Family Medicine · Year 3 · from Family Medicine

Case 1: Knee Osteoarthritis

Patient Demographics

  • Age: 62 years old
  • Sex: Female
  • Occupation: Retired postal worker

Chief Complaint

"My right knee has been hurting for months, and it's getting harder to walk."

History of Present Illness

Mrs. Patricia Williams is a 62-year-old woman presenting with progressive right knee pain over 6 months. The pain is described as a deep ache, worse with weight-bearing activities like walking and climbing stairs. She reports morning stiffness lasting about 20 minutes that improves with movement. The knee occasionally "gives way" when walking, and she has noticed mild swelling at the end of the day. She has been taking ibuprofen 400 mg twice daily with partial relief. No history of knee trauma, locking, or significant swelling.

She notes increasing difficulty with her daily walks and has stopped attending her water aerobics class due to pain getting to the pool.

Past Medical History

  • Hypertension
  • Obesity
  • Gastroesophageal reflux disease
  • Bilateral hip replacement 8 years ago (for osteoarthritis)

Family History

  • Mother: Osteoarthritis, knee replacement
  • Father: Hypertension

Social History

  • Never smoker
  • Occasional alcohol
  • Widowed, lives alone in two-story home
  • Previously active, now limited by knee pain

Physical Examination

  • Vital Signs: BP 134/82 mmHg, HR 72, BMI 33
  • General: Well-appearing, antalgic gait favoring right leg
  • Right Knee:
  • Mild warmth, small effusion
  • Bony enlargement along medial joint line
  • Crepitus with range of motion
  • Tenderness along medial joint line
  • Range of motion: 5-120 degrees (slight flexion contracture)
  • Ligaments stable, negative McMurray test
  • No popliteal fullness (Baker's cyst)
  • Left Knee: Minimal crepitus, no effusion, full ROM

Clinical Image

Image: Anteroposterior radiograph of a knee with osteoarthritis demonstrating medial joint space narrowing, osteophyte formation, and subchondral sclerosis, characteristic findings of degenerative joint disease.

Image Source: Wikimedia Commons Attribution: James Heilman, MD, CC BY-SA 3.0 URL: https://commons.wikimedia.org/wiki/File:Osteoarthritis_of_the_left_knee.jpg

Outpatient Workup

  • Right knee X-ray (weight-bearing AP, lateral, sunrise views):
  • Medial compartment joint space narrowing
  • Osteophyte formation medially
  • Subchondral sclerosis
  • Kellgren-Lawrence Grade 3
  • Labs (if inflammatory arthritis suspected): Not indicated given classic OA presentation

Assessment and Diagnosis

  1. Right knee osteoarthritis, moderate-severe - Kellgren-Lawrence Grade 3, significant functional impairment
  2. Obesity - Contributing to joint stress
  3. GERD - Limits NSAID use
  4. Chronic NSAID use concern - Risk of GI and renal complications

Management Plan

Non-Pharmacologic:

  • Weight loss counseling: Every pound lost = 4 pounds less force on knee
  • Physical therapy referral: Quadriceps strengthening, ROM exercises
  • Low-impact exercise: Swimming, water aerobics, stationary cycling
  • Assistive devices: Cane for opposite hand, consider knee brace
  • Heat/ice therapy for symptom relief

Pharmacologic:

  • Discontinue scheduled ibuprofen (GERD, chronic use risks)
  • Topical diclofenac gel 1% applied 4 times daily to knee (first-line, lower systemic risk)
  • Acetaminophen 1000 mg every 8 hours as needed (max 3 g/day)
  • If topical inadequate: Duloxetine 30-60 mg daily (SNRI approved for chronic musculoskeletal pain, also helps mood)

Injection Therapy:

  • Intra-articular corticosteroid injection: Triamcinolone 40 mg
  • Can provide 4-12 weeks of relief
  • Limit to 3-4 injections per year per joint
  • Discuss that injections are temporizing, not disease-modifying

Referral Considerations:

  • Orthopedic surgery referral for joint replacement evaluation if:
  • Failed conservative management
  • Significant functional limitation
  • Continued pain affecting quality of life
  • Discuss patient's goals and expectations

Follow-Up

  • Return in 6-8 weeks to assess response to conservative measures
  • Repeat injection in 3-4 months if initial response but recurrence
  • Consider orthopedic referral if not responding

Teaching Points

  1. Clinical diagnosis of knee OA: Based on age >50, morning stiffness <30 minutes, crepitus, bony tenderness, bony enlargement, and no palpable warmth. X-ray confirms but is not always necessary for diagnosis.
  1. Weight management: Most important modifiable risk factor. Each kilogram of weight loss results in 4-fold reduction in load on knee with each step.
  1. Stepped approach to OA management:
  • First-line: Education, exercise, weight loss, topical NSAIDs
  • Second-line: Oral NSAIDs (short-term), duloxetine, intra-articular steroids
  • Third-line: Surgical referral (arthroplasty)
  1. NSAID cautions: In this patient with GERD and chronic use, prefer topical NSAIDs or alternatives. If oral NSAIDs needed, use lowest effective dose for shortest duration with PPI.

All cases for this lecture as Markdown