Transient osteoporosis of the hip with a contralateral delayed involvement: a case report.

We describe a case of non-simultaneous bilateral hip pain with bone marrow edema occurring in an adult male, with the contralateral hip being involved 12 years later after the onset of symptoms. On the basis of clinical and imaging findings, together with a complete resolution after conservative management, a post-hoc diagnosis of metachronous bilateral transient osteoporosis of the hip (TOH) was made. Non-simultaneous bilateral presentation of TOH is exceptional, and contralateral involvement with a 12-year delay has never been previously described.