Total knee arthroplasty (TKA) aims to alleviate pain and restore joint biomechanics to an equivalent degree to age-matched peers.

Zimmer Biomet's Nexgen TKA was the most common implant in the UK between 2003 and 2016. This study compared the biomechanical outcomes of the Nexgen implant against a cohort of healthy older adults to determine whether knee biomechanics is restored post-TKA.

Patients with a primary Nexgen TKA and healthy adults >55 years old with no musculoskeletal deficits or diagnosis of arthritis were recruited locally.

Eligible participants attended one research appointment. Bilateral knee range of motion (RoM) was assessed with a goniometer. A motorised arthrometer (GENOUROB) was then used to quantify the anterior-posterior laxity of each knee. Finally, gait patterns were analysed on a treadmill. An 8-camera Vicon motion capture system generated the biomechanical model.

Preliminary statistical analyses were performed in SPSS (α = 0.05; required sample size for ongoing study: n=21 per group).

The patient cohort (n=21) was older and had a greater BMI than the comparative group (n=13). Patients also had significantly poorer RoM than healthy older adults. However, there were no inter-group differences in knee laxity, walking speed or cadence. Gait kinematics were comparable in the sagittal plane during stance phase. Peak knee flexion during swing phase was lower in the patient group, however (49.0° vs 41.1°).

Preliminary results suggest that knee laxity and some spatiotemporal and kinematic parameters of gait are restored in Nexgen TKA patients.

While knee RoM remains significantly poorer in the patient cohort, an average RoM of >110° was achieved. This suggests the implant provides sufficient RoM for most activities of daily living. Further improvements to knee kinematics may necessitate additional rehabilitation.

Future recruitment drives will concentrate on adults over the age of 70 for improved inter-group comparability.

Malnutrition is considered a risk factor for postoperative complications in total hip and knee arthroplasty, though prospective studies investigating this assumption are lacking. The aim of this study was to prospectively analyse the 90-day postoperative complications, postoperative length of stay (LOS) and readmission rates of patients undergoing primary total hip and total kneearthroplasty using albumin, total lymphocyte count (TLC) and transferrin as serum markers of potential malnutrition.

603 primary hip and 823 primary knee arthroplasties over a 3-year period from a single centre wereprospectively analysed. BMI, demographic and comorbidity data were recorded. Complications werecategorised as surgical site infection, venous thromboembolism (deep vein thrombosis andpulmonary embolus), implant related (such as dislocation), and non-implant related (such aspneumonia). Outcomes were compared between groups, with malnutrition defined as serumalbumin <3.5g/dL, transferrin <200 mg/dL, or TLC <1,500 cells/mm³.

Potential malnutrition was present in 9.3% of the study population. This group experienced a longeraverage LOS at 6.5 days compared to the normal albumin group at 5.0 days (p=0.003). Surgical siteinfection rate was higher in the malnourished group (12.5 vs 7.8%, p=0.02). There was no differencebetween the two groups in implant related complications (0.8 vs 1.0%, p=0.95) medicalcomplications (7.8 vs 13.3%, p=0.17), rate of venous thromboembolism (2.3 vs 2.7%) or 90-dayreadmission rate (14.1 vs 17.0%, p=0.56). TLC and transferrin were not predictive of any of theprimary outcomes measured (p<0.05). Pacific Island (p<0.001), Indian (p=0.02) and Asian (p=0.02) patients had lower albumin than NZ European.

This study demonstrates an association between low albumin levels and increased postoperativeLOS and surgical site infection in total joint arthroplasty, providing rationale for consideration ofpreoperative nutritional screening and optimisation.

To test and evaluate the effectiveness of local injection of autologous fat-derived mesenchymal stem cells (MSCs) into fracture site to prevent non-union in a clinically relevant model.

5 male Wistar rats underwent the same surgical procedure of inducing non-union. A mid-shaft tibial osteotomy was made with 1mm non-critical gap. Periosteum was stripped around the two fracture ends. Then, the fracture was fixed by ante-grade intramedullary nail. The non-critical gap was maintained by a spacer with minimal effect on the healing surface area. At the same surgical time, subcutaneous fat was collected from the ipsilateral inguinal region and stem cells were isolated and cultured in vitro. Within three weeks postoperatively, the number of expanded stem cells reached 5×10⁶ and were injected into the fracture site. Healing was followed up for 8 weeks and the quality was measured by serial x-rays, microCT, mechanical testing and histologically. Quality of healing was compared with that of previously published allogenic, xenogeneic MSCs and Purified Buffered Saline (PBS) controls.

All the five fractures united fully after 8 weeks. There was a progressive increase in the callus radiopacity during the eight-week duration, the average radiopacity in the autologous fat-MSC injected group was significantly higher than that of the allogeneic MSCs, xenogeneic MSCs and the control group, P < 0.0001 for treatment, time after injection, and treatment-time interaction (two-way repeated measure ANOVA). MicroCT, mechanical testing and histology confirmed radiological findings.

