# Clinical Cases: Osteoarthritis

## Case 1: Primary Knee Osteoarthritis with Varus Deformity

### Patient Presentation
**Demographics:** 67-year-old woman

**Chief Complaint:** "My right knee has been getting worse over the past two years, and now I can barely walk to the mailbox."

**History of Present Illness:**
The patient describes gradually progressive right knee pain that began insidiously approximately five years ago. The pain is located primarily over the medial aspect of the knee and is worse with weight-bearing activities, particularly walking, climbing stairs, and rising from a seated position. She notes morning stiffness lasting approximately 15-20 minutes that improves with movement. The pain is relieved with rest but has become more constant over the past six months, occasionally awakening her at night. She has tried over-the-counter acetaminophen and ibuprofen with modest relief. She denies any history of significant knee trauma.

**Past Medical History:**
- Hypertension
- Type 2 diabetes mellitus
- Obesity (BMI 34 kg/m2)
- No prior joint surgeries

**Medications:**
- Lisinopril 20 mg daily
- Metformin 1000 mg twice daily
- Acetaminophen 650 mg as needed

**Social History:**
- Retired schoolteacher
- Never smoker
- No alcohol use

**Family History:**
- Mother had knee replacement at age 72

### Physical Examination
- **Vital Signs:** BP 138/82 mmHg, HR 78 bpm, BMI 34 kg/m2
- **Gait:** Antalgic gait favoring the right leg, visible varus (bow-legged) deformity
- **Right Knee:**
  - Bony enlargement of the joint margins
  - Palpable crepitus with range of motion
  - Tenderness along the medial joint line
  - Small cool effusion present
  - Range of motion: 5-110 degrees (reduced from normal 0-135 degrees)
  - No warmth or erythema
  - Varus alignment of approximately 10 degrees
  - Stable ligamentous examination
- **Left Knee:** Mild crepitus, no effusion, full range of motion

### Workup and Results

**Laboratory Studies:**
| Test | Result | Reference Range |
|------|--------|-----------------|
| ESR | 12 mm/hr | 0-20 mm/hr |
| CRP | 0.4 mg/dL | <0.5 mg/dL |
| Rheumatoid Factor | Negative | Negative |
| Uric Acid | 5.8 mg/dL | 2.5-7.0 mg/dL |

**Imaging:**
- **Weight-bearing AP and lateral knee radiographs:**
  - Kellgren-Lawrence Grade 4 changes in the medial compartment
  - Marked medial joint space narrowing with bone-on-bone contact
  - Large marginal osteophytes
  - Subchondral sclerosis and cyst formation
  - Varus angulation of 10 degrees
  - Lateral compartment relatively preserved

### Clinical Image

![Knee osteoarthritis radiograph](case_01_image.jpg)

*Standing anteroposterior radiograph of the knee demonstrating advanced osteoarthritis with marked joint space narrowing, osteophyte formation, and subchondral changes. Source: [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Osteoarthritis_left_knee.jpg), CC BY-SA 3.0.*

### Diagnosis
**Primary Osteoarthritis of the Right Knee, Kellgren-Lawrence Grade 4**

**Diagnostic Criteria Met:**
- Age over 50 years
- Activity-related joint pain with relief at rest
- Morning stiffness less than 30 minutes
- Bony enlargement and crepitus on examination
- Characteristic radiographic findings (joint space narrowing, osteophytes, sclerosis)
- Normal inflammatory markers excluding inflammatory arthropathy

### Treatment Plan

**Non-Pharmacologic Management:**
1. **Weight loss:** Referral to nutritionist with goal of 10% body weight reduction
2. **Physical therapy:** Quadriceps strengthening, range of motion exercises, gait training
3. **Assistive device:** Cane to be used in the left hand
4. **Activity modification:** Low-impact exercise (swimming, cycling)
5. **Knee sleeve:** For proprioceptive support

**Pharmacologic Management:**
1. **Topical diclofenac gel:** Applied to knee four times daily
2. **Scheduled acetaminophen:** 650 mg three times daily
3. **Intra-articular corticosteroid injection:** Triamcinolone 40 mg for acute symptom relief

**Surgical Consultation:**
Given the severe radiographic changes, varus malalignment, and functional limitation despite conservative measures, the patient was referred for orthopedic evaluation for total knee arthroplasty.

