INTRODUCTION. Intervertebral disc (IVD) degeneration is not completely understood because of the lack of relevant models. In vivo models are inappropriate because animals are quadrupeds. IVD is composed of the Nucleus Pulposus (NP) and the Annulus Fibrosus (AF), an elastic tissue that surrounds NP. AF consists of concentric lamellae made of collagen I and glycosaminoglycans with fibroblast-like cells located between layers. In this study, we aimed to develop a novel 3D in vitro model of Annulus Fibrosus to study its degeneration. For this purpose, we reproduced the microenvironment of AF cells using 3D printing. METHOD. An ink consisting of dense collagen (30 mg.mL. -1. ) and tyramine-functionalized hyaluronic acid (THA) at 7.5 mg.mL. -1. was first designed by modulating pH and [NaCl] in order to inhibit the formation of polyionic complexes between collagen and THA. Then, composite inks were printed in different gelling baths to form collagen hydrogels. Last, THA photocrosslinking using eosin and green light was performed to strengthen hydrogels. Selected 3D printed constructs were then cellularized with fibroblasts. RESULTS. The physicochemical study revealed that collagen/THA solutions (4:1 ratio) used at pH 5 with 200 mM NaCl were homogenous. In addition, collagen fibrils were observed in these solutions. The dense composite collagen/THA inks printed in a 2X PBS bath rapidly gelled and the photo-crosslinking increased the mechanical properties by 2 to reach 25 kPa (Young's modulus). Then, 3D printing parameters were optimized (85 kPa, extrusion, 4.5 mm/s speed and 80% fill-in percentage) to generate flat and anisotropic lamellae observed by polarized light microscopy. For the in vitro study, several anisotropic layers were printed and fibroblasts seeded between them. Cells adhered to layers, spread, proliferate and aligned along the axis of printed layers. CONCLUSION. Taken together, these results show it is possible to reproduce in vitro the main AF's biochemical and physical properties

Abstract. Objectives. Biomechanics is an essential form of measurement in the understanding of the development and progression of osteoarthritis (OA). However, the number of participants in biomechanical studies are often small and there is limited ways to share or combine data from across institutions or studies. This is essential for applying modern machine learning methods, where large, complex datasets can be used to identify patterns in the data. Using these data-driven approaches, it could be possible to better predict the optimal interventions for patients at an early stage, potentially avoiding pain and inappropriate surgery or rehabilitation. In this project we developed a prototype database platform for combining and sharing biomechanics datasets. The database includes methods for importing and standardising data and associated variables, to create a seamless, searchable combined dataset of both healthy and knee OA biomechanics. Methods. Data was curated through calls to members of the OATech Network+ (. https://www.oatechnetwork.org/. ). The requirements were 3D motion capture data from previous studies that related to analysing the biomechanics of knee OA, including participants with OA at any stage of progression plus healthy controls. As a minimum we required kinematic data of the lower limbs, plus associated kinetic data (i.e. ground reaction forces). Any additional, complementary data such as EMG could also be provided. Relevant ethical approvals had to be in place that allowed re-use of the data for other research purposes. The datasets were uploaded to a University hosted cloud platform. The database platform was developed using Javascript and hosted on a Windows server, located and managed within the department. Results. Three independent datasets were curated following the call to OATech Network+ members. These originated from separate studies collected from biomechanics labs at Cardiff University, Keele University, and Imperial College London. Participants with knee OA were at various stages of progression and all datasets included healthy controls. The total sample size of the three datasets is n=244, split approximately equally between healthy and knee OA participants. Naming conventions and formatting of the exported data varied greatly across datasets. Datasets were therefore formatted into a common format prior to upload, with guidelines developed for future contributions. Uploading data at the marker set level was too complicated for combination at the prototype stage. Therefore, processed variables relating to joint angles and joint moments were used. The resulting prototype database included an import function to align and standardise variables. A a simple query tool was further developed to extract outputs from the database, along with a suitable user interface for basic data exploration. Conclusion. Combining biomechanics dataset presents a wide range of challenges from both a technical and data governance context. Here we have taken the first steps to demonstrate a proof-of-concept that can combine heterogenous data from independent OA-related biomechanics studies into a combined, searchable resource. Expanding this in the future to a fully open access database will create an essential resource that will facilitate the application of data-driven models and analyses for better understanding, stratification and prediction of OA progression. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Aims and objectives. Our aim was to evaluate the indications for patients undergoing magnetic resonance imaging (MRI) of the knee prior to referral to an orthopaedic specialist, and ascertain whether these scans altered initial management. Materials and Method. We retrospectively reviewed all referrals received by a single specialist knee surgeon over a 1-year period. Patient demographics, relevant history, examination findings and past surgical procedures were documented. Patients having undergone MRI prior to referral were identified and indications for the scans recorded. These were reviewed against The NHS guidelines for Primary Care Physicians to identify if the imaging performed was appropriate in each case. Results. A total of 261 patients were referred between 1. st. July 2018 and 30. th. June 2019. 87/261 patients underwent MRI of the knee joint prior to referral. The mean patient age was 53 years with predominance of male patients (52 verses 35 females). 21/87 patients (24%) underwent the appropriate imaging prior to referral with only 13% of patients undergoing x-ray imaging before their MRI. In cases where MRI was not indicated, patients waited an average of 12 weeks between their scan and a referral being sent to the specialist knee surgeon. Conclusion. 76% of patients referred to orthopaedics had inappropriate MRI imaging arranged by their primary care physician. For a single consultant's referrals over 1 year these unnecessary MRI scans cost the NHS £13,200. Closer adherence to the guidelines by primary care physicians would result in a financial saving for the NHS, faster referral times and a more effective use of NHS resources

