Diagnosis of Osteoarthritis

1. Clinical Symptoms

• Pain - mechanical in nature; occurs with activity and use; typically worse toward the end of the day; relieved by rest. In advanced disease, pain can occur at rest and at night.
• Morning/inactivity stiffness - a key distinguishing feature: brief and localized, usually lasting less than 15-30 minutes (compare to rheumatoid arthritis where stiffness lasts >1 hour).
• Crepitus - grating or grinding sensation audible and/or palpable during joint movement.
• Functional limitation - difficulty going up/down stairs or rising from a chair (knee OA); putting on shoes or getting in/out of cars (hip OA); opening jars (hand OA).
• Catching or locking, especially at the knee, which can cause falls.

2. Physical Examination Findings

EULAR Proposition 5 (evidence level Ib): In adults aged >40 years with usage-related knee pain, only short-lived morning stiffness, functional limitation, and one or more typical examination findings (crepitus, restricted movement, bony enlargement), a confident diagnosis of knee OA can be made without radiographic examination - even if radiographs appear normal.

3. ACR Classification Criteria

• Age > 50 years
• Morning stiffness < 30 minutes
• Crepitus on active motion
• Bony tenderness
• Bony enlargement
• No palpable warmth

• Hip pain + at least 2 of: ESR <20 mm/hr, femoral or acetabular osteophytes on X-ray, joint space narrowing

• Hand pain/aching/stiffness + hard tissue enlargement of ≥2 of 10 specified joints + fewer than 3 swollen MCP joints

4. Risk Factors That Support the Diagnosis

• Age >50 years
• Female sex
• Higher BMI / obesity
• Previous joint injury or malalignment
• Joint laxity
• Occupational or recreational overuse
• Family history of OA
• Presence of Heberden nodes

5. Imaging

• Knee: Weight-bearing, semi-flexed posteroanterior (PA) view + lateral + skyline (patellofemoral) view
• Hip: Anteroposterior pelvis view

The Kellgren-Lawrence (KL) grading scale (grades 0-4) is widely used to grade radiographic severity; KL grade ≥2 (definite osteophyte) is the standard definition of radiographic OA.

6. Laboratory Tests

• ESR / CRP - typically normal or mildly elevated in OA; significant elevation suggests inflammatory arthritis
• Rheumatoid factor / anti-CCP - to exclude rheumatoid arthritis
• Uric acid - to exclude gout
• Synovial fluid analysis - in OA, the fluid is non-inflammatory (WBC <2000 cells/µL). This distinguishes OA from septic arthritis or crystal arthropathy.

7. Red Flags (Suggesting an Alternative Diagnosis)

• Severe local inflammation, erythema, or warmth
• Progressive pain unrelated to activity/usage
• Prolonged morning stiffness (>1 hour) - suggests RA
• Recent significant trauma
• Hot, swollen joint - suggests crystal arthropathy (gout/pseudogout) or septic arthritis
• Involvement of unusual joints (e.g., wrist, MCP joints, shoulders) - suggests another systemic arthritis

Summary

Treatments for Osteoarthritis

1. Non-Pharmacological (Core Treatments - First Line for All Patients)

Patient Education & Self-Management

• All patients should receive education about the nature of OA, treatment options, and realistic expectations.
• Self-management programs (in-person, telehealth, or app-based) help patients build self-efficacy, reduce reliance on health care providers, and improve adherence to lifestyle interventions.
• Programs can include behavioral strategies, activity modification, and assistive device training. - Firestein & Kelley's Textbook of Rheumatology, p. 2213

Weight Management

• Obesity both causes and worsens lower-extremity OA by increasing joint loading and contributing low-grade systemic inflammation from adipose tissue.
• The 2019 ACR guidelines strongly recommend weight loss for anyone with a BMI ≥25 kg/m².
• Programs combining diet + exercise are more effective than diet alone (preserves lean muscle mass).
• There is a dose-response relationship: weight loss of ≥20% provides the greatest benefits; even 5-10% weight loss yields meaningful pain and function improvements.
• Bariatric surgery may be considered in severely obese patients. - Firestein & Kelley's Textbook of Rheumatology, p. 2214

Exercise (Strongly Recommended)

• The 2025 BMJ network meta-analysis (PMID 41093618) confirms exercise remains among the most effective modalities for knee OA.
• Tai chi is strongly recommended by the 2019 ACR guidelines for knee and hip OA - it combines meditation, breathing, and slow movements to improve pain and physical function.
• The AAOS evidence-based guideline gives a strong recommendation for supervised, unsupervised, and aquatic exercise. - Miller's Review of Orthopaedics (9th Edition), p. 6123

Biomechanical / Load-Modifying Interventions

• Walking aids (canes, crutches): Reduce loading on the affected joint; AAOS gives a moderate recommendation for canes.
• Knee braces: Offloader braces for unicompartmental OA (e.g., valgus brace for medial knee OA); patellofemoral bracing for patellofemoral OA.
• Foot orthotics: Insoles can be considered; however, lateral wedge insoles are not recommended by AAOS for medial knee OA.
• Gait retraining: Techniques to reduce abnormal knee loading (e.g., increased toe-out walking), though widespread implementation is limited by technology and compliance.
• Hand OA: Thumb carpometacarpal (CMC) orthoses are recommended; cushioned utensils and jar-opening devices reduce grip-related pain.

Manual Therapy

• Includes joint manipulation/mobilization, muscle stretching, and soft tissue massage.
• Benefits when used in isolation are unclear; recent evidence questions utility over exercise alone.
• The AAOS gives a limited recommendation for manual therapy in addition to exercise.

Physical and Electrotherapeutic Modalities

• TENS (transcutaneous electrical nerve stimulation): May improve pain; AAOS gives a limited recommendation.
• Therapeutic ultrasound, heat, and cold: Heat and cold packs provide symptom relief; therapeutic ultrasound has unclear efficacy due to protocol heterogeneity.
• Neuromuscular electrical stimulation (NMES): Used adjunctively in some rehabilitation programs.

2. Pharmacological Treatments

Topical Agents (Preferred first - lowest systemic exposure)

Oral Analgesics

Intra-articular (Joint) Injections

3. Complementary & Mind-Body Approaches

• Tai chi: Strongly recommended by ACR for knee and hip OA; improves pain and function, including in RCTs.
• Yoga: Incorporates meditation, breathing, and movement; evidence supports benefits for knee OA.
• Acupuncture: Conditionally recommended by ACR; improves pain vs. usual care, but effects vs. sham acupuncture are inconsistent. Reasonable to try in patients who believe in it.
• Pain coping skills training / CBT: Addresses catastrophizing and maladaptive coping; shown to improve self-management of OA pain.

4. Surgical Treatments

Summary: Treatment Pyramid

         [Surgery - arthroplasty/osteotomy]
              ↑ when all else fails
        [Intra-articular injections]
              ↑ persistent/localized symptoms
      [Oral/Topical pharmacology]
              ↑ inadequate response to core Rx
   [CORE: Exercise + Weight loss + Education]
              (ALL patients, always)

Key principle: Treatments should be individually tailored, addressing the patient's specific joints, comorbidities, functional goals, and preferences. Even after joint replacement, core non-pharmacological strategies (exercise, weight management) should be continued. - Goldman-Cecil Medicine, p. 2769; Firestein & Kelley's Textbook of Rheumatology, p. 2213