Bone Tissue Response to Different Grown Crystal Batches of Octacalcium Phosphate in Rat Long Bone Intramedullary Canal Area

The microstructure of biomaterials influences the cellular and biological responses in the bone. Octacalcium phosphate (OCP) exhibits higher biodegradability and osteoconductivity than hydroxyapatite (HA) during the conversion process from OCP to HA. However, the effect of the microstructure of OCP crystals on long tubular bones has not been clarified. In this study, two types of OCPs with different microstructures, fine-OCP (F-OCP) and coarse-OCP (C-OCP), were implanted in rat tibia for 4 weeks. F-OCP promoted cortical bone regeneration compared with C-OCP. The osteoclasts appearance was significantly higher in the C-OCP group than in the control group (defect only) at 1-week post-implantation. To investigate whether the solubility equilibrium depends on the different particle sizes of OCPs, Nano-OCP, which consisted of nanometer-sized OCPs, was prepared. The degree of supersaturation (DS) tended to decrease modestly in the order of C-OCP, F-OCP, and Nano-OCP with respect to HA and OCP in Tris-HCl buffer. F-OCP showed a higher phosphate ion concentration and lower calcium ion concentration after immersion in the buffer than C-OCP. The crystal structures of both OCPs tended to be converted to HA by rat abdominal implantation. These results suggest that differences in the microstructure of OCPs may affect osteoclastogenesis and result in osteoconductivity of this material in long tubular bone by altering dissolution behavior.

Сryoablation technology for bone metastases

Puncture cryoablation of tumor lesions was performed as a part of complex palliative treatment of 32 patients with the fourth stage of the disease with bone metastases. Each patient, depending on the extent of the lesion, underwent from one to eight procedures. New domestic nitrogen equipment with reusable instruments was used. Cryoablation procedures were performed in the room for Computed Tomography (CT) using robotic navigation, as well as in the operating room under ultrasound monitoring. The indications for the procedure were severe pain syndrome, disease progression, prevention of pathological fractures, and the impossibility of performing the surgical treatment in patients with comorbidities. When performing cryoablation, the number and diameter of cryoprobes, the length of the needle and cryoprobe tip, the direction of insertion, and their mutual positioning were determined depending on the size and shape of the tumor lesion. The technique of puncture approaches and monitoring rules are described in detail. It is recommended to avoid the destruction of the pelvic ring, hip joint, to be careful in cases of tumor localization in the body and arches of the vertebrae, in the lateral parts of the sacrum, in the places where the nerve trunks adhere to the bone. The cryoablation procedure cannot be planned if the skin, the wall of a hollow organ, and the spinal cord are involved in the tumor process. There is a high risk of fracture after performing total cryoablation of metastasis if it covers more than a third of the diameter of the tubular bone.

Evaluating the results of long tubular bone distraction with an advanced rod monolateral external fixator for achondroplasia

The work aimed to evaluate the effectiveness of the developed distraction system based on the rod external monolateral fixation mechanisms by comparing it with the classical technique of long tubular bones distraction based on the circular multi-axial system. The study included patients with a genetically confirmed diagnosis of achondroplasia. The experimental group consisted of 14 patients who underwent surgical limb lengthening by the rod monolateral external fixator with a distraction system developed by the authors. The lengthening was performed on 28 segments of tubular bones. The majority of the experimental group patients achieved the lengthening value close to the planned one and the deformation correction. The fixation period was averagely 83.8 ± 3.7 days, the regenerate length was 8.5 ± 0.6 cm, and the mechanical strength of the distraction regenerate was 10.3° ± 2.18°. The rod external fixator with a control distraction system developed by the authors has small dimensions and low weight of the external supporting elements of high durability. It is reported to provide a good psychological tolerance of the treatment process and significantly outperforms the circular multi-axis system. Considering the aforementioned, the proposed apparatus can grant good orthopedic care to patients with achondroplasia.

