Radial Diaphysis Research Articles

Repair of a Radial Fracture with Radial Head Luxation in a Bugio Monkey (Alouatta caraya)

AbstractBugio monkeys (Alouatta caraya) need their arms for locomotion, hygiene, and defence, and possess well-developed dexterity of their hands, depending on them for proper feeding. For this reason, appropriate treatment of thoracic limb fractures is not only essential but also challenging in this species. This report describes the successful treatment of a radial fracture associated with luxation of the radial head in a female, adult Alouatta caraya. The patient was admitted after a suspected traumatic event with a complete transverse fracture of the right radial diaphysis and subluxation of the ipsilateral radius head. Using a craniomedial approach to the radius, surgical stabilization was performed using a 1.7 mm micro series Fixin locking plate after open reduction in bone fragments. The patient had early use of the limb (24 hours postoperatively) and progressive improvement in its usual activities over the following weeks. Radiographic monitoring was performed at 30, 60, and 360 days postoperatively, and bone healing occurred with no complications. The treatment of fractures in primates is potentially challenging, requiring adaptation to primate anatomy and the specific living conditions of the species. Open reduction and stabilization of the radial fracture with a plate and manually reducing the luxated radial head effectively lead to long-term restoration of full function and of normal activities.

Three-dimensional printed poly (L-lactide) and hydroxyapatite composite for reconstruction of critical bone defect in rabbits.

ABSTRACTPurposeTo use a 3D printed poly (L-lactide) acid (PLLA) and hydroxyapatite (HA) composite as a bone substitute for reconstruction of a critical bone defect in the radius of rabbits.MethodsA 1.5 cm ostectomy was performed in the radial diaphysis of 60 New Zealand white rabbits. The rabbits were divided into three groups according to surgical treatment of the bone defect (group I – control, group II – bone graft, group III – 3D PLLA). Each group was divided into four subgroups with different radiographic and histopathologic evaluation times (T1 – 15 days, T2 – 30 days, T3 – 60 days, T4 – 90 days).ResultsThe implant group had greater clinically lameness (p = 0.02), edema (p = 0.007), pain (p = 0.04) and more complications at the surgical site (p = 0.03). Histologically, this group showed greater congestion (p = 0.04), hemorrhage (p = 0.04) and inflammation. Osteogenesis was microscopically similar between days (p = 0.54) and treatments (p = 0.17), even though radiographically, more effective bone healing occurred in the graft group (II), with more callus and bone bridge formation.ConclusionsThe customization of a 3D PLLA/HA scaffold was successful. However, in animals receiving the polymer-ceramic composite less bone callus and bone bridge was formed compared to the graft group.

Bone Microarchitecture and Strength Adaptation to Physical Activity: A Within-Subject Controlled HRpQCT Study.

Physical activity benefits bone mass and cortical bone size. The current study assessed the impact of chronic (≥10 yr) physical activity on trabecular microarchitectural properties and microfinite element analyses of estimated bone strength. Female collegiate-level tennis players (n = 15; age = 20.3 ± 0.9 yr) were used as a within-subject controlled model of chronic unilateral upper-extremity physical activity. Racquet-to-nonracquet arm differences at the distal radius and radial diaphysis were assessed using high-resolution peripheral quantitative computed tomography. The distal tibia and the tibial diaphysis in both legs were also assessed, and cross-country runners (n = 15; age = 20.8 ± 1.2 yr) included as controls. The distal radius of the racquet arm had 11.8% (95% confidence interval [CI] = 7.9% to 15.7%) greater trabecular bone volume/tissue volume, with trabeculae that were greater in number, thickness, connectivity, and proximity to each other than that in the nonracquet arm (all P < 0.01). Combined with enhanced cortical bone properties, the microarchitectural advantages at the distal radius contributed a 18.7% (95% CI = 13.0% to 24.4%) racquet-to-nonracquet arm difference in predicted load before failure. At the radial diaphysis, predicted load to failure was 9.6% (95% CI = 6.7% to 12.6%) greater in the racquet versus nonracquet arm. There were fewer and smaller side-to-side differences at the distal tibia; however, the tibial diaphysis in the leg opposite the racquet arm was larger with a thicker cortex and had 4.4% (95% CI = 1.7% to 7.1%) greater strength than the contralateral leg. Chronically elevated physical activity enhances trabecular microarchitecture and microfinite element estimated strength, furthering observations from short-term longitudinal studies. The data also demonstrate that tennis players exhibit crossed symmetry wherein the leg opposite the racquet arm possesses enhanced tibial properties compared with in the contralateral leg.

