Distinguishing transient osteoporosis of the hip from avascular necrosis
Anita Balakrishnan1, Emil H Schemitsch, Dawn Pearce
1Upper Extremity Reconstructive Service, St. Michael's Hospital and the University of Toronto, Toronto, Ont.
Insights
Transient osteoporosis of the hip (TOH) is often misdiagnosed as avascular necrosis (AVN) in young men. Increased physician awareness is crucial for accurate diagnosis and to prevent unnecessary surgery for this self-resolving condition.
Area of Science:
- Orthopedics
- Radiology
- Medical Diagnostics
Background:
- Transient osteoporosis of the hip (TOH) is frequently misdiagnosed as avascular necrosis (AVN).
- This diagnostic challenge is particularly noted in young men presenting with hip pain.
- Physician awareness regarding TOH prevalence and diagnosis requires enhancement.
Purpose of the Study:
- To review cases of misdiagnosed TOH as AVN.
- To increase physician awareness of TOH in young men.
- To highlight diagnostic criteria and management of TOH.
Main Methods:
- Retrospective chart review of patients with TOH misdiagnosed as AVN.
- Analysis of demographic data, risk factors, imaging, and outcomes.
- Inclusion criteria: patients referred between 1998-2001 with a diagnosis of AVN.
Main Results:
- Ten young men (12 hips) were identified with TOH misdiagnosed as AVN.
- Nine patients had MRI scans showing characteristic TOH changes prior to referral.
- All patients were referred for surgery; correct diagnosis led to spontaneous resolution without intervention.
Conclusions:
- TOH in young men remains underdiagnosed and its MRI findings misinterpreted.
- Distinctive MRI features can help differentiate TOH from AVN.
- Increased awareness can prevent unnecessary surgical interventions for TOH, promoting conservative management.
Introduction:
To review the circumstances surrounding the misdiagnosis of transient osteoporosis of the hip (TOH) as avascular necrosis (AVN) and to increase physician awareness of the prevalence and diagnosis of this condition in young men, we reviewed a series of cases seen in the orthopedic unit at St. Michael's Hospital, University of Toronto.
Methods:
We studied the charts of patients with TOH referred between 1998 and 2001 with a diagnosis of AVN for demographic data, risk factors, imaging results and outcomes.
Results:
Twelve hips in 10 young men (mean age 41 yr, range from 32-55 yr) were identified. Nine men underwent magnetic resonance imaging (MRI) before referral, which showed characteristic changes of TOH. All 10 patients were referred for surgical intervention for a diagnosis of AVN. The correct diagnosis was made after reviewing patients' charts and the scans and was confirmed by spontaneous resolution of both symptoms and MRI findings an average of 5.5 months and 7.5 months, respectively, after consultation.
Conclusions:
Despite recent publications, the prevalence of TOH among young men is still overlooked and the distinctive MRI appearance still misinterpreted. Symptoms may be severe but resolve over time with reduced weight bearing. The absence of focal changes on MRI is highly suggestive of a transient lesion. A greater level of awareness of this condition is needed to differentiate TOH from AVN, avoiding unnecessary surgery and ensuring appropriate treatment.
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