Articular cartilage is a multi-zonal tissue that coats the epiphysis of long bones and avoids its wear during motion. An unusual friction could micro-fracture this connective membrane and progress into an osteochondral defect (OD), where the affected cartilage suffers inflammation, fibrillation, and forfeiture of its anisotropic structure. Clinical treatment for ODs has been focused on micro-fracture techniques, where the defect area is removed and small incisions are performed in the subchondral bone, which allows the exudation of mesenchymal stem cells (hMSCs) to the abraded zone. However, hMSCs represent less than 0.01% of the total cell population and are not able to self-organise coherently, so the treatments fail in the long term. To select, support and steer hMSCs from the bone marrow into a specific differentiation stage, and recreate the cartilage anisotropic microenvironment, multilayer dual-porosity 3D-printed scaffolds were developed. Dual-porosity scaffolds were printed using prepared inks, containing specific ratios of poly-(d,l)lactide-co-caprolactone copolymer and gelatine microspheres of different diameters, which acted as sacrificial micro-pore templates and were leached after printing. The cell adhesion capability was investigated showing an increased cell number in dual-porosity scaffolds as compared to non-porous ones. To mimic the stiffness of the three cartilage zones, several patterns were designed, printed, and checked by dynamic-mechanical analysis under compression at 37 ºC. Three patterns with specific formulations were chosen as candidates to recreate the mechanical properties of the cartilage layers. Differentiation studies in the selected scaffolds showed the formation of mature cartilage by gene expression, protein deposition and biomolecular analysis. Given the obtained results, designed scaffolds were able to guide hMSC behaviour. In conclusion, biocompatible, multilayer and dual-porosity scaffolds with cell entrapment capability were manufactured. These anisotropic scaffolds were able to recreate the physical microenvironment of the natural cartilage, which in turn stimulated cell differentiation and the formation of mature cartilage. Acknowledgments: This work was supported by the EMAKIKER grant

Although much has been published on the causes of slipped upper femoral epiphysis and the results of treatment, little attention has been given to the mechanism of the slip. This study presents the results of the analysis of 13 adolescent femora, and the attempts to reproduce the radiological appearances of a typical slip. The mean age of the skeletons was 13 years (11 to 15). It was found that the internal bony architecture in the zone of the growth plate was such that a slip of the epiphysis on the metaphysis (in the normal meaning of the word slip) could not take place, largely relating to the presence of a tubercle of bone projecting down from the epiphysis. The only way that the appearance of a typical slipped upper femoral epiphysis could be reproduced was by rotating the epiphysis posteromedially on the metaphysis. The presence and size of this peg-like tubercle was shown radiologically by CT scanning in one pair of intact adolescent femurs

Abstract. Objective. A higher prevalence of cam morphology has been reported in the athletic population but the development of the cam morphology is not fully understood. The purpose of this systematic review is to establish the timing of development of the cam morphology in athletes, the proximal femoral morphologies associated with its development, and other associated factors. Methods. Embase, MEDLINE and the Cochrane Library were searched for articles related to development of the cam morphology, and PRISMA guidelines were followed. Data was pooled using random effects meta-analysis. Study quality was assessed using the Downs and Black criteria and evidence quality using the GRADE framework. Results. This search identified 16 articles involving 2,028 participants. In males, alpha angle was higher in athletes with closed physes than open physes (SMD 0.71; 95% CI 0.23, 1.19). Prevalence of cam morphology was associated with age during adolescence when measured per hip (β 0.055; 95% CI 0.020, 0.091) and per individual (β 0.049; 95% CI 0.034, 0.064). Lateral extension of the epiphysis was associated with an increased alpha angle (r 0.68; 95% CI 0.63, 0.73). A dose-response relationship was frequently reported between sporting frequency and cam morphology. There was a paucity of data regarding the development of cam morphology in females. Conclusions. Very low and low quality evidence suggests that in the majority of adolescent male athletes’ osseous cam morphology developed during skeletal immaturity, and that prevalence increases with age. Very low quality evidence suggests that osseous cam morphology development was related to lateral extension of the proximal femoral epiphysis

