Transient osteoporosis of the hip:Presentation of (a)typical cases and a review of the literature

Transient osteoporosis of the hip (TOH) is a rare disorder affecting primarily middle-aged men and women during the last trimester of pregnancy. The disease is character-ized by pain in the involved joint with temporary osteopenia apparent on radiology without joint space narrowing or destruction, in the absence of other recognizable causes of synovitis or osteoporosis. Within a few months the pain as well as radiological abnormalities disappear spontaneously with complete resolution. In this paper the literature is reviewed, with particular focus on the topic of the role of magnetic resonance imaging (MRI) in the diagnostic procedure. Two patients with TOH, a father and daughter; are described. Such a familial appearance has not been reported before. Based on HLA-typing, the existence of an HLA-associated genetic predisposition nevertheless seems unlikely.