Basics
Description
- Avascular (aseptic) necrosis results from the interruption of the blood supply to bone (either traumatic or nontraumatic occlusion).
- The femoral head is the most common site.
- A particular type of self-limiting idiopathic avascular necrosis of the hip that occurs in children is known as Perthes disease (see the "Perthes Disease" chapter).
Risk Factors
Genetics
Variable, depending on cause
Pathophysiology
- Death and necrosis of bone with gradual return of blood supply
- Necrotic bone gradually resorbed and replaced by new bone
- During bone resorption, structural integrity of femoral head may be reduced, leading to collapse.
Etiology
- Traumatic
- Hip fracture
- Hip dislocation
- Slipped capital femoral epiphysis
- Complication of casting, bracing, surgery
- Nontraumatic
- Idiopathic (older, after physeal closure); similar to adult avascular necrosis
- Idiopathic (younger, before physeal closure, Perthes disease)
- Caisson disease
- Sickle cell disease
- Septic arthritis
- Steroids or chemotherapy
- Malignancy (leukemia)
- Gaucher disease
- Viral infection (HIV, CMV)
- Radiation therapy
- Hypercoagulable states
Diagnosis
History
- Onset (gradual or after traumatic event)
- Association with the following:
- Trauma
- Medications (steroids or chemotherapy)
- Casting, splinting, surgery (iatrogenic)
- Pain, limping
- Stiffness (decreased range of motion)
- Perthes disease may occasionally be bilateral or occur in contralateral hip at a later time point.
Physical Exam
- Gait
- Limping
- Antalgic ("against pain") gait (shortened stance phase relative to swing phase)
- Trendelenburg gait
- Note range of motion:
- Flexion and extension
- Abduction and adduction
- Internal and external rotation
- Hip joint irritability (short arc rotation)
- Signs of other disease processes associated with avascular necrosis (e.g., sickle cell disease)
- Physical examination pearl
- Loss of internal rotation is usually the first and most affected loss of motion seen.
Diagnostic Tests & Interpretation
Lab
- Laboratory examinations should be normal in most forms of avascular necrosis of the femoral head.
- Exceptions:
- Sickle cell disease
- Septic arthritis
- Chemotherapy
Imaging
- Radiographic findings:
- Sclerosis
- Subchondral fracture
- Collapse
- Reossification
- Repair
- Magnetic resonance imaging (MRI)
- Bone edema
- If contrast medium used, area of reduce blood flow evident
- Bone scan
- Reduced signal in affected hip
- Other potential findings:
- Cysts
- Physeal growth arrest (young)
- Early osteoarthritis
- Subluxation
Differential Diagnosis
- Trauma
- Osteochondral fracture
- Impaction fracture
- Epiphyseal/physeal fracture
- Infection
- Osteomyelitis
- Septic arthritis
- Neoplastic process: epiphyseal tumors (chondroblastoma, Trevor disease, etc.)
- Rheumatologic processes
- Skeletal dysplasia, particular if bilateral hip involvement
Treatment
Medication
- NSAIDs may reduce pain by decreasing associated inflammation but may also reduce new bone formation.
- If associated with corticosteroid use, discontinuation or elimination of steroids may be helpful if appropriate.
- Bisphosphonate therapy may help preserve joint shape.
Additional Therapies
General Measures
- Maintain range of motion (physical therapy, traction, continuous passive motion).
- Contain the femoral head in the acetabulum (see treatment principles listed in "Perthes Disease" chapter).
- Duration of therapy variable, depending on cause
- Reduced weight bearing on affected hip may help prevent collapse.
Surgery/Other Procedures
Redirectional osteotomy
- Femoral or acetabular reorientation
- Core decompression to stimulate new blood supply
Ongoing Care
Diet
- Thought not to alter disease process
- Recommend general balanced diet
- During immobilization, excessive weight gain may occur.
Prognosis
- Depends on extent of femoral head collapse
- Good if mild involvement and patient is young
- When to expect improvement: variable, depending on cause
- Moderate to severe cases often have significant collapse and end up requiring a total hip replacement.
Complications
- Joint collapse with decreased range of motion, pain, limping
- Osteoarthritis
- Physeal arrest with growth disturbance
Alert
Signs to watch for:
- Subluxation
- Early osteoarthritis
- Growth arrest
Additional Reading
- Lahdes-Vasama T, Lamminen A, Merikanto J, et al. The value of MRI in early Perthes' disease: an MRI study with a 2-year follow-up. Pediatr Radiol. 1997;27(6):517-522. [View Abstract]
- Mont MA, Jones LC, Hungerford DS. Nontraumatic osteonecrosis of the femoral head: ten years later. J Bone Joint Surg Am. 2006;88(5):1117-1132. [View Abstract]
- Roposch A, Mayr J, Linhart WE. Age at onset, extent of necrosis, and containment in Perthes disease. Results at maturity. Arch Orthop Trauma Surg. 2003;123(2):68-73. [View Abstract]
- Shipman SA, Helfand M, Moyer VA, et al. Screening for developmental dysplasia of the hip: a systematic literature review for the US Preventive Services Task Force. Pediatrics. 2006;117(3):e557-e576. [View Abstract]
- Tokmakova KP, Stanton RP, Mason DE. Factors influencing the development of osteonecrosis in patients treated for slipped capital femoral epiphysis. J Bone Joint Surg Am. 2003;85-A(5):798-801. [View Abstract]
Codes
ICD09
- 733.42 Aseptic necrosis of head and neck of femur
- 732.1 Juvenile osteochondrosis of hip and pelvis
ICD10
- M87.059 Idiopathic aseptic necrosis of unspecified femur
- M91.10 Juvenile osteochondrosis of head of femur, unspecified leg
- M87.052 Idiopathic aseptic necrosis of left femur
- M87.051 Idiopathic aseptic necrosis of right femur
- M91.11 Juvenile osteochondrosis of head of femur, right leg
- M91.12 Juvenile osteochondrosis of head of femur, left leg
SNOMED
- 444904004 aseptic necrosis of head of femur (disorder)
- 111255008 Avascular necrosis of the capital femoral epiphysis (disorder)
- 15739006 Juvenile osteochondrosis of hip AND/OR pelvis (disorder)
FAQ
- Q: What type of medication is most often associated with avascular necrosis of the hip?
- A: Corticosteroids
- Q: For avascular necrosis in children (Perthes disease of the hip, for example), is younger or older age associated with a better prognosis?
- A: Younger age (<8 years)