Aim. To investigate the effect of the eight plate position in sagittal plane on tibial slope in temporary epiphysiodesis technique applied to the proximal tibia and whether there is a rebound effect after removing the plate. Method. Forty New Zealand rabbits (6 weeks old) were divided into four groups. In all groups, two 1.3 mm mini plates and cortical screws implantation were placed on both medial and lateral side of the proximal epiphysis of the right tibia. In Group 1 and 3, the plates were placed on anterior of the proximal tibial anatomical axis in the sagittal plane, and placed posteriorly in Group 2 and 4. The left tibia was examined as control in all groups. Group 1 and Group 2 were sacrificed after four week-follow-up. In Group 3 and Group 4, the implants were removed four weeks after index surgery and the rabbits were followed four more weeks to investigate the rebound effect. The tibial slope was measured on lateral X-rays every two weeks. Both medial and lateral plateau slopes were evaluated on photos of the dissected tibia. Results. In Group 1, right MTPA (medial tibial plateau angle) and left MTPA, right LTPA (lateral tibial plateau angle) and left LTPA, and right 4wTPPA (the tibial proximal posterior angle at 4th week) and left 4wTPPA values were compared with each other. There was a significant difference in MTPA, LTPA, and 4wTPPA in Group 1 (p: 0.003, 0.006, 0.004). In Group 1, the medial and lateral slope significantly decreased after 4 weeks. There was no significant difference in MTPA, LTP and 4wTPPA measurements in Group 2 (p= 0.719, 0.306, 0.446, respectively). In Group 2, the slope did not change in four weeks. There was a significant difference in MTPA, LTPA, 4wTPPA, and 8wTPPA (tibial proximal posterior angle at 8th week) in Group 3 (p= 0.005, 0.002, <0.001, <0.001, respectively). In Group 3, the slope decreased at 4th week and remained stabile during the next four week-follow up and no rebound effect was observed. There was no significant difference in MTPA, LTPA, 4wTPPA, and 8wTPPA measurements in Group 4 (p= 0.791, 0.116, 0.232, 0.924), respectively. In group 4, slope did not change at 4th week of index surgery and no rebound effect was observed in the next four week-follow up. Conclusion. If eight plates were placed on anterior of lateral proximal tibia axis on both medial and lateral side, the tibial slope would reduce, and remain stabile after implant removal. Care should be taken to place the plates on the line of proximal tibial axis in sagittal plane in temporary epiphysiodesis technique performed due to angular knee deformities. Changing the slope due to plate placement can be used as a secondary gain for patients who will benefit from slope change, such as adolescent ACL surgery

Introduction. Although osteonecrosis of the femoral head has been observed in young adult patients with autoimmune diseases such as SLE and MCTD that are treated by corticosteroids, the pathogenesis of the osteonecrosis remains unclear. We established a rat model with osteonecrosis of the femoral head by injecting lipopolysaccharide (LPS) and corticosteroid, and assessed consequences of the histopathological alteration of the femoral head, the systemic immune response, and the lipid synthesis. Methods. Male Wistar rats were given 2 mg/kg LPS intravenously on days 0 and 1 and intramuscularly 20 mg/kg methylprednisolone on days 2, 3, and 4. The animals were sacrificed 1, 2, 3, or 4 weeks after the last injection of the methylprednisolone. Histopathological and biochemical analyses were performed every week. The bone samples were then processed for routine hematoxylin and eosin staining to assess the general architecture and injury of the tissue. The triglyceride and the total cholesterol concentrations in the PRP were measured. The levels of various cytokines (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-10, GM-CSF, IFN-γ, TNF-α) in blood samples were measured. Results. The body weight of the rats over time decreased for 2 weeks but had recovered by week 4. The plasma triglyceride concentrations had decreased significantly by weeks 2 and 3. The total plasma cholesterol concentrations had increased significantly by week 1 but then decreased significantly by week 4. The plasma concentrations of IL-1?α, IL-2, IL-4, IL-6, IL-10, GM-CSF, IFN-γ and TNF-α had increased significantly by week 1. These cytokines can all be induced by toll-like receptor 4 (TLR4) signaling. We defined osteonecrosis as the diffuse presence of empty lacunae or pyknotic nuclei of osteocytes in the bone trabeculae, accompanied by surrounding bone marrow cell necrosis. Osteonecrosis of the femoral head was observed only in the epiphysis of the femoral head in sacrificed specimen every week. Histological analysis revealed osteocytic death surrounded by necrotic bone marrow with or without repaired tissue. Conclusion. We established a new rat model of corticosteroid-induced femoral head osteonecrosis. The necrosis that is generated in this model is similar to that seen in patients treated with corticosteroid. In particular, the necrotic lesion was exclusively observed in the proximal epiphysis. LPS is known to activate the immune system via the TLR4 signaling pathway. It has been recognized that the unique immunogenic effects of LPS promote autoimmune disease . LPS and methylprednisolone induced osteonecrosis of the femoral head in rats and this was associated with a disruption of the innate immune system and lipid synthesis. These findings suggest that the TLR4 signaling pathway plays an important role in the pathogenesis for osteonecrosis of the femoral head