The autologous fat-MSCs are effective in prevention of atrophic non-union by stimulation of the healing process leading to a solid union. The quality and speed of repair are higher than those of the other types of cell transplantation tested.

In 2021, Vigdorchik et al. published a large multicentre study validating their simple Hip-Spine Classification for determining patient-specific acetabular component positioning in total hip arthroplasty (THA). The purpose of our study was to apply this Hip-Spine Classification to a sample of Australian patients undergoing THA surgery to determine the local acetabular component positioning requirements. Additionally, we propose a modified algorithm for adjusting cup anteversion requirements.

790 patients who underwent THA surgery between January 2021 and June 2022 were assessed for anterior pelvic plane tilt (APPt) and sacral slope (SS) in standing and relaxed seated positions and categorized according to their spinal stiffness and flatback deformity. Spinal stiffness was measured using pelvic mobility (PM); the ΔSS between standing and relaxed seated. Flatback deformity was defined by APPt <−13° in standing. As in Vigdorchik et al., PM of <10° was considered a stiff spine. For our algorithm, PM of <20° indicated the need for increased cup anteversion. Using this approach, patient-specific cup anteversion is increased by 1° for every degree the patient's PM is <20°.

According to the Vigdorchik simple Hip-Spine classification groups, we found: 73% Group 1A, 19% Group 1B, 5% Group 2A, and 3% Group 2B. Therefore, under this classification, 27% of Australian THA patients would have an elevated risk of dislocation due to spinal deformity and/or stiffness. Under our modified definition, 52% patients would require increased cup anteversion to address spinal stiffness.

The Hip-Spine Classification is a simple algorithm that has been shown to indicate to surgeons when adjustments to acetabular cup anteversion are required to account for spinal stiffness or flatback deformity. We investigated this algorithm in an Australian population of patients undergoing THA and propose a modified approach: increasing cup anteversion by 1° for every degree the patient's PM is <20°.

Osteoarthritis (OA) is a common cause of chronic pain. Subchondral bone is highly innervated, and bone structural changes directly correlate with pain in OA. Mechanisms underlying skeletal–neural interactions are under-investigated. Bone derived axon guidance molecules are known to regulate bone remodelling. Such signals in the nervous system regulate neural plasticity, branching and neural inflammation. Perturbation of these signals during OA disease progression may disrupt sensory afferents activity, affecting tissue integrity, nociception, and proprioception.

Osteocyte mechanical loading and IL-6 stimulation alters axon guidance signalling influencing innervation, proprioception, and nociception.

Human Y201 MSC cells, embedded in 3D type I collagen gels (0.05 × 106 cell/gel) in 48 well plastic or silicone (load) plates, were differentiated to osteocytes for 7 days before stimulation with IL-6 (5ng/ml) with soluble IL-6 receptor (sIL-6r (40ng/ml) or unstimulated (n=5/group), or mechanically loaded (5000 μstrain, 10Hz, 3000 cycles) or not loaded (n=5/group). RNA extracted 1hr and 24hrs post load was quantified by RNAseq whole transcriptome analysis (NovaSeq S1 flow cell 2 × 100bp PE reads and differentially expressed neurotransmitters identified (>2-fold change in DEseq2 analysis on normalised count data with FDR p<0.05). After 24 hours, extracted IL-6 stimulated RNA was quantified by RT-qPCR for neurotrophic factors using 2–∆∆Ct method (efficiency=94-106%) normalised to reference gene GAPDH (stability = 1.12 REfinder). Normally distributed data with homogenous variances was analysed by two-tailed t test.

All detected axonal guidance genes were regulated by mechanical load. Axonal guidance genes were both down-regulated (Netrin1 0.16-fold, p=0.001; Sema3A 0.4-fold, p<0.001; SEMA3C (0.4-fold, p<0.001), and up-regulated (SLIT2 2.3-fold, p<0.001; CXCL12 5-fold, p<0.001; SEMA3B 13-fold, p<0.001; SEMA4F 2-fold, p<0.001) by mechanical load. IL6 and IL6sR stimulation upregulated SEMA3A (7-fold, p=0.01), its receptor Plexin1 (3-fold, p=0.03). Neutrophins analysed in IL6 stimulated RNA did not show regulation.

Here we show osteocytes regulate multiple factors which may influence innervation, nociception, and proprioception upon inflammatory or mechanical insult. Future studies will establish how these factors may combine and affect nerve activity during OA disease progression.

