To be able to assess the biomechanical and functional effects of ankle injury and disease it is necessary to characterise healthy ankle kinematics. Due to the anatomical complexity of the ankle, it is difficult to accurately measure the Tibiotalar and Subtalar joint angles using traditional marker-based motion capture techniques. Biplane Video X-ray (BVX) is an imaging technique that allows direct measurement of individual bones using high-speed, dynamic X-rays. The objective is to develop an in-vivo protocol for the hindfoot looking at the tibiotalar and subtalar joint during different activities of living. A bespoke raised walkway was manufactured to position the foot and ankle inside the field of view of the BVX system. Three healthy volunteers performed three gait and step-down trials while capturing Biplane Video X-Ray (125Hz, 1.25ms, 80kVp and 160 mA) and underwent MR imaging (Magnetom 3T Prisma, Siemens) which were manually segmented into 3D bone models (Simpleware Scan IP, Synopsis). Bone position and orientation for the Talus, Calcaneus and Tibia were calculated by manual matching of 3D Bone models to X-Rays (DSX Suite, C-Motion, Inc.). Kinematics were calculated using MATLAB (MathWorks, Inc. USA). Pilot results showed that for the subtalar joint there was greater range of motion (ROM) for Inversion and Dorsiflexion angles during stance phase of gait and reduced ROM for Internal Rotation compared with step down. For the tibiotalar joint, Gait had greater inversion and internal rotation ROM and reduced dorsiflexion ROM when compared with step down. The developed protocol successfully calculated the in-vivo kinematics of the tibiotalar and subtalar joints for different dynamic activities of daily living. These pilot results show the different kinematic profiles between two different activities of daily living. Future work will investigate translation kinematics of the two joints to fully characterise healthy kinematics

Abstract. Objectives. Impingement of total hip replacements (THRs) can cause rim damage of polyethylene liners, and lead to dislocation and/or mechanical failure of liner locking mechanisms[1]. A geometric model of a THR in situ was previously developed to predict impingement for different component orientations and joint motions of activities[2]. However, the consequence of any predicted impingement is unknown. This study aimed to develop an in-vitromethod to investigate the effects of different impingement scenarios. Method. A ProSim electro-mechanical single-station hip simulator (Simulation Solutions) was used, and the 32mm diameter metal-on-polyethylene THRs (DePuy Synthes) were assessed. The THR was mounted in an inverted orientation, and the input (motion and loading) applied simulated a patient stooping over to pick an object from the floor[3]. The impingement severity was varied by continuing motion past the point of impingement by 2.5° or 5°, and compressive load applied in the medial-lateral direction was varied from 100N to 200N. Each test condition was applied for 40,000 cycles (n=3). Rim penetration was assessed using a CMM and component separation was measured during the tests. Results. Varying the impingement severity from 2.5° to 5° increased rim penetration two-fold (by >0.05mm) and increased medial-lateral component separation three-fold (by >0.3mm) (both p<0.001). Increasing the medial-lateral load had less effect on the rim penetration and component separation, with exception of rim penetration with the higher impingement severity condition. Conclusion. The impingement severity influenced the medial-lateral component separation, suggesting that increasing the impingement severity could increase the risk of dislocation. The impingement severity, which could be predicted from geometric modelling, was also found to significantly affect rim penetration, meaning this method could be used alongside geometric modelling to predict impingement severity in a range of scenarios. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

We have developed a novel technique to analyse bone, using imaging mass cytometry (IMC) without the constraints of using immunofluorescent histochemistry. IMC can measure the expression of over 40 proteins simultaneously, without autofluorescence. We analysed mitochondrial respiratory chain (RC) protein deficiencies in human bone which are thought to contribute to osteoporosis with increasing age.

Osteoporosis is characterised by reduced bone mineral density (BMD) and fragility fractures. Humans accumulate mitochondrial mutations and RC deficiency with age and this has been linked to the changing phenotype in advancing age and age-related disease. Mitochondrial mutations are detectable from the age of 30 onwards, coincidently the age BMD begins to decline. Mitochondria contain their own genome which accumulates somatic variants at around 10 times the rate of nuclear DNA. Once these mutations exceed a threshold, RC deficiency and cellular dysfunction occur. The PolgD257A/D257A mouse model expresses a proof-reading deficient version of PolgA, a mtDNA polymerase. These mice accumulate mutations 3-5 times higher than wild-type mice showing enhanced levels of age-related osteoporosis and RC deficiency in osteoblasts.

