailed images to assess the soft tissues including the location of the tear and any other associated injuries to the knee structures.

Prompt and accurate diagnosis followed by appropriate treatment is essential to regain optimal knee function. Both patellar tendon and quadriceps tendon ruptures are significant injuries and require surgical intervention in most patients.