Knee Pain

Knee Pain is a topic covered in the 5-Minute Clinical Consult.

To view the entire topic, please or .

Medicine Central™ is a quick-consult mobile and web resource that includes diagnosis, treatment, medications, and follow-up information on over 700 diseases and disorders, providing fast answers—anytime, anywhere. Explore these free sample topics:

-- The first section of this topic is shown below --

Basics

Description

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.

Epidemiology

Incidence

  • 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.

Prevalence

  • 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)

Risk Factors

  • Obesity
  • Malalignment
  • 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

General Prevention

  • 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

-- To view the remaining sections of this topic, please or --

Basics

Description

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.

Epidemiology

Incidence

  • 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.

Prevalence

  • 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)

Risk Factors

  • Obesity
  • Malalignment
  • 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

General Prevention

  • 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

There's more to see -- the rest of this topic is available only to subscribers.