This injury is an unhealed partial tear usually at the bone-tendon interface.1
Jumper’s Knee: Clinical Presentation
When the patellar tendon, the tissue connecting the patella to the tibia, is overused, it can become inflamed. Continuously irritating or injuring this tissue with jumping often leads to severe pain, proximal tendon injury, or tendinopathy / tear.
Jumper’s Knee: Injury
Infrapatellar rupture is usually sports-related in athletes, and focal signal at the infrapatellar teno-osseous junction without rupture is known as “jumper’s knee”.
Jumper’s Knee: Pearls
- “Jumper’s knee” is seen in volleyball and basketball players:1
- High prevalence in high level volleyball players [30-40%]
- Volleyball involves 60 maximal jumps per hour
- Middle blockers jump more than others and are especially prone
- More powerful jumpers are more prone
- lnfrapatellar tendinitis (subpatellar) is also called jumper's knee with intermediate T1 signal and hyperintense signal on fat-suppressed water emphasized images at the inferior patellotendinous attachment1
Jumper’s Knee: Associations
May be associated with Sinding-Larsen-Johansson disease1 and infrapatellar spurs
Jumper’s Knee: References
- Pomeranz SJ. Gamuts & Pearls in MRI & Orthopedics. Ohio, The Merten Company, 1997.
Jumper’s Knee: Example
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This 30-year-old male presents with knee pain after a motor vehicle accident. However, his imaging should have you immediately thinking about his athletic background. Which two sports stand out as his likely hobbies? Bonus points if you know a position in one of the sports that seems to see this injury even more frequently.
Image 1 - Sagittal PD Image 2 - Sagittal PD
This man likely plays volleyball and/or basketball. He has “jumper’s knee” (images 1 and 2, arrows) or infrapatellar tendinopathy with retropatellar swelling. Middle blockers in volleyball are especially prone to this abnormality.
Osseous structures appear grossly intact. Subtle diffuse reactive osteoedema is identified in the distribution of the patella without evidence of fracture. Prepatellar and infrapatellar soft tissue swelling is noted. Diffuse retropatellar soft tissue swelling is also demonstrated. Partial thickness interstitial tear is identified involving substance of the infrapatellar tendon at the patellar tenoosseous junction, measuring approximately 4 mm in length. Tendinosis is a term often used to describe a diffusely large hypertrophic tendon surrounded by scar tissue.