Patellar tendinopathy is mainly a clinical diagnosis made through a detailed history and meticulous physical examination. Appropriate questions which will cue-in the diagnosis: Sport practiced, schedule of practice and competition, which position the athlete plays, level of performance. The patient will usually complain of well-localized pain and tenderness on the inferior tip of the patella.[11][1]

Patellar tendinopathy shares other common signs and symptoms of other knee pathologies such as pain with prolonged sitting, squatting, and stair climbing. Usually, during activities that store and release energy in the patellar tendon, load-related pain increases with demand on the knee extensors. Sudden tendon pain occurs with loading and usually stops almost immediately when the load is removed. Rarely does a patient feel pain when they are resting.[12]

A thorough examination of the entire lower extremity is needed to identify relevant deficits at the hip, knee, and ankle/foot region. Often malalignment of the foot, heel, or tibia can place excess stress on the knee extensor tendons increasing the risk of tendinopathy.[12]

Currently, there is no widely accepted gold standard diagnostic technique. [13] Ultrasound offers several advantages; it is time and cost-saving, it is non-invasive, repeatable, and accurate and provides a dynamic image of the knee structures.[1] Both ultrasound and magnetic resonance image (MRI) can be used to detect abnormalities in the patellar tendon itself. Imaging can also be used to guide clinicians as to the severity of the pathology.[14]

Radiographic changes on the tendon are noted (elongation of the involved pole of the patella, calcification and increased density within the patellar tendon matrix), although these changes are rare in the first six months of symptoms. Thickening of the patellar tendon along with foci of increased signal intensity may also be seen on CT and MRI. Although not usually indicated, a bone scan can be used in the initial stages of the disease. This test will demonstrate increased pooling of blood and localized tracer activity in the affected region.[15]

There is no evidence-based, preferred treatment of choice for jumper's knee. Refractory response to treatment is also typical for the condition which often leaves the health professional and patients searching for alternative therapies.[16]

Most patients with jumper's knee are managed through medical and rehabilitative treatment in the initial stages of the disease.[17] Early recognition and diagnosis of jumper’s knee are vital as it can have a progressive course. Although non-steroidal anti-inflammatory drugs were used traditionally, these have recently become less judicious as more physicians come to realize that the disease is not inflammatory. Hence, NSAIDs may not provide significant long-term benefit in tendinopathy.[3]

Eccentric training has been suggested to play a key role in the rehabilitation of jumper's knee.[18][19][1] According to Rodriguez-Merchan eccentric training appears to be the treatment of choice for patients suffering from patellar tendinopathy.[20] Athletes must avoid activities such as excessive jumping or impact loading of the knee which only aggravate the situation. As the pain begins to subside, the intensity of rehabilitation therapy and sport-specific training can be slowly increased.[1] Given the refractory response to many initial treatments, new methods have recently emerged. These include dry-needling, sclerosing injections, platelet-rich plasma therapy, extracorporeal shock wave treatment and hyperthermia thermotherapy.[16]

Surgery usually remains the last resort for chronic refractory cases. Traditionally, the gold standard for surgical treatment of patellar tendinopathy involved open debridement of the inferior pole of the patella, as well as debridement of the patella tendon. Recently, knee arthroscopy has gained popularity for tissue debridement and release.[16]

Jumper's knee can be mistaken for other injuries or pathologies such as Osgood-Schlatter disease, meniscal injuries, patellofemoral syndrome, knee bursitis (superficial and deep infrapatellar bursae), patellar subluxation, pathologies of the knee fat pad, chondromalacia, or a patellar tracking problem.[5]

Blazina et al. first used the term jumper's knee in 1973. They also classified the pathology by stage according to the onset of pain in relation to physical activity. This classification along with its modifications are still widely employed. Blazina et al. suggest 4 stages.

1. Pain after sports activity 
2. Pain at the beginning of sports activity yet disappearing with warm-up and sometimes reappearing with fatigue 
3. Pain at rest and during activity 
4. Rupture of the tendon[21]

It may be useful to classify the pathology into 3 stages according to the duration of symptoms.