Role of aspanning plate as an internal fixator in complex distal radius fractures.

Minimally invasive temporary internal wrist arthrodesis as an alternative treatment method in complex distal radius fractures. Complex distal radius fractures with dorsal and/or palmar comminution and little to no reconstruction possibilities, radiocarpal ligamentous injury, need for early weight bearing through the affected wrist (walking aids). Complex hand injuries limiting the possibility to safely secure the plate at either the metacarpal or the radial shaft. Percutaneous or open reduction and fixation of the distal radius fracture. Determine the location for the two stab incisions under fluoroscopy; one over the distal radial diaphysis and one over the second or third metacarpal. Athird incision over Lister's tubercle allows transposition of the extensor pollicis longus (EPL) tendon, excision of the posterior interosseous nerve and dorsal arthrotomy. Retrograde insertion of the spanning plate. Placement of afirst nonlocking screw through the glide hole into the metacarpal shaft. Under traction, aproximal screw hole is filled with anonlocking screw into the radial diaphysis. Tightening of the cortical screws under lateral fluoroscopic view. The remaining screw holes at both the distal and proximal ends of the plate are filled with locking screws. Layered wound closure. A removable wrist splint is worn during 2weeks. Weight bearing through the injured wrist is immediately allowed. Removal of the spanning plate is scheduled at 3months after radiographic evidence of fracture consolidation. In total, twelve distal radius fractures were treated by dorsal spanning plate fixation between January 2018 and January 2019. Average age was 53.3 ± 24.5years (range 22-95years). Both 3.5 mm and 2.4/2.7 mm plates were used. All twelve fractures were healed after 3months. The mean Disabilities of Arm, Shoulder and Hand (DASH) score was 36.4 (range 8.3-70.0). There was one EPL tendon rupture, one case with extensor tendon adhesions, one periosteosynthetic fracture of the radial shaft and one complex regional pain syndrome. There was no implant failure and no infection.

X-ray and macromorphological evaluation of reparative osteogenesis by implantation of hydroxyapatite composite doped with germanium

Fragmentary fractures require not only the use of complex methods of osteosynthesis, but also the replacement of the defect site with implants to optimize reparative osteogenesis. A large number of osteosubstitute materials are used, including hydroxyapatite ceramics. To enhance its osteointegration properties, microelements with osteoinductive properties are added. The aim of the work is X-ray and macromorphological evaluation of the influence of hydroxyapatite ceramics doped with germanium on reparative osteogenesis in model fractures of the femur and radius in rabbits. Model defects were formed in the radial diaphysis and femur metaphysis in rabbits with a drill with a diameter of 3 mm and 4.2 mm, respectively. Anesthesia included acepromazine, thiopenate, and lidocaine infiltration anesthesia. In the experimental group (n=12) defects were replaced by granules of hydroxyapatite ceramics doped with germanium, and in the control group (n=12) – undoped. The use of hydroxyapatite ceramics doped with germanium is accompanied by a moderate course of the inflammatory-resorptive phase of reparative osteogenesis. At the same time on the radiographs of animals of the experimental group on the 14th day the periosteal reaction is moderate, and on the 30th day it is barely noticeable with increased radiological density. In control animals after trauma to the compact bone proximal and distal to its location showed a thickened and compacted periosteum with a contrasting composite material. On the 60th day in the cancellous bone of experimental animals, the area of injury acquired an X-ray density close to normal, in the control – it remained elevated. Hydroxyapatin composite doped with germanium acquires osteoinductive properties and may be promising for the replacement of bone defects and correction of reparative osteogenesis in animals. Key words: bioceramics, germanium, bone fractures, compact and spongy bone tissue, rabbits.

