Osteogenesis imperfecta is a heterogeneous group of collagen type 1 defects. The resulting fragile bone with increased risk of fractures and deformity is the primary orthopaedic challenge. Surgical treatment is aimed at reducing the risk of fracture, correcting deformity and improving ambulatory status.

Management of the growing child with extensible intramedullary device was introduced in the 1960’s by Bailey and Dubow. Since then a number of different nails have been used. The current report presents our experience with the Fassier-Duval intramedullary nail in the first ten patients.

Materials and Method: The first ten children who had been operated between 2005 and 2008 with the Fassier-Duval (FD) nail were reviewed. The indication for surgery in all patients was to stabilise the long bones of the lower extremity to promote mobility. Correction of the axis of the long bones was obtained with wedged osteotomies. There where 7 girls and 3 boys.

Median follow-up was 2 years and 3 months (Range 1 – 4 years and 3 month).

Results: 22 FD nails were inserted in 13 operations in 10 children. 8 FD nails (4 operations) were primary FD nail insertions. The mean age at insertion was 2 years. 14 FD nails (9 operations) were exchanges of other devices. In this group the mean age at insertion of the FD nail was 6 years. In both groups mean admission was 4,5 days.

5 operations were reoperations due to complications. All of these were in femora. 5 patients had a fracture despite the nail. 3 were reoperated due to bending or perforation of the nail. 2 were treated conservatively. All 5 healed uneventfully. 1 patient was reoperated 3 times. First due to migration of the nail, secondly failure of the nail to elongate and thirdly because of a fracture with bending of the nail. There were no infections, neurological- or vascular damage.

At follow-up 6 patients were walking without any aid. 2 were mobilised with aids. 2 were mobilised in wheelchair.

No radiographic evidence of growth arrest has been noted secondary to the crossing of the epiphysealplate by the nails.

Discussion: Our result supports the reported benefits of extensible intramedullary device in children suffering from osteogenesis imperfecta. Minimizing the crippeling effects of OI is aimed at reducing the risk of fracture, correcting deformity and improving ambulatory status. There are also complications with the Fassier-Duval nail. However these are less than reported with other extensible intramedullary nails. Indeed one could in some cases argue that a bended nail or a fracture after nail insertion is a consequence of the better mobility on the way to a better quality of life.

Since the approval of parathyroid hormone (PTH) as an anabolic treatment for osteoporosis, PTH has increasingly been investigated for other potential clinical uses such as bone repair and regeneration. The microstructure of newly formed bone during distraction osteogenesis enhanced by PTH treatment has yet to be studied. Therefore, the purpose of the study was to investigate the effects of intermittent parathyroid hormone PTH (1–34) treatment on the microstructure of regenerated bone during distraction osteogenesis in rabbits. After tibial mid-diaphyseal osteotomy the callus was distracted 1 mm/day for 10 days. The rabbits were divided in to 3 groups, which daily received a PTH injection for 30 days, a saline injection for 10 days and a PTH injection for 20 days, or a saline injection for 30 days. The new-trabecular structure of the regenerate callus was assessed by micro computed tomography (μCT). In all 51 specimen obtained from the lengthened tibia were scanned and evaluated morphometrically using three different volume of interests. The investigated μCT parameters included trabecular number Tb.N*, trabecular thickness Tb.Th*, trabecular separation Tb.Sp*, bone volume fraction (BV/TV), bone volume (BV), connectivity density (CD), and degree of anisotropy (DA). The results showed that intermittent treatment with PTH during distraction osteogensis resulted in a significantly higher Tb.N*, a more isotropic trabecular orientation, a higher connectivity density, and a higher bone mass. We also found preliminary evidence suggesting that the newly regenerated calluses treated with PTH were more mature than the non-treated calluses. In conclusion: the study demonstrated that treatment with PTH resulted in an enhanced microstructure of the newly regenerated bone indicating that PTH has a potential role as a stimulating agent for distraction osteogenesis.

INTRODUCTION: Medial open-wedge HTO is an alternative in the treatment of medial knee OA for the young and active patient. However this technique leaves an open gap that requires stable fixation to achieve bony healing. As a bone substitute injectable calcium-phosphate-cements could be an alternative to autograft.

MATERIAL AND METHODS: Biomechanical testings were performed on open wedge HTO to investigate load to failure and displacement after cyclic loading (viscous and/or damaged material response). A medial 10 mm open-wedge osteotomy was performed on 7 pairs of composite (Sawbone) left tibiaes, and 8 pairs of preserved cadaver tibiaes. Osteosynthesis where performed with the Dynafix system. In half of the bones the gap was filled with 15 g of Calcibon®. The composite tibiaes were loaded at a ramp speed of 20 mm/min and failures of the constructs were recorded visually. On the cadaver tibiaes, cyclical loading were performed with a maximum load of 2250 N.