Bone samples were analysed from young and old patients, developing a protocol and analysis framework for IMC in bone tissue sections to analyse osteoblasts in-situ for RC deficiency.

Samples from the femoral neck of 10 older healthy volunteers aged 40 – 85 were compared with samples from young patients aged 1-19. We have identified RC complex I defect in osteoblasts from 6 of the older volunteers, complex II defects in 2 of the older volunteers, complex IV defect in just 1 older volunteer, and complex V defect in 4 of the older volunteers.

These observations are consistent with the PolgD257A/D257A mouse-model and suggest that RC deficiency, due to age-related pathogenic mitochondrial DNA mutations, may play a significant role in the pathogenesis of human age-related osteoporosis.

In the course of uneventful secondary bone healing, a fracture gap is progressively overgrown by callus which subsequently calcifies and remodels into new bone. It is widely accepted that callus formation is promoted by mechanical stimulation of the tissue in the fracture gap. However, the optimal levels of the interfragmentary motion's amplitude, frequency and timing remain unknown. The aim of this study was to develop an active fixation system capable of installing a well-controlled mechanical environment in the fracture gap with continuous monitoring of the bone healing progression. The experimental model was adapted from Tufekci et al. 2018 and required creation of a critical size defect and an osteotomy in a sheep tibia. They were separated by a mobile bone fragment. The distal and proximal parts of the tibia were fixed with an external fixator, whereas the mobile fragment was connected to the proximal part with an active fixator equipped with a linear actuator to move it axially for mechanical stimulation of the tissue in the fracture gap. This configuration installed well-controlled mechanical conditions in the osteotomy, dependent only on the motion of the active fixator and shielded from the influence of the sheep's functional weightbearing. A load sensor was integrated to measure the force acting in the fracture gap during mechanical stimulation. The motion of the bone fragment was controlled by means of a custom-made controller allowing to program stimulation protocols of various profiles, amplitudes and frequencies of loading events. Following in vitro testing, the system was tested in two Swiss White Alpine Sheep. It was configured to simulate immediate weightbearing for one of the animals and delayed weightbearing for the other. The applied loading protocol consisted of 1000 loading events evenly distributed over 12 hours resulting in in a single loading event every 44 seconds. Bench testing confirmed the ability of the system to operate effectively with frequencies up to 1Hz over a range of stimulation amplitudes from 0.1 to 1.5 mm. Continuous measurements of in vivo callus stiffness revealed progressive fracture consolidation in the course of each experiment. A delayed onset of fracture healing was observed in the sheep with simulated delayed weightbearing. The conducted preclinical experiments demonstrated its robustness and reliability. The system can be applied for further preclinical research and comprehensive in-depth investigation of fracture healing

It is well documented that implant loosening rate in sickle cell disease patients is higher than that seen in patients with hip arthroplasty from other indications. The Hypoxic inducible factor(HIF) - is activated in the microcellular hypoxic environment and this through a cascade of other enzymatic reactions promotes the activity of other factors and further help enhance angiogenesis and osteogenesis. The aim of this study was to investigate and propose a potential model for investigating osseointegration in a hypoxic microcellular environment using osteoblasts(MG63). Human MG63 osteoblastic cells were cultured under normoxia and hypoxic conditions (20%; and 1% oxygen saturation) for 72 hours under two different condition- with and without cobalt chloride. The samples cultured under normoxic condtions without cobalt chloride acted as control. Using qualitative polymerase chain reaction-(qPCR) - HIF expression was assessed under the above conditions in relation to the control. The results showed there was significant expression of the HIF 1 alpha protein under hypoxic condition with cobalt chloride in comparison with the control samples- all at 72hours incubation. Mann-Whitney U test was used to deduce level of significance of fold change.(p=0.002; <0.05). This was deemed as being a significant difference in the level of expression of HIF compared to the control. The results show that the hypoxic inducible factor can be expressed using the above tested. experimental invitro-model with significant results which can be a foundation for further research into improving hip implant prosthesis design to help enhance osseo-integration in sickle cell disease patient with AVN

