II. Epidemiology
- Children age 4-9 years old typically affected (may affect ages 3-12 years old)
- Peak onset at ages 5 to 7 years old
- Boys affected 4-5 times more often than girls
- Familial in 20% of cases
- Incidence 1:1000 to 1:10,000
- Caucasian more often affected than african american
- Bilateral in 10-20% at time of diagnosis
- Typical body habitus
- Short to average height
- Average weight to Overweight (but not typically obese as seen in Slipped Capital Femoral Epiphysis)
III. Risk Factors
- Boys
- Low birth weight
- Short Stature
- Abnormal birth presentation (e.g. Breech Presentation)
- Family History
- Higher birth order
- Lower socioeconomic status
- Hyperactivity
- Obesity
- Passive Smoke Exposure
IV. Pathophysiology
- Juvenile idiopathic, spontaneous onset, avascular necrosis of femoral head
- Results from a partial interruption of the blood supply to the femoral head
- Repeat episodes result in infarction and necrosis of the femoral head
- Subchondral Stress Fractures with remodeling over ensuing 2-4 years
- Femoral head flattens and subluxes
V. Etiology
- Idiopathic Osteochondrosis
VI. Symptoms
- Insidious onset of Hip Pain or Pediatric Limp, worse with activity
-
Anterior Hip Pain and Groin Pain
- May be referred as Knee Pain
- Unilateral Hip Pain in 84-90% of cases (bilateral Hip Pain in the remainder)
VII. Signs
- Antalgic Gait
- Child walks with a limp on affected side
- Decreased Hip Range of Motion (pain may be absent)
- Limited hip abduction
- Limited hip internal rotation
- Leg Length Discrepancy (shortening on affected side)
VIII. Imaging
-
Hip XRay
- Views
- Anteroposterior Pelvis
- Frog-leg lateral hip
- Findings
- XRay may appear normal early in condition
- Joint space widening
- Irregular physis widening
- Proximal femur growth center (capital epiphysis) with fragmentation, flattening, and sclerosis
- May demonstrate a subchondral Stress Fracture line
- Crescent sign
- Subcortical lucency represents bony destruction
- Views
- Hip MRI
- Indicated if non-diagnostic XRay results
- Bone Marrow changes may be present
- Hip Effusion
- Labrum and Articular Cartilage changes
IX. Differential Diagnosis
- Septic Hip
- Transient Hip Synovitis
- Proximal femur Osteomyelitis
X. Management
- Orthopedic Consultation in all cases (within 1 week)
- Non-weight bearing initially
- NSAIDs may be used for pain
- Difficult management
- Long-term treatment
- Limited activity until resolution
- Bracing and Casting for up to 1-2 years
- Maintains femoral head within the acetabulum
- Surgical osteotomy to improve Hip Joint congruity
- Indicated in failed conservative management (esp. for over age 8 years old)
- Allows child back to activity in 4-6 months
XI. Complications
- Severe degenerative hip disease (femoral head deformity)
- Requires hip replacement by middle age in 50% cases
- Proximal thigh atrophy and limb shortening
- Other complications
- Hip subluxation
- Premature physeal closure
- Hip Labral Tear
- Osteochondritis Dissecans
- Acetabular Dysplasia
- Femoral head deformity
XII. Prognosis
- Fair at best to avoid longterm Arthritis (see complications above)
- Best prognosis for optimal range of motion is with early treatment at young age
- Age under 6 years old often fully recover without longterm deficit
- Predictors of worse prognosis
- Age over 6 years at onset of condition
- More severely affected femoral head deformity
- Hip Joint incongruity
- Decreased Hip Range of Motion
XIII. References
- Claudius and Behar in Majoewsky (2012) EM:RAP-C3 2(8): 1
- Gardiner (2018) Crit Dec Emerg Med 37(5): 3-14
- Jhun and Raam in Herbert (2016) EM:Rap 16(2):15-6
- Schleihauf (2019) Crit Dec Emerg Med 33(5): 19-28
- Achar (2019) Am Fam Physician 99(10): 610-8 [PubMed]
- Atanda (2011) Am Fam Physician 83(3): 285-91 [PubMed]
- Wiig (2008) J Bone Joint Surg Br 90(10): 1364-71 [PubMed]