Deriving autologous mesenchymal stem cells (MSCs) from adipose tissues without using enzymes requires sophisticated biomedical instruments. Applied pressure on tissues and cells are adjusted manually although centrifugation and filtration systems are frequently used. The number of derived MSCs therefore could differ between instruments. We compared the number of MSCs obtained from four commercially available devices and our newly designed and produced instrument (A2, B3, L3, M2 and T3). Three-hundred mL of adipose tissue was obtained from a female patient undergoing liposuction using the transillumination solution. Obtained tissue was equally distributed to each device and handled according to the producers' guides. After handling, 3 mL stromal vascular fraction (SVF) was obtained from each device. Freshly isolated SVF was characterized using multi-color flow cytometry (Navios Flow Cytometer, Beckman Coulter, USA). Cell surface antigens were chosen according to IFATS and ISCT. CD31-FITC, CD34-PC5,5, CD73-PE, CD90-PB and CD45-A750 (Backman Coulter, USA) fluorochrome-labeled monoclonal antibodies were assessed. Markers were combined with ViaKrome (Beckman Coulter, USA) to determine cell viability. At least 10⁵ cells were acquired from each sample. A software (Navios EX, Beckman Coulter, USA) was used to create dot plots and to calculate the cell composition percentages. The data was analyzed in the Kaluza 2.1 software package (Beckman Coulter, USA). Graphs were prepared in GraphPad Prism. CD105 PC7/CD31 FITC cell percentages were 23,9%, 13,5%, 24,6%, 11,4% and 28,8% for the A2, B3, L3, M2 and T3 devices, respectively. We conclude that the isolated MSC percentage ranged from 11,4% to 28,8% between devices. The number of MSCs in SVF are key determinants of success in orthobiological treatments. Developing a device should focus on increasing the number of MSCs in the SVF while preserving its metabolic activity.

Acknowledgments: Scientific and Technological Research Council of Türkiye (TÜBİTAK)- Technology and Innovation Funding Program Directorate (TEYDEB) funded this project (#321893). Servet Kürümoğlu and Bariscan Önder of Disposet Ltd., Ankara, Türkiye (www.disposet.com) contributed to the industrial design and research studies. Ali Tuncel and Feza Korkusuz are members of the Turkish Academy of Sciences (TÜBA). Nilsu Baysal was funded by the STAR Program of TÜBITAK Grant # 3210893.

Integrin α2β1 is one of the major transmembrane receptors for fibrillary collagen. In native bone we could show that the absence of this protein led to a protective effect against age-related osteoporosis. The objective of this study was to elucidate the effects of integrin α2β1 deficiency on fracture repair and its underlying mechanisms.

Standardised femoral fractures were stabilised by an intramedullary nail in 12 week old female C57Bl/6J mice (wild type and integrin α2^-/-). After 7, 14 and 28 days mice were sacrificed. Dissected femura were subjected to µCT and histological analyses. To evaluate the biomechanical properties, 28-day-healed femura were tested in a torsional testing device. Masson goldner staining, Alizarin blue, IHC and IF staining were performed on paraffin slices. Blood serum of the animals were measured by ELISA for BMP-2. Primary osteoblasts were analysed by in/on-cell western technology and qRT-PCR.

Integrin α2β1 deficient animals showed earlier transition from cartilaginous callus to mineralized callus during fracture repair. The shift from chondrocytes over hypertrophic chondrocytes to bone-forming osteoblasts was accelerated. Collagen production was increased in mutant fracture callus. Serum levels of BMP-2 were increased in healing KO mice. Isolated integrin deficient osteoblast presented an earlier expression and production of active BMP-2 during the differentiation, which led to earlier mineralisation. Biomechanical testing showed no differences between wild-type and mutant bones.

Knockout of integrin α2β1 leads to a beneficial outcome for fracture repair. Callus maturation is accelerated, leading to faster recovery, accompanied by an increased generation of extra-cellular matrix material. Biomechanical properties are not diminished by this accelerated healing. The underlying mechanism is driven by an earlier availability of BMP-2, one main effectors for bone development. Local inhibition of integrin α2β1 is therefore a promising target to accelerate fracture repair, especially in patients with retarded healing.

In the native articular cartilage microenvironment, chondrocytes are constantly subjected to dynamic physical stimuli that maintains tissue homeostasis. They produce extra cellular matrix (ECM) components such as collagens (type II mainly, 50-75%), proteoglycans (10-30%) and other type of proteins¹ . While collagen offers a large resistance in tension, proteoglycans are the responsible of the viscoelastic response under compression due to the negative charge they confer to the ECM allowing it to entrap a large amount of interstitial fluid. In pathologic states (e.g. osteoarthritis), this ECM is degenerated and the negative charge becomes unbalanced, losing the chondroprotective properties and resulting on an overloaded chondrocytes that further degenerate the matrix.

