Intraoperative bleeding in patients with osteogenesis imperfecta type III treated by Fassier-Duval femoral rodding: analysis of risk factors.

The surgical treatment of osteogenesis imperfecta (OI) is negatively influenced by clinical features such as osteoporosis, limb deformities and bone changes caused by bisphosphonate therapy. Blood loss during femoral nailing surgeries in patients with OI is a serious problem. Platelet anomalies have been associated with an elevation of the serum pyrophosphate originating from the platelets during clotting, even if the causality with the platelet dysfunction has not yet been established. To identify predictive risk factors regarding intraoperative bleeding, a retrospective analysis was conducted on 23 patients aged between 6 and 13 years, affected by OI type III, who were treated to correct femoral deformities or to perform an osteosynthesis for femoral shaft fractures, using the Fassier-Duval telescopic nail. Osteotomies were performed in 14 cases of deformities and in two out of seven cases of fractures. A survey about the bleeding had been obtained by calculating the sum of the blood aspirated and that lost with the gauzes or present on the surgical drapes. To obtain an estimate of the intraoperative blood losses, one must resort to a calculation based on an algorithm that evaluates the ratio between the effective blood loss divided by the total blood volume expected as per age and weight (γ distribution). The average blood loss was 237.4 ml (0.12 γ). In seven cases, it was necessary to perform postoperative transfusions, owing to an average blood loss of 502.8 ml (0.27 γ). Patients aged less than 10 years had a minor blood loss. A greater number of osteotomies was associated with a significant increase of average bleeding (P=0.046). Patients who were never treated with bisphosphonates showed a significantly greater bleeding rate (P=0.048). Patients affected by OI type III have a high risk of severe blood loss during surgery, even caused by the platelet disfunction, which characterizes this OI type. In addition to this predisposing factor, there are other risk factors to consider in preoperative surgical planning. In patients who were never treated with bisphosphonates, the bleeding was higher than in the ones treated with bisphosphonates since at least 1 year. The effects of bisphosphonates on bone tissue (such as the medullar canal narrowing and the bone cortex thickening) could reduce the spongious bone amount and the bleeding. Inhibiting the farnesyl pyrophosphate synthase enzyme and reducing the prenylation of many plasma proteins, including the methylene tetrahydrofolate reductase, the bisphosphonates could lead to an alteration of the coagulation cascade. The correlation found with the intake of bisphosphonates, capable of inhibiting the action of the farnesyl pyrophosphate synthase enzyme, thus influencing coagulation, requires further prospective studies with research of the methylene tetrahydrofolate reductase mutation in patients with OI type III undergoing surgical procedures. The number of osteotomies, the patient's age and the intake of bisphosphonates for at least 1 year seem to be the best predictive factors for blood loss.

Isolated olecranon fractures in children affected by osteogenesis imperfecta type I treated with single screw or tension band wiring system: Outcomes and pitfalls in relation to bone mineral density.

The purpose of this study is to compare the results of 2 techniques, tension band wiring (TBW) and fixation with screws, in olecranon fractures in children affected with osteogenesis imperfecta (OI) type I. Between 2010 and 2014, 21 olecranon fractures in 18 children with OI (average age: 12 years old) were treated surgically. Ten patients were treated with the screw fixation and 11 with TBW. A total of 65% of olecranon fractures occurred as a result of a spontaneous avulsion of the olecranon during the contraction of the triceps muscle. The average follow-up was 36 months. Among the children treated with 1 screw, 5 patients needed a surgical revision with TBW due to a mobilization of the screw. In this group, the satisfactory results were 50%. In patients treated with TBW, the satisfactory results were 100% of the cases. The average Z-score, the last one recorded in the patients before the trauma, was -2.53 in patients treated with screw fixation and -2.04 in those treated with TBW. TBW represents the safest surgical treatment for patients suffering from OI type I, as it helps to prevent the rigidity of the elbow through an earlier recovery of the range of motion, and there was no loosening of the implant. In analyzing the average Z-score before any fracture, the fixation with screws has an increased risk of failure in combination with low bone mineral density.

Osteochondritis dissecans of the lateral femoral condyle in a patient affected by osteogenesis imperfecta: a case report.

Osteochondritis dissecans is a very uncommon phenomenon in osteogenesis imperfecta (OI). A 14-year-old boy, affected by OI and followed in our Center for Congenital Osteodystrophies, had a knee trauma and MRI indicated a hollowed area of 2.5×1.5 cm in the lateral femoral condyle, which was classified as grade III. The patient underwent surgery, performed as a one-step surgical treatment: the osteochondral fragment was removed, curettage of lesion's bottom was performed, and a biphasic scaffold was used to fill the defect, implanted with a press-fit technique. MRI at 12 and 24 months after surgery showed scaffold integration. At the final follow-up, the patient did not feel any pain or articular limitations. It is difficult to provide a guideline on osteochondritis dissecans in patients affected by OI because of the lack of literature reports on this rare disorder in a rare disease. According to our experience, in these patients, osteosynthesis of the bone fragment and the use of autograft are not recommended because of the patient's bone weakness and osteoporosis. Moreover, compared with two-step surgery, one-step surgery is preferred to reduce the risk related to anesthesia, often observed to be higher in these patients.