**Follow-up:**
- Reassess response to conservative measures in 6-8 weeks
- Optimize diabetes and weight prior to potential surgery
- Continue physical therapy

### Teaching Points
1. **Weight-bearing radiographs:** Essential for accurate assessment of joint space narrowing in knee osteoarthritis; non-weight-bearing films underestimate cartilage loss
2. **Varus deformity:** Results from preferential medial compartment cartilage loss, altering knee biomechanics and accelerating progression
3. **Surgical indications:** Failure of conservative management, significant functional limitation, and radiographic evidence of advanced disease support total knee arthroplasty consideration
4. **Obesity and OA:** Weight loss reduces mechanical joint loading (4 pounds of force reduction per pound lost) and systemic inflammation

---

## Case 2: Hand Osteoarthritis with First Carpometacarpal Involvement

### Patient Presentation
**Demographics:** 58-year-old woman

**Chief Complaint:** "I'm having trouble opening jars and my thumbs hurt constantly."

**History of Present Illness:**
The patient reports progressive pain and stiffness in both hands over the past three years, most pronounced at the base of both thumbs and in the finger joints. She notices bony bumps on her fingers that have slowly enlarged. She experiences difficulty with pinching and gripping activities, particularly opening jars, turning keys, and writing. Morning stiffness lasts approximately 10-15 minutes. She works as a seamstress and is concerned about her ability to continue her profession.

**Past Medical History:**
- Hypothyroidism
- Osteoporosis
- Postmenopausal (menopause at age 52)

**Medications:**
- Levothyroxine 75 mcg daily
- Alendronate 70 mg weekly
- Calcium and vitamin D supplements

**Family History:**
- Mother and maternal grandmother both had "knotty fingers"

### Physical Examination
- **Vital Signs:** BP 128/76 mmHg, HR 72 bpm, BMI 24 kg/m2
- **Hands:**
  - Bilateral Heberden nodes (DIP joints) with bony enlargement
  - Bilateral Bouchard nodes (PIP joints), less prominent
  - Squared appearance of bilateral thumb bases (first CMC joints)
  - Tenderness at bilateral first CMC joints with positive grind test
  - Crepitus with thumb range of motion
  - No synovitis or warmth
  - Reduced grip and pinch strength bilaterally
  - MCP joints normal without swelling or tenderness

### Workup and Results

**Laboratory Studies:**
| Test | Result | Reference Range |
|------|--------|-----------------|
| ESR | 8 mm/hr | 0-20 mm/hr |
| CRP | 0.2 mg/dL | <0.5 mg/dL |
| Rheumatoid Factor | Negative | Negative |
| Anti-CCP | Negative | Negative |

**Imaging:**
- **Hand radiographs (AP and oblique):**
  - DIP and PIP joint space narrowing with osteophytes bilaterally
  - Subchondral sclerosis at affected joints
  - First CMC joint narrowing with radial subluxation bilaterally
  - No erosions
  - MCP joints preserved

### Clinical Image

![Heberden nodes in hand osteoarthritis](case_02_image.jpg)

*Clinical photograph demonstrating Heberden nodes (bony enlargement at the distal interphalangeal joints) characteristic of nodal hand osteoarthritis. Source: [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Heberden-Arthrose.JPG), CC BY 3.0.*

### Diagnosis
**Nodal Hand Osteoarthritis with First Carpometacarpal (Thumb Base) Osteoarthritis**

**Supporting Features:**
- Typical joint distribution (DIP, PIP, first CMC) with sparing of MCP joints
- Heberden and Bouchard nodes
- Strong family history consistent with genetic predisposition
- Postmenopausal woman (higher risk)
- Normal inflammatory markers excluding inflammatory arthritis
- Radiographic findings consistent with osteoarthritis without erosions

### Treatment Plan

**Non-Pharmacologic Management:**
1. **Hand therapy:** Strengthening exercises, joint protection education
2. **Thumb spica splint:** For first CMC support during aggravating activities
3. **Adaptive equipment:** Jar openers, ergonomic tools, built-up handles
4. **Paraffin wax baths:** For pain and stiffness relief
5. **Activity modification:** Avoid prolonged pinching, adjust work techniques

**Pharmacologic Management:**
1. **Topical diclofenac gel:** Applied to hands three times daily (hands are superficial and respond well to topical therapy)
2. **Acetaminophen:** 650 mg as needed for flares
3. **Intra-articular corticosteroid injection:** Consider for first CMC joints if refractory

**Follow-up:**
- Reassess in 6-8 weeks
- Occupational therapy referral for work modifications
- If severe first CMC involvement progresses, surgical options include trapeziectomy or arthroplasty