Virtual Fracture Clinic (VFC) is a consultant-led orthopaedic trauma outpatient triage and management service. The use of VFC has recently become commonplace in the United Kingdom. It allows multiple referral sources to the orthopaedic team, with clinical information and imaging reviewed by a consultant in VFC who formulates an appropriate management plan with the patient contacted; either to attend clinic for consultation or discharged with advice over the phone. The VFC is more efficient than a traditionally delivered outpatient fracture clinic service. We have utilized VFC for 1 year at our hospital, East Kent University Hospital Foundation Trust (EKHUFT), and undertook a closed loop audit to evaluate the service and highlight potential areas of improvement. The Objective of the study was to identify whether the implementation of new re-designed VFC referral guidelines together with teaching set across one of the hospitals in EKHUFT improved the effectiveness and standards of VFC referrals. An initial audit was performed of all referrals made to VFC over a 2 weeks period in December 2018. Changes to the VFC referral pathway were implemented, and teaching sessions performed by the orthopaedic team to all referring units, including minor injury units (MIU) and the emergency department (ED). After implementation, re-audit of VFC referrals was performed in February 2019 over a similar 2 weeks period. Patient demographics, diagnosis and outcomes were collected from the online patient record with images reviewed using PACS software. Following intervention, referral rates dropped by 27.7% (136 vs 188 patients) over the 2 weeks periods. Patient demographics, injury type and severity remained the same between the 2 groups. 51.5% (70/136) did not meet VFC pathway criteria after the intervention and were considered inappropriate, compared to 70% in the original group. 15.4% (21/136) referrals could have been managed in the emergency department using the new guidelines and leaflet discharge. 5.1% (7/136) of the referrals should have been referred to orthopaedic on-call acutely and 22% (30/136) of the referrals had a soft tissue injury or no injury identified. This did not change between the 2 groups despite intervention. Referring MIU and ED units require continued support and teaching over a prolonged time period to hopefully see further improvements. Immediate hot reporting of radiographs may further benefit the service, but staffing and funding issues particularly out of hours, means this remains an aspiration

Osteonecrosis is a potentially devastating condition with poorly defined pathogenesis that can affect several anatomical areas with or without a previous traumatic insult. Post traumatic osteonecrosis (PON) in the foot and ankle has been commonly described in the talus and navicular but rarely in the distal tibia. PON of the distal tibia is a rarely reported and infrequent complication of fracture dislocations of the ankle. Its scarcity can lead to misdiagnosis and inappropriate management due to a lack of clinical knowledge or suspicion with resultant severe functional compromise. We aim to highlight the clinical and radiological features of PON of the distal tibia and report the findings in a series of four patients following a fracture dislocation of the ankle. Three patients sustained a SER4 fracture dislocation and one patient sustained a PER4 fracture dislocation in keeping with standard patterns of injury seen in most trauma units. In each case, PON of the distal tibia presented with progressive anterolateral tibial plafond collapse and valgus deformity of the ankle. The radiological features previously reported in the literature are based on plain film x-ray, CT and MRI but no description of SPECT-CT findings. One of the patients in the series underwent SPECT-CT following clinical suspicion of PON and thus we describe the findings not previously reported. Our objective is to highlight this rare condition as a potential cause for ongoing pain following fracture dislocation of the ankle as well as advocating the use of SPECT/CT as a useful imaging modality to aid in the diagnosis

