The quadriceps tendon is the combined tendon of the four quadriceps heads inserting on the superior patellar pole, completing the proximal half of the extensor mechanism. It has three layers reflecting the three contributing tendons, with the rectus femoris being most superficial, the vasti intermediate, and the articularis genus deepest. Rupture produces the same functional deficit as patellar ligament rupture but occurs in older patients and produces a low-riding patella.
| Origin | Combined quadriceps femoris muscle bellies |
|---|---|
| Insertion | Superior pole of the patella |
| Actions | Transmits quadriceps force to the patella for knee extension |
|---|
Quadriceps tendon rupture has an older patient profile than patellar ligament rupture, typically occurring in patients over 50 with systemic conditions including renal failure, diabetes, and fluoroquinolone use. The lateral radiograph shows patella baja (low-riding patella) and a palpable gap above the patella. Surgical repair within days restores good function; delayed repair requires tendon lengthening procedures.
Complete disruption in patients typically over 50 with systemic risk factors, producing inability to extend the knee, palpable suprapatellar gap, and patella baja on lateral radiograph, requiring urgent surgical repair.
