title: Radiographic characteristics of the hand and cervical spine in fibrodysplasia ossificans progressiva.
abstract: Fibrodysplasia ossificans progressiva (FOP) is a disabling heritable disorder of connective tissue characterized by progressive heterotopic ossification in various extraskeletal sites. Early correct diagnosis of FOP is important to prevent additional iatrogenic harm or trauma. Congenital malformation of the great toes is a well-known diagnostic clue, but some patients show normal-appearing great toes. The thumb shortening and cervical spine abnormalities are other skeletal features often observed in FOP. This study aimed to address the quantitative assessment of these features in a cohort of patients with FOP, which potentially helps early diagnosis of FOP. Radiographs of the hand and cervical spine were retrospectively analyzed from a total of 18 FOP patients (9 males and 9 females) with an average age of 13.9 years (range 0.7-39.3 years). The elevated ratio of the second metacarpal bone to the distal phalanx of the thumb (> +1SD) was a consistent finding irrespective of the patient's age and gender. Infant FOP patients, in addition, exhibited an extremely high ratio of the second metacarpal bone to the first metacarpal bone (> +3SD). The height/depth ratio of the C5 vertebra increased in patients over 4 years of age (> +2SD). Additionally, the ratio of (height+depth) of the C5 spinous process to the C5 vertebral depth was markedly elevated in young patients (> +2SD). We quantitatively demonstrated the hand and cervical spine characteristics of FOP. These findings, which can be seen from early infancy, could be useful for early diagnosis of FOP even in patients without great toe abnormalities.
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan;
authors.forename: Kenichi
authors.initials: K
authors.lastname: Mishima
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan; ; The Research Committee on Fibrodysplasia Ossificans Progressiva, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitoh
authors.affiliation: The Research Committee on Fibrodysplasia Ossificans Progressiva, Tokyo, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Haga
authors.affiliation: The Research Committee on Fibrodysplasia Ossificans Progressiva, Tokyo, Japan.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Nakashima
authors.affiliation: The Research Committee on Fibrodysplasia Ossificans Progressiva, Tokyo, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Kamizono
authors.affiliation: The Research Committee on Fibrodysplasia Ossificans Progressiva, Tokyo, Japan.
authors.forename: Takenobu
authors.initials: T
authors.lastname: Katagiri
authors.affiliation: The Research Committee on Fibrodysplasia Ossificans Progressiva, Tokyo, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Susami
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan;
authors.forename: Masaki
authors.initials: M
authors.lastname: Matsushita
authors.affiliation: Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan;
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishiguro
keywords: Fibrodysplasia ossificans progressiva; early diagnosis; radiographic characteristics