Low-Intensity Pulsed Ultrasound Stimulation (LIPUS) has been used to generate acoustic (pressure) waves that create bubbles that collapse with cells, inducing a stimulus that can modulate cell response². This mechanical stimulation promotes the expression of type II collagen, type X collagen, aggrecan and TGF-β, appearing as a great strategy to regenerate cartilage. However, current strategies make use of extrinsic forces to stimulate cartilage formation overlooking the physico-chemical properties of the degenerated cartilage, resulting in an excessive load-transfer to chondrocytes and the consequent hypertrophy and degeneration.

Here, interpenetrated networks (IPNs) with different compositions were created using methacrylated gelatin (GelMA), to mimic the collagen, and alginate functionalized with tyramine (Alg-tyr) to mimic glycosaminoglycans and to introduce a negative charge in the model. Within the matrix chondrocytes where encapsulated and stimulated under different conditions to identify the ultrasound parameters that enhance tissue formation. Samples with and without stimulation were compared analysing the expression and deposition of collagen II, aggrecan, collagen X and TGF-β. The results suggested that the chondrogenic marker expression of the samples stimulated for 10 minutes per day for 28 days, was two times higher overall in all of the cases, which was correlated to the tissue formation detected.

Acknowledgments: The authors would like to thank the Basque Government for the “Predoctoral Training Program for Non-Doctoral Research Staff 2021-2022” (Grant ref.: PRE_2021_1_0403). This work was supported by the RETOS grant PID2020-114901RA-I00 of the Ministry of Science and Innovation (MICINN).

Orthopedic Device-Related Infections (ODRIs) are a major medical challenge, particularly due to the involvement of biofilm-encased and multidrug-resistant bacteria. Current treatments, based on antibiotic administration, have proven to be ineffective. Consequently, there is a need for antibiotic-free alternatives. Antimicrobial peptides (AMPs) are a promising solution due to their broad-spectrum of activity, high efficacy at very low concentrations, and low propensity to induce resistance. We aim to develop a new AMP-based chitosan nanogel to be injected during orthopedic device implantation to prevent ODRIs. Chitosan was functionalized with norbornenes (NorChit) through the reaction with carbic anhydride and then, a cysteine-modified AMP, Dhvar5, a peptide with potent antibacterial activity, even against methicillin-resistant Staphylococcus aureus (MRSA), was covalently conjugated to NorChit (NorChit- Dhvar5), through a thiol-norbornene photoclick chemistry (UV= 365 nm). For NorChit-Dhvar5 nanogels production, the NorChit-Dhvar5 solution (0.15% w/v) and Milli-Q water were injected separately into microfluidic system. The nanogels were characterized regarding size, concentration, and shape, using Transmission Electron Microscopy (TEM), Nanoparticle Tracking Analysis (NTA) and Dynamic light scattering (DLS). The nanogels antibacterial properties were assessed in Phosphate Buffer (PBS) for 6 h, against four relevant microorganisms (Pseudomonas aeruginosa, S. aureus and MRSA, and in Muller- Hinton Broth (MHB), 50% (v/v) in PBS, supplemented with human plasma (1% (v/v)), for 6 and 24 h against MRSA. The obtained NorChit-Dhvar5 nanogels, presented a round-shaped and ∼100 nm. NorChit- Dhvar5 nanogels in a concentration of 10¹⁰ nanogels/mL in PBS were capable of reducing the initial inoculum of P. aeruginosa by 99%, S. aureus by 99%, and MRSA by 90%. These results were corroborated by a 99% MRSA reduction, after 24 h in medium. Furthermore, NorChit-Dhvar5 nanogels do not demonstrate signs of cytotoxicity against MC3T3-E1 cells (a pre-osteoblast cell line) after 14 days, having high potential to prevent antibiotic-resistant infection in the context of ODRIs.

Virtual mechanical testing is a method for measuring bone healing using finite element models built from computed tomography (CT) scans. Previously, we validated a dual-zone material model for ovine fracture callus that differentiates between mineralized woven bone and soft tissue based on radiodensity.¹ The objective of this study was to translate the dual-zone material model from sheep to two important clinical scenarios: human tibial fractures in early-stage healing and late-stage nonunions.

CT scans for N = 19 tibial shaft fractures were obtained prospectively at 12 weeks post-op. A second group of N = 33 tibial nonunions with CT scans were retrospectively identified. The modeling techniques were based on our published method.² The dual-zone material model was implemented for humans by performing a cutoff sweep for both the 12-week and nonunion groups. Virtual torsional rigidity (VTR) was calculated as VTR = ML/φ [N-m²/°], where M is the moment reaction, L is the diaphyseal segment length, and φ is the angle of twist.

As the soft tissue cutoff was increased, the rigidity of the clinical fractures decreased and soft tissue located within the fracture gaps produced higher strains that are not predicted without the dual zone approach. The structural integrity of the nonunions varied, ranging from very low rigidities in atrophic cases to very high rigidities in highly calcified hypertrophic cases, even with dual-zone material modeling.