Furosemide administration onehour before bone scintigraphy examination in horses does not improve the image quality or reduce the radiation dose rate.

This prospective, cross-sectional, pilot study aimed to investigate the effects of furosemide as a diureticon the image quality of bone scintigraphy performed using 99m Tc-HDP and to investigate the impact of furosemide on the radiation dose rate. Thirty-one horses undergoing bone scintigraphy were included. The horses were divided into the control (n=14) and furosemide group (n=17), which received 1mg/kg furosemide intravenously 1 h post 99m Tc-HDP administration. The image quality was assessed subjectively and semi-quantitatively. The bone-to-soft tissue (B:S) ratio was calculated from the counts per pixel of regions of interest (ROI) positioned over the left radial diaphysis (bone ROI) and its caudal soft tissue area (soft tissue ROI). The radiation rate dose (μSv/h) of both groups was measured at 0, 3, 6, 12, 18, and 24h post 99m Tc-HDP administration at a distance of 0, 30, and 100cm from the head, kidney, and pelvis. The results showed no significant differences in the B:S ratio or the radiation dose rate observed between the groups. However, the radiation dose rate decreased by 56% at 3h post 99m Tc-HDP administration and keeping a distance of 30cm reduced the radiation dose rate by 65%. Administering furosemide does not improve the image quality or reduce the radiation dose rate. The authors recommend commencing with bone scintigraphy 3h post 99m Tc-HDP administration and keeping at least a distance of 30cm from the horse to reduce the staff radiation dose.

Biomimetic periosteum-bone substitute composed of preosteoblast-derived matrix and hydrogel for large segmental bone defect repair

Repairing large segmental bone defects above a critical size remains challenging with high risk of delayed union or even non-union. From the perspective of bone development and clinical experience, periosteum plays an indispensable role in bone repair and reconstruction. In this study, we explored the feasibility of using preosteoblast-derived matrix (pODM) as a biomimetic periosteum. By culturing MC3T3-E1 cell sheet on poly(dimethylsiloxane) and performing decellularization, an integral cell-free sheet of pODM could be readily harvested. Bone marrow mesenchymal stem cells (BMSCs) adhered and proliferated well on pODM. In addition, pODM exhibited a chemotactic effect on BMSCs in a concentration-dependent manner and also promoted osteogenic differentiation of BMSCs. Following that, pODM was wrapped around a gelatin methacryloyl (GelMA) hydrogel to construct an engineered periosteum-bone substitute. A rabbit radius segmental bone defect model was used to examine the bone repair efficacy of pODM/GelMA. Upon implantation of pODM/GelMA construct for 12 weeks, the critical-sized bone defects completely healed with remarkable full reconstruction of medullary cavity at the radial diaphysis. Together, this work proposes a high potency of using precursor cell-derived matrix as a biomimetic periosteum, which preserves the beneficial biological factors while avoids the limitations of using exogenous cells for bone regeneration. Combining precursor cell-derived matrix with hydrogel may provide a promising periosteum-bone biomimetic substitute for bone repair. Statement of SignificanceRepairing large segmental bone defects above a critical size remains challenging. As the periosteum plays an essential role in bone repair, this study aimed to explore the use of preosteoblast-derived matrix (pODM), harvested from decellularized MC3T3-E1 cell sheet, as a biomimetic periosteum to facilitate bone repair. We found that in vitro, pODM exhibited considerable chemotactic effect and osteogenic induction capability to bone marrow mesenchymal stem cells (BMSCs). In vivo, implantation of pODM/gelatin methacryloyl (GelMA) constructs as engineered periosteum-bone substitutes effectively repaired the critical-sized segmental bone defects at rabbit radius. Surprisingly, remarkable full reconstruction of medullary cavity at the diaphysis was achieved. Therefore, combining pODM with hydrogel may provide a promising biomimetic substitute for bone repair.

