The quadriceps tendon attaches the quadriceps muscle to the patella. Tears most often occur just above the insertion on the patella. They more commonly occur in men (8:1 ratio) and patients report hearing a popping sensation doing activities that involve a change of direction while jumping or landing from a jump. Diagnosis can often be clinical. Patient will have tenderness on exam just superior to the patella with a palpable defect (see pic above) and may have inability to extend the knee against resistance.
These patients typically require pain control, knee immobilizer, crutches, and orthopedic follow up for outpatient MRI (gold standard in diagnosis). But whilst in the ER…..don’t forget the X-ray! Quadriceps tendon ruptures are often associated with patellar fractures from the shear force.
Bianchi S et al. Ultrasound appearance of tendon tears. Part 2: lower extremity and myotendinous tears. Skeletal Radiol. 2006 Feb;35(2):63-77.
McKean J. Quadriceps Tendon Injuries