Human fracture calluses are heterogeneous, comprising of woven bone and interstitial soft tissue. Use of a dual-zone callus material model may be instrumental in identifying delayed unions during early healing when callus formation is minimal and/or predominantly fibrous with little mineralization.

Bone regeneration is pivotal for the healing of fractures. In case this process is disturbed a non-union can occur. This can be induced by environmental factors such as smoking, overloading etc. Co-morbidities such as diabetes, osteoporosis etc. may be more intrinsic factors besides other disturbances in the process. Those pathways negatively influence the bone regeneration process. Several intrinsic signal transduction pathways (WNT, BMP etc.) can be affected. Furthermore, on the transcriptional level, important mRNA expression can be obstructed by deregulated miRNA levels. For instance, several miRNAs have been shown to be upregulated during osteoporotic fractures. They are detrimental for osteogenesis as they block bone formation and accelerate bone resorption. Modulating those miRNAs may revert the physiological homeostasis. Indeed, physiological fracture healing has a typical miRNA signature. Besides using molecular pathways for possible treatment of non-union fractures, providing osteogenic cells is another solution. In 5 clinical cases with non-union fractures with defects larger than 10 cm, successful administration of a 3D printed PCL-TCP scaffold with autologous bone marrow aspirate concentrate and a modulator of the pathogenetic pathway has been achieved. All patients recovered well and showed a complete union of their fractures within one year after start of the regenerative treatment.

Thus, non-union fractures are a diverse entity. Nevertheless, there seem to be common pathogenetic disturbances. Those can be counteracted at several levels from molecular to cell. Compositions of those may be the best option for future therapies. They can also be used in a more personalized fashion in case more specific measurements such as miRNA signature and stem cell activity are applied.

Device-associated bacterial infections are a major and costly clinical challenge. This project aimed to develop a smart new biomaterial for implants that helps to protect against infection and inflammation, promote bone growth, and is biodegradable. Gallium (Ga) doped strontium-phosphate was coated on pure Magnesium (Mg) through a chemical conversion process. Mg was distributed in a graduated manner throughout the strontium-phosphate coating GaSrPO4, with a compact structure and a Ga-rich surface. We tested this sample for its biocompatibility, effects on bone remodeling and antibacterial activities including Staphylococcus aureus, S. epidermidis and E. coli - key strains causing infection and early failure of the surgical implantations in orthopaedics and trauma.

Ga was distributed in a gradient way throughout the entire strontium-phosphate coating with a compact structure and a gallium-rich surface. The GaSrPO4 coating protected the underlying Mg from substantial degradation in minimal essential media at physiological conditions over 9 days. The liberated Ga ions from the coatings upon Mg specimens inhibited the growth of bacterial tested. The Ga dopants showed minimal interferences with the SrPO4 based coating, which boosted osteoblasts and undermined osteoclasts in in vitro co-cultures model.

The results evidenced this new material may be further translated to preclinical trial in large animal model and towards clinical trial.

Acknowledgements: Authors are grateful to the financial support from the Australian Research Council through the Linkage Scheme (ARC LP150100343). The authors acknowledge the facilities, and the scientific and technical assistance of the RMIT University and John Curtin School of Medical Research, Australian National University.

The objectives of this study are to evaluate the impact of the CoVID-19 pandemic on the development of relevant emerging digital healthcare trends and to explore which digital healthcare trend does the health industry need most to support HCPs.

A web survey using 39 questions facilitating Five-Point Likert scales was performed from 1.8.2020 – 31.10.2020. Of 260 participants invited, 90 participants answered the questionnaire. The participants were located in the Hospital/HCP sector in 11.9%, in other healthcare sectors in 22.2%, in the pharmaceutical sector in 11.1%, in the medical device and equipment industry in 43.3%. The Five-Point Likert scales were in all cases fashioned as from 1 (strongly disagree) to 5 (strongly agree).

As the top 3 most impacted digital health care trends strongly impacted by CoVID-19, respondents named:

- remote management of patients by telemedicine, mean answer 4.44

- shared data governance under patient control, mean answer 3.80

- new virtual interaction between HCP´s and medical industry, mean answer 3.76

Respondents were asked which level of readiness of the healthcare system currently possess to cope with the current trend impacted by CoVID-19.

- Digital and efficient healthcare logistics, mean answer 1.54

- Integrated health care, mean answer 1.73

- Use of big data and artificial intelligence, mean answer 2.03

Asked if collaborative research in the form of digital data platforms for research data sharing and increasing collaboration with multi-centric consortia would have a positive impact on the healthcare sector, the agreement was high with a value of mean 4.10 on the scale.