Objectives. To assess the sensitivity and specificity of self-reported osteoporosis compared with dual energy X-ray absorptiometry (DXA) defined osteoporosis, and to describe medication use among participants with the condition. Methods. Data were obtained from a population-based longitudinal study and assessed for the prevalence of osteoporosis, falls, fractures and medication use. DXA scans were also undertaken. Results. Overall 3.8% (95% confidence interval (CI) 3.2 to 4.5) of respondents and 8.8% (95% CI 7.5 to 10.3) of those aged ≥ 50 years reported that they had been diagnosed with osteoporosis by a doctor. The sensitivity (those self-reporting osteoporosis and having low bone mineral density (BMD) on DXA) was low (22.7%), although the specificity was high (94.4%). Only 16.1% of those aged ≥ 50 years and with DXA-defined osteoporosis were taking bisphosphonates. Conclusions. The sensitivity of self-reporting to identify osteoporosis is low. Anti-osteoporotic medications are an important part of osteoporosis treatment but opportunities to use appropriate medications were missed and inappropriate medications were used

Background. Treatment of cartilage defects requires in vitro expansion of human articular chondrocytes (HACs) for autologous chondrocyte implantation (ACI). During standard expansion culture (i.e. plasma osmolarity, 280 mOsm) chondrocytes inevitably lose their specific phenotype (i.e. collagen type II (COL2) expression). This de-differentiation makes them inappropriate for ACI. Physiological osmolarity (i.e. 380 mOsm) improves COL2 expression in vitro, but the underlying reason is unknown. However, an accepted key regulator of chondrocyte differentiation, transforming growth factor beta (TGFβ), is known to stimulate COL2 production. In this study we aimed to elucidate if TGFβ signaling could potentially be driving the COL2 expression under physiological culture conditions. Material and methods. After informed consent was obtained, HACs were isolated from five osteoarthritis (OA) patients and cultured in cytokine-free medium of 280 or 380 mOsm, respectively, under standard 2D in vitro conditions with or without lentiviral TGFβ2 knockdown (RNAi). Expression of TGFβ isoforms, superfamily receptors and chondrocyte marker genes was evaluated by qRT-PCR, TGFβ2 protein secretion by ELISA and TGFβ bioactivity using luciferase reporter assays. Statistical significance was assessed by a student's t-test. Results. TGFβ isoform expression was differentially altered by physiological osmolarity. Specifically, 380 mOsm increased TGFβ2 expression and protein secretion, as well as TGFβ activity. Upon TGFβ2 isoform-specific knockdown COL2 expression was induced. Physiological osmolarity and TGFβ2 RNAi also induced TGFβ1, TGFβ3 and their type I receptor ALK5. Conclusions. We showed that TGFβ2 knockdown increases COL2 expression in human osteoarthritic chondrocytes in vitro, possibly through a regulatory feedback loop involving TGFβ1, TGFβ3 induction and an increased ALK5/ALK1 ratio. This study indicates that TGFβ signalling is involved in osmolarity-induced chondrocyte marker gene expression. Pharmacological targeting of this pathway holds potential to further improve future osmolarity-mediated phenotypic stabilisation in advanced cell-based cartilage repair strategies. Level of Evidence. preclinical. Disclosure. We have nothing to disclose