Crown copyright 2009. Published with the (permission of the Defence Science and Technology Laboratory on behalf of the Controller of HMSO. Introduction. The optimum strategy for the care of war wounds is yet to be established. A need exists to model complex extremity injury, allowing investigation of wound management options. Aim. To develop a model of militarily relevant extremity wounding. Study Design. Laboratory study with New Zealand White Rabbits. Methods. Phase 1. Development of injury. Following induction of general anaesthesia, a muscle belly on the flexor aspect of the forelimb of the rabbit was exposed. This was achieved by creating a fascial tunnel under the belly of flexor carpi ulnaris (FCU). Utilising a custom built drop test rig a high energy, short duration impact was delivered. To replicate casualty evacuation timelines, the animal was maintained under anaesthesia for three hours and recovered. The wound was dressed with saline soaked gauze and supportive bandaging. 48 hrs later, the animal was culled and the muscle harvested for histological analysis. Analgesia was administered once a day. Animals were checked by experienced staff at least twice a day and body temperature recorded by a subcutaneous transponder. Phase 2. Contamination of muscle injury. Sequential animals had inoculums of 1×102/100μl, 1×106/100μl and 1×108/100μl of Staphylococcus aureus administered to the muscle immediately after injury. Animals were recovered from anaesthetic and monitored as per phase 1. Delivery was evaluated by droplet spread and via injection by fine bore needle into the muscle belly. At the 48 hour point, the animals were culled, dressings removed, the muscle harvested and auxiliary lymph nodes sampled. Quantitative microbiological analysis was performed to determine colony forming unit counts (CFU) at 24 hours post-collection. Results. Phase 1. Six animals were exposed to a loading of 0.5kg. Histological analysis demonstrated a consistent injury pattern with 20% of the muscle belly becoming necrotic. Following discussion with subject matter experts this was found to be representative of the nature of injury from ballistic limb trauma and was adopted as standard. Phase 2. Twenty-two animals were exposed to the standardised injury and then inoculated at the prescribed challenge doses and delivery methods. A challenge dose of 1×106/100μl S. aureus delivered by droplet provided the greatest consistency. A group of six animals with an average challenge dose of 3.3×106/100μl yielded growth at 48hrs on average of 9.2×106 CFU. There were no adverse effects on animal welfare throughout, with body temperatures within normal limits at all times. Discussion. The use of rabbits in the investigation of musculoskeletal injury and infection is well established. No study to date however has addressed high energy complex soft tissue wounding, contamination and its optimum management. Considering the current burden of such wounds the need for this question to be answered in a research setting is transparent. This model enables a significant, reproducible, contaminated soft tissue injury to be delivered in vivo. It will allow the investigation of complex wound management options including wound coverage and fracture fixation

The ankle radiograph is a commonly requested investigation as the ankle joint is commonly injured. Each radiograph exposes 0.01 mSv of radiation to the patient that is equivalent to 1.5 days of natural background radiation [1]. The aim of the clinical audit was to use the Ottawa Ankle Rule to attempt to reduce the number of ankle radiographs taken in patients with acute ankle injuries and hence reduce the dose of ionising radiation the patient receives. A retrospective audit was undertaken. 123 ankle radiograph requests and radiographs taken between May and July 2018 were evaluated. Each ankle radiograph request including patient history and clinical examination was graded against the Ottawa Ankle Rule. The rule states that 1 point(s) indicates radiograph series; (1) malleolar and/or midfoot pain; (1) tenderness over the posterior 6cm or tip of the lateral or medial malleolus (ankle); (1) tenderness over the navicular or the base of the fifth metatarsal (foot); (1) unable to take four steps both immediately and in the emergency department [2]. Patients who score 0 do not need radiograph series. Each radiograph was reviewed if a fracture was present or not. The clinical audit identified 14 true positives where the Ottawa Ankle Rule scored 1 and the patient had an ankle fracture, and 2 false negatives (sensitivity 88%). There were 81 false positives, and 23 true negatives (specificity 22%). Therefore, a total of 23/123 ankle radiographs were unnecessary which is equivalent to 34.5 days of background radiation. The negative predictive value of the Ottawa Ankle Rule in this audit was 92%. The low rate of Ottawa rule utilisation may unnecessarily cause patient harm that should be addressed. An educational intervention with physicians combined with integration of the Ottawa rule scoring in ankle radiograph requests is planned with re-audit in 6 months