We can conclude that the impact of COVID-19 appears to be a high agreement of necessary advances in digitalization in the health care sector and in the collaboration of HCPs with the health care industry. Health care professional are unsure, in how far the national health care sector is capable of transformation in healthcare logistics and integrated health care.

The goal was to analyze the cellular response, specifically the osteogenic capacity, of titanium (Ti) implants harbouring a novel laserbased-surface-structure with the overall aim: augmented osteointegration. Surface micro-/nanoproperties greatly influence cell behaviour at the tissue-implant-interface and subsequent osteointegration. We investigated Ti-materials subjected to a specially developed shifted-Laser-Surface-Texturing (sLST) technology and compared them to a standard roughening-technique (sand-blasting-acid-etching, SLA). The biological response was evaluated with hMSCs, which are naturally available at the bone-implant-interface. We hypothesized: the novel surface is beneficial for our three different (young/healthy-YH; aged/healthy-AH;aged/osteoporotic-OP) cohorts.

The sLST was performed using a SPI-G3-series laser (beam-wavelength=1064nm, pulse-duration=200ns). For the SLA surface, Ti was sandblasted, afterwards acid-etched (HCl/H2SO4). Three different hMSC cohorts were studied: YH: n=6,29±6; AH: n=5,79±5; OP: n=5,76±5 years (osteoporosis confirmed via DEXA-scan). OP hMSCs show e.g. ColI-deficient-matrix and decreased mineralization. Cells were examined for survival, cell proliferation and cytoskeleton arrangement. Osteogenic differentiation was carried out over 21 days, matrix mineralization was validated with Alizarin-Red-S-staining and quantification.

Laser-texturing generated precisely the desired microgeometry. On nanostructural level, differently-sized Ti-droplets were formed stochastically by laser-induced-Ti-plasma. Live/dead-/Actin-stainings showed comparable results for all cohorts and surfaces in terms of survival and cell shape. On Ti-materials, cell growth showed no significant difference between the 3 cohorts. Alizarin quantification revealed the highest levels on laser-textured-surfaces; highest value for YH, followed by AH, lastly OP; no significance between AH/YH, but between OP/YH (p<0.0001). However, mineralization of all cohorts cultured on laser-textured-surfaces increased significantly (p<0.0001) compared to respective SLA-group, with >20fold higher value in the OP-cohort (AH:11fold, YH:6fold).

The data proves the biocompatibility of the laser-structured-Ti for young+aged cohorts. Osteogenic differentiation was significantly augmented on laser-treated-Ti. Most intriguingly, OP-donors could reach manifold increased mineralization, suggesting the novel laser texturing can counteract the osteoporotic phenotype. As osteogenesis-enhancing capacities may be related to mechanisms controlling cellular shape/fate, further investigations referring to this are currently ongoing. In conclusion, our laser-textured-Ti-materials are safe, can have a demand-oriented designer-surface-topography and represent a great potential for development into next-generation-implants suitable for different patient-cohorts, especially osteoporosis patients.

Flat-top talus (FTT) is a complication well-known to those treating clubfoot. Despite varying anecdotal opinions, its association with different treatments, especially the Ponseti method, remains uncertain. This systematic review aimed to establish the aetiology and prevalence of FTT, as well as detailing management strategies and their efficacy.

A systematic review was conducted according to PRISMA guidelines to search for articles using MEDLINE, EMBASE and Web of Science until November 2021. Studies with original data relevant to one of three questions were included: 1) Possible aetiology 2) Prevalence following different treatments 3) Management strategies and their outcomes.

32 original studies were included, with a total of 1473 clubfeet. FTT may be a pre-existing feature of the pathoanatomy of some clubfeet as well as a sequela of treatment. It can be a radiological artefact due to positioning or other residual deformity. The Ponseti method is associated with a higher percentage of radiologically normal tali (57%) than both surgical methods (52%) and non-Ponseti casting (29%). Only one study was identified that reported outcomes after surgical treatment for FTT (anterior distal tibial hemiepiphysiodesis).

The cause of FTT remains unclear. It is seen after all treatment methods but the rate is lowest following Ponseti casting. Guided growth may be an effective treatment.

Key words:

Clubfoot, Flat-top talus, Ponseti method, guided growth

Disclosures: The authors have no relevant disclosures.

Osteoporosis is a common problem in postmenopausal women and the elderly. 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) is a bi-directional enzyme that primarily activates glucocorticoids (GCs) in vivo, which is a considerable potential target as treatment for osteoporosis. Previous studies have demonstrated its effect on osteogenesis, and our study aimed to demonstrate its effect on osteoclast activation.

