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knee pain

Etiology: (Differential Diagnosis) 1) traumatic acute knee injury (see traumatic knee injury) 2) non-traumatic acute knee pain a) common causes - arthritis - gout - pseudogout - referred pain - adults - herniated disc - muscle strain - hip injury - children - hip pathology b) uncommon causes - septic knee - ruptured Baker's cyst c) rare cause - ruptured popliteal aneurysm 3) chronic knee pain a) common causes - arthritis - patellofemoral pain syndrome (PFPS) (< 45 years) b) less common causes - patellar tendonitis "jumper's knee" - iliotibial band syndrome "runner's knee" (lateral knee pain) - meniscal tear - prepatellar bursitis - pes anserine bursitis - Osgood-Schlatter disease (adolescents) - quadriceps tendonitis - medial retinaculitis c) uncommon causes - Baker's cyst - plica syndrome (focal synovitis) - recurrent patellar subluxation - loose bodies 'joint mice' - chondral or osteochondral fracture d) rare causes - osteochondritis dessicans (OCD) - neoplasm - vascular disease (venous or arterial) - popliteal aneurysm Clinical manifestations: 1) injury (see traumatic knee injury) 2) swelling (see traumatic knee injury) 3) pain 1) sharp, stabbing - mechanical 2) dull, aching - degenerative of overuse - anterior knee pain worsened by climbing stairs, running, or prolonged sitting (patellofemoral pain syndrome) [3] 3) sharp, sudden - loose body (joint mice) 4) buckling 1) anterior cruciate ligament (ACL) 2) meniscal tear 5) pseudobuckling (feeling of buckling without knee giving way) 1) anterior cruciate ligament (ACL) 2) patellofemoral pain syndrome 3) arthritis 6) locking (knee getting caught in specific positions) 1) meniscal injury 2) loose bodies 3) osteochondritis dessicans 4) patellar dislocation 7) pseudolocking (feels like it catches, but does not lock) 1) patellofemoral pain syndrome 2) arthritis 3) patellar subluxation 8) general a) effusion b) quadriceps atrophy c) standing position d) gait e) alignment of joint - malalignments frequently associated with overuse - common malalignments - Q-angle, patellar position, tibial torsion f) palpation: effusion, patellar facets, tendons, joint line g) range of motion: passive, active, resisted, patellar tracking h) specific physical examination testing - Lachman test, anterior drawer test & pivot shift test evaluate anterior cruciate ligament (ACL) stability - posterior drawer test, shelf test & posterior sag test evaluate posterior cruciate ligament (PCL) stability - varus & valgus stress testing evaluate lateral & medial collateral ligament integrity, respectively - Grind test, crepitus test, compression test & shrug test evaluate patellofemoral pain syndrome - patellar apprehension test evaluates patella subluxation & dislocation - McMurray's test & Appley test (circumduction tests) evaluate medial & lateral menisci - pain with resisted quadriceps contraction (knee should be partially flexed) - functional tests - walking (forward & backward) - squatting - bounce - stairs - running - figure 8's - jumping Laboratory: 1) ESR or CRP 2) serologic tests for rheumatologic diseases 3) complete blood count (CBC) 4) serum uric acid 5) joint aspiration for cell count, crystals, Gram stain & culture if indicated Radiology: 1) plain radiographs (see Ottawa knee rule) 2) magnetic resonance imaging (MRI) a) excellent for meniscal & articular cartilage b) poorly demonstrates ligamentous injury 3) computed tomography (CT) 4) bone scan 5) arthrography Management: 1) pharmacologic agents a) non-steroidal anti-inflammatory drugs (NSAIDs) b) tricyclic antidepressants c) acetaminophen d) topical capsaicin e) short-term narcotics for acute pain f) joint injection with anesthetic/corticosteroid - symptom improvement may last 24 weeks [5] - number needed to treat 4.4 for 1 to benefit at 16-24 weeks 2) physical modalities a) heat, ice, ultrasound b) rest, compression, elevation c) physical therapy to maintain range of motion & strengthen target muscle groups when pain is adequately controlled d) quadriceps strength training [3] e) weight loss f) address mechanical abnormalities in the foot & ankle - medial arch orthotics - heel lifts g) neoprene sleeve h) reduced weight-bearing using cane in opposite hand i) needle or laser acupuncture of no benefit for chronic knee pain [7] 3) internet-based therapy of benefit [8] - interactive online training in pain-coping skills (8 automated sessions) - videoconferencing with a physiotherapist focused on lower-limb-strengthening exercises (7 sessions) 4) surgery Note: Management of knee pain secondary to septic arthritis or osteomyelitis differs from that described above.

Related

knee injury, traumatic medial retinaculitis osteoarthritis of the knee Ottawa knee rule physical examination of the knee

Specific

anterior knee pain patellofemoral pain syndrome; chondromalacia patella (PFPS)

General

lower leg joint pain

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 745
  2. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998
  3. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 16, 17. American College of Physicians, Philadelphia 1998, 2006, 2009, 2012, 2015
  4. Clyman B, in: UCLA Intensive Course in Geriatric Medicine & Board Review, Marina Del Ray, CA, Sept 12-15, 2001
  5. Journal Watch 24(11):86, 2004 Arroll B, Goodyear-Smith F. Corticosteroid injections for osteoarthritis of the knee: meta-analysis. BMJ. 2004 Apr 10;328(7444):869. Epub 2004 Mar 23. PMID: 15039276 http://bmj.bmjjournals.com/cgi/content/full/328/7444/869
  6. Schraeder TL, Terek RM, Smith CC. Clinical evaluation of the knee. N Engl J Med. 2010 Jul 22;363(4):e5 PMID: 20660399
  7. Hinman RS et al Acupuncture for Chronic Knee Pain. A Randomized Clinical Trial. JAMA. 2014;312(13):1313-1322. PMID: 25268438 http://jama.jamanetwork.com/article.aspx?articleid=1910110
  8. Bennell KL, Nelligan R, Dobson F et al Effectiveness of an Internet-Delivered Exercise and Pain-Coping Skills Training Intervention for Persons With Chronic Knee Pain: A Randomized Trial. Ann Intern Med. Feb 21, 2017. PMID: 28241215 http://annals.org/aim/article/2605025/effectiveness-internet-delivered-exercise-pain-coping-skills-training-intervention-persons - Mandl LA Improving Symptoms in Knee Osteoarthritis: Can We Get There From Here? Ann Intern Med. Feb 21, 2017. PMID: 28241277 http://annals.org/aim/article/2605038/improving-symptoms-knee-osteoarthritis-can-we-get-from-here