Natural History of Hyperplastic Callus Formation in Osteogenesis Imperfecta Type V

Abstract

Hyperplastic callus formation was assessed in 23 patients with osteogenesis imperfecta type V. Hyperplastic callus mostly affected long bones in the lower extremities and occurred predominantly during phases of rapid growth.Introduction: Hyperplastic callus (HPC) formation is one of the most conspicuous features of osteogenesis imperfecta (OI) type V, but the natural history of HPC has not been well characterized. Materials and Methods:In this retrospective single-center study, we assessed HPC in 23 OI type V patients (9 females and 14 males). Results: Fifteen patients (65%) had HPC at 48 skeletal sites, 30 of which affected the lower limbs. The number of HPC sites per patient ranged from 0 to 7, with an average of 2.6 for men and 1.1 for women (p ‫ס‬ 0.047 for this sex difference; t-test). New HPC formation was observed both after fractures and outside of the context of fractures. Only a minority of lower limb fractures (26%) precipitated HPC formation. After an initial enlargement phase, HPC lesions usually stabilized, but could also resolve completely (n ‫ס‬ 2) or progress and lead to bone deformation. The most common complication of HPC was a fracture through the lesion (n ‫ס‬ 7). Neither pamidronate nor indomethacin seemed to influence the course of HPC. Conclusions: HPC is a potentially serious complication of OI type V. Given the rarity of the disorder, treatment studies will require multicenter collaborations.

Clinical and Molecular Characterization of Osteogenesis Imperfecta Type V

“…Changes in bone mineralization arising from an increase in ectopic ossification lead to a characteristic osteoporotic phenotype in all of these patients; however, they also present with exuberant bone formation, reflected by the HPC development, which is unique to this type of OI [Cheung et al, 2007;Cho et al, 2012;Shapiro et al, 2013]. Histomorphometrically, there are also differences in OI-V, as these individuals exhibit a lower rate of bone remodeling activation due to lower bone formation and resorption parameters when compared to patients with OI-IV [Glorieux et al, 2000].…”

“…HPC is a soft tissue anomaly characterized by exuberant bone formation with extensive expansion beyond the site of fracture, which occurs following fracture or surgery, and whose etiology remains unclear [Cheung et al, 2007;Shapiro et al, 2013]. In general, during the formation of HPC, biochemical changes are observed that include an increase of serum alkaline phosphatase and urinary excretion of N-telopeptide [Glorieux et al, 2000].…”

Evolution of the radiographic appearance of the metaphyses over the first year of life in type V osteogenesis imperfecta: Clues to pathogenesis

“…This is more common during the periods of rapid growth in infancy and puberty. (1) Other features include anterior dislocation of the radial head and the appearance of a radiodense band under the growth plate of long bones. Histology is definitive with a unique meshlike pattern of lamellation under polarized light.…”

Osteogenesis imperfecta type V

“…It is reported that while not all OI type V patients have hypertrophic callus formation, all patients with hypertrophic callus formation are OI type V in the proper clinical context [1,4]. Lesions form during the growth years at sites of rapid periosteal apposition.…”

“…Lesions form during the growth years at sites of rapid periosteal apposition. The long bones are most often affected, particularly in the lower extremities [4]. Hypertrophic callus can be precipitated by fracture or surgery, or arise spontaneously.…”