Allogenic Bone Graft Enriched by Periosteal Stem Cell and Growth Factors for Osteogenesis in Critical Size Bone Defect in Rabbit Model: Histopathological and Radiological Evaluation.

Background & Objective:This study aimed to investigate the effect of decellularized allogeneic bone graft enriched by periosteal stem cells (PSCs) and growth factors on the bone repair process in a rabbit model, which could be used in many orthopedic procedures.Methods:In this experimental study, a critical size defect (CSD) (10 mm) was created in the radial diaphysis of 40 rabbits. In group A, the defect was left intact with no medical intervention. In group B, the defect was filled by a decellularized bone graft. In group C, the defect was implanted by a decellularized bone graft enriched with platelet growth factors. In group D, the defect was treated by a decellularized bone graft seeded by periosteal mesenchymal stem cells (MSCs). Also, in group E, the defect was filled by a decellularized bone graft enriched with platelet growth factors and periosteal MSCs. Radiological evaluation was done on the first day and then in the second, fourth, and eighth weeks after the operation. The specimens were harvested on the 28th and 56th postoperative days and evaluated for histopathological criteria.Results:The radiologic and microscopic analysis of the healing process in bone defects of the treated groups (C, D, and E) revealed more advanced repair criteria than those of groups A and B significantly (P<0.05).Conclusion:Based on this study, it appears that implantation of concentrated PSCs in combination with growth factors and allogeneic cortical bone graft is an effective therapy for the repair of large bone defects.

Postcranial hominin remains from the Late Pleistocene of Pešturina Cave (Serbia)

The Central Balkans represents a significant geographical gap in the human fossil record of Eurasia. Here we present two new human fossils from Pešturina Cave, Serbia: a partial atlas vertebra (C1) and a fragment of radial diaphysis. The atlas (Pes-1) derives from the lower portion of Layer 2 and conforms to modern human morphology. This layer is characterized by Gravettian industry despite uncertainties caused by bioturbation and difficulties in separating Layers 2 and 3. The radial fragment (Pes-2) was recovered from the contact zone between Layers 3 and 4, both of which represent Mousterian industries, and is tentatively assessed as Neanderthal based on morphology. With the recent publication of a Neanderthal molar (Pes-3) from the same site, Pešturina currently stands as the only Neanderthal fossil-bearing site in Serbia. These additional finds make Pešturina Cave the only site in the Central Balkans which preserves both modern human and Neanderthal remains with associated lithic industries and highlights the importance of Pešturina in the current discourse on hominin dispersals and migrations in the Balkans.

Radial diaphysis fracture associated with dislocation of the ipsilateral radial head: A case report

Dislocation of the radial head with fracture of the ipsilateral diaphysis is a very rare lesion, few cases have been reported in the literature. We report a case of a 45-year-old patient admitted for management of a fracture of the humeral diaphysis associated with dislocation of the ipsilateral radial head, the mechanism of which was a hyperpronation of the forearm tense that the elbow was hyperflexion. The reduction was open-cast by a proximal anteropteral approach to the forearm. The evolution was favorable on a follow-up of 18 months.

Seven-year follow-up for malrotation of a radial diaphysis fracture in a child corrected by osteotomy for loss of motion: A case report.