A set of bone tools in the case from the settlement Asaviec 2 in the Krivina peat bog (northern Belarus)

In 2010, during the investigation of the site Asaviec 2 (Krivina peat bog, Beankovičy District, Viciebsk Region, Belarus) a unique set of tools in a case was revealed. It consists of an ornamented case made of the tubular bone of a large bird, an awl made of the lateral metapody of an elk, and a pointed bone item with an extension in the form of a wedge at one end. The method of experimental-traceological analysis was employed to determine the details of the manufacturing technology and the functional purpose of the find. According to the results of the study, a separate use of the tools was established - working with plant materials, which may indicate evidence of knitting or weaving products from organic fibers. Following experimental observations, some possible ways of working with these implements are considered. Thus, on the basis of the structural and contextual features of the artefacts, a variant of their use in a composite form, where the case served also as a handle is proposed. Bone awls or points are a widespread type of tools on sites from the Stone to the Bronze Age. However, the unique set found in situ allows us to expand our knowledge of the economy and productive activities of the past. Archaeological material, revealed an accompanying set of tools and a radiocarbon date from the underlying finding of conditional layer - 3810 50 BP (cal BC 2460-2064) (Le 10465), allow us to reconcile it with the antiquities of the Zhyzhyca-Kryvina stage of the Northern Belarusian Culture, middle of the 3rd-first half of the 2nd mill. BC.

A PREOPERATIVE PLANNING METHOD FOR LONG TUBULAR BONE OSTEOSYNTHESIS

Objective. To compare the shape and size of human contralateral humerus bones based on the «Autoplan» program to justify the possibility of using healthy bone in a preoperative planning for bone osteosynthesis (on the example of the humerus). Methods. 20 patients underwent computed tomography of the chest, shoulder girdleand upper extremities. Two-dimensional medical imaging of separate layers were converted into three-dimensional models of the humerus bone STL format, which is used for 3D printing in all 3D printers. Preliminary registration to superimpose the mirrored left humerus bone on the right one was carried out for at least 4 key points; their matching in shape and size was analyzed. A comparison was made of the contralateral humerus bones of one patient according to computed tomograms of 20 people. The main anatomical landmarks of the humerus bones and the distance between adjacent points were selected for comparison when the bones were superimposed on each other. Superimposed humeral bones were compared using the Hausdorff distance calculation algorithm, which is used to measure the difference between scanned models and the ground-truth model separately. To visualize the result of calculating of Hausdorff distance, that is, the difference between the bones, color mapping of the latter was performed, where the proximity to red color means the difference tends to zero, the proximity to blue - to 1 cm (the maximal obtained difference). Results. The greatest difference was recorded in humeral heads - up to 6.8 mm, and in the epicondyle: the medial epicondyle - up to 4.5 mm, the lateral epicondyle - up to 4.4 mm. Color mapping allowed to see that the difference between the heads of the humerus increases from the center of the articular surface to the attachment points of the capsule. At the level of the diaphysis, from the anatomical neck to the condyles, the size differencesamong allbones in 20 patients was no more than 1.5 mm. Conclusion. Thereby, the comparison of the shape and size of the contralateral bones of the human humerus based on the «Autoplan» program will allow applying a three-dimensional model of healthy contralateral bone in the preoperative planning for bone osteosynthesis: thus reducing the surgical risks and injury for the patient. What this paper adds For the first time, the use of a 3-dimensional model for a preoperative planning method for long tubular bone osteosynthesis using the contralateral healthy bone for affected bone has been proposed. It has been found that in the preoperative period during osteosynthesis of the diaphysis of long tubular bones, it is possible to use a healthy contralateral bone for plate of the damaged bone (on the example of the humerus fracture). The identity of the shape and size of the humerus diaphyses with an accuracy of 1.5 mm has been proved, and the possibility of using a 3-dimensional model of a healthy bone for preoperative planning for long tubular bone osteosynthesis is justified.