As cartilage has poor intrinsic repair capacity, in vitroexpansion of human articular chondrocytes (HACs) is required for cell-based therapies to treat cartilage pathologies. During standard expansion culture (i.e. plasma osmolarity, 280 mOsm) chondrocytes inevitably lose their specific phenotype and de-differentiate, which makes them inappropriate for autologous chondrocyte implantation. It has been shown that physiological osmolarity (i.e. 380 mOsm) increases collagen type II (COL2) expression in vitro, but the underlying molecular mechanism is unknown. Transforming growth factor beta (TGFβ) super family members are accepted key regulators of chondrocyte differentiation and known to stimulate COL2 production. In this study we aimed to elucidate the role of TGFβ superfamily member signalling as a molecular mechanism potentially driving the COL2 expression under physiological (380 mOsm) culture conditions. HACs from OA patients (p1) were cultured in cytokine-free medium of 280 or 380 mOsm, under standard 2D in vitroconditions, with or without lentiviral TGFβ2 knockdown (RNAi). Expression of TGFβ isoforms, BMPs and chondrocyte marker genes was evaluated by QPCR. TGFβ2 protein secretion was evaluated using ELISA and bioactivity was determined using an established reporter cell line. Involvement of BMP signaling was investigated by culturing OA HACs (p1) in the presence or absence of dorsomorphin (10 µM). Physiological osmolarity increased TGFβ2 and TGFβ3 mRNA expression, TGFβ2 protein secretion as well as general TGFβ activity by 380 mOsm. Upon TGFβ2 isoform-specific knockdown COL2 mRNA expression was induced. TGFβ2 RNAi induced expression of several BMPs (e.g. BMP2,-4,-6) and this induction was enhanced in culture conditions with physiological osmolarity. Dorsomorphin inhibited physiological osmolarity induced COL2 mRNA expression. TGFβ2 knockdown under 380 mOsm increases COL2 expression in human osteoarthritic chondrocytes in vitromost likely through a regulatory feedback loop via BMP signaling, which is involved in osmolarity-induced COL2 expression. Future studies will further elucidate the BMP-mediated regulatory feedback loop after TGF β2 knockdown and its influence on COL2 expression

Total ankle replacement (TAR) is the main surgical option in case of severe joint osteoarthritis. The high failure rate of current TAR is often associated to inappropriate prosthetic articulating surfaces designed according to old biomechanical concepts such the fixed axis of rotation, thus resulting in non-physiological joint motion. A recent image-based 3D morphological study of the normal ankle (Siegler et al. 2014) has demonstrated that the ankle joint surfaces can be approximated by a saddle-shaped cone with its apex located laterally (SSCL). We aimed at comparing the kinematic effects of this original solution both with the intact joint and with the traditional prosthetic articulating surfaces via in-silico models and in-vitro measurements. Native 3D morphology of ten normal cadaver ankle specimens was reconstructed via MRI and CT images. Three custom-fit ankle joint models were then developed, according to the most common TAR designs: cylindrical, symmetrically-truncated medial apex cone (as in Inman's pioneering measures), and the novel lateral apex cone, i.e. SSCL. Bone-to-bone motion, surface-to-surface distance maps, and ligament forces and deformations were evaluated via computer simulation. Prototypes of corresponding prosthesis components were designed and manufactured via 3D-printing, both in polymer-like-carbon and in cobalt-chromium-molybdenum powders, for in-vitro tests on the cadaver specimens. A custom testing rig was used for application of external moments to the ankle joint in the three anatomical planes; a motion tracking system with trackers pinned into the bone was used to measure tibial, talar and calcaneal motion (Franci et al. 2009), represented then as tibiotalar, subtalar and ankle complex 3D joint rotations. Each ankle specimen was tested in the intact joint configuration and after replacement of the articulating surfaces according with the three joint models: cylindrical, medial apex cone and SSCL. Results. Small intra-specimen data variability in cycle-to-cycle joint kinematics was found in all cadaver ankles, the maximum standard deviation of all rotation patterns being smaller than 2.0 deg. In-silico ligament strain/stress analysis and in-vitro joint kinematic and load transfer measurements revealed that the novel SSCL surfaces reproduce more natural joint patterns than those with the most common surfaces used in current TAR. TAR based on a saddle-shaped skewed truncated cone with lateral apex is expected to restore more normal joint function. Additional tests are undergoing for further biomechanical validation. The present study has also demonstrated the feasibility and the quality of the full process of custom TAR design and production for any specific subject. This implies a thorough procedure, from medical imaging to the production of artificial surfaces via 3D printing, which is allowing for personalised implants to become the future standard in total joint replacement

