Msk Dermatology · Year 2 · from Msk Dermatology

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:

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

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