Working Diagnosis:
Idiopathic transient osteoporosis of the hip (ITOH)

Treatment:
Conservative care was initiated with protected partial weight bearing. Due to balance issues and shoulder pains, this was accomplished with a walker for 6 weeks. Significant improvements in the bony edema of the right femoral head and neck were seen from initial visit Case Photo #1 (Photo 1. Initial MRI coronal image). Case Photo #2 (Photo 2. Initial MRI axial image) from 6 week follow-up visit Case Photo #3 (Photo 3. Follow-up MRI coronal image). Case Photo #4 (Photo 4. Follow-up MRI axial image). Further activity modifications to avoid pain were done over a 4 months period. At final visit, her gait was normal with no pain in hip range of motion.

Outcome:
After protected partial weight bearing with walker for 6 weeks and activity modifications, the patient improved over a course of 4-months without complications. She will follow up with Gynecologist for osteopenia and repeat DEXA.

Author's Comments:
Idiopathic transient osteoporosis of the hip classically occurs in middle-aged males or in 3rd trimester of pregnancy. Its etiology is unknown, is a diagnosis of exclusion and ultimately is self-limiting. Initial work-up raised concern for atypical fracture, AVN or ITOH. While our patient had risk factors for atypical fractures (bisphosphonate use) and AVN (prednisone tapers for asthma), these were excluded based on exams with retained range of motion and repeat imaging showing significant improvement. The repeat MRI with improvement in the homogenous pattern of bony edema is more consistent with ITOH as compared to the progressive focal edema of AVN. Ultimately, conservative management was successful.

Editor's Comments:
This is a great presentation of idiopathic transient osteoporosis of the hip (ITOH). This is also known as bone marrow edema syndrome. As stated from the author, it is not common to see this presentation in an post-menopausal female. MRI is the imaging study of choice to evaluate patients with bone marrow abnormalities.

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