Patellar tendinitis, also known as jumper's knee, is an
overuse injury
A repetitive strain injury (RSI) is an injury to part of the musculoskeletal or nervous system caused by repetitive use, vibrations, compression or long periods in a fixed position. Other common names include repetitive stress disorders, cumula ...
of the
tendon that straightens the
knee
In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...
.
[ Symptoms include pain in the front of the knee.][ Typically the pain and tenderness is at the lower part of the kneecap, though the upper part may also be affected.][ Generally there is no pain when the person is at rest.][ Complications may include patellar tendon rupture.][
Risk factors include being involved in athletics and being ]overweight
Being overweight or fat is having more body fat than is optimally healthy. Being overweight is especially common where food supplies are plentiful and lifestyles are sedentary.
, excess weight reached epidemic proportions globally, with mo ...
.[ It is particularly common in athletes who are involved in jumping sports such as basketball and volleyball.][ The underlying mechanism involves small tears in the tendon connecting the kneecap with the shinbone.][ Other conditions that can appear similar include infrapatellar bursitis, ]chondromalacia patella
Chondromalacia patellae (also known as CMP) is an inflammation of the underside of the patella and softening of the cartilage.
The cartilage under the kneecap is a natural shock absorber, and overuse, injury, and many other factors can cause inc ...
and patellofemoral syndrome
Patellofemoral pain syndrome (PFPS; not to be confused with jumper's knee) is knee pain as a result of problems between the kneecap and the femur. The pain is generally in the front of the knee and comes on gradually. Pain may worsen with sitti ...
.[
Treatment often involves resting the knee and ]physical therapy
Physical therapy (PT), also known as physiotherapy, is one of the allied health professions. It is provided by physical therapists who promote, maintain, or restore health through physical examination, diagnosis, management, prognosis, patient ...
.[ Evidence for treatments, including rest, however is poor.][Plinsinga M.L., Meeus M., Brink M., Heugen N., Van Wilgen P. Evidence of Widespread Mechanical Hyperalgesia but Not Exercise-Induced Analgesia in Athletes with Mild Patellar Tendinopathy Compared with Pain-Free Matched Controls: A Blinded Exploratory Study. ''Am. J. Phys. Med. Rehabil..'' 2021;100(10):946-951. doi:10.1097/PHM.0000000000001673][ It is relatively common with about 14% of athletes currently affected; however research reflects that more than half of athletes with this injury end their careers as a result.][ The term "jumper's knee" was coined in 1973.][
]
Signs and symptoms
People report anterior knee pain, often with an aching quality. The symptom onset is insidious. Rarely is a discrete injury described. Usually, the problem is below the kneecap but it may also be above. Jumper's knee can be classified into 1 of 4 stages, as follows:[
Stage 1 – ''Pain only after activity, without functional impairment''
Stage 2 – ''Pain during and after activity, although the person is still able to perform satisfactorily in his or her sport''
Stage 3 – ''Prolonged pain during and after activity, with increasing difficulty in performing at a satisfactory level''
Stage 4 – ''Complete tendon tear requiring surgical repair''
It begins as inflammation in the patellar tendon where it attaches to the patella and may progress by tearing or degenerating the tendon. People present with an ache over the patella tendon. Most people are between 10 and 16 years old. Magnetic resonance imaging can reveal ]edema
Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's Tissue (biology), tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels t ...
(increased T2 signal intensity) in the proximal aspect of the patellar tendon.
Causes
It is an overuse injury from repetitive overloading of the extensor mechanism of the knee
In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...
. The microtears exceed the body's healing mechanism unless the activity is stopped.
Among the risk factors for patellar tendonitis are low ankle dorsiflexion, weak gluteal muscles, and muscle tightness, particularly in the calves, quadriceps muscle, and hamstrings
In human anatomy, a hamstring () is any one of the three posterior thigh muscles in between the hip and the knee (from medial to lateral: semimembranosus, semitendinosus and biceps femoris). The hamstrings are susceptible to injury.
In quadrupe ...
.
It may be associated with stiff ankle movement and ankle sprains.
Diagnosis
Diagnosis is generally based on symptoms and a physical examination.[ Ultrasound or ]magnetic resonance imaging
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio wave ...
may help clarify how severe the problem is.[
]
Treatment
Evidence for treatment is poor.[ In the early stages ]rest, ice, compression, and elevation
RICE is a mnemonic acronym for the four elements of a treatment regimen that was once recommended for soft tissue injuries: rest, ice, compression, and elevation. It was considered a first-aid treatment rather than a cure and aimed to contro ...
may be tried. Tentative evidence supports exercises involving eccentric muscle contractions of the quadriceps on a decline board.Corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involv ...
injections and NSAIDs are generally recommended.[
]
Procedures
Dry needling, sclerosing injections, platelet-rich plasma, extracorporeal shock wave treatment, and heat therapy have been tried.[
]
Surgery
Surgery may be tried if other measures fail.[ This may involve removal of myxoid degeneration in the tendon. This is reserved for people with severe pain for 6–12 months despite conservative measures. Novel treatment modalities targeting the abnormal blood vessel growth which occurs in the condition are currently being investigated. Knee operations in most cases have no better effects than exercise programs.
]
Epidemiology
It is relatively common with about 14% of athletes currently affected.[ Males are more commonly affected than females.][
]
References
External links
{{Use dmy dates, date=August 2020
Overuse injuries
Soft tissue disorders
Patella
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