Radiological features of bisphosphonate therapy in children with osteogenesis imperfecta.

steogenesis imperfecta (OI) is a genetic disorder of type-I collagen, which is one of the most prevalent osteoporotic syndromes in children. It is characterized by repeated fractures and skeletal deformities. No universal and effective medical therapy is available for this disorder. Many therapeutic agents have been tried without any convincing benefit. However, several recent clinical studies have reported beneficial effects of bisphosphonates in children with OI.1,2 These studies showed that intravenous pamidronate improves symptoms of chronic bone pain, recurrent fractures rate, motor function and bone mineral density (BMD). The objective of this study is to determine and describe the radiographic features of cyclic pamidronate administration on the growing skeleton in children with OI. We retrospectively reviewed the radiographs of 10 children (7 male, 3 female) treated with pamidronate. The age of these children ranged from 2-10 years. Pamidronate, which is an osteoclast inhibitor was administrated intravenously at 4 months intervals at the Pediatric Endocrinology Clinic, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia for 2 years. The annual total dose was 9mg/kg/year. Radiographic frontal views of the hands, wrists, and knees were obtained every 6 months. Other radiographs obtained for clinical indications during the treatment and follow-up periods were also reviewed as part of this study. Lumbar and whole body BMD were assessed biannually. Bone mineral density determinations were performed using a Hologic QDR4500 dual-energy x-ray absorptiometer with pediatric scan and analysis functions. Z scores, the number of standard deviations (SD) for BMD above or below the mean for age-matched controls, were derived on the basis of the manufacturer’s data. Prior to treatment, baseline radiographs showed generalized osteopenia, bone bowing and fractures with fracture deformities. Post treatment, there were multiple sclerotic metaphyseal bands seen in all children in the long bones paralleling to the growth Figure 1 Radiographs showing a) Multiple sclerotic metaphyseal bands are seen in the distal ends of the ulna and the radius, b) distal ends of the femur and proximal end of the tabia, which are parallel to the growth plates and correspond to the number of treatment cycle. a O