Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Hip Arthritis

Basics
Description
  • Hip arthritis is caused by loss of the articular cartilage of the acetabulum and proximal femur.
  • As the cartilage is lost, the subchondral bone of the proximal femur and the acetabulum rub, causing pain with ambulation, loss of motion, and disability.
General Prevention
  • Low-impact exercise (swimming, biking, walking)
  • Activity modification
  • Weight loss
Epidemiology
  • Hip arthritis is caused by loss of the articular cartilage of the acetabulum and proximal femur.
  • Some hips are more susceptible to arthritis than others, which is thought to be secondary to subtle differences in hip alignment, such as hip dysplasia or femoroacetabular impingement.
Prevalence
It is estimated that 12% of the population in the United States suffers from arthritis.
 
Risk Factors
  • Trauma
  • Osteonecrosis
  • Infections
  • Hemophilia
  • Hip dysplasia
  • Femoroacetabular impingement
  • Perthes disease
  • SCFE
  • Inflammatory arthritis:
    • Rheumatoid arthritis
    • Systemic lupus erythematosus
    • Psoriatic arthritis
Etiology
  • The cause of primary osteoarthritis is unknown, but it is thought to be secondary to a combination of factors:
    • Differences in cartilage properties
    • Mechanical differences of alignment of the joint, such as hip dysplasia or femoroacetabular impingement
Classification
  • Hip arthritis is classified broadly as:
    • Primary osteoarthritis
    • Inflammatory arthritis
    • Secondary osteoarthritis
Associated Conditions
  • Spine degenerative disc disease
  • Knee arthritis
Diagnosis
Signs and Symptoms
  • Patients present with a diffuse ache over the hip.
  • Classically, pain occurs in the anterior groin, often with radiation of pain to the buttock and knee, especially on the medial side.
  • Occasionally, knee pain is the predominant symptom.
  • Patients often describe limping and fatigue with walking.
  • As patients lose ROM, they have difficulty tying their shoes and getting in and out of cars.
History
  • Typically, the pain is gradual in onset, of long duration, and relieved by rest.
  • Night pain or constant pain implies cancer or infection.
  • Pain with activity is typical of hip arthritis.
  • Primary osteoarthritis is a disorder of patients >50 years old.
  • Hip arthritis in a young person is usually secondary to trauma, osteonecrosis, or developmental causes.
Physical Exam
  • Assess the patient’s ROM.
    • Loss of internal fixation is one of the earliest signs of hip arthritis.
    • Hip flexion also is limited.
  • Check for flexion contracture, gait abnormalities, leg-length discrepancy, and muscle weakness.
  • A resisted straight-leg raise (Stinchfield test) loads the joint and reproduces the pain.
  • Palpate the greater trochanter to assess for trochanteric bursitis.
  • Perform a careful neurologic examination and straight-leg-raise test to assess for radicular signs.
  • Assess for leg-length discrepancy and pelvic tilt.
  • Evaluate the spine for scoliosis or tenderness.
Tests
Lab
Rheumatologic screening tests should be ordered if one suspects inflammatory arthritis.
  
Imaging
  • Plain radiographs (the 1st step):
    • An AP view of the pelvis and AP and lateral views of the involved hip to rule out fracture and assess joint space narrowing, osteophyte formation, sclerosis, and subchondral cysts
    • AP and lateral views of the lumbosacral spine if any suggestion of radiculopathy is present
  • Special imaging:
    • Technetium bone scans to screen the entire body for occult bone disease in the presence of severe pain and no apparent areas of disease
    • MRI of the hip and pelvis:
      • An excellent modality for excluding bone and soft-tissue disease of the pelvis and hip
      • Ensure that the pathologic area is in the field of the scan.
Diagnostic Procedures/Surgery
Intra-articular injection of local anesthetic agents may be used as a test for diagnosing hip arthritis when the diagnosis is unclear.
  