Summary. Cognitive testing scores do not correlate with physical braking performance. Psychological questioning shows patients are more dependent on driving than a control group. Introduction. Returning to driving after surgery is a multifaceted issue. There are the medical aspects to consider- whether the patient is medically fit to drive. The term ‘medically fit to drive’ can encompass a range of issues which fall to doctors to solve, including the psychological and mental wellbeing. Groups whose governance involves patients or driving do not issue sound advice for patients or doctors to follow. Investigation of aspects affecting a driver's ability to control their vehicle in a safe manner could go towards providing an evidence base for guidance to be issued in the future. Methods. A custom force assessment rig was used to gather peak force and reaction time measurements from a group of patients waiting for, or having undergone lower limb surgery. A bespoke questionnaire that investigated patient's attitudes towards returning to driving; their behaviours and concerns was issued. Other mobility questions were also issued to these patients, including the lower extremity functional scale (LEFS). The final tests (Stroop task, tower of Hanoi, and the opposite worlds test [OWT]) were aimed at assessing a patient's neurological function, in an attempt to investigate the effect of post-operative cognitive dysfunction (POCD) on driving ability. These data were compared against a control cohort. Results. No significant differences were observed in the physical results between cohorts. However, significant differences between the control cohort and patient cohort were observed in a number of tests. The tower of Hanoi was the only significantly different neurological test (p=0.027). The Stroop task and OWT were not significantly different (p=0.103, p=0.131 respectively). There were significant differences in many of the psychological and mobility questions posed (reliance on driving [p<0.001], keenness to return [p=0.014], anxiety about being unable to drive [p=0.019], depression at being unable to drive [p=0.011], worries that driving would cause them pain [p<0.001], and confidence in using public transport [p=0.002]). Activity rankings also had a significant difference, with driving becoming a higher priority in the patient group (p=0.002). There were no significant differences between cohorts in physical testing, but LEFS was significantly different (p<0.001). There was no significant correlation between physical testing and neurological function, so we cannot prove nor disprove that neurological deficits affect physical function. Psychological variables and physical function did not correlate, but LEFS was correlated to a number of psychological variables. Conclusions. Due to the insignificance of correlations between neurological function tests and physical function, further work is recommended to conclusively determine whether there is a link or not. Different and/or additional neurological test batteries should be also considered, for example the CANTAB. Future studies should stratify cohorts based on surgical indication. Extension of the psychological research could identify the most popular goals or activities for those returning from surgery, potentially creating targets for the rehabilitation process

Aim. The knee radiograph is a commonly requested investigation as the knee joint is commonly injured. Each radiograph exposes 0.01mSv of radiation to the patient that is equivalent to 1.5 days of natural background radiation. Also, each knee radiograph costs approximately £37.16 to produce. The aim of the clinical audit was to use the Pittsburgh knee rules to attempt to reduce the number of knee radiographs taken in patients with acute knee injuries and hence reduce the dose of ionising radiation the patient receives. Method. A retrospective audit was undertaken. 149 knee requests and radiographs taken during October 2016 were evaluated. Each knee radiograph request including patient history and clinical examination was graded against the Pittsburgh knee rules to give a qualifying score. The Pittsburgh knee rules assigns 1 point for each of the following; blunt trauma or a fall, age less than 12 years or over 50 years, and unable to take 4 limping weight bearing steps in the emergency department. A Pittsburgh knee rule qualifying score warranting a knee radiograph is 2 or more points, where the patient must have had blunt trauma or a fall. A Pittsburgh knee rule score less than 2 points predicts a non-fractured knee and hence no radiograph warranted. Each radiograph was reviewed if a fracture was present or not. Results. The clinical audit identified 85 true negative patients where their Pittsburgh knee rule score was less than 2 points and they did not have a fracture of the knee joint. The Pittsburgh knee rule score of less than 2 points did not warrant obtaining knee radiographs. Therefore, a total of 85 knee radiographs were unnecessary which is equivalent to 127.5 days of background radiation. The financial burden of these unnecessary radiographs is £2648.60. The negative predictive value of the Pittsburgh knee rules in this audit was 93.4%. Discussion. The clinical audit shows that the use of the Pittsburgh knee rules scoring system can reduce the number of knee radiographs obtained by 57.4% and hence the doses of ionising radiation patients are exposed to. The audit also showed this clinical scoring system has a high negative predictive value that when utilised can discern patients with a normal knee joint who do not require a knee radiograph. In conclusion employing the Pittsburgh knee rule scoring system can improve patient safety by reducing ionising radiation exposure and can reduce financial costs of patient encounters