RESULTS: Filling of the gap with Calcibon® resulted in significant different load-to-failure patterns with failure at 10.2 kN compared to 2.7 kN in the group without Calcibon®. Displacement at the end of cyclical loading was 1.2 mm in the group with Calcibon® and 2.7 mm in the group without Calcibon®. This difference also was significant.

CONCLUSION: The injectable calcium-phosphate-cement Calcibon® enhances primary stability during load to failure and during cyclical loading in open wedge osteotomies on proximal tibia. Clinical studies are performed to investigate whether Calcibon® has any clinical advantage on wedge healing and stability.

Introduction. Chronic aquired anterior dislocation of the radial head, Bado type I Monteggia equivalent lesion is a uncommen occurence in children. We present our results of sixteen childrn treated with an angular corrective osteotomy

Material and methods. Sixteen children, mean age at the time of injury was six years and eight years at the time of surgery. Time from dislocation to diagnosis was median 30 weeks. Preoperatively decreased range of motion was detected. All children underwent angular ulnar osteotomy using Boyd-Thompson approach. The osteotomy was fixed using a single Steinmann pin. Long arm cast was applied until radiographic healing was detected.

Results. Follow-up showed all but one had successful reduction. Non-union was not detected. All children were pain free at follow up. The total flexion-extension arc of motion measured median 135 degrees. Total rotation of forearm measured median 145 degrees.

Conclusion. Correct treatment of Monteggia equivalent lesionsare demanding. Both in relation to obtaining the correct diagnosis without delay as well as the best treatment procedure. Full antebrachium X-rays are recommended in order to get exact diagnosis initially. Corrective angular ulnar osteotomy is recommened as soft tissue procedures alone is insufficient for alignment of the elbow.

Structure model type and trabecular thickness are important characteristics in describing cancellous bone architecture. It has been qualitatively observed that a radical change of trabeculae from plate-like to rod-like occurs in aging, bone remodeling, and osteoporosis. Thickness of trabeculae has traditionally been measured using model-based histomorphometric methods on two-dimensional (2-D) sections. However, no quantitative study has been published based on three-dimensional (3-D) methods on the age-related changes in structure model type and trabecular thickness for human peripheral (tibial) cancellous bone.

In this study, 160 human proximal tibial cancellous bone specimens from 40 normal donors, aged 16 to 85 years, were collected. These specimens were micro-CT scanned, then the micro-CT images were segmented using optimal thresholds. From accurate 3-D data sets, structure model type and trabecular thickness were quantified by means of novel 3-D methods. Structure model type was assessed by calculating the structure model index (SMI). The SMI was quantified based on a differential analysis of the triangulated bone surface of a structure. This technique allowed quantification of structure model type, such as plate, rod objects or mixture of plates or rods. Trabecular thickness was calculated directly from 3-D images, which is especially important for an a priori unknown or changing structure. Furthermore, 2-D trabecular thickness was also calculated based on the plate model.

Our results showed that structure model type changed towards more rod-like in the elderly, and that trabecular thickness declined significantly with age. These changes become significant after 80 years of age for human tibial cancellous bone, whereas both properties seem to remain relatively unchanged between 20 and 80 years. Although a fairly close relationship was seen between 3-D trabecular thickness and 2-D trabecular thickness, real 3-D trabecular thickness was significantly underestimated using 2-D method.

Osteoarthrosis (OA) stands alongside cancer and heart disease as one of the major causes of suffering and disability amongst the elderly. Changes related to OA occur in all elements of the joint, and there are indications that sub-chondral cancellous bone plays a primary role in the cartilage degeneration in OA. Most previous investigations have been focused on moderate and late OA, whereas little is known about the changes in cancellous bone microstructure in human early OA. This study quantified cancellous bone microstructure in early-stage OA using three-dimensional (3D) methods.

Subchondral cancellous bone specimens, produced from 10 human post-mortem early-stage osteoarthrotic (OA) proximal tibiae and 10 normal age- and gender-matched proximal tibiae, were allocated to 4 groups: medial OA, lateral control, normal medial control, and normal lateral control. OA initiates mostly at the medial condyle, and histological analysis was done to confirm this change. The cylindrical specimens were micro-computed tomography (micro-CT) scanned. From accurate 3D data sets, structural parameters were determined by means of true, unbiased and assumption-free 3D methods. The data were assessed statistically, and a p< 0.05 was considered significant.

Our data supported the hypothesis that significant microstructural changes – other than density changes – occur in early-stage OA cancellous bone. OA cancellous bone is markedly plate-like, less anisotropic, less interconnected, but lower in mechanical properties which suggests a disorganisation in the microstructure as OA initiation. Structure model type best explains the mechanical properties for the OA and the normal controls. However, the determination coefficients (R2) for the OA group are largely reduced. These results indicate significant property and quality deterioration in early-stage OA subchondral cancellous bone.