Summary Statement. Increased Dkk-1 signaling is associated with OA occurrence and joint microenvironment damage. Interruption of Dkk1 action is beneficial to improve OA knees. Introduction. Osteoarthritis (OA) is a leading cause of disability and healthcare financial burden for total knee arthroplasty, rehabilitation, and disability. Inappropriate mechanical stress, immunological, or biochemical regulation reportedly disturbs homeostasis among cartilage, synovium and subchondral bone microstructure that contributes to OA pathogenesis. Control of joint-deleterious factor action is an emerging strategy to ameliorate OA-induced joint deterioration. Dickkopf-1 (Dkk-1) is a potent inhibitor for Wnt/β-catenin signaling regulation of tissue development and remodeling in physiological or pathological contexts. Dkk-1 also acts as a master deleterious factor that represses osteoblast differentiation capacity and bone repair. Associations among Dkk-1 expression, chondrocyte fate, synovial fibroblast behavior or OA incidence are merit of characterization. Patients & Methods. Cartilage, synovial tissue and fluid were harvested from informed consent OA patients underwent arthroplasty and patient with knee injuries without OA changes as controls. Primary chondrocyte cultures and synovial fibroblasts were treated with inflammatory cytokines or Dkk-1 antisense oligonucleotide or monoclonal antibodies. Knees in experimental animals were subjected to anterior cruciate ligament transection- or intra-articular collagenase injection to induce OA. Joint inflammation, integrity and subchondral bone microstructure in knees as well gait profiles were quantified using 2-deoxyglucose-probed near-infrared in vivo image, µCT, catwalk and histomorphometric analyses. Results. In clinical vignettes, patients with end-stage OA knee had higher abundances of Dkk-1 in cartilage, synovial tissue, and synovial fluid compared to control patients. Disruption of DKk-1 signaling ameliorated the promoting effects of inflammatory cytokines on the survival and cartilage matrix synthesis in primary cartilage chondrocyte cultures. Of interest, Dkk-1 neutralization attenuated the excessive angiogenic activities and matrix metalloproteinase secretion in primary synovial fibroblasts of OA knees. Dkk-1 modulation of survival or metabolic activities in chondrocytes and synovial fibroblasts were through β-catenin-dependent and -independent signaling pathways. Moreover, increased Dkk-1 expression in lesion sites and sera was associated with the incidence of femoral head osteonecrosis. Loss of Dkk-1 action alleviated bone cell apoptosis in osteonecrotic bone microenvironments. In experimental OA knee models, knockdown of Dkk-1 alleviated articular cartilage damage as evidenced by improved Mankin score in OA knees. Dkk-1 disruption also alleviated the adverse effects of OA on subchondral bone exposure and loss of trabecular bone volume and mineral acquisition in injured joints. Loss of Dkk-1 function reduced joint inflammation, vessel number, leukocyte infiltration in synovium compartment of OA joint and improved gait profiles of affected limbs. Conclusion. Dkk-1 signaling is associated with the OA knee occurrence and accelerates apoptosis, matrix degradation and angiogenic activities in chondrocytes and synovial fibroblasts of OA joint. Dkk-1 interference alleviates the promoting effects of OA on cartilage, synovial and subchondral bone remodeling. Blocking the deleterious actions of Dkk-1 in joint microenvironment will be a prospective molecular regime beneficial for retarding excessive joint deterioration in OA knees

Knee injuries in cyclists are often thought to result from an imbalance of load during the cycling motion as a consequence of inappropriate bike set-up. Recently, it has been postulated that incorrect foot positioning may be a significant factor in lower limb injury and poor cycling performance. The purpose of this study is to assess the effect of changing the foot position at the shoe-pedal interface on Vastus Medialis (VM) and Vastus Lateralis (VL) activity (mean and mean peak), knee angle and knee displacement. Maximum power tests were completed on a first visit, with data collection on a second visit recorded at 60% of the subjects maximum. Video footage and surface electromyography (SEMG) from VM and VL muscles was obtained. Data was recorded over 10 crank cycles in 3 experimental conditions; neutral, 10 degrees inversion and 10 degrees eversion using Ethylene Vinyl Acetate (EVA) wedges fitted between the cyclists shoe and the shoe cleat. Raw data (mean SEMG, mean peak SEMG) was obtained using Noraxon and SiliconCOACH measured knee angle and knee displacement. Data was analyzed using Friedmans test with appropriate post hoc tests. 12 male subjects (range 26-45, mean 35.9 years) completed the study. Mean and mean peak SEMG data showed no significant differences between the 3 experimental conditions for VM and VL. VM:VL ratios from raw mean SEMG data demonstrated a decrease in synchronicity in inversion and eversion compared to neutral. Pronators demonstrated most synchronicity in inversion and least synchronicity in eversion. There were statistically significant differences in knee angle and knee displacement between neutral, inversion and eversion (p<0.05). Inversion promoted smaller knee valgus angles and greater knee displacement from the bike. Eversion promoted larger knee valgus angles and a smaller displacement from the bike. By altering the foot position to either 10 degrees inversion or 10 degrees eversion, knee angle and knee displacement can be significantly influenced. Clinically, subjects who foot type is classified as pronating may benefit from some degree of forefoot inversion posting. Further research on subjects with knee pain needs to be undertaken

Summary Statement. The tensile properties of a number of synthetic fibre constructs and porcine MCLs were experimentally determined and compared to allow the selection of an appropriate synthetic collateral ligament model for use in a kinematic knee simulator. Introduction. As patient expectations regarding functional outcomes of total knee arthroplasty rise the need to assess the kinematics of new implants in vitro has increased. This has traditionally been done using cadaveric models, which can demonstrate high physiological relevance but also substantial inter-specimen variability. More recently there has been a shift towards the use of in silico and non-cadaveric methods. Such methods require significant simplifications of the joint and the modelling of soft tissue structures such as the collateral ligaments. Collateral ligaments are often modelled in in silico studies but have not, in the published literature, been modelled in in vitro knee kinematic simulators. Tensile testing of ligament tissue, to provide reference data, and the subsequent analysis of potential synthetic analogues was carried out. The overall aim of the study was to develop a synthetic ligament analogue for use in kinematic knee simulators. Methods. Porcine MCLs were chosen as these are of a similar size and are a readily available alternative to human ligaments. Six porcine knee specimens were sourced and the MCLs dissected by an orthopaedic registrar. Testing was carried out on an Instron MTS fitted with a 5kN load cell. Each specimen was subjected to 5 pre-conditioning loading cycles before cross-sectional and length measurements were made. Each specimen was then cyclically loaded from 0–200N for 30 cycles before being loaded to failure at a rate of 100mm/min. Ten potential synthetic analogues were also assessed using the same procedure: the Lars 80 (Corin Ltd) synthetic ligament reconstruction system and a selection of readily available synthetic constructs. Results. The porcine specimens demonstrated 6% ± 1% strain (mean ± standard error) after 30 cycles of loading, and a tensile stiffness of 100 N/mm ± 8.9 N/mm. The results of the load to failure tests also indicated a substantial toe region and highlighted the substantial variability associated with cadaveric specimens. The Lars system demonstrated a tensile stiffness of nearly 9 times that of the porcine specimens. However, non-parametric Mann-Whitney U analyses indicated that three of the synthetic samples did not have statistically significantly different tensile stiffness values compared to the porcine specimens (p < 0.05). Of these samples, the polyester braided cord demonstrated the longest and most physiologically relevant toe region. All of the polyester load-displacement traces fell within the range demonstrated by the porcine specimens. Discussion/Conclusion. The tensile properties of the porcine specimens analysed were similar to those reported in in the literature for human ligaments1. Porcine MCLs are thus a fair model of human collateral ligaments and were a suitable reference material for the selection of a synthetic analogue. The tensile testing carried out in the present study indicated that commercially available synthetic ligaments are over engineered in terms of strength and inappropriate for use in kinematic analysis. However, a polyester braided cord did demonstrate appropriate basic mechanical properties and would be appropriate as an analogue model on kinematic knee rigs