While high-performance ceramics like alumina and zirconia exhibit excellent wear resistance, they provide poor osseointegration capacity. As osseointegration is crucial for non-cemented joint prostheses, new techniques have been successfully developed for biofunctionalizing high-performance ceramic surfaces. Stable cell adhesion can be achieved by covalently bound specific peptides. In this study we investigate the effect of sterilization processes on organo-chemically functionalized surfaces. To enhance the performance of alumina-toughened zirconia ceramics (ATZ), a 3-aminopropyldiisopropylethoxysilane (APDS) monolayer was applied and coupled with cyclo-RGD peptides (cRGD) by using bifunctional crosslinker bis(sulfosuccinimidyl)suberat (BS³). The samples were sterilized using e-beam or gamma-sterilization at 25 kGy, either before or after biofunctionalization with cRGD. Functionalization stability was investigated by contact angle measurements. The functionality of cRGD after sterilization was demonstrated using proliferation tests and cytotoxicity assays. Immunofluorescence staining (pFAK, Actin, DAPI) was conducted to evaluate the adhesion potential between the samples and human mesenchymal stem cells (hMSCs). Functionalized samples before and after sterilization showed no significant difference regarding their contact angles. A proliferation test demonstrated that the cells on functionalized samples proliferate significantly more than on untreated samples before and after sterilization. hMSCs showed a significant higher proliferation on gamma sterilized samples compared to all other groups after 14 days. It was confirmed that the samples did not exhibit cytotoxic behavior before or after sterilization. Fluorescence microscopy demonstrated that both, cells on sterilized and on non-sterilized samples, expressed high levels of pFAK-Y397. The investigated functionalization enables improved adhesion and proliferation of hMSCs and is stable against the investigated sterilization processes. This is of importance as the option of having a sterile product enables the start of the translation of this biofunctional coating towards preclinical and subsequently first-in-man applications. Acknowledgments: We acknowledge the financial support of the Federal Ministry of Education and Research, BMBF (13GW0452A-C)

Several synthetic polymers have been widely investigated for their use in bone tissue engineering applications, but the ideal material is yet to be engineered. Triazine-trione (TATO) based materials and their derivatives are novel in the field of biomedical engineering but have started to draw interest. Different designs of the TATO monomers and introduction of different chemical linkages and end-groups widens the scope of the materials due to a range of mechanical properties. The aim of our work is to investigate novel TATO based materials, with or without hydroxyapatite filler, for their potential in bone tissue engineering constructs. Initially the biocompatibility of the materials was tested, indirectly and directly, according to ISO standards. Following this the osteoconductive properties were investigated with primary osteoblasts and an osteoblastic cell line. Bone marrow derived mesenchymal stem cells were used to evaluate the osteogenic differentiation and consequently the materials potential in bone tissue engineering applications

The use of mesenchymal stromal cells (MSCs) in regenerative medicine and tissue engineering is well established, given their properties of self-renewal and differentiation. However, several studies have shown that these properties diminish with age, and understanding the pathways involved are important to provide regenerative therapies in an ageing population. In this PRISMA systematic review, we investigated the effects of chronological donor ageing on the senescence of MSCs. We identified 3023 studies after searching four databases including PubMed, Web of Science, Cochrane, and Medline. Nine studies met the inclusion and exclusion criteria and were included in the final analyses. These studies showed an increase in the expression of p21, p53, p16, ROS, and NF- B with chronological age. This implies an activated DNA damage response (DDR), as well as increased levels of stress and inflammation in the MSCs of older donors. Additionally, highlighting the effects of an activated DDR in cells from older donors, a decrease in the expression of proliferative markers including Ki67, MAPK pathway elements, and Wnt/ -catenin pathway elements was observed. Furthermore, we found an increase in the levels of SA- -galactosidase, a specific marker of cellular senescence. Together, these findings support an association between chronological age and MSC senescence. The precise threshold for chronological age where the reported changes become significant is yet to be defined and should form the basis for further scientific investigations. The outcomes of this review should direct further investigations into reversing the biological effects of chronological age on the MSC senescence phenotype

Aims. This study intended to investigate the effect of vericiguat (VIT) on titanium rod osseointegration in aged rats with iron overload, and also explore the role of VIT in osteoblast and osteoclast differentiation. Methods. In this study, 60 rats were included in a titanium rod implantation model and underwent subsequent guanylate cyclase treatment. Imaging, histology, and biomechanics were used to evaluate the osseointegration of rats in each group. First, the impact of VIT on bone integration in aged rats with iron overload was investigated. Subsequently, VIT was employed to modulate the differentiation of MC3T3-E1 cells and RAW264.7 cells under conditions of iron overload. Results. Utilizing an OVX rat model, we observed significant alterations in bone mass and osseointegration due to VIT administration in aged rats with iron overload. The observed effects were concomitant with reductions in bone metabolism, oxidative stress, and inflammation. To elucidate whether these effects are associated with osteoclast and osteoblast activity, we conducted in vitro experiments using MC3T3-E1 cells and RAW264.7 cells. Our findings indicate that iron accumulation suppressed the activity of MC3T3-E1 while enhancing RAW264.7 function. Furthermore, iron overload significantly decreased oxidative stress levels; however, these detrimental effects can be mitigated by VIT treatment. Conclusion. Collectively, our data provide compelling evidence that VIT has the potential to reverse the deleterious consequences of iron overload on osseointegration and bone mass during ageing. Cite this article: Bone Joint Res 2024;13(9):427–440