The choice of methods for fixing bone fragments in autoplasty of long tubular bone defects

The aim of the study was to analyze the effect of different methods of fixing bone fragments after transplantation of the fibula into a large defect of long tubular bones on the results of treatment. The study included 10 patients (group 1) with major tibia defects in whom the method of postoperative fixation of the segment of the operated limb allowed to give an early mechanical load on the graft itself and 10 patients (group 2) where the impact of mechanical load on the graft was excluded due to its transplantation into the hummers defect (6 cases) or minimized when replacing the tibia defect (4 cases). The degree of graft hypertrophy, the rate of its fusion with the recipient bed, and the number of postoperative complications under different conditions of mechanical stimulation of the fibula graft were studied. The rate of fusion of the graft with the recipient bed in both groups of patients was the same, but the incidence of complete stress fractures of the fibula graft in the second group was three times higher than in the first and was 30%, against the background of a slight degree of graft hypertrophy (from 19% to 45%). The use of the Ilizarov device for fixing fragments of the post-resection bone bed and graft in a stable and dynamic mode allows to give an early postoperative load on the lower limb, stimulates the rate of graft hypertrophy and reduces the likelihood of developing complete stress fractures.

Targeted Ptpn11 deletion in mice reveals the essential role of SHP2 in osteoblast differentiation and skeletal homeostasis

The maturation and function of osteoblasts (OBs) rely heavily on the reversible phosphorylation of signaling proteins. To date, most of the work in OBs has focused on phosphorylation by tyrosyl kinases, but little has been revealed about dephosphorylation by protein tyrosine phosphatases (PTPases). SHP2 (encoded by PTPN11) is a ubiquitously expressed PTPase. PTPN11 mutations are associated with both bone and cartilage manifestations in patients with Noonan syndrome (NS) and metachondromatosis (MC), although the underlying mechanisms remain elusive. Here, we report that SHP2 deletion in bone gamma-carboxyglutamate protein-expressing (Bglap+) bone cells leads to massive osteopenia in both trabecular and cortical bones due to the failure of bone cell maturation and enhanced osteoclast activity, and its deletion in Bglap+ chondrocytes results in the onset of enchondroma and osteochondroma in aged mice with increased tubular bone length. Mechanistically, SHP2 was found to be required for osteoblastic differentiation by promoting RUNX2/OSTERIX signaling and for the suppression of osteoclastogenesis by inhibiting STAT3-mediated RANKL production by osteoblasts and osteocytes. These findings are likely to explain the compromised skeletal system in NS and MC patients and to inform the development of novel therapeutics to combat skeletal disorders.

Rational perioperative antibiotic prophylaxis for open damages of brush in children

Introduction. Today, hand injuries are one of the most pressing and common problems in modern traumatology worldwide. Results obtained statistically indicate a fairly high frequency of hand injuries, including open ones. Often, an incorrect prescription of antibiotics in the form of unjustified antibiotic therapy in the absence of direct indications is done. Aim. This study aimed to develop a rational algorithm for perioperative antibiotic prophylaxis for open hand injuries in children based on experimental and clinical research. Materials and methods. The study was divided into two phases: experimental and clinical. The experiment was carried out on 60 sexually mature, outbred guinea pigs. During the experiment, the analysis of clinical signs of inflammation, complete blood count and biochemical blood analysis, spiral computed tomography, and morphological study of the consolidation zone were performed. The clinical part of the work is based on the analysis of surgical treatment results of 120 children with open hand injuries, which were divided into two groups: the main group that included 50 children receiving treatment according to the experimentally developed perioperative antibiotic prophylaxis (PAP) algorithm, and the comparison group included 70 children receiving a perioperative course of antibiotics from 0 to 7 days, without a well-defined algorithm. Results. In the analysis of clinical results, laboratory, radiation, and morphological methods of studying the experimental material, the absence of antibiotic prophylaxis in open fractures of small tubular bones with a 90% probability was found to entail pro-inflammatory complications in the area of postoperative wound; however, a one day short-term course of PAP will prevent complications and will not have statistically significant differences with a longer course of three days. Discussion. Results of a clinical study proved the effectiveness of the developed algorithm and showed better results in early and late postoperative period in comparison with the chaotic prescription of antibacterial drugs without a clear algorithm; however, no statistically significant differences in the level of postoperative complications were found. Conclusion. On the basis of an experimental model of an open fracture of the tubular bone, osteosynthesis and various courses of antibiotic prophylaxis has proven that a short-term course of PAP within 24 h is the most optimal one, and achieving minimal risks of inflammatory complications and better anatomical and functional outcomes in clinical practice.