A greenstick fracture is an incomplete fracture where the compressive side of the cortex is still intact but plastically deformed. The incidence of poor results following the closed treatment of greenstick fractures in children >10 years of age is seriously underestimated. Therefore, fixing the position of the forearm is important for initial treatment. In cases of greenstick fracture, the possibility of inadequate remodeling of angulated deformities during growth, and in particular, the lack of correction between rotational malalignment and growth when the diaphyseal forearm is involved in the fracture, should be considered. A male, 10-year-old, left hand-dominant, Asian patient fell while playing in the garden and was immediately assessed by an orthopedic doctor at an Emergency Orthopaedic Clinic. Initial examination revealed a deformity of his dominant left forearm and an angulated greenstick fracture of the radius. However, after 3 months, he developed loss of supination of his left forearm and complained of limitation of left forearm supination. Radiography demonstrated a volar angulation of 20°. The patient underwent open reduction, internal fixation and 10° bending with a plate for correction without corrective rotation. At 12 months after injury, the patient did not exhibit pain or limitation of the elbow and wrist. After follow-up for 7 years, the patient was able to perform normal day-to-day activities with no adverse symptoms. The present case indicated that corrective osteotomy is required following the loss of supination after a greenstick fracture of the diaphysis of the radius. The patient of the current study exhibited rotation due to the central band of the interosseous membrane. In the treatment of greenstick fractures, a radius apex angulation of 20° must be corrected via osteotomy due to loss of rotation. The present case indicated that corrective osteotomy of the radius apex alone without rotational correction, in combination with plate bending improved the loss of forearm rotation.

Repair of Critical-Sized Long Bone Defects Using Dipyridamole-Augmented 3D-Printed Bioactive Ceramic Scaffolds.

There are over two million long bone defects treated in the United States annually, of which ~5% will not heal without significant surgical intervention. While autogenous grafting is the standard of care in simple defects, a customized scaffold for large defects in unlimited quantities is not available. Recently, a three-dimensionally (3D)-printed bioactive ceramic (3DPBC) scaffold has been successfully utilized in the of repair critical-sized (CSD) long bone defects in vivo. In this study, 3DPBC scaffolds were augmented with dipyridamole (DIPY), an adenosine A2A receptor (A2A R) indirect agonist, because of its known effect to enhance bone formation. CSD full thickness segmental defects (~11 mm × full thickness) defects were created in the radial diaphysis in New Zealand white rabbits (n = 24). A customized 3DPBC scaffold composed of β-tricalcium phosphate was placed into the defect site. Groups included scaffolds that were collagen-coated (COLL), or immersed in 10, 100, or 1,000 μM DIPY solution. Animals were euthanized 8 weeks post-operatively and the radii/ulna-scaffold complex retrieved en bloc, for micro-CT, histological, and mechanical analysis. Bone growth was assessed exclusively within scaffold pores and evaluated by microCT and advanced reconstruction software. Biomechanical properties were evaluated utilizing nanoindentation to assess the newly regenerated bone for elastic modulus (E) and hardness (H). MicroCT reconstructions illustrated bone in-growth throughout the scaffold, with an increase in bone volume dependent on the DIPY dosage. The histological evaluation did not indicate any adverse immune response while revealing progressive remodeling of bone. These customized biologic 3DPBC scaffolds have the potential of repairing and regenerating bone. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2499-2507, 2019.

Influence of loading condition and anatomical location on human cortical bone linear micro-cracks

Human cortical bone fracture toughness depends on the anatomical locations under quasi-static loading. Recent results also showed that under fall-like loading, cortical bone fracture toughness is similar at different anatomical locations in the same donor. While cortical bone toughening mechanisms are known to be dependent on the tissue architecture under quasi-static loading, the fracture mechanisms during a fall are less studied. In the current study, the structural parameters of eight paired femoral diaphyses, femoral necks and radial diaphyses were mechanically tested under quasi-static and fall-like loading conditions (female donors, 70 ± 14 y.o., [50–91 y.o.]). Synchrotron radiation micro-CT imaging was used to quantify the amount of micro-cracks formed during loading. The volume fraction of these micro-cracks was significantly higher within the specimens loaded under a quasi-static condition than under a loading representative of a fall. Under fall-like loading, there was no difference in crack volume fraction between the different paired anatomical locations. This result shows that the micro-cracking toughening mechanism depends both on the anatomical location and on the loading condition.

The relationship between whole bone stiffness and strength is age and sex dependent

Accurately estimating whole bone strength is critical for identifying individuals that may benefit from prophylactic treatments aimed at reducing fracture risk. Strength is often estimated from stiffness, but it is not known whether the relationship between stiffness and strength varies with age and sex. Cadaveric proximal femurs (44 Male: 18–78 years; 40 Female: 24–95 years) and radial (36 Male: 18–89 years; 19 Female: 24–95 years) and femoral diaphyses (34 Male: 18–89 years; 19 Female: 24–95 years) were loaded to failure to evaluate how the stiffness-strength relationship varies with age and sex. Strength correlated significantly with stiffness at all sites and for both sexes, as expected. However, females exhibited significantly less strength for the proximal femur (58% difference, p < 0.001). Multivariate regressions revealed that stiffness, age and PYD were significant negative independent predictors of strength for the proximal femur (Age: M: p = 0.005, F: p < 0.001, PYD: M: p = 0.022, F: p = 0.025), radial diaphysis (Age: M = 0.055, PYD: F = 0.024), and femoral diaphysis (Age: M: p = 0.014, F: p = 0.097, PYD: M: p = 0.003, F: p = 0.091). These results indicated that older bones tended to be significantly weaker for a given stiffness than younger bones. These results suggested that human bones exhibit diminishing strength relative to stiffness with aging and with decreasing PYD. Incorporating these age- and sex-specific factors may help to improve the accuracy of strength estimates.

Form and functional repair of long bone using 3D-printed bioactive scaffolds.

Injuries to the extremities often require resection of necrotic hard tissue. For large-bone defects, autogenous bone grafting is ideal but, similar to all grafting procedures, is subject to limitations. Synthetic biomaterial-driven engineered healing offers an alternative approach. This work focuses on three-dimensional (3D) printing technology of solid-free form fabrication, more specifically robocasting/direct write. The research hypothesizes that a bioactive calcium-phosphate scaffold may successfully regenerate extensive bony defects in vivo and that newly regenerated bone will demonstrate mechanical properties similar to native bone as healing time elapses. Robocasting technology was used in designing and printing customizable scaffolds, composed of 100% beta tri-calcium phosphate (β-TCP), which were used to repair critical sized long-bone defects. Following full thickness segmental defects (~11mm×full thickness) in the radial diaphysis in New Zealand white rabbits, a custom 3D-printed, 100% β-TCP, scaffold was implanted or left empty (negative control) and allowed to heal over 8, 12, and 24weeks. Scaffolds and bone, en bloc, were subjected to micro-CT and histological analysis for quantification of bone, scaffold and soft tissue expressed as a function of volume percentage. Additionally, biomechanical testing at two different regions, (a) bone in the scaffold and (b) in native radial bone (control), was conducted to assess the newly regenerated bone for reduced elastic modulus (Er ) and hardness (H) using nanoindentation. Histological analysis showed no signs of any adverse immune response while revealing progressive remodelling of bone within the scaffold along with gradual decrease in 3D-scaffold volume over time. Micro-CT images indicated directional bone ingrowth, with an increase in bone formation over time. Reduced elastic modulus (Er ) data for the newly regenerated bone presented statistically homogenous values analogous to native bone at the three time points, whereas hardness (H) values were equivalent to the native radial bone only at 24weeks. The negative control samples showed limited healing at 8weeks. Custom engineered β-TCP scaffolds are biocompatible, resorbable, and can directionally regenerate and remodel bone in a segmental long-bone defect in a rabbit model. Custom designs and fabrication of β-TCP scaffolds for use in other bone defect models warrant further investigation.

