Osteoarthritis (OA) of the Hip

Background

• OA of the hip is a joint disorder characterized by articular cartilage loss, osteophyte formation, and sclerosis at joint margins, resulting in joint pain, stiffness, and functional limitations.
• 1 in 4 adults will develop symptomatic hip OA by age 85 years.
• Risk factors include older age, history of previous hip injury, and excess body weight.
• Rarely, OA of the hip can be primary (idiopathic), but most often is secondary to conditions such as femoroacetabular impingement (FAI), hip dysplasia, or other anatomic abnormality, preceding event, or disease that predisposes the hip to mechanical factors leading to joint degeneration.
• The onset of pain is usually gradual and increases with joint use and is relieved with rest.

Evaluation

• Suspect the diagnosis based on patient history and physical exam, including
  • achy groin pain, particularly with activity and worsening at end of day
  • pain worsened by internal rotation of the hip is the strongest clinical indicator of hip OA
  • decreased passive and active hip range of motion associated with pain (typically internal range of motion is lost first)
• X-ray can be used to confirm diagnosis of hip OA; typical findings include
  • moderate loss of joint space
  • osteophyte formation
  • subchondral sclerosis
• American College of Rheumatology (ACR) classification criteria for hip OA
  • Combined clinical and radiographic classification criteria includes hip pain and ≥ 2 of the following:
    • erythrocyte sedimentation rate < 20 mm/hour
    • radiographic evidence of femoral or acetabular osteophytes
    • radiographic evidence of superior, axial, or medial joint space narrowing
  • Criteria reported to have 89% sensitivity and 91% specificity for diagnosis of hip OA
  • Criteria originally derived for improved classification of patients with hip OA in clinical research
• Blood tests and synovial fluid analysis are usually not performed unless inflammatory arthritis is suspected.

Management

• The goal of treatment is to relieve pain and preserve hip function.
• Optimal management of OA may require a combination of nonpharmacologic and pharmacologic modalities.
• Nonpharmacologic management
  • Self-management and education programs are advised for patients with hip OA (Strong recommendation).
  • Encourage patients to participate in general exercise programs (Strong recommendation); selection of exercise type (aquatic- or land-based exercises) should be individualized, and based on patient preferences and ability to perform exercises.
  • In patients with hip OA and mild-to-moderate symptoms, refer for physical therapy to improve function and reduce pain (Strong recommendation).
• Pharmacologic management
  • For initial pain management, nonsteroidal anti-inflammatory drugs (NSAIDs) (Strong recommendation) or acetaminophen (Weak recommendation) may be used initially.
    • NSAIDs may be more effective than acetaminophen for reducing pain and improving function in patients with hip OA, and various nonselective NSAIDs and COX-2 inhibitors appear to have similar efficacy; however, acetaminophen may cause fewer gastrointestinal adverse events than nonselective NSAIDs, and both NSAIDs and COX-2 inhibitors appear associated with increased risk of cardiovascular harm.
  • In patients failing to obtain adequate pain relief with oral analgesic/anti-inflammatory agents, intra-articular corticosteroid injections should be considered as an option in the management of hip OA (Strong recommendation).
  • For treatment of refractory pain, where other pharmacologic agents have been ineffective or are contraindicated, consider tramadol (Weak recommendation).
• Operative management
  • In patients not obtaining adequate pain relief and functional improvement from combination of nonpharmacologic and pharmacologic treatment, consider joint replacement surgery (Weak recommendation).
  • In young adults with symptomatic hip OA, consider joint-preserving surgical procedures (hip arthroscopy and hip resurfacing) (Weak recommendation).