The evaluation of patellar tendon rupture begins with a history and physical exam.

Physical findings in someone with patellar tendon rupture may include:

• Inability to straighten the knee
• Knee tenderness:
• Over the patellar tendon
• Leg tenderness:
• Over the tibia, just below the kneecap
• Abnormal position of the kneecap:
• The kneecap moves up, over the thigh

Tests may not necessary to make the diagnosis of patellar tendon rupture. Imaging tests help exclude injuries to the bone.

Tests that may be used to evaluate patellar tendon rupture include:

• Knee x-ray
• MRI scan of the knee
• Surgical exploration