### Teaching Points
1. **Nodal osteoarthritis:** Strongly hereditary form affecting DIP (Heberden nodes) and PIP (Bouchard nodes) joints; common in postmenopausal women
2. **First CMC osteoarthritis:** Squared thumb base appearance; grind test (axial compression with rotation) elicits pain and crepitus
3. **MCP sparing:** Involvement of MCP joints suggests rheumatoid arthritis or other inflammatory arthropathy rather than primary osteoarthritis
4. **Topical NSAIDs:** Particularly effective for hand osteoarthritis given superficial joint location; reduced systemic side effects compared to oral NSAIDs
5. **Erosive osteoarthritis:** A more inflammatory and destructive variant with central erosions and "gull wing" or "saw tooth" deformities may occur in some patients

---

## Case 3: Secondary Hip Osteoarthritis Following Developmental Dysplasia

### Patient Presentation
**Demographics:** 45-year-old woman

**Chief Complaint:** "I've had worsening hip pain for years, and now it's affecting my ability to work."

**History of Present Illness:**
The patient reports progressive left hip pain that began approximately 8 years ago and has gradually worsened. The pain is located in the groin and anterior thigh, with occasional radiation to the knee. Pain is worse with prolonged walking, climbing stairs, and getting in and out of her car. She has noticed decreasing range of motion and now has difficulty putting on her shoes and socks. She works as a registered nurse and is finding it increasingly difficult to complete her 12-hour shifts. She recalls being told as a child that she had "clicky hips" that required a brace as an infant.

**Past Medical History:**
- Developmental dysplasia of the hip (DDH) treated with Pavlik harness as infant
- No other significant medical history

**Medications:**
- Ibuprofen 400 mg as needed (uses 3-4 times weekly)

**Social History:**
- Works as a registered nurse
- Non-smoker
- Exercises regularly (walking, yoga)

### Physical Examination
- **Vital Signs:** BP 118/74 mmHg, HR 68 bpm, BMI 23 kg/m2
- **Gait:** Antalgic with shortened stance phase on left, positive Trendelenburg sign
- **Left Hip:**
  - Groin tenderness
  - Significantly reduced internal rotation (10 degrees vs. 40 degrees normal)
  - Reduced flexion (90 degrees vs. 120 degrees normal)
  - Pain at extremes of motion
  - Leg length discrepancy (left leg 1 cm shorter)
- **Right Hip:** Full range of motion, no tenderness

### Workup and Results

**Laboratory Studies:**
| Test | Result | Reference Range |
|------|--------|-----------------|
| ESR | 6 mm/hr | 0-20 mm/hr |
| CRP | 0.3 mg/dL | <0.5 mg/dL |

**Imaging:**
- **Pelvic and left hip radiographs:**
  - Shallow acetabulum with lateral acetabular undercoverage (residual dysplasia)
  - Joint space narrowing predominantly in the superior aspect
  - Marginal osteophytes
  - Subchondral sclerosis and cyst formation
  - Secondary degenerative changes

### Diagnosis
**Secondary Osteoarthritis of the Left Hip due to Developmental Dysplasia**

**Key Features:**
- Young age at presentation (atypical for primary OA)
- History of DDH treated in infancy
- Radiographic evidence of residual acetabular dysplasia
- Characteristic superior joint space narrowing pattern in dysplasia-related OA
- No inflammatory features

### Treatment Plan

**Non-Pharmacologic Management:**
1. **Physical therapy:** Hip strengthening (abductors, external rotators), flexibility
2. **Assistive device:** Cane in right hand for longer distances
3. **Activity modification:** Avoid high-impact activities
4. **Weight management:** Maintain healthy BMI

**Pharmacologic Management:**
1. **Transition from PRN to scheduled ibuprofen:** 400 mg TID with meals for 2 weeks, then PRN
2. **Add PPI:** Omeprazole 20 mg daily for GI protection
3. **Consider duloxetine:** For chronic pain component if inadequate response

**Surgical Consultation:**
Given her young age, functional impairment, and secondary osteoarthritis, early surgical consultation is warranted. At 45, joint preservation strategies versus total hip arthroplasty will be discussed. She understands that eventual joint replacement may be needed with possible revision during her lifetime.

### Teaching Points
1. **Secondary osteoarthritis:** Occurs in younger patients due to underlying structural abnormality; always consider secondary causes when OA presents before age 50
2. **Developmental dysplasia of the hip:** Increases OA risk due to abnormal joint loading and reduced contact area; even successfully treated DDH predisposes to early OA
3. **Hip OA symptoms:** Groin pain (anterior) is more typical than lateral pain; referred pain to the knee can mislead diagnosis
4. **Internal rotation loss:** Often the first and most sensitive physical examination finding in hip osteoarthritis
5. **Joint replacement timing:** In young patients, balancing symptom relief against limited prosthesis longevity (15-20 years) requires careful discussion of expectations and likely need for revision surgery