In vivo, we used 11β-HSD1 knock-off (KO) and C57BL6/J mice to undergo the ovariectomy-induced osteoporosis (OVX). In vitro, In vivo, We used 11β-HSD1 knockoff (KO) and C57BL6/J mice to undergo the ovariectomy-induced osteoporosis (OVX). In vitro, bone marrow-derived macrophages (BMM) and bone marrow mesenchymal stem cell (BMSC) of KO and C57BL6/J mice were extracted to test their osteogenic and osteoclastic abilities. We then created osteoclastic 11β-HSD1 elimination mice (Ctsk::11β-HSD1fl/fl) and treated them with OVX. Micro-CT analysis, H&E, immunofluorescence staining, and qPCR were performed. Finally, we conducted the high-throughput sequencing to find out 11β-HSD1 and osteoclast activation related genes.

We collected 6w samples after modeling. We found that KO mice were resistant to loss of bone trabeculae. The same effect was observed in osteoclastic 11β-HSD1 elimination mice. Meanwhile, BVT-2733, a classic inhibitor of 11β-HSD1, inhibited the osteoclast effect of cells without affecting osteogenic effect in vitro. High-throughput sequencing suggested that glucocorticoid receptor (GR) may play a key role in the activation of osteoclasts, which was verified by immunofluorescence staining and WB in vivo and in vitro.

In the process of osteoporosis, 11β-HSD1 expression of osteoclasts is abnormally increased, which may be a new target for inhibiting osteoclast activation and treating osteoporosis.

In 2020 almost 90% of femoral heads for total hip implants in Germany were made of ceramic. Nevertheless, the cellular interactions and abrasion mechanisms in vivo have not been fully understood until now. Metal transfer from the head-neck taper connection, occurring as smear or large-area deposit, negatively influences the surface quality of the articulating bearing. In order to prevent metal transfer, damage patterns of 40 Biolox delta ceramic retrievals with CoC and CoPE bearings were analysed.

A classification of damage type and severity for each component (n=40) was done according to an established scoring system. To investigate the physical properties, the surface quality was measured using confocal microscopy, quantitative analysis of phase composition were performed by Raman spectroscopy and qualitative analysis of metal traces was done by scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX). The periprosthetic tissue was analysed for abrasion particles with SEM and EDX.

Both bearing types show different damage patterns. Dotted/ drizzled metal smears were identified in 82 % of CoC (n=16) and 96 % of CoPE (n=24) bearings. Most traces on the ceramic heads were identified in the proximal area while they were observed predominantly in the distal area for the ceramic inlays. The identified marks are similar to those of metallic bearings. Metallic smears lead to an increase of up to 30 % in the monoclinic crystalline phase of the ceramic. The roughness increases by up to six times to Ra=48 nm. Ceramic and metallic wear particles from the articulating surfaces or head neck taper junctions were found in the periprosthetic tissue.

Damage patterns on CoC hip implants seem to be similar to those of metallic implants. More detailed analysis of CoC implants are needed to understand the described damage patterns and provide advice for prevention.

In 2021 the bone grafting market was worth €2.72 billion globally. As allograft bone has a limited supply and risk of disease transmission, the demand for synthetic grafting substitutes (BGS) continues to grow while allograft bone grafts steadily decrease. Synthetic BGS are low in mechanical strength and bioactivity, inspiring the development of novel grafting materials, a traditionally laborious and expensive process. Here a novel BGS derived from sustainably grown coral was evaluated. Coral-derived scaffolds are a natural calcium carbonate bio-ceramic, which induces osteogenesis in bone marrow mesenchymal stem cells (MSCs), the cells responsible for maintaining bone homeostasis and orchestrating fracture repair. By 3D printing MSCs in coral-laden bioinks we utilise high throughput (HT) fabrication and evaluation of osteogenesis, overcoming the limitations of traditional screening methods.

MSC and coral-laden GelXA (CELLINK) bioinks were 3D printed in square bottom 96 well plates using a CELLINK BIO X printer with pneumatic adapter Samples were non-destructively monitored during the culture period, evaluating both the sample and the culture media for metabolism (PrestoBlue), cytotoxicity (lactose dehydrogenase (LDH)) and osteogenic differentiation (alkaline phosphatase (ALP)). Endpoint, destructive assays used included qRT-PCR and SEM imaging.

The inclusion of coral in the printed bioink was biocompatable with the MSCs, as reflected by maintained metabolism and low LDH release. The inclusion of coral induced osteogenic differentiation in the MSCs as seen by ALP secretion and increased RUNX2, collagen I and osteocalcin transcription.

Sustainably grown coral was successfully incorporated into bioinks, reproducibly 3D printed, non-destructively monitored throughout culture and induced osteogenic differentiation in MSCs. This HT fabrication and monitoring workflow offers a faster, less labour-intensive system for the translation of bone substitute materials to clinic.

Acknowledgements: This work was co-funded by Enterprise Ireland and Zoan Biomed through Innovation Partnership IP20221024.