Periprosthetic joint infections (PJI) are one of the most common reasons for orthopedic revision surgeries. In previous studies, it has been shown that silver modification of titanium (Ti-6Al-4V) surfaces by PMEDM (powder mixed electrical discharge machining) has an antibacterial effect on Staphylococcus aureus adhesion. Whether this method also influences the proliferation of bacteria has not been investigated so far. Furthermore, the effect is only limitedly investigated on the ossification processes. Therefore, the aim of this work is to investigate the antibacterial effect as well as the in vitro ossification process of PMEDM machined surfaces modified by integration of silver. In this study, we analyzed adhesion and proliferation of S. aureus in comparison to of surface roughness, silver content and layer thickness of the silver-integrated-PMEDM surfaces (N = 5). To test the in vitro ossification, human osteoblasts (SaOs-2) and osteoclasts (differentiated from murine-bone-marrow-macrophages) were cultured on the silver surfaces (N = 3). We showed that the attachment of S. aureus on the surfaces was significantly lower than on the comparative control surfaces of pure Ti-6Al-4V without incorporated silver, independently of the measured surface properties. Bacterial proliferation, however, was not affected by the silver content. No influence on the in vitro ossification was observed, whereas osteoclast formation was drastically reduced on the silver-modified surfaces. We showed that 1 to 3% of silver in the surface layer significantly reduced the adhesion of S. aureus, but not the proliferation of already attached bacteria. At the same time, no influence on the in vitro ossification was observed, while no osteoclasts were formed on the surface. Therefore, we state that PMEDM with simultaneous silver modification of the machined surfaces represents a promising technology for endoprostheses manufacturing to reduce infections while at the same time optimizing bone ingrowth

Low back pain (LBP) is the main cause of disability worldwide and is primarily triggered by intervertebral disc degeneration (IDD). Although several treatment options exist, no therapeutic tool has demonstrated to halt the progressive course of IDD. Therefore, several clinical trials are being conducted to investigate different strategies to regenerate the intervertebral disc, with numerous studies not reaching completion nor being published. The aim of this study was to analyze the publication status of clinical trials on novel regenerative treatments for IDD by funding source and identify critical obstacles preventing their conclusion. Prospective clinical trials investigating regenerative treatments for IDD and registered on . ClinicalTrials.gov. were included. Primary outcomes were publication status and investigational treatment funding. Fisher's exact test was utilized to test the association for categorical variables between groups. 25 clinical trials were identified. Among these, only 6 (24%) have been published. The most common source of funding was university (52%), followed by industry (36%) and private companies (12%). Investigational treatments included autologous (56%) or allogeneic (12%) products alone or in combination with a carrier or delivery system (32%). The latter were more likely utilized in industry or privately funded studies (Fig. 1, p=0.0112). No significant difference was found in terms of funding regarding the publication status of included trials (Table 1, p=0.9104). Most clinical trials investigating regenerative approaches for the treatment of IDD were never completed nor published. This is likely due to multiple factors, including difficult enrollment, high dropout rate, and publication bias. 3. More accurate design and technical support from stakeholders and clinical research organization (CROs) may likely increase the quality of future clinical trials in the field. For any figures or tables, please contact the authors directly

