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EBMG

Painful Knee

Essentials

  • The suspicion of purulent arthritis necessitates urgent hospital examinations.
  • History taking, examination of the patient's status and x-ray studies are usually sufficient.
  • In prolonged cases, attention should also be paid to hip and ankle joints as well as to how the lower limbs and the pelvis work together.
  • It is important to maintain the range of knee motion by exercises and physical activity.
  • A separate article on knee injuries is available Knee Injuries.

Patient history

  • Onset of pain: sudden or gradually increasing
  • History of injuries, endoscopic procedures or surgery
  • Does the pain occur on exertion, when standing, at rest, or is there pain at night?
  • Does the pain compromise daily functions or hobbies; walking distance?
  • Symptoms in any other joints

Aetiology

  • Table T1 lists the essential symptoms and findings indicating specific conditions or injuries.

The painfull knee - diagnostic clues

Symptoms, findings, typical patientsCondition
Pain due to prolonged sitting with the knees bent (e.g. in the movies: "movie sign") is typical for chondromalaciaChondromalacia Patellofemoral Pain (Pfp)
Pain on descending stairs or on squatting; tenderness and crepitation at grinding when moving the patellaChondromalacia Patellofemoral Pain (Pfp), patellofemoral pain syndrome
Tender and swollen tibial tuberosity; patient 10-15 years oldOsgood-Schlatter disease Knee Complaints in Growing Children
Tenderness at the lower margin of the patella and at the patellar ligament; people practising sports involving jumpingJumper´s knee Treatment and Prevention of Sports Injuries, patellofemoral pain syndrome
Sequela of knee injury
Knee injuries Knee Injuries
Locking, hydrops, giving way
Meniscal tear Degenerative Meniscus Tear
Osteochondritis dissecans Osteochondritis Dissecans (OCD) of the Knee
Patellar dislocation tendency Dislocation of the Patella
Swelling behind the kneeBaker´s cyst Baker's Cyst
Prepatellar swellingPrepatellar bursitis Bursitis
Painful and/or swollen knee without injury, morning stiffnessArthritis Clinical Diagnosis of Joint Inflammation in the Adult
Pain on exertion in middle-aged or older patient, periodic swelling, pain when starting motion or when walking stairs; deformityOsteoarthritis
Lateral pain on exertion, lateral epicondyle of the femur painful on palpationFriction pain of the iliotibial band
Rotation movements of the hip joint are painfulHip osteoarthritis (the pain radiates to the knee)

Examination

  • How the patient moves (walks, crouches), use of aids
  • Examination with both lower limbs naked
  • Limb axes, posture, unequal length in standing position
  • Examination of meniscal injuries

Workup

  • Laboratory tests
    • Required if an inflammatory process or rheumatic disease is suspected (ESR, CRP, basic blood count with platelet count, RF, CCPAb, urate, synovial fluid analysis)
  • X-ray examinations
    • When clinically significant osteoarthritis or a condition such as abnormal bone structure (e.g. tumours) is suspected
    • Always take AP and lateral projections
    • If osteoarthritis is suspected, x-ray both knees in the standing position.
    • If recurrent patellar luxation is suspected, also take a patellar projection.
  • Ultrasound examination
    • As necessary if the presence of hydrops cannot be determined in clinical examination or if Baker's cyst is suspected
  • MRI
    • Complements plain x-ray if some other disease than osteoarthritis is suspected that can be treated surgically

Treatment

  • If a specific diagnosis can be made, treat accordingly (see table T1).
  • Physiotherapy
    • Active knee rehabilitation should be carried out to preserve knee function and ranges of movement regardless of the cause of the pain or of other treatment.
  • Good, if necessary individually fitted shoes
  • Pharmacotherapy of pain
    • For short-term treatment of acute pain anti-inflammatory analgesics (NSAIDs) and for severe pain possibly opioids
    • For the treatment of chronic pain, paracetamol is the drug with the least adverse effects and should be used if it is sufficiently effective. The adverse effects of NSAIDs and opioids are emphasized in more long-term treatment. Policies mainly the same as in the treatment of osteoarthritis: see Osteoarthritis of the Hip and Knee.
  • Any bacterial infections should be treated with oral or intravenous antimicrobial drugs depending on the location and severity of the infection.
  • Surgical treatment should be used for advanced osteoarthritis causing significant functional impairment. Other aetiologies of knee pain rarely require surgical treatment.

References

  • Messier SP, Mihalko SL, Beavers DP ym. Effect of High-Intensity Strength Training on Knee Pain and Knee Joint Compressive Forces Among Adults With Knee Osteoarthritis: The START Randomized Clinical Trial. JAMA 2021;325(7):646-657. [PubMed]
  • Fraenkel L, Buta E, Suter L ym. Nonsteroidal Anti-inflammatory Drugs vs Cognitive Behavioral Therapy for Arthritis Pain: A Randomized Withdrawal Trial. JAMA Intern Med 2020;180(9):1194-1202. [PubMed]
  • de Oliveira Silva D, Pazzinatto MF, Rathleff MS ym. Patient Education for Patellofemoral Pain: A Systematic Review. J Orthop Sports Phys Ther 2020;50(7):388-396. [PubMed]
  • Reichenbach S, Felson DT, Hincapié CA ym. Effect of Biomechanical Footwear on Knee Pain in People With Knee Osteoarthritis: The BIOTOK Randomized Clinical Trial. JAMA 2020;323(18):1802-1812. [PubMed]