Quadriceps Tendon Rupture

Introduction

Quadriceps tendon rupture is an uncommon but not rare injury seen in the Emergency Department. The clinical history, age of patient, clinical findings and radiographic appearances will usually afford a confident diagnosis.

Epidemiology

Quadriceps tendon rupture is more common in patients over 40 years of age and may be associated with prior degenerative changes in the knee extensor mechanism. <a class="external" href="http://emedicine.medscape.com/article/1249621-overview" rel="nofollow" target="_blank">(http://emedicine.medscape.com/article/1249621-overview)</a> Patients with complete quadriceps tendon rupture will not be able to extend their knees against gravity.

Anatomy

Quadriceps Tendon source: <a class="external" href="http://orthoinfo.aaos.org/topic.cfm?topic=A00294" rel="nofollow" target="_blank">http://orthoinfo.aaos.org/topic.cfm?topic=A00294</a>	Quadriceps Tendon source: <a class="external" href="http://orthoinfo.aaos.org/topic.cfm?topic=A00294" rel="nofollow" target="_blank">http://orthoinfo.aaos.org/topic.cfm?topic=A00294</a>	Quadriceps Tendon Rupture source: <a class="external" href="http://orthoinfo.aaos.org/topic.cfm?topic=A00294" rel="nofollow" target="_blank">http://orthoinfo.aaos.org/topic.cfm?topic=A00294</a>
The quadriceps muscle attaches distally to the quadriceps tendon which inserts into the patella.

Case 1

	This 68 year old male presented to the Emergency Department following a fall onto a concrete floor. His right knee was painful and deformed with a very prominent patella. He described a hyperflexion injury to his right knee. He was referred for right knee radiography. His right knee was seen to have a depression in the skin immediately superior to the upper pole of the patella. This was not evident on the contralateral side.
	The depression superior to the right patella(arrowed) was not evident on the contra-lateral side.
	The AP knee image is unremarkable.
	The lateral knee image demonstrates abnormal orientation of the patella. There is a some mixed density within Hoffa's triangle. There is also loss of definition of soft tissue structures and mixed fat/fluid density in the region of the suprapatellar pouch. There is a well corticated bony density in the region of the suprapatellar pouch and a quadriceps tendon <a class="external" href="http://wiki.answers.com/Q/What_is_an_enthesophyte" rel="nofollow" target="_blank">enthesophyte</a>.
	The patella is pulled and tilted inferiorly by the action of patellar tendon in the absence of a countering traction from the quadriceps muscle associated with a quadriceps tendon rupture.
	The skyline projection was destined for failure given the rupture of the quadriceps tendon