Abstract
Purpose: To review the MRI findings in transient osteoporosis of the hip (TOH) and to investigate the pattern of perfusion in dynamic studies.
Material and Methods: Twenty-seven patients (29 hips), 23–66 years old, were referred for hip pain without history of trauma. In all patients the diagnosis of TOH based on x-rays (decrease bone density of the femoral head) and MRI (bone marrow edema-BME) was confirmed after complete resolution of symptoms and MRI findings after 6–18 months. MRI studies included T1-w SE, T2-w-SPIR-TSE and contrast enhanced T1-w TFE in dynamic mode and delayed SE. Imaging assessment included joint effusion, location and extent of BME (types A–D), sparing of the femoral head, subchondral linear lesions, and collapse.
Results: Joint effusion was observed in 28 of 29 hips. The extent of BME in the femoral head was type A in 5/29 hips, B in 2/29, C in 16/29, D in 6/29. Associated BME of the acetabulum was depicted in 6/29 hips. In 12/29 hips the bone marrow edema was sparing the subchondral area. Subchondral line was only found in 2/29 hips. On dynamic T1–w images all hips presented with a delayed pattern of perfusion up to 40 sec.
Conclusion: MRI findings are useful in diagnosing TOH and differentiating this entity from early AVN.
The abstracts were prepared by Eleni Koutsoukou. Correspondence should be addressed to him at the Hellenic Association of Orthopaedic Surgery and Traumatology (HAOST), 20, A. Fleming str, 15123 Marousi, Athens, Greece.