1. Acute when symptoms have been present for 0 to 6 weeks
2. Sub-acute when symptoms have been present between 6 to 12 weeks
3. Chronic after more than 3 months[22] 

Most cases of patellar tendinopathy will resolve with nonoperative management.[9] Nevertheless, mild to moderate pain may persist for 15 years in adult athletes with patellar tendinopathy but does not appear to limit leisure-time physical activity.[23]

Rudavsky and Cook say that the process of returning to sports play is slow. This process is often dependent on a variety of factors ranging from the severity of pain, grade of dysfunction, the sport practiced, the quality of rehabilitation, the athlete's performance level, and the presence of intrinsic and extrinsic factors.[5] A previous study that used imaging technology to classify the severity of the lesion said that mild pathologies might take anywhere from 20 days for the patient to return to sport, whereas more severe cases might take 90 days.[24] Other experts mention that athletes with severe dysfunction might need anywhere from 6 to 12 months to recover. Lang and coworkers published a study were they analyzed patients who were treated surgically (arthroscopic patellar release). They determined that the meantime to return to play was 4.03 plus or minus 3.18 months.[25]

Joshua et al. performed a systemic search of previous studies to compare the efficacy of treatment for commonly used invasive and non-invasive treatment options. The conclusion reached was that eccentric squat-based therapy, shockwave, or PRP could be used as monotherapies or as adjunct therapies to accelerate recovery. Surgery or shockwave can be considered for patients who fail to improve after six months of conservative treatment. Since patellar tendinopathy is not inflammatory, corticosteroid injections should not be used.[26] 

Patellar tendinopathy may cause long-lasting symptoms that can lead to the athlete's early retirement from sport. In a small prospective case-control study, Kettunen et al. found that 53% of their symptomatic subjects with Jumper's knee had quit their sport when compared to their asymptomatic counterpart in which only 7% quit.[23]

Athletes, clinicians, coaches, and athletic trainers need to understand that the treatment for patellar tendinopathy can be a slow and sometimes frustrating process. There are multiple pitfalls to be aware of, including the failure to control pain. The athlete’s beliefs about pain and pathology may influence the development and management of unresponsive tendinopathies. Because some athletes may have been told that they have weakened tendons due to tears and degeneration, and hence an increased risk of rupture, they may develop fear-avoidance behavior, which can be associated with poorer functional outcomes in individuals suffering from lower-limb tendinopathy. Over-reliance on non-invasive therapies like shockwave therapy and injections instead of including rehabilitation exercises as part of the treatment plan can also lead to complications. Failure to address the athletes landing kinematics can also bring difficulties. Athletes should have their jump-landing mechanics retrained after adequate rehabilitation.[12]

There is currently insufficient evidence for preventative interventions specific to patellar tendinopathy.[27] Some of the proposed preventive measures are proprioception training, eccentric training and stretching of the patellar tendon, reducing the training duration or frequency, and bracing or taping.

• Studies have shown that rehabilitation exercises have a vital role in the treatment of jumper's knee.
• NSAIDs and steroid injections should be discouraged in the management of jumper's knee.
• The athlete and all personnel in charge of the care and training of the athlete should be aware that the jumper's knee management can be a lengthy process that can sometimes have long-lasting effects.

Managing patellar tendinopathy is a job for physicians trained in the care of musculoskeletal conditions along with other members of the interprofessional healthcare team. Sports medicine physicians, physiatrists, and rheumatologists provide the first line of care. Orthopedic surgeons are consulted for refractory cases or when the knee extensor tendons are partially or completely torn. A team of professionals from multiple disciplines including athletic trainers, physical therapists, sports biomechanists, and sports psychologists is needed since the condition commonly affects athletes. The orthopedic specialty nurse is often responsible for the coordination of care and follow up and reporting concerns to the clinician.

Initially, the physical therapist must work at hand with physicians to implement a nonoperative regimen consisting of therapy with isometric or eccentric exercises as the mainstay treatment. In a level 2 study, at 12 weeks, patients undergoing an eccentric exercise program showed significant improvement compared with those undergoing a concentric exercise program.[9] As the treatment progresses, plyometrics and sport-specific training is required to return the athlete to sport at the highest level

Alternative medical treatments have been studied at different levels of evidence, demonstrating mixed and inconclusive results. Acceptable outcomes have been obtained from surgical interventions in refractory cases.

An interprofessional team approach involving clinicians, specialists, orthopedic nursing, and therapists will yield the best results.