Knee pain/swelling

The most common reasons of knee pain can include;

Acute knee pain

 * Ligament injuries
 * Tendon injuries (tendinitis)
 * Meniscus injuries
 * Loose body
 * Dislocated kneecap
 * Osgood-Schlatter disease
 * Iliotibial band syndrome
 * Hyperextended knee
 * Septic arthritis

Chronic knee pain

 * Rheumatoid arthritis
 * Osteoarthritis
 * Gout
 * Chondromalacia of the patella, or patellofemoral pain

Complete differential diagnosis of causes of knee pain/sweling

 * Acute gouty arthritis
 * Adult Still's Disease
 * Anterior cruciate ligament (ACL) injury
 * Baker's cyst
 * Bone, ligament or cartilage damage
 * Bursitis
 * Chondromalacia patellae
 * Chronic gouty arthritis
 * Discoid meniscus
 * Gonococcemia
 * Hip or foot/ankle disease with referred pain to the knee
 * Iliotibial Band Syndrome
 * Joint effusion
 * Joint infection
 * Lateral collateral ligament (LCL) injury
 * Malignancy
 * Medial collateral ligament (MCL) injury
 * Meniscus tear
 * Osgood-Schlatter Disease
 * Osteoarthritis
 * Osteochondritis Dissecans (OCD)
 * Osteomyelitis
 * Osteosarcoma
 * Patellofemoral syndrome
 * Pes anserine bursitis
 * Posterior cruciate ligament (PCL) injury
 * Pseudogout
 * Psoriatic arthritis
 * Reiter's Syndrome
 * Rheumatoid Arthritis
 * Scleroderma
 * Systemic Lupus Erythematosus

History and Symptoms

 * Gait abnormalities
 * Swelling
 * Erythema
 * Deformity
 * Muscle atrophy

Physical Examination

 * Range of motion
 * Palpate area of concern
 * "Milk the joint"
 * McMurray circumduction test
 * Ligament testing

Laboratory Findings

 * Complete blood count
 * C-reactive protein
 * Uric acid
 * Alkaline phosphatase
 * Erythrocyte sedimentation rate (ESR)

X-Ray

 * Anteroposterior, lateral and merchant (or sunrise) films of both knees
 * Tunnel views of knee
 * Merchant and sunrise of the patella

MRI and CT

 * MRI for confirmation of suspected diagnosis

Other Diagnostic Studies

 * Bone scan
 * Joint aspiration

Treatment

 * Conservative therapy is best
 * Lifestyle changes
 * Physical therapy
 * Exercise

Acute Pharmacotherapies

 * Anti-inflammatory medications
 * Joint medications
 * Antibiotics

Surgery and Device Based Therapy

 * Surgery necessary for most ACL injuries
 * Meniscal tears may require surgical repair
 * Joint infection requires surgery (emergency)
 * Surgery may be necessary for osteoarthritis, if conservative treatment fails

Acknowledgements
The content on this page was first contributed by C. Michael Gibson, M.S., M.D.

List of contributors: