Osteoarthritis

Osteoarthritis (OA) is the most common joint disorder in the United States and most often affects the knees, hips, hands, cervical and lumbar spine, and metatarsophalangeal joints of the great toes. Patients typically present with chronic pain that is worsened with activity and improves with rest. Stiffness of the affected joint is common and usually lasts for a short duration (<30 minutes), unlike inflammatory arthritis, in which prolonged stiffness (>1 hour) is typical, especially in the morning. Exacerbations of pain are frequently described but occur with a variable pattern.

OA can occur as a primary disease (often related to a genetic predisposition) or secondary to damage from prior or coexisting conditions (e.g., inflammatory arthritis or trauma to the affected joints). A helpful mnemonic to remember causes of secondary OA is THE CHARMIN: trauma, hemarthrosis, endocrinopathy, crystal, hypermobility, rheumatic disease, metabolic disease (especially iron overload), infection, neonatal/congenital. In this section, we focus on primary OA.

Diagnosis

• History and physical examination are the keys to diagnosis; often, no further workup is needed.

  • Characteristics of OA include activity-related pain, insidious onset, brief morning stiffness (e.g., <30 minutes), and no systemic symptoms.

  • Physical examination may reveal bony enlargement in characteristic locations:

    • Heberden nodes in the distal interphalangeal (DIP) joints, Bouchard nodes in the proximal interphalangeal (PIP) joints

    • squaring of the first carpometacarpal (CMC) joint

    • bony prominence medial to the first metatarsophalangeal (MTP) joint

    • palpable bony enlargement of the knee

  • View a video review of how to perform a clinical knee examination here and examination of the hand and wrist here.

• Laboratory tests are not routinely required unless there is suspicion of other causes of joint pain such as infection or inflammatory arthritis.

  • Complete blood count (CBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) testing may be helpful to evaluate other possible diagnoses, but abnormalities in these tests will not rule out or rule in OA.

• Synovial fluid examination (see Undifferentiated Inflammatory Arthritis for more details) is not routinely required unless there is suspicion of other articular processes, such as infection, crystal disease, hemarthrosis, or inflammatory arthritis.

  • Synovial fluid white blood cell (WBC) counts between 200-2000 cells/mm³ with <70% (typically <25%) polymorphonuclear leukocytes are consistent with OA or another noninflammatory joint disease.

• Radiography: Plain films are not routinely indicated, as the radiographic changes do not correlate well with the symptoms experienced by patients. Plain films may be useful to document the presence and severity of OA, to differentiate OA from other conditions (e.g., inflammatory arthritis with erosive changes, fracture, osteonecrosis, bone tumors/metastases, fracture), or in the planning for total joint replacement.

  • Radiographic features of OA include asymmetric joint-space narrowing, osteophytes, sclerosis, and subchondral cysts. In the interphalangeal joints, central erosions (i.e., those located in the center of the joint space) leading to a gull-wing radiographic appearance of the joint are typical of erosive osteoarthritis.

(Source: Psoriatic Arthritis. N Engl J Med 2017.)

Treatment

The treatment of OA starts with maximizing nonpharmacologic measures. If improvement is not adequate, pharmacologic measures should then be considered.

Nonpharmacologic therapies:

• Patient education and self-efficacy and self-management programs focus on building education and skills in managing OA and include goal setting, problem-solving, joint protection measures, and exercise recommendations.

• Land- or water-based exercises or physical therapy (PT) may produce lessening of pain and improvement of function. PT and exercise programs are the mainstay of OA treatment.

• In patients with BMI in the overweight and obese range, weight loss of as little as 5% of body weight is associated with symptomatic improvement, and the degree of improvement is positively correlated with the amount of weight lost.

• Biomechanical realignment can be provided with braces or shoe inserts (for knee or foot OA).

• For hand OA, a hand or occupational therapist should conduct an assessment with the aim of providing exercises to increase strength and joint mobility and equipping patients with devices (e.g., splints) to aid with activities of daily living and joint protection.

• Balance training, yoga, and tai chi are safe and often effective interventions.

Pharmacologic therapies:

• topical nonsteroidal anti-inflammatory drugs (NSAIDs; preferred in patients aged ≥75 years)

• oral NSAIDs (see a study on cardiovascular safety of NSAIDs)

• acetaminophen: conditionally recommended for or against in different guidelines; typically provides mild and short-term relief

• topical capsaicin

• duloxetine (may be helpful in OA affecting multiple joints)

• intra-articular glucocorticoid injections (PT was superior to intra-articular glucocorticoids in a landmark trial)

(Source: 2019 American College of Rheumatology/Arthritis Foundation Guideline for the Management of Osteoarthritis of the Hand, Hip, and Knee. Arthritis Rheumatol 2020).

Treatments with uncertain or unfavorable balance of risks and benefits:

• tramadol

  • Non-tramadol opioids should be reserved for use after failure of other therapy or avoided all together due to risks associated with use of these medications.

• glucosamine, chondroitin

• fish oil

• acupuncture

• disease-modifying antirheumatic drugs (such as methotrexate, hydroxychloroquine, sulfasalazine)

• oral glucocorticoids

• transcutaneous electrical nerve stimulation (TENS)

• intra-articular hyaluronic acid and platelet-rich plasma

Surgical interventions:

Total knee replacement and total hip replacement:

• Indications for elective (nonemergency) knee and hip surgery include failure of conservative treatments, significantly impaired function and quality of life, radiographic evidence of significant OA deemed responsible for symptoms, lack of comorbidities that would make surgery unacceptably risky, and patient preference and willingness to accept the risks of surgery.

• Timing of surgery can be tricky, but the general principle is to avoid performing surgery too soon (when symptoms are mild and revision surgery may be necessary in the future) or too late (when the patient may no longer be a good surgical candidate and years of suffering have been endured).

• Arthroscopic surgery is not beneficial for knee OA.