A common outpatient complaint with a broad differential
- Knee pain may be acute, chronic, or an acute exacerbation of a chronic condition.
- Trauma, overuse, and degenerative change are frequent causes.
- A detailed history, including patient’s age, pain onset and location, mechanism of injury, and associated symptoms can help narrow the differential diagnosis.
- A thorough and focused examination of the knee (as well as the back, hips, and ankles) helps to establish the correct diagnosis and appropriate treatment.
- Knee complaints account for 12.5 million primary care visits annually.
- The incidence of knee osteoarthritis (OA) is 240 cases per 100,000 person-years.
- The knee is a common site of lower extremity injury.
- Patellar tendinopathy and patellofemoral syndrome are the most common causes of knee pain in runners.
- OA of the hip/knee is 11th cause of global disability and 38th most common cause of disability-adjusted life years (DALYs).
Etiology and Pathophysiology
- Trauma (ligament or meniscal injury, fracture, dislocation)
- Overuse (tendinopathy, patellofemoral syndrome, bursitis, apophysitis)
- Age (arthritis, degenerative conditions in older patients; apophysitis in younger patients)
- Rheumatologic (rheumatoid arthritis [RA], systemic lupus erythematosus [SLE])
- Crystal arthropathies (gout, pseudogout)
- Infectious (bacterial, postviral, Lyme disease)
- Referred pain (hip, back)
- Vascular (popliteal artery aneurysm, deep vein thrombosis)
- Others (tumor, cyst, plica)
- Poor flexibility, muscle imbalance, or weakness
- Rapid increases in training frequency and intensity
- Improper footwear, training surfaces, technique
- Activities that involve cutting, jumping, pivoting, deceleration, kneeling
- Previous injuries
- Maintain normal body mass index.
- Proper exercise technique, volume, and equipment; avoid overtraining.
- Correct postural strength and flexibility imbalances.
Commonly Associated Conditions
- Fracture, contusion
- Effusion, hemarthrosis
- Patellar dislocation/subluxation
- Meniscal or ligamentous injury
- Tendinopathy, bursitis
- Osteochondral injury
- OA, septic arthritis
- Muscle strain
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Domino, Frank J., et al., editors. "Knee Pain." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2020. www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116899/all/Knee_Pain.
Knee Pain. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2020. https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116899/all/Knee_Pain. Accessed June 6, 2023.
Knee Pain. (2020). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (27th ed.). Wolters Kluwer. https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116899/all/Knee_Pain
Knee Pain [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2020. [cited 2023 June 06]. Available from: https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116899/all/Knee_Pain.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Knee Pain ID - 116899 ED - Domino,Frank J, ED - Baldor,Robert A, ED - Golding,Jeremy, ED - Stephens,Mark B, BT - 5-Minute Clinical Consult, Updating UR - https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116899/all/Knee_Pain PB - Wolters Kluwer ET - 27 DB - 5-Minute Clinical Consult DP - Unbound Medicine ER -