An 81 year old man was walking in a parking lot when he was struck on his left knee at low speed by a van. He was unable to ambulate.
On examination he had pain and swelling distal to the left patella. He was unable to straight-leg-raise actively.
Here is the ultrasound examination of the patellar tendon on the unaffected right side (click to play video):
Note the fibrillar patellar tendon that is seen uniformly between the patella and the tibia without disruption.
Here is the ultrasound examination of the patellar tendon on the affected left side:
Note the disrupted tendon with hematoma distal to the rupture.
Here is a comparison of the affected and unaffected sides:
Diagnosis: patellar tendon rupture
This patient had clinical and ultrasound findings suggestive of a patellar tendon rupture. Xray showed no fracture but a ‘patella alta’. He was subsequently taken to the operating room for tendon repair.