Patellar Tendinitis - Knee & Sports

Introduction
Definition activity-related anterior knee pain associated with focal patellar-tendon tenderness also known as "jumper's knee" Epidemiology incidence up to 20% of jumping athletes demographics / risk factors males > females volleyball most common more common in adolescents/young adults quadriceps tendinopathy is more common in older adults poor quadriceps and hamstring flexibility Pathophysiology mechanism repetitive, forceful, eccentric contraction of the extensor mechanism histology degenerative, rather than inflammatory micro-tears of the tendinous tissue are commonly seen
Classification
Blazina classification system phase I pain after activity only phase II pain during and after activity phase III persistent pain with or without activities deterioration of performance
Presentation
Symptoms insidious onset of anterior knee pain at inferior border of patella initial phase pain following activity late phase pain during activity pain with prolonged flexion ("movie theater sign") Physical exam inspection may have swelling over tendon palpation tenderness at inferior border of patella provocative tests Basset's sign tenderness to palpation at distal pole of patella in full extension no tenderness to palpation at distal pole of patella in full flexion
Imaging
Radiographs recommended views AP, lateral, skyline views of knee findings usually normal may show inferior traction spur (enthesophyte) in chronic cases Ultrasound findings thickening of tendon hypoechoic areas MRI indications chronic cases surgical planning findings tendon thickening more diagnostic than presence of edema increased signal intensity on both T1 and T2 images loss of the posterior border of fat pad in chronic cases
Treatment
Nonoperative ice, rest, activity modification, followed by physical therapy indications most cases technique physical therapy stretching of quadriceps and hamstrings eccentric exercise program ultrasound treatment may be helpful taping or Chopat's strap can be used to reduce tension across patellar tendon cortisone injections are contraindicated due to risk of patellar tendon rupture Operative surgical excision and suture repair as needed indications Blazina Stage III disease chronic pain and dysfunction not amendable to conservative treatment partial tears technique can be done open or arthroscopic resect angiofibroblastic and mucoid degenerative area follow with bone abrasion at tendon insertion and suture repair/anchors as needed postoperative rehab initial immobilization in extension progressive range-of-motion and mobilization exercises as tolerated weight bearing as tolerated outcomes return to activities is achieved by 80% to 90% of athletes there may be activity-related aching for 4 to 6 months after surgery