Introduction. Civilian fractures have been extensively studied with in an attempt to develop classification systems, which guide optimal fracture management, predict outcome or facilitate communication. More recently, biomechanical analyses have been applied in order to suggest mechanism of injury after the traumatic insult, and predict injuries as a result of a mechanism of injury, with particular application to the field so forensics. However, little work has been carried out on military fractures, and the application of civilian fracture classification systems are fraught with error. Explosive injuries have been sub-divided into primary, secondary and tertiary effects. The aim of this study was to 1. determine which effects of the explosion are responsible for combat casualty extremity bone injury in 2 distinct environments; a) in the open and b) enclosed space (either in vehicle or in cover) 2. determine whether patterns of combat casualty bone injury differed between environments Invariably, this has implications for injury classification and the development of appropriate mitigation strategies. Method. All ED records, case notes, and radiographs of patients admitted to the British military hospital in Afghanistan were reviewed over a 6 month period Apr 08-Sept 08 to identify any fracture caused by an explosive mechanism. Paediatric cases were excluded from the analysis. All radiographs were independently reviewed by a Radiologist, a team of Military Orthopaedic Surgeons and a team of academic Biomechanists, in order to determine the fracture classification and predict the mechanism of injury. Early in the study it became clear that due to the complexity of some of the injuries it was inappropriate to consider bones separately and the term ‘Zone of Insult’ (ZoI) was developed to identify separate areas of injury. Results. 62 combat casualties with 115 ZoIs (mean 1.82 zones) were identified in this study. 34 casualties in the open sustained 56 ZoIs (mean 1.65); 28 casualties in the enclosed group sustained 59 ZoIs (mean 2.10). There was no statistical difference in the mean ZoIs per casualty in the open vs enclosed group (Student t-test, p=0.24). Open fractures were more prevalent in the open group compared to the enclosed group (48/59 vs 20/49, Chi-squared test p<0.001). Of the casualties in the open, 1 zone of injury was due to the primary effects of blast, 10 a combination of primary and secondary blast zones, 23 due to secondary effects and 24 from the tertiary effects of blast. In contrast, there were no primary or combined primary and secondary blast zones and only 2 secondary blast zones in the enclosed group. Tertiary blast effects predominated in the enclosed group, accounting for 96% of injury zones (57/59). Analysis of the pattern of injury revealed that there were a higher proportion of lower limb injuries in the Enclosed group (54/59) compared to the Open group (40/58, Chi-squared p<0.05). In the Open group the mechanism of lower limb injury was more evenly distributed amongst mixed primary and secondary blast effects (10), secondary (10) and tertiary (20). In the enclosed group, lower limb injuries were almost exclusively caused by tertiary blast effects (47/48). A similar pattern was also seen in the Upper limb with 4/5 in the enclosed group was injured by tertiary effects compared to 4/18 in the Open Group. In the open group fragmentation injury was the predominant cause of injury (13/18). Conclusions. This data clearly demonstrates two distinct injury groups based upon the casualties' environment. The enclosed environment afforded by buildings and vehicles appears to mitigate the primary and secondary effects of the explosion. However, tertiary blast effects were the predominant mechanism of injury, with severe axial loading to the lower extremity being a characteristic of the fractures seen. In contrast, secondary fragments from the explosion were more likely to result in fractures of casualties caught in the open. The development of future mitigation strategies must be focused on reducing all the different mechanisms of injury caused by an explosion. This will require a better understanding on the effects of bone in high strain environments. This method of forensic biomechanics involving clinicians and engineers, combined with accurate physical and numerical simulations can form the basis in reducing the injury burden to the combat soldier

Objectives

Meniscal injuries are often associated with an active lifestyle. The damage of meniscal tissue puts young patients at higher risk of undergoing meniscal surgery and, therefore, at higher risk of osteoarthritis. In this study, we undertook proof-of-concept research to develop a cellularized human meniscus by using 3D bioprinting technology.

Objectives

The aim of this study was to systematically review the literature on measurement of muscle strength in patients with femoroacetabular impingement (FAI) and other pathologies and to suggest guidelines to standardise protocols for future research in the field.

Objectives

We sought to determine if a durable bilayer implant composed of trabecular metal with autologous periosteum on top would be suitable to reconstitute large osteochondral defects. This design would allow for secure implant fixation, subsequent integration and remodeling.

Objectives

“Virtual fracture clinics” have been reported as a safe and effective alternative to the traditional fracture clinic. Robust protocols are used to identify cases that do not require further review, with the remainder triaged to the most appropriate subspecialist at the optimum time for review. The objective of this study was to perform a “top-down” analysis of the cost effectiveness of this virtual fracture clinic pathway.