3D micro structural analysis of human cortical bone in paired femoral diaphysis, femoral neck and radial diaphysis.

Human bone is known to adapt to its mechanical environment in a living body. Both its architecture and microstructure may differ between weight-bearing and non-weight-bearing bones. The aim of the current study was to analyze in three dimensions, the morphology of the multi-scale porosities on human cortical bone at different locations. Eight paired femoral diaphyses, femoral necks, and radial diaphyses were imaged using Synchrotron Radiation µCT with a 0.7 µm isotropic voxel size. The spatial resolution facilitates the investigation of the multiscale porosities of cortical bone, from the osteonal canals system down to the osteocyte lacunar system. Our results showed significant differences in the microstructural properties, regarding both osteonal canals and osteocytes lacunae, between the different anatomical locations. The radius presents significantly lower osteonal canal volume fraction and smaller osteonal canals than the femoral diaphysis or neck. Osteocytes lacunae observed in the radius are significantly different in shape than in the femur, and lacunar density is higher in the femoral neck. These results show that the radius, a non-weight-bearing bone, is significantly different in terms of its microstructure from a weight-bearing bone such as the femur. This implies that the cortical bone properties evaluated on the femoral diaphysis, the main location studied within the literature, cannot be generalized to other anatomical locations.

Relationships between human cortical bone toughness and collagen cross-links on paired anatomical locations.

Human cortical bone fracture processes depend on the internal porosity network down to the lacunar length scale. Recent results show that at the collagen scale, the maturation of collagen cross-links may have a negative influence on bone mechanical behavior. While the effect of pentosidine on human cortical bone toughness has been studied, the influence of mature and immature enzymatic cross-links has only been studied in relation to strength and work of fracture. Moreover, these relationships have not been studied on different paired anatomical locations. Thus, the aim of the current study was to assess the relationships between both enzymatic and non-enzymatic collagen cross-links and human cortical bone toughness, on four human paired anatomical locations. Single Edge Notched Bending toughness tests were performed for two loading conditions: a quasi-static standard condition, and a condition representative of a fall. These tests were done with 32 paired femoral diaphyses, femoral necks and radial diaphyses (18 women, age 81 ± 12 y.o.; 14 men, age 79 ± 8 y.o.). Collagen enzymatic and non-enzymatic crosslinks were measured on the same bones. Maturation of collagen was defined as the ratio between immature and mature cross-links (CX). The results show that there was a significant correlation between collagen cross-link maturation and bone toughness when gathering femoral and radial diaphyses, but not when considering each anatomical location individually. These results show that the influence of collagen enzymatic and non-enzymatic cross-links is minor when considering human cortical bone crack propagation mechanisms.

The effects of gelatin, fibrin-platelet glue and their combination on healing of the experimental critical bone defect in a rat model: radiological, histological, scanning ultrastructural and biomechanical evaluation.

Fibrin-platelet glue (FPG) is a blood derivative, in which platelets and fibrinogen are concentrated in a small plasma volume, by differential centrifugation and precipitation. It can form a three-dimensional and biocompatible fibrin scaffold with a myriad of growth factors and proteins that are released progressively to the local environment and contribute to the accelerated postoperative bone healing. Gelatin (Gel) is a derivative of collagen and can promote cell adhesion and proliferation due to its unique sequence of amino acids, so it is suitable for bone tissue applications. This study examined the effects of Gel, FPG and their combinations as bone scaffold on the healing of surgically created critical-size defects in rat radius. Fifty critical size defects of 5mm long were bilaterally created in the radial diaphysis of 25 rats. The animals were randomly divided into five equal groups as empty defect, autograft, Gel, FPG and Gel-FPG groups (n=10 in each group). Radiographs of each forelimb were taken postoperatively on the 1st day and then at the 28th and 56th days post injury to evaluate bone formation, union and remodeling of the defect. After 56days, the rats were euthanized and their harvested healing bone samples were evaluated by histopathology, scanning electron microscopy (SEM) and biomechanical testing. The results of present study showed that the Gel alone did not significantly affect bone healing and regeneration; however, the Gel treated defects promoted healing more than those that were left untreated (negative control). Furthermore, the FPG-enhanced grafts provided a good scaffold containing numerous growth factors for proliferation of osteoinduction and was effective in improving the structural and functional properties of the newly formed bone more than that of the untreated and also the Gel treated groups. Incorporation of Gel into the FPG scaffold improved healing potential of the FPG scaffold; however, it was still inferior to the autograft (positive control). Although the Gel-FPG scaffolds had best effectiveness during bone regeneration, it still needs to be further enhanced by incorporation of the ceramic and osteoinductive biomaterials.