Metabolic bone diseases, such as osteoporosis and osteopetrosis, result from an imbalanced bone remodeling process. In vitro bone models are often used to investigate either bone formation or resorption independently, while in vivo, these processes are coupled. Combining these processes in a co-culture is challenging as it requires finding the right medium components to stimulate each cell type involved without interfering with the other cell type's differentiation. Furthermore, differentiation stimulating factors often comprise growth factors in supraphysiological concentrations, which can overshadow the cell-mediated crosstalk and coupling. To address these challenges, we aimed to recreate the physiological bone remodeling process, which follows a specific sequence of events starting with cell activation and bone resorption by osteoclasts, reversal, followed by bone formation by osteoblasts. We used a mineralized silk fibroin scaffold as a bone-mimetic template, inspired by bone's extracellular matrix composition and organization. Our model supported osteoclastic resorption and osteoblastic mineralization in the specific sequence that represents physiological bone remodeling. We also demonstrated how culture variables, such as different cell ratios, base media, and the use of osteogenic/osteoclast supplements, and the application of mechanical load, can be adjusted to represent either a high bone turnover system or a self-regulating system. The latter system did not require the addition of osteoclastic and osteogenic differentiation factors for remodeling, therefore avoiding growth factor use. Our in vitro model for bone remodeling has the potential to reduce animal experiments and advance in vitro drug development for bone remodeling pathologies like osteoporosis. By recreating the physiological bone remodeling cycle, we can investigate cell-cell and cell-matrix interactions, which are essential for understanding bone physiology and pathology. Furthermore, by tuning the culture variables, we can investigate bone remodeling under various conditions, potentially providing insights into the mechanisms underlying different bone disorders

Unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) are well-established operative interventions in the treatment of knee osteoarthritis (KOA). However, which of these interventions is more beneficial, to patients with KOA, is not known and remains a topic of much debate. Aims: (i) To determine whether UKA or HTO is more beneficial in the treatment of isolated medial compartment KOA, via an assessment of patient-reported outcome measures (PROMs). (ii) To investigate the relationship between PROMs and radiographic parameters of knee joint orientation/alignment. This longitudinal observational study assessed a total of 42 patients that had undergone UKA (n=23) or HTO (n=19) to treat isolated medial compartment KOA. The PROMs assessed, pre-operatively and 1-year post-operatively, consisted of the: self-administered comorbidity questionnaire; short form-12; oxford knee score; knee injury and osteoarthritis outcome score; and the EQ-5D-5L. The radiographic parameters of knee joint alignment/orientation assessed, pre-operatively and 8-weeks post-operatively, included the: hip-knee-ankle angle; mechanical axis deviation; and the angle of the Mikulicz line. Statistical analysis demonstrated an overall significant (p<0.001), pre-operative to post-operative, improvement in the PROM scores of both groups. There were no significant differences in the post-operative PROM scores of the UKA and HTO group. Correlation analyses revealed that pre-operatively, a more distolaterally angled Mikulicz line was associated with worse knee function (p<0.05) and overall health (p<0.05); a relationship that, until now, has not been investigated nor commented upon within the literature. UKAs and HTOs are both efficacious operations that provide a comparable degree of clinical benefit to patients with isolated medial compartment KOA. To further the scientific/medical community's understanding of the factors that impact upon health-outcomes in KOA, future research should seek to investigate the mechanism underlying the relationship, between Mikulicz line and PROMs, observed within the current study

A key cause of low back pain is the degeneration of the intervertebral disc (IVD). Causality between infection of the IVD and its degenerative process gained great interest over the last decade. Granville Smith et al. (2021) identified 36 articles from 34 research studies investigating bacteria in human IVDs. Bacteria was identified in 27 studies, whereas 9 attributed bacterial presence to contamination. Cutibacterium acnes was the most abundant, followed by coagulase-negative staphylococcus. However, whether bacteria identified were present in vivo or represent perioperative contamination remains unclear. This study investigated whether bacteria are present in IVDs and what potential effects they may have on native disc cells. Immunohistochemical staining for Gram positive bacteria was performed on human IVD tissue to identify presence and characterise bacterial species. Nucleus pulposus (NP) cells in monolayer and 3D alginate were stimulated with LPS and Peptidoglycan (0.1-50 µg/ml) for 48hrs. Following stimulation qPCR for factors associated with disc degeneration including matrix genes, matrix degrading enzymes, cytokines, neurotrophic factors and angiogenic factors and conditioned media collected for ELISA and luminex analysis. Gram positive bacteria was detected within human IVD tissue. Internalisation of bacteria by NP cells influenced the cell and nuclei morphology. Preliminary results of exposure of NP cells to bacterial components indicate that LPS as well as Peptidoglycan increase IL-8 and ADAMTS-4 gene expression following 48 hours of stimulation with a dose response seen for IL-8 induction by peptidoglycan compared to the control group. Underlining these results, IL-8 protein release was increased for treated groups compared to non-treated control. Further analysis is underway investigating other output measures and additional biological repeats. This study has demonstrated bacteria are present within IVD cells within IVD tissue removed from degenerate IVD and is determining the potential influence of these on disc degeneration

