From the Guidelines
Jumper's knee, or patellar tendinopathy, is a degenerative condition characterized by chronic pain and tenderness at the inferior pole of the patella, diagnosed through a comprehensive physical examination and understanding of its underlying pathology. The exam typically includes palpation of the inferior pole of the patella where tenderness is usually maximal, observation for swelling, and functional tests like the single-leg decline squat which often reproduces pain, as noted in studies such as 1. The Victorian Institute of Sport Assessment (VISA-P) questionnaire may be used to quantify symptoms. Imaging studies such as ultrasound or MRI can confirm the diagnosis by showing tendon thickening, hypoechoic areas, or signal changes.
Pathologically, jumper's knee represents a degenerative tendinopathy rather than an inflammatory condition, characterized by collagen disorganization, increased ground substance, neovascularization, and abnormal tenocyte proliferation, as discussed in 1. This occurs due to repetitive overloading of the patellar tendon, particularly in activities involving jumping and landing. The condition typically develops in stages, progressing from pain only after activity to pain during activity that limits performance, and eventually to complete tendon rupture if left untreated.
Key features of the condition include:
- Activity-related anterior knee pain
- Pain exacerbated by navigating stairs and prolonged sitting
- Tenderness at the inferior pole of the patella
- Positive decline squat test
- Tendon thickening, hypoechoic areas, or signal changes on imaging studies, as summarized in 1. Understanding this pathology explains why treatment focuses on progressive tendon loading through eccentric exercises rather than anti-inflammatory approaches, as the goal is to stimulate tendon remodeling and restore normal structure and function, as recommended in 1.
From the Research
Jumper's Knee Exam and Pathology
- Jumper's knee, also known as patellar tendinopathy, is a condition characterized by anterior knee activity-related pain, commonly found in athletes engaged in jumping sports 2, 3.
- The diagnosis of patellar tendinopathy is primarily clinical, but imaging techniques can also be useful 3.
- Risk factors for patellar tendinopathy differ between sexes, playing conditions, the kind of sport, playing level, and personal characteristics 3.
Treatment Options
- Nonoperative management is the first choice for treating patellar tendinopathy, with several nonsurgical treatment options available, including eccentric exercises, cryotherapy, platelet-rich plasma (PRP) injections, and anti-inflammatory strategies 2, 4, 3.
- Eccentric exercises may be the strategy of choice in the short-term, but multiple PRP injections may offer more satisfactory results at long-term follow-up 2.
- Surgical treatment is effective in many refractory cases unresponsive to nonoperative modalities, but there is no clear evidence on what is the most effective approach to address patellar tendinopathy 4, 3.
Pathology
- Patellar tendinopathy appears to involve a failed healing process in the tendon, rather than inflammation, which has consequences for the treatment strategy 5.
- The condition is characterized by a gradual increase in pain in the patellar tendon, and it can persist for years, affecting athletic performance 3.
- The use of preventative methods is imperative due to the persistence of this condition, especially in elite athletes who sometimes end their career after long and failed treatments 3.