Patellar Tendon Injuries

The quadriceps muscles on the front of the thigh join to form the quadriceps tendon, which attaches to the top of the kneecap (patella). The patellar tendon runs from the bottom of the kneecap to a bony prominence on the front of the shin bone called the tibial tubercle. Together, the quadriceps, the kneecap, and these two tendons form the extensor mechanism.

When the quadriceps contracts, force is transmitted through the kneecap and patellar tendon to straighten the knee. The tendon also absorbs and releases large forces during jumping and landing, which is why it is so frequently injured in sports that involve repetitive jumping.

Injuries to this tendon fall into two distinct categories that behave very differently.

• Patellar tendon rupture: An acute complete or partial tear of the tendon. Once the tendon tears completely, the extensor mechanism is disrupted, and the knee can no longer be straightened actively.
• Patellar tendinopathy: Often called jumper’s knee, this is a chronic overuse injury. Repetitive jumping and landing produce microscopic damage where the tendon attaches to the bottom of the kneecap, and when that damage outpaces the body’s ability to repair it, the tendon becomes degenerative rather than inflamed. This distinction explains why rest and anti-inflammatories alone rarely resolve the problem and why loading the tendon in a controlled way, usually in a supervised physical therapy program, is the treatment that works.

A patellar tendon rupture usually occurs when the quadriceps contracts forcefully against a bent, loaded knee, such as landing awkwardly from a jump, stumbling down a step, or catching a fall. Ruptures most often occur in active adults under the age of 40. The risk is higher in patients with pre-existing tendinopathy.

Patellar tendinopathy develops gradually from repetitive loading. It is most common in athletes who play basketball, volleyball, soccer, and other sports with frequent jumping, cutting, and deceleration. Contributing factors include rapid increases in training volume or intensity, quadriceps and hip weakness, tight quadriceps and hamstrings, and limited ankle mobility, which shifts more load to the knee during landing.

Symptoms differ sharply depending on which injury has occurred. Dr. Rynecki Baker emphasizes that a suspected rupture should be evaluated promptly, as early treatment produces better results.

A patellar tendon rupture typically causes symptoms that may include:

• A pop and immediate pain: A distinct tearing sensation at the front of the knee at the moment of injury, followed by rapid swelling.
• Inability to straighten the knee or lift the leg: The hallmark finding. Patients cannot perform a straight leg raise or hold the knee extended against gravity.
• A palpable gap and a high-riding kneecap: A defect below the kneecap, which sits noticeably higher than on the other side.
• Difficulty bearing weight: The knee buckles because the extensor mechanism can no longer stabilize it.

Patellar tendinopathy typically causes symptoms that may include:

• Pain at the bottom of the kneecap: Localized tenderness at the lower pole of the kneecap, reproduced by pressing directly on that spot.
• Pain with jumping, squatting, and stairs: Discomfort with activities that load the tendon, especially landing and deceleration.
• Pain that warms up and then returns: Stiffness and soreness at the start of activity that eases as the tendon warms up, then worsens afterward.

Diagnosis begins with a thorough evaluation by Dr. Rynecki Baker. She will take a detailed history, including whether symptoms came on gradually or with a single event, what activities provoke the pain, and any prior injections, tendon problems, or medical conditions affecting tendon health. On examination, she will assess the ability to perform a straight leg raise and to hold the knee fully extended, feel along the tendon for tenderness or a defect, and compare kneecap height between sides.

Imaging confirms the diagnosis and guides treatment. X-rays assess kneecap position and rule out fracture. In a complete rupture, the kneecap is typically displaced upward on the side view. Ultrasound evaluates the tendon dynamically and is useful for tendinopathy. MRI is the gold standard for confirming the diagnosis, defining whether a tear is partial or complete, and assessing the degree of tendon degeneration, which influences the treatment plan.

Patellar tendon injuries sit at opposite ends of a spectrum, and each is commonly mishandled. Tendinopathy is often rested rather than loaded, and ruptures are sometimes missed at the initial visit when a patient can still walk with a stiff, straight leg. Dr. Rynecki Baker’s training at NYU Langone Health and Hospital for Special Surgery, combined with her published research in sports medicine, means patients receive care from a specialist who recognizes these injuries accurately and treats them decisively.

As a former collegiate soccer player who underwent four knee surgeries of her own and returned to play, she also understands the frustration of a chronic tendon problem and the fear that follows a sudden injury. She approaches every patient as an individual, taking the time to understand each person’s symptoms, sport, and goals before recommending treatment.