The study of the chondrocyte maturation cycle and endochondral ossification showed that the developing vascular supply has appeared to play a key role in determining the cortical or trabecular structure of the long bones. The chondrocyte maturation cycle and endochondral ossification were studied in human, foetal cartilage anlagen and in postnatal meta-epiphyses. The relationship between the lacunar area, the inter territorial fibril network variations and CaP nucleation in primary and secondary ossification centres were assessed using light microscopy and SEM morphometry. The anlage topographic, zonal classification derived from the anatomical nomenclature of the completely developed long bone (diaphysis, metaphyses and epiphyses) allowed to follow the development of long bones cartilage model. A significant increase in chondrocyte lacunar area (p<0.001) was documented from the anlage epiphyseal zone 4 and 3 to zone 2 (metaphysis) and zone 1 (diaphysis), with the highest variation from zone 2 to zone 1. An inverse reduction in the intercellular matrix area (p<0.001) and matrix interfibrillar empty space (p<0.001) was also documented. These findings are consistent with the osmotic passage of free cartilage water from the interfibrillar space into the swelling chondrocytes, raising ion concentrations up to the critical threshold for mineral precipitation in the matrix. The mineralised cartilage served as a scaffold for osteoblasts apposition both in primary and secondary ossification centres and in the metaphyseal growth plate cartilage, but at different periods of bone anlage development and with distinct patterns for each zone. They all shared a common initial pathway, but it progressed with different times, modes and organisation in diaphysis, metaphysis and epiphysis. In the ossification phase the developing vascular supply has appeared to play a key role in determining the cortical or trabecular structure of the long bones

Dysplasia Epiphysealis Hemimelica (DEH) also known as Trevor's Disease is a rare developmental disorder resulting in cartilaginous overgrowth of the epiphysis of long bones. DEH is usually diagnosed in children between two and eight years old and it is three times more often diagnosed in boys. The most reported complaints are pain, limitation in range of motion, and deformity or swelling of the affected joint. Treatment of symptomatic lesions consists of surgical resection of the lesion, resulting in good long-term results. Based on histological evaluation, DEH is often described as an osteochondroma or an osteochondroma-like lesion, although there are clinical, radiological and genetic differences between DEH and osteochondromas. To investigate the hypothesis that DEH and osteochondromas are histologically identical, two cases of DEH and two cases of osteochondromas in patients with Hereditary Multiple Osteochondroma (HMO) are compared at histological level. Tissue samples from patients with a histopathologically confirmed diagnosis of DEH were compared with two age and gender matched patients diagnosed with HMO. After tissue sampling and processing, (immuno)histological stainings were performed for Collagen type II, Collagen type X, Sox-9 and Safranin-O. Histologically, clumping of chondrocytes in a fibrillar matrix, a thick disorganized cartilage cap and ossification centres with small amounts of unresorbed cartilage were observed in DEH. In contrast, chondrocyte organisation in cartilage of osteochondromas displays characteristics of the normal growth plate. In addition, differences in expression of collagen type II, collagen type X and Sox9 were observed. Collagen type II was expressed in the extracellular matrix surrounding proliferative and hypertrophic chondrocytes in osteochondromas, while weak expression was observed in the entire cartilage cap in DEH. Collagen type X was not expressed in DEH, while expressed in the pericellular matrix surrounding hypertrophic chondrocytes in osteochondromas. Staining for Sox9 was positive in the hypertrophic chondrocytes in osteochondromas, while expressed in the nuclei of all chondrocyte clusters in DEH. Both morphological and immunohistological differences were observed in histological sections of DEH and osteochondromas. These findings reject our hypothesis, and supports the earlier observed clinical, radiological and genetic differences and implies a different aetiology between DEH and osteochondroma formation in HMO