Healing potential of nanohydroxyapatite, gelatin, and fibrin-platelet glue combination as tissue engineered scaffolds in radial bone defects of rats

ABSTRACTDifferent biomaterials have been used in orthopedic surgery. Evaluation of biomaterials for bone healing promotion has been a wide area of research of the orthopedic field. Sixty critical size defects of 5 mm long were bilaterally created in the radial diaphysis of 30 rats. The animals were randomly divided into six equal groups as empty defect, autograft, nanohydroxyapatite (nHA), Gelatin (Gel)-nHA, fibrin-platelet glue (FPG)-nHA, and Gel-FPG-nHA groups (n = 10 in each group). Radiographs of each forelimb were taken postoperatively on the 1st day and then at the 28th and 56th days post injury. After 56 days, the rats were euthanized and their harvested healing bone samples were evaluated by histopathology, scanning electron microscopy, and biomechanical testing.All the treated defects demonstrated significantly superior new bone formation, remodeling, and bone tissue volume. Moreover, the defects treated with FPG-nHA showed significantly higher ultimate load, yield load, and stiffness. The Gel-FPG-nHA moderately improved bone regeneration that was not close to the autograft in some parameters, whereas FPG-nHA significantly improved bone healing closely comparable with the autograft group in most parameters. In conclusion, although all the nHA-containing scaffolds had some beneficial effects on bone regeneration, the FPG-nHA scaffold was more effective in improving the structural and functional properties of the newly formed bone and was more osteoinductive than the Gel and was comparable to the autograft. Therefore, the FPG can be regarded as a promising option to be used in conjunction with mineral scaffolds for bone tissue engineering.

Please Don't Move—Evaluating Motion Artifact From Peripheral Quantitative Computed Tomography Scans Using Textural Features

Most imaging methods, including peripheral quantitative computed tomography (pQCT), are susceptible to motion artifacts particularly in fidgety pediatric populations. Methods currently used to address motion artifact include manual screening (visual inspection) and objective assessments of the scans. However, previously reported objective methods either cannot be applied on the reconstructed image or have not been tested for distal bone sites. Therefore, the purpose of the present study was to develop and validate motion artifact classifiers to quantify motion artifact in pQCT scans. Whether textural features could provide adequate motion artifact classification performance in 2 adolescent datasets with pQCT scans from tibial and radial diaphyses and epiphyses was tested. The first dataset was split into training (66% of sample) and validation (33% of sample) datasets. Visual classification was used as the ground truth. Moderate to substantial classification performance (J48 classifier, kappa coefficients from 0.57 to 0.80) was observed in the validation dataset with the novel texture-based classifier. In applying the same classifier to the second cross-sectional dataset, a slight-to-fair (κ = 0.01–0.39) classification performance was observed. Overall, this novel textural analysis-based classifier provided a moderate-to-substantial classification of motion artifact when the classifier was specifically trained for the measurement device and population. Classification based on textural features may be used to prescreen obviously acceptable and unacceptable scans, with a subsequent human-operated visual classification of any remaining scans.