Introduction. Osteoporosis accounts for a major risk factor of fracture-associated disability or premature death in the elderly. Enhancement of bone anabolism for slowing osteoporosis is highly demanding. Exerkine fibronectin type III domain containing 5 (FNDC5) regulates energy metabolism, inflammation, and aging. This study was aimed to investigate whether Fndc5 signaling in osteoblasts changed estrogen deficiency-mediated bone loss or microarchitecture deterioration. Method. Female osteoblast-specific Fndc5 transgenic mice (Fndc5Tg), which overexpressed Fndc5 under the control of key osteoblast marker osteocalcin promoter, were given bilateral ovariectomy to induce estrogen deficiency-mediated osteoporosis. Bone mass, microstructures, and biomechanical properties were quantified using μCT imaging and material testing. Dynamic bone formation was traced using fluorescence calcein. Osteogenic differentiation and adipocyte formation of bone-marrow mesenchymal cells were investigated using von Kossa staining and Nile red staining, respectively. Serum osteocalcin, CTX-1 and TRAP5b levels were quantified using designated ELISA kits. Mitochondrial respiration was investigated using Seahorse Extracellular Flux Analyzer. Result. Fndc5Tg mice developed relatively higher bone mass and microarchitecture than wild-type mice. Fndc5 overexpression attenuated the losses of bone mineral density and trabecular network, including trabecular volume, thickness, and trabecular number, and improved cortical thickness and porosity in ovariectomized mice. Gain of Fndc5 function preserved biomechanical characteristics (maximum load, breaking force, and energy), serum bone formation marker osteocalcin levels, and bone formation rate, whereas it reduced serum bone resorption makers CTX-1 and TRAP5b levels, osteoclast overburden, and marrow adiposis. In vitro, Fndc5 reversed the estrogen deficiency-mediated mineralized matrix underproduction and adipocyte formation of bone-marrow mesenchymal cells, and inhibited osteoclast formation in osteoporotic bone. Mechanistically, Fndc5 activated AMPK signaling, promoting mitochondrial respiration and ATP production to enhance osteoblastic activity. Conclusion. Fndc5 signaling exerted bone-protective actions delaying estrogen deficiency-mediated osteoporosis. This study highlighted a new molecular remedial option for osteoporosis development by manipulating Fndc5 functions

Introduction. Promoting bone mass homeostasis keeps skeleton away from osteoporosis. a-Ketoglutarate (a-KG) is an indispensable intermediate of tricarboxylic acid cycle (TCA) process for cellular energy production. a-KG mitigates cellular senescence, tissue degeneration, and oxidative stress. We investigated whether a-KG affected osteoblast activity or osteoporosis development. Method. Serum and bone specimens were biopsied from 26 patients with osteoporosis or 24 patients without osteoporosis who required spinal surgery. Ovariectomized or aged mice were fed 0.25% or 0.75% a-KG in drinking water for 8 – 12 weeks ad libitum. Bone mineral density, trabecular/cortical bone microarchitecture, mechanical strength, bone formation, and osteoclastic erosion were investigated using mCT, material testing device, in vivo calcein labelling, and TRAP histochemical staining. Serum a-KG, osteocalcin, and TRAP5b levels were quantified using ELISA kits. Bone-marrow mesenchymal cells and macrophages were incubated osteogenic and osteoclastogenic media. Histone H3K27me3 levels and enrichment were investigated using immunoblotting and chromatin precipitation-PCR. Result. Serum a-KG levels in patients with osteoporosis were less than controls; and were correlated with T-scores of hips (R2 = 0.6471, P < 0.0001) and lumbar spine (R2 = 0.7235, P < 0.001) in osteoporosis (AUC = 0.9941, P < 0.001). a-KG supplement compromised a plethora of osteoporosis signs in ovariectomized or aged mice, including bone mass loss, trabecular bone microarchitecture deterioration, and mechanical strength loss. It elevated serum osteocalcin levels and decreased serum TRAP5b. a-KG preserved caclein-labelling bone formation and repressed osteoclast resorption. It reversed osteogenic differentiation of bone-marrow stromal cells and reduced osteoclast formation in ovariectomized mice. Mechanically, a-KG attenuated H3K27 hypermethylation and Runx2 transcription repression, improving mineralized matrix production in osteogenic cells. Conclusion. Decreased serum a-KG is correlated with human and murine osteoporosis. a-KG reverses bone loss by repressing histone methylation in osteoblasts. This study highlighted a-KG supplement as a new biochemical option for protecting osteoporosis