Osteoarthritis is a common joint disease that affects the cartilage, bone, synovium and soft tissues. The etiology is complex and due to a combination of biomechanical, proinflammatory mediators, and enzymatic (proteases) factors.
Risk factors include age, previous joint injury, higher bone density, obesity, genetics, individual anatomical aspects (such as joint shape and alignment), particular activities (occupations or sports), and gender (OA of the hands and knees is more common in women).
CLINICAL SIGNS AND SYMPTOMS:
Although the disease sometimes may be identified as an incidental finding, patients usually complain of progressive chronic joint pain related to joint use and relieved by rest, stiffness (worse in the morning, usually improves within 30-60 minutes) and some degree of limitation.
It can be mono or oligo articular, but rarely poliarticular. The joints most commonly affected are the knees, hips, interphalangeal, CMC (carpometacarpal), MTP (metacarpophalangeal) and apophyseal joints of the spine (lower cervical and lower lumbar). When it is poliarticular it often presents with nodes such as Heberden`s nodes (DIP joints posterolateral hard swellings) and/or Bouchard’s nodes (posterolateral swellings of the PIP)
Physical examination may reveal pain during movement, tenderness, swelling, deformity, instability, or mobility limitation.
Patients with tenderness and crepitus but no swelling are considered patients with “noninflammatory OA”. Patients with swelling and signs of synovitis are considered the ones with inflammatory OA.
The presence of inflammatory signs other than swelling and pain such as erythema may indicate a different cause of arthritis.
History and physical examination are often enough to diagnose OA in patients with persistent usage-related joint pain, age >= 45 years or morning stiffness <=30 minutes.
If the diagnosis is not clear, other methods can be used, such as:
X-Ray of the affected joint: Marginal osteophytes, subchondral sclerosis, cysts and joint space narrowing may be observed.
USG of the affected joint: It is useful to identify changes in nearby structures such as tendons, as well as synovial inflammation, effusion and osteophytes.
MRI of the affected joint
Arthrocentesis of the affected joint with analysis of the synovial fluid: The fluid is usually non or mildfly inflammatory, with < 2000 WBC/mm3, mostly mononuclear cells. Calcium pyrophosphate may be present
Differential diagnosis include a wide variety of causes of arthritis, such as infections, rheumatoid arthritis, psoriatic arthritis, crystalline arthritis, hemochromatosis and seronegative arthritis. Patients with these conditions will often present with systemic symptoms, different locations and other clinical features that will suggest the need for further testing such as CBC, ANA, and rheumatoid factor, among others. Primary osteoarthritis does not typically involve the metacarpophalangeal joints; if this occurs, suspicion should be raised for secondary osteoarthritis.
Exercise, weight loss, patient education and orthoses may help some individuals.
When pharmacological therapy is needed, acetaminophen is the option for patients with no inflammation and mild disease. If there is inflammation, moderate to severe pain or inadequate response to acetaminophen patient should receive a NSAID. Patients receiving NSAID should be monitored for blood, kidney and liver side effects. Topical NSAIDs or capsaicin may be beneficial for patients that cannot tolerate oral medication.
Glucosamine and chondroitin are often used by clinicians and may reduce pain, but there is still controversial evidence about how effective they are. Diacerein (not available in USA) is also another medication that is sometimes used, but there is controversy among clinicians about its effectiveness.
Patients that do not respond to the treatments mentioned before may benefit from intraarticular glucocorticoids. Triamcinolone acetonide is a good option, with a dose of 10mg for small joints (IP, MCP, MTP), 20mg for medium-sized joints (wrist, elbow, ankle, acromioclavicular) and 40mg for large joints (shoulder, knee, hip). It may be repeated every 3 months.
Patients that are resistant to initial therapy may benefit from intraarticular hyaluronans (such as High Molecular Weight Hyaluronic Acid Injection – ORTHOVISC, 2mL in the knee every week for 3-4 weeks).
If the patient does not respond to any of the above and still complains of severe pain, opiates (codeine or tramadol) may be considered if there is no surgical alternative. They should be used with caution because there is the risk of addiction.
Joint replacement (total joint arthroplasty) may be used for the hip, should or knee and it is a definitive treatment for OA that is useful for patients that failed previous therapy and persist with pain and debilitation.
SOURCES & FURTHER READING:
- McAllindon TE et al. OARSI Guidelines for the non-surgical management of knee osteoarthritis. Osteoarthritis and Cartilage 22 (2014) 363-388.
- Hochberg MC et al. American College of Rheumatology 2012 Recommendations for the Use of Nonpharmacologic and Pharmacologic Therapies in Osteoarthritis of the Hand, Hip, and Knee. Arthritis Care & Research. 2012. 64(4) 465-474.
- Sinusas K. Osteoarthritis: Diagnosis and Treatment. Am Fam Physician. 2012 Jan 1;85(1):49-56.
- TREATMENT OF OSTEOARTHRITIS OF THE KNEE. AAOS. 2013.