Bone Abstracts

Introduction: The effectiveness of intravenous pamidronate was assessed independently and in combination with corrective osteotomy surgery for lower extremity deformities in children with osteogenesis imperfecta.

Methods: Orthopaedic treatment was conducted in 21 patients with OI (type I–ten patients, type III–11 patients), including 13 males and eight females with mean age 9.4±0.6. All patients received calcium supplements and active forms of vitamin D. Pamidronate was administered cyclically during the year and controled by serum calcium level. Cycles were separated by three month intervals. In type I of OI, withC-Terminal Telopeptide or CTX of 0.5–1.5 ng/ml, z-score −2.5 to −3.5, pamidronate was administered at 0.5 mg/kg per cycle. In type III OI (CTX 1.5–3.5 ng/ml, z-score −3.5 and below), pamidronate was administered at 1 mg/kg per cycle. Pamidronate was administered independently in ten patients an in conjunction with surgery in 11 patients.

Results: Treatment outcomes were evaluated clinically (number of fractures, gait recovery) and biochemically (CTX as bone resorption marker) after 6 months in all patients and by lumbar spine DEXA z-score after a year of treatment in 18 patients. After treatment, 18 patients had no repeat pathological fractures, two patients sustained femur fractures and one sustained a tibia fracture. Among operative patients, only four were independent ambulators before surgery; by 1.5 years after surgery, nine of 11 patients were ambulatory. Among all patients, the mean CTX decreased by 0.46 (37%), P=0.021 and mean z-score increased by 1.13 (27%). Patients who underwent surgery experienced less decrease in CTX (0.26 ng/ml) than those who did not (0.67) due to the increased bone turnover associated with osteotomy healing.

Conclusions: The use of pamidronate independently or in combination with corrective osteotomies in patient with osteogenesis imperfecta leads to fewer pathologic fractures, decreased bone turnover, and increased bone density, and in combination with corrective osteotomies may facilitate improved ambulatory status.

Disclosure: The authors declared no competing interests.