Unilateral Hip Osteoarthritis: Diagnosis and Treatment
For unilateral hip osteoarthritis, diagnose with plain radiographs showing joint space narrowing and osteophytes, then initiate oral NSAIDs (if not contraindicated) combined with physical therapy, reserving total hip arthroplasty for patients with end-stage disease refractory to conservative management.
Diagnostic Workup
Clinical Examination
Look for these specific findings that confirm hip OA 1:
- Pain with internal hip rotation (most sensitive physical exam finding)
- Antalgic gait pattern
- Groin or lateral hip pain exacerbated by activity and relieved by rest
- Bony enlargement on palpation
Imaging
Plain radiographs are the diagnostic standard 2, 1:
- Anteroposterior pelvis and lateral hip views
- Key radiographic features: marginal osteophytes and joint space narrowing
- Joint space width <2.0 mm at the narrowest point has the best inter-observer reliability (kappa = 0.87) for defining OA 3
- Kellgren-Lawrence grading can supplement assessment but has only moderate inter-observer agreement
MRI is not routinely indicated for diagnosis but may be considered when planning salvage procedures in younger patients, as success depends on existing cartilage damage 4.
Treatment Algorithm
First-Line Conservative Management (Mild-to-Moderate Disease)
Start with this combination 2, 5:
Oral NSAIDs (strong recommendation, high-quality evidence) - when not contraindicated 2
- Most strongly supported pharmacologic option
Physical therapy (moderate recommendation, high-quality evidence) 2, 6
- Appropriate for mild-to-moderate symptomatic hip OA
- Can use either formal PT or unsupervised home exercise
Weight loss if appropriate 1
- Critical for obese patients (BMI predicts contralateral disease progression 7)
Patient education 1
- Written materials and structured programs
Second-Line Options (When First-Line Inadequate)
Acetaminophen (consensus option) - may be considered when NSAIDs contraindicated 2
Intra-articular corticosteroid injections (moderate recommendation, high-quality evidence) - provide short-term pain relief 2, 5
Duloxetine - demonstrated efficacy for OA pain 1
Treatments to AVOID
Strongly recommend AGAINST 5:
- Intra-articular hyaluronic acid (strong recommendation against for hip - higher quality evidence of lack of benefit compared to knee) 2, 5
- Platelet-rich plasma injections
- Stem cell injections
- Botulinum toxin injections
- Prolotherapy
- TNF inhibitors and IL-1 receptor antagonists
Avoid opioids 2, 1 - should not be used for chronic OA management
Surgical Intervention
Total hip arthroplasty is indicated when 2:
- End-stage radiographic disease (severe joint space narrowing, large osteophytes)
- Symptoms refractory to conservative measures
- Significant functional limitation despite optimal non-operative treatment
Preoperative optimization 2:
- Address social determinants of health (affects length of stay, cost, mortality)
- Preoperative education with written materials
- Plan for adequate postoperative support
- Control comorbidities (diabetes, smoking cessation)
Postoperative rehabilitation: Either formal PT or unsupervised home exercise is supported (moderate recommendation) 2
Critical Pitfalls
Do not delay THA indefinitely in end-stage disease - patients with advanced structural damage are appropriate candidates, and delaying causes unnecessary disability 1
Do not use hyaluronic acid in the hip - unlike knee OA where evidence is mixed, hip evidence clearly shows lack of benefit 5
Screen for bilateral disease - 24% of patients require contralateral THA within 18 months; predictors include higher BMI, alpha angles >61.5°, and multiple osteophytes 7
Address racial/ethnic disparities - these persist in joint replacement utilization and outcomes 1