Differential Diagnosis
  • The differential diagnosis is extensive:
    • Neoplasms:
      • Young patients (4-20 years old): Osteosarcoma, Ewing sarcoma
      • Patients >50 years old: Metastatic bone disease, multiple myeloma
    • Stress fractures of the femoral neck:
      • Runners and osteoporotic patients
    • Greater trochanteric bursitis:
      • Lateral hip pain
    • Radiculopathy:
      • Pain distal to the knee
Treatment
General Measures
  • Weight reduction and activity modification are the major general measures.
  • Initial arthritis care begins with:
    • Activity modification and avoidance of provocative activities, such as running and heavy lifting
    • NSAIDs
    • Cortisone injection
    • Tylenol for patients with contraindications to NSAIDs
    • Cane support in the opposite hand
    • Weight reduction if appropriate
Special Therapy
Physical Therapy
  • Patients are instructed on the use of a cane and on appropriate exercises to prevent contractures.
  • Strengthening of the hip and leg muscles may help pain symptoms and strengthen the limb for later surgery
Complementary and Alternative Therapies
  • Randomized trials have not been performed for many therapies.
  • Alternative medicines with some evidence of effectiveness include:
    • Devil’s claw (Harpagophytum procumbens)
    • Avocado-soybean unsaponifiables
    • Capsaicin cream
    • Phytodolor
  • Little evidence exists for magnet or laser therapy.
  • The role of acupuncture is unclear and therefore should not be performed in patients susceptible to infections.
Medication
  • Acetaminophen
  • NSAIDs
  • Occasional intra-articular steroid injections
  • Glucosamine
Surgery
  • Surgery is indicated for patients for whom activity modification, NSAIDs, and other medical treatments have failed.
  • Core decompression may be used for patients with osteonecrosis of the femoral head.
  • Hip fusion may be indicated in young, active patients.
  • In some young patients with acetabular or proximal femoral dysplasia, acetabular or proximal femoral osteotomy can be used to reduce the joint forces and improve cartilage physiology.
  • Young patients with symptomatic femoroacetabular impingement may benefit from a femoral reshaping procedure.
  • Total hip replacement is the main surgical procedure.
Follow-up
Prognosis
  • In patients with early arthritis, acetaminophen or NSAIDs may relieve all pain and substantially improve function.
  • The prognosis after total hip replacement is excellent: Virtually all such patients attain pain relief, good motion, and functional improvement.
Complications
  • Complications of nonoperative care:
    • Hip stiffness
    • Leg-length discrepancy
    • Limp
    • Muscle weakness
    • Inability to ambulate
    • Pain
  • Complications of total hip replacement:
    • Hip stiffness
    • Infection
    • Dislocation (more common in revision hip arthroplasty surgery)
    • Femoral or acetabular fracture
    • Nerve palsy (sciatic nerve most commonly)
    • DVT, PE
    • Heterotopic ossification
    • Loosening of components
    • Wear of the acetabular liner
    • Osteolysis or bone loss around the components
Patient Monitoring
Patients with hip arthritis should be reassessed if symptoms change or pain worsens.
 
Miscellaneous
Codes
ICD9-CM
715.95 Arthropathy not otherwise specified, pelvis
 
Patient Teaching
  • Patients are instructed on the importance of compliance with weight reduction, the use of NSAIDs, and the avoidance of painful activities.
  • The role of hip replacement is discussed.
Activity
  • Patients can perform activities as tolerated but should avoid those that cause pain and may hasten the arthritic changes, such as running, racquetball, and heavy lifting.
  • Water therapy is an effective exercise for patients with hip arthritis.
Prevention
Prevention is achieved in some young patients with recognized hip dysplasia or femoroacetabular impingement by surgery to realign the joint or to reshape the femoral head.
 
FAQ
Q: When is a patient ready for hip replacement?
A: This decision is individualized and made by the patient in discussion with the surgeon. Every patient has different levels of pain and disability that does not correlate with the radiographic progression of disease. Patients must understand the risks of surgery and believe that the chance of improving their disability and pain is worth those risks.
 
Q: Does progressive wear make a hip replacement harder to perform?
A: In general, wear does not happen quickly, and the hip replacement can be performed with little difficulty. Progressive hip stiffness, limp, and muscular weakness do make the postsurgical recovery of function more difficult.

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