Summary Statement. We used three-dimensional software to assess different anatomic variables in the femur. The canal of Femur twisted slightly below the lesser trochanter in cases with a larger angle of anteversion. Introduction. Accurate positioning of the joint prosthesis is essential for successful total hip arthroplasty (THA). To aid in tailoring of the prosthesis, we used three-dimensional software to assess different anatomic variables in the femur. Patients & Methods. We used CT imaging data of the unaffected normal side of the 25 patients (22 females, age range 30 to 81 years) who underwent THA in 2012 in our hospital. The femur was reconstructed from CT data and measured using three-dimensional modeling software (Mimics 16.0 Materialise, Leuven, Belgium). We measured ellipse fitting to the medullary canal in the axial plane of the femur at 20-mm intervals. The angle between the major axis of those ellipses and the axis of the femoral neck was measured and expressed as the canal rotation. The distance between the lesser trochanter and the center of the femoral head was measured along the Z axis. Results. The major axes of the ellipses direct to medial, front and medial side in the level of epiphysis, above isthmus and distal portion respectively in all cases. The maximum rotated level was above isthmus. The rotation angle in the proximal portion ranged from 36 to 84 degrees (mean, 60.6 degrees, SD ± 12.1). The rotation angle of the distal portion ranged from 71 to 95 degrees (mean, 86.1 degrees, SD ± 6.1). Discussion/Conclusion. The torsion of the canal varied more widely between individuals in the proximal portion than did the distal portion. In addition, the torsion of the proximal aspect, although more variable, was on average smaller when the angle of anteversion was large. Because the canal twisted slightly below the lesser trochanter in cases with a larger angle of anteversion, it is suggested that attention to the degree of anteversion of a flat prosthesis stem is warranted

Treatment with corticosteroids is a risk factor for non-traumatic avascular necrosis of the femoral head, but the pathological mechanism is poorly understood. Short-term treatment with high doses of methylprednisolone is used in severe neurotrauma and after kidney and heart transplantation. We investigated the effect of such treatment on the pattern of perfusion of the femoral head and of bone in general in the pig. We allocated 15 immature pigs to treatment with high-dose methylprednisolone (20 mg/kg per day intramuscularly for three days, followed by 10 mg/kg intramuscularly for a further 11 days) and 15 to a control group. Perfusion of the systematically subdivided femoral head, proximal femur, acetabulum, humerus, and soft tissues was determined by the microsphere technique. Blood flow in bone was severely reduced in the steroid-treated group. The reduction of flow affected all the segments and the entire epiphysis of the femoral head. No changes in flow were found in non-osseous tissue. Short-term treatment with high-dose methylprednisolone causes reduction of osseous blood flow which may be the pathogenetic factor in the early stage of steroid-induced osteonecrosis

We have used an experimental model employing the bent tail of rats to investigate the effects of mechanical forces on bones and joints. Mechanical strain could be applied to the bones and joints of the tail without direct surgical exposure or the application of pins and wires. The intervertebral disc showed stretched annular lamellae on the convex side, while the annulus fibrosus on the concave side was pinched between the inner corners of the vertebral epiphysis. In young rats with an active growth plate, a transverse fissure appeared at the level of the hypertrophic cell layer or the primary metaphyseal trabecular zone. Metaphyseal and epiphyseal trabeculae on the compressed side were thicker and more dense than those of the distracted part of the vertebra. In growing animals, morphometric analysis of hemiepiphyseal and hemimetaphyseal areas, and the corresponding trabecular bone density, showed significant differences between the compressed and distracted sides. No differences were observed in adult rats. We found no significant differences in osteoclast number between compressed and distracted sides in either age group. Our results provide quantitative evidence of the working of ‘Wolff’s law’. The differences in trabecular density are examples of remodelling by osteoclasts and osteoblasts; our finding of no significant difference in osteoclast numbers between the hemiepiphyses in the experimental and control groups suggests that the response of living bone to altered strain is mediated by osteoblasts