Our previous research has demonstrated that minor adjustments to in vitro cellular aggregation parameters, i.e. alterations to aggregate size, can influence temporal and spatial mineral depositions within maturing bone cell nodules. What remains unclear, however, is how aggregate size might affect mineralisation within said nodules over long-term in vivo culture.

In this study, we used an osteoblast cell line, MLO-A5, and a primary cell culture, mesenchymal stem cells (MSC), to compare small (approximately 80 µm) with large (approximately 220 µm) cellular aggregates for potential bone nodule development after 8 weeks of culturing in a mouse model (n = 4 each group). In total, 30 chambers were implanted into the intra-peritoneal cavity of 20 male, immunocompromised mice (MF1-Nu/Nu, 4 – 5 weeks old). Nine small or three large aggregates were used per chamber. Neoveil mesh was seeded directly with 2 × 10³ cells for monolayer control. At 8 weeks, the animals were euthanised and chambers fixed with formalin. Aggregate integrity and extracellular material growth were assessed via light microscopy and the potential mineralisation was assessed via micro-CT.

Many large aggregates appeared to disintegrate, whilst the small aggregates maintained their form and produced additional extracellular material with increased sizes. Both MLO-A5 cells and MSC cells saw similar results. Interestingly, however, the MSCs were also seen to produce a significantly higher volume of dense material compared to the MLO-A5 cells from micro-CT analysis.

Overall, a critical cell aggregate size appeared to exist balancing optimal tissue growth with oxygen diffusion, and cell source may influence differentiation pathway despite similar experimental parameters. The MSCs, for example, were likely producing bone via the endochondral ossification pathway, whilst the matured bone cells, MLO-A5 cells, were likely producing bone via the intramembranous ossification pathway.

Acetabular morphology and orientation differs from ethnic group to another. Thus, investigating the normal range of the parameters that are used to assess both was a matter of essence. Nevertheless, the main aim of this study was clarification the relationship between acetabular inclination (AI) and acetabular and femoral head arcs’ radii (AAR and FHAR).

A cross-sectional retrospective study that had been done in a tertiary center where Computed tomography abdomen scouts’ radiographs of non-orthopedics patients were included. They had no history of pelvic or hips’ related symptoms or fractures in femur or pelvis.

A total of 84 patients was included with 52% of them were females. The mean of age was 30.38± 5.48. Also, Means of AI were 38.02±3.89 and 40.15±4.40 (P 0.02, significant gender difference) for males and females, respectively. Nonetheless, Head neck shaft angle (HNSA) means were 129.90±5.55 and 130.72±6.62 for males and females, respectively. However, AAR and FHAR means for males and females were 21.3±3.1mm, 19.9±3.1mm, P 0.04 and 19.7±3.1mm, 18.1±2.7mm, P 0.019, respectively. In addition, negative significant correlations were detected between AI against AAR, FHAR, HNSA and body mass index (BMI) (r 0.529, P ≤0.0001, r 0.445, P ≤0.0001, r 0.238, P 0.029, r 0.329, P ≤0.007, respectively). On the other hand, high BMI was associated with AAR and FHAR (r 0.577, P 0.0001 and r 0.266, p 0.031, respectively).

This study shows that high AI is correlated with lower AAR, FHAR. Each ethnic group has its own normal values that must be studied to tailor the path for future implications in clinical setting.

Mesenchymal stem cells (MSCs) have the potential to repair and regenerate damaged tissues in response to injury, such as fracture or other tissue injury. Bone marrow and adipose tissue are the major sources of MSCs. Previous studies suggested that the regenerative activity of stem cells can be enhanced by exposure to tissue microenvironments. The aim of our project was to investigate whether extracellular matrix (ECM) engineered from human induced pluripotent stem cells-derived mesenchymal-like progenitors (hiPSCs-MPs) can enhance the regenerative potential of human bone marrow mesenchymal stromal cells (hBMSCs).

ECM was engineered from hiPSC-MPs. ECM structure and composition were characterized before and after decellularization using immunofluorescence and biochemical assays. hBMSCs were cultured on the engineered ECM, and differentiated into osteogenic, chondrogenic and adipogenic lineages. Growth and differentiation responses were compared to tissue culture plastic controls.

Decellularization of ECM resulted in efficient cell elimination, as observed in our previous studies. Cultivation hBMSCs on the ECM in osteogenic medium significantly increased hBMSC growth, collagen deposition and alkaline phosphatase activity. Furthermore, expression of osteogenic genes and matrix mineralization were significantly higher compared to plastic controls. Chondrogenic micromass culture on the ECM significantly increased cell growth and expression of chondrogenic markers, including glycosaminoglycans and collagen type II. Adipogenic differentiation of hBMSCs on the ECM resulted in significantly increased hBMSