Quadriceps tendon or patellar tendon rupture: what is the difference?

Where each tendon sits

The quadriceps tendon runs from the thigh muscle down to the top of the kneecap. The patellar tendon runs from the bottom of the kneecap to a bump on the shin bone called the tibial tubercle. Together with the kneecap they form the extensor mechanism, which lets you straighten the leg, climb stairs and land from a jump.

Who tends to get which

Quadriceps tendon ruptures are seen more often in people in middle age and beyond, frequently after a stumble or a missed step. Conditions that weaken tendons, such as diabetes, kidney disease, gout and long-term steroid use, make them more likely.

Patellar tendon ruptures are more typical in younger, active people, often during explosive sport such as basketball, volleyball, football or high jumps. Many have a history of pain below the kneecap from patellar tendinopathy, or of steroid injections into that area.

How they look on examination

In both, you usually cannot lift a straight leg if the tear is complete. The clue is where the gap is and where the kneecap sits.

• Quadriceps tear: gap above the kneecap, which may sit lower than normal
• Patellar tear: gap below the kneecap, which rides higher than on the other side

An X-ray comparing kneecap height, plus ultrasound or MRI, confirms which tendon is torn.

Repair and recovery

Both are usually repaired by stitching the tendon back to the kneecap, ideally early. A patellar tendon repair is sometimes protected with an additional reinforcing suture or tape. Rehabilitation follows a similar path: a brace locked straight, gradual bending over weeks and a long strengthening phase. Return to jumping sport after a patellar tendon repair often takes the better part of a year.