Objectives

The objectives of this study were: 1) to examine osteophyte formation, subchondral bone advance, and bone marrow lesions (BMLs) in osteoarthritis (OA)-prone Hartley guinea pigs; and 2) to assess the disease-modifying activity of an orally administered phosphocitrate ‘analogue’, Carolinas Molecule-01 (CM-01).

Objectives

This study aims to evaluate if micro-CT can work as a method for the 3D assessment and analysis of cancellous bone by comparing micro-CT with undecalcified histological sections in OVX rats.

Objectives

To assess the structure and extracellular matrix molecule expression of osteogenic cell sheets created via culture in medium with both dexamethasone (Dex) and ascorbic acid phosphate (AscP) compared either Dex or AscP alone.

Objectives

The aim of this experimental study on New Zealand’s white rabbits was to investigate the transplantation of autogenous growth plate cells in order to treat the injured growth plate. They were assessed in terms of measurements of radiological tibial varus and histological characteristics.

Objectives

Electromagnetic fields (EMF) are widely used in musculoskeletal disorders. There are indications that EMF might also be effective in the treatment of osteoporosis. To justify clinical follow-up experiments, we examined the effects of EMF on bone micro-architectural changes in osteoporotic and healthy rats. Moreover, we tested the effects of EMF on fracture healing.

Our aim was to investigate the relationship between urinary excretion of deoxypyridinoline (DPD) as a marker of bone resorption, and Perthes’ disease. There were 39 children with Perthes’ disease in the florid stage who collected first-morning urine samples at regular intervals of at least three months. The level of urinary DPD was analysed by chemiluminescence immunoassay and was correlated with the radiological stage of the disease as classified by Waldenström, and the severity of epiphyseal involvement according to the classification systems of Catterall and Herring. The urinary DPD levels of a group of 44 healthy children were used as a control.

The median urinary DPD/creatinine (CREA) ratio was significantly reduced (p < 0.0001) in the condensation stage and increased to slightly elevated values at the final stage (p = 0.05) when compared with that of the control group. Herring-C patients showed significantly lower median DPD/CREA ratios than Herring-B patients (p = 0.03). The significantly decreased median DPD/CREA ratio in early Perthes’ disease indicated a reduced bone turnover and supports the theory of a systemic aetiology. Urinary levels of DPD may therefore be used to monitor the course of Perthes’ disease.

Objectives

Acetabular component orientation in total hip arthroplasty (THA) influences results. Intra-operatively, the natural arthritic acetabulum is often used as a reference to position the acetabular component. Detailed information regarding its orientation is therefore essential. The aim of this study was to identify the acetabular inclination and anteversion in arthritic hips.

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.

Objectives

An experimental piglet model induces avascular necrosis (AVN) and deformation of the femoral head but its secondary effects on the developing acetabulum have not been studied. The aim of this study was to assess the development of secondary acetabular deformation following femoral head ischemia.

We have examined the deterioration of implant fixation after withdrawal of parathyroid hormone (PTH) in rats. First, the pull-out force for stainless-steel screws in the proximal tibia was measured at different times after withdrawal. The stimulatory effect of PTH on fixation was lost after 16 days. We then studied whether bisphosphonates could block this withdrawal effect. Mechanical and histomorphometric measurements were conducted for five weeks after implantation. Subcutaneous injections were given daily. Specimens treated with either PTH or saline during the first two weeks showed no difference in the mechanical or histological results (pull-out force 76 N vs 81 N; bone volume density 19% vs 20%). Treatment with PTH for two weeks followed by pamidronate almost doubled the pull-out force (152 N; p < 0.001) and the bone volume density (37%; ANOVA, p < 0.001). Pamidronate alone did not have this effect (89 N and 25%, respectively). Thus, the deterioration can be blocked by bisphosphonates. The clinical implications are discussed.