Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Patellar tendinitis (patellar tendinopathy, also known as jumper's knee), is a relatively common cause of pain in the inferior patellar region in athletes.
It begins as inflammation in the patellar tendon where it attaches to the patella and may progress by tearing or degenerating the tendon. Patients present with an ache over the patella tendon.
It is an overuse injury from repetitive overloading of the extensor mechansism of the knee. The microtears exceed the body's healing mechanism unless the activity is stopped.
The injury occurs in many athletes, but is most common in sports such as Soccer, Volleyball, Track & Field, Freerunning, Parkour, American Football, Netball or Basketball which require explosive movements.
Early stages may be treated conservatively. Uncommonly it may require surgery to remove myxoid degeneration in the tendon. This is reserved for patients with debilitating pain for 6-12 months despite conservative measures.
- Jumper's Knee by Bridget Mikysa, M.D., University of Washington Department of Radiology
- Kaplan, Helms, Dussault, Anderson, and Major Musculoskeletal MRI 2001 .
- Patellar tendinosis (jumper's knee): findings at histopathologic examination, US, and MR imaging. Victorian Institute of Sport Tendon Study Group. Radiology, 1996;200:821-827.
- Long-term prognosis for Jumper's knee in male athletes: a prospective follow-up study American Journal of Sports Medicine, Sept-Oct, 2002 by Jyrki A. Kettunen, Martti Kvist, Erkki Alanen, Urho M. Kujala http://www.findarticles.com/p/articles/mi_m0918/is_5_30/ai_92519868
|Diseases of the musculoskeletal system and connective tissue (M, 710-739)|
|Arthropathies||Arthritis (Septic arthritis, Reactive arthritis, Rheumatoid arthritis, Psoriatic arthritis, Felty's syndrome, Juvenile idiopathic arthritis, Still's disease) - crystal (Gout, Chondrocalcinosis) - Osteoarthritis (Heberden's node, Bouchard's nodes)
acquired deformities of fingers and toes (Boutonniere deformity, Bunion, Hallux rigidus, Hallux varus, Hammer toe) - other acquired deformities of limbs (Valgus deformity, Varus deformity, Wrist drop, Foot drop, Flat feet, Club foot, Unequal leg length, Winged scapula)
patella (Luxating patella, Chondromalacia patellae)
Protrusio acetabuli - Hemarthrosis - Arthralgia - Osteophyte
|Polyarteritis nodosa - Churg-Strauss syndrome - Kawasaki disease - Hypersensitivity vasculitis - Goodpasture's syndrome - Wegener's granulomatosis - Arteritis (Takayasu's arteritis, Temporal arteritis) - Microscopic polyangiitis - Systemic lupus erythematosus (Drug-induced) - Dermatomyositis (Juvenile dermatomyositis) - Polymyositis - Scleroderma - Sjögren's syndrome - Behçet's disease - Polymyalgia rheumatica - Eosinophilic fasciitis - Hypermobility|
|Dorsopathies||Kyphosis - Lordosis - Scoliosis - Scheuermann's disease - Spondylolysis - Torticollis - Spondylolisthesis - Spondylopathies (Ankylosing spondylitis, Spondylosis, Spinal stenosis) - Schmorl's nodes - Degenerative disc disease - Coccydynia - Back pain (Radiculopathy, Neck pain, Sciatica, Low back pain)|
|Soft tissue disorders||muscle: Myositis - Myositis ossificans (Fibrodysplasia ossificans progressiva)
synovium and tendon: Synovitis/Tenosynovitis (Calcific tendinitis, Stenosing tenosynovitis, Trigger finger, DeQuervain's syndrome) - Irritable hip - Ganglion cyst
bursa: bursitis (Olecranon, Prepatellar, Trochanteric) - Baker's cyst
fibroblastic disorders (Dupuytren's contracture, Plantar fasciitis, Nodular fasciitis, Necrotizing fasciitis, Fasciitis, Fibromatosis)
shoulder lesions: Adhesive capsulitis - Rotator cuff tear - Subacromial bursitis
enthesis: enthesopathies (Iliotibial band syndrome, Achilles tendinitis, Patellar tendinitis, Golfer's elbow, Tennis elbow, Metatarsalgia, Bone spur, Tendinitis)
other, NEC: Muscle weakness - Rheumatism - Myalgia - Neuralgia - Neuritis - Panniculitis - Fibromyalgia
|Osteopathies||disorders of bone density and structure: Osteoporosis - Osteomalacia - continuity of bone (Pseudarthrosis, Stress fracture) - Monostotic fibrous dysplasia - Skeletal fluorosis - Aneurysmal bone cyst - Hyperostosis - Osteosclerosis|
Osteomyelitis - Avascular necrosis - Paget's disease of bone - Algoneurodystrophy - Osteolysis - Infantile cortical hyperostosis
|Chondropathies||Juvenile osteochondrosis (Legg-Calvé-Perthes syndrome, Osgood-Schlatter disease, Köhler disease, Sever's disease) - Osteochondritis - Tietze's syndrome|
|See also congenital conditions (Q65-Q79, 754-756)|