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.

The re-establishment of vascularity is an early event in fracture healing; upregulation of angiogenesis may therefore promote the formation of bone. We have investigated the capacity of vascular endothelial growth factor (VEGF) to stimulate the formation of bone in an experimental atrophic nonunion model.

Three groups of eight rabbits underwent a standard nonunion operation. This was followed by interfragmentary deposition of 100 μg VEGF, carrier alone or autograft.

After seven weeks, torsional failure tests and callus size confirmed that VEGF-treated osteotomies had united whereas the carrier-treated osteotomies failed to unite. The biomechanical properties of the groups treated with VEGF and autograft were identical. There was no difference in bone blood flow.

We considered that VEGF stimulated the formation of competent bone in an environment deprived of its normal vascularisation and osteoprogenitor cell supply. It could be used to enhance the healing of fractures predisposed to nonunion.

We obtained medial and lateral subchondral cancellous bone specimens from ten human postmortem proximal tibiae with early osteoarthritis (OA) and ten normal age- and gender-matched proximal tibiae. The specimens were scanned by micro-CT and the three-dimensional microstructural properties were quantified.

Medial OA cancellous bone was significantly thicker and markedly plate-like, but lower in mechanical properties than normal bone. Similar microstructural changes were also observed for the lateral specimens from OA bone, although there had been no sign of cartilage damage. The increased trabecular thickness and density, but relatively decreased connectivity suggest a mechanism of bone remodelling in early OA as a process of filling trabecular cavities. This process leads to a progressive change of trabeculae from rod-like to plate-like, the opposite to that of normal ageing. The decreased mechanical properties of subchondral cancellous bone in OA, which are due to deterioration in architecture and density, indicate poor bone quality.

Previous studies have shown that low-density, rod-like trabecular structures develop in regions of low stress, whereas high-density, plate-like trabecular structures are found in regions of high stress. This phenomenon suggests that there may be a close relationship between the type of trabecular structure and mechanical properties.

In this study, 160 cancellous bone specimens were produced from 40 normal human tibiae aged from 16 to 85 years at post-mortem. The specimens underwent micro-CT and the microstructural properties were calculated using unbiased three-dimensional methods. The specimens were tested to determine the mechanical properties and the physical/compositional properties were evaluated.

The type of structure together with anisotropy correlated well with Young’s modulus of human tibial cancellous bone. The plate-like structure reflected high mechanical stress and the rod-like structure low mechanical stress. There was a strong correlation between the type of trabecular structure and the bone-volume fraction. The most effective microstructural properties for predicting the mechanical properties of cancellous bone seem to differ with age.

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.

We aimed to highlight the relationship between age and the architectural properties of trabecular bone, to outline the patterns in which the variations in these properties take place, and to investigate the influence of the architecture on the mechanical properties of trabecular bone in growing animals. We studied 30 lambs in three age groups and 20 sheep in two age groups. Cubes of subchondral bone were cut from the proximal tibia according to a standardised protocol. They were serially sectioned and their architectural properties were determined. Similar cubes were obtained from the identical anatomical position of the contralateral tibia and their compressive mechanical properties measured. The values obtained from the skeletally immature and mature individuals were compared. Multiple regression analyses were performed between the architectural and the mechanical properties.

The bone volume fraction, the mean trabecular volume, the architectural and the mechanical anisotropy, the elastic modulus, the bone strength, the energy absorption to failure, and the elastic energy correlated positively with increasing age whereas the connectivity density, the bone surface density, the ultimate strain, the absorption of viscoelastic energy and the relative loss of energy correlated inversely. The values of all variables were significantly different in the skeletally mature and immature groups. We determined the patterns in which the variations took place. The bone volume fraction of the trabecular bone tissue was found to be the major predictor of its compressive mechanical properties. Together with the mean trabecular volume and the bone surface density, it explained 81% of the variations in the compressive elastic modulus of specimens obtained from the contralateral tibiae.

Our aim was to determine the relationship between age and the mechanical and physical properties of trabecular bone, to describe the patterns in which the variations in these properties take place, and to investigate the influence of the physical properties on the mechanical characteristics of trabecular bone during growth. We used 30 lambs in three age groups and 20 sheep in two age groups. Cubes of subchondral bone were cut from the proximal tibia according to a standardised protocol. We performed non-destructive compression tests of the specimens in three orthogonal directions and compression tests to failure in the axial direction. The physical properties of the specimens were also determined. The data were correlated with age and compared in skeletally immature and mature animals. Multiple regression analyses were performed between the mechanical and the physical properties.

Age correlated positively with elastic modulus, bone strength, energy absorption to failure, elastic energy, mechanical anisotropy ratio, tissue density, apparent density, apparent ash density, and bone mineral content, and inversely with ultimate strain, viscoelastic energy absorption, relative energy loss, the collagen content of bone and the percentage porosity. The values of all variables were significantly different in the skeletally mature and immature groups. The apparent density of trabecular bone tissue was found to be the major predictor of its compressive mechanical properties. Together with the content of bone muscle and bone collagen, the apparent density could explain 84% of the variation in the elastic modulus, whereas only a small portion of the variation in ultimate strain could be explained by the variation in apparent density.

We tested in compression specimens of human proximal tibial trabecular bone from 31 normal donors aged from 16 to 83 years and determined the mechanical properties, density and mineral and collagen content.

Young’s modulus and ultimate stress were highest between 40 and 50 years, whereas ultimate strain and failure energy showed maxima at younger ages. These age-related variations (except for failure energy) were non-linear.

Tissue density and mineral concentration were constant throughout life, whereas apparent density (the amount of bone) varied with ultimate stress. Collagen density (the amount of collagen) varied with failure energy. Collagen concentration was maximal at younger ages but varied little with age.

Our results suggest that the decrease in mechanical properties of trabecular bone such as Young’s modulus and ultimate stress is mainly a consequence of the loss of trabecular bone substance, rather than a decrease in the quality of the substance itself. Linear regression analysis showed that collagen density was consistently the single best predictor of failure energy, and collagen concentration was the only predictor of ultimate strain.

We have reviewed at an average period of ten years the results of 71 consecutive primary arthroplasties with the Insall-Burstein total condylar knee prosthesis in patients with rheumatoid arthritis. Their mean age at surgery was 52 years (24 to 72). At follow-up the overall results (Hospital for Special Surgery knee rating score) were excellent or good in 77%, fair in 11% and poor in 11%. There was residual pain in only 5% of patients with prostheses in situ; 58% could walk more than 500 m, and the median range of motion was 108 degrees. Eight knees had been revised. Five underwent arthrodesis because of deep infection and three needed revision arthroplasty for mechanical loosening. The crude survival rate of the arthroplasties was 89%. The presence of radiolucency around the tibial component correlated significantly with the severity of residual pain.

We report the results of 75 consecutive primary press-fit Kinemax arthroplasties with an average follow-up of 14 months (three to 28). We reviewed 26 cemented and 49 non-cemented tibial components implanted into 72 patients (30 men and 42 women, median age 70 years). At the latest follow-up the overall evaluation (Hospital for Special Surgery knee rating scale) for cemented cases was excellent in 54%, good in 42% and poor in 4%. No cemented prosthesis loosened. Of the non-cemented cases 55% were excellent, 23% good, and 2% fair. Ten tibial implants (20%) loosened and required revision. Residual pain marred the result in 24% of the non-cemented prostheses and in 4% of the cemented group. We do not recommend the press-fit, smooth-surfaced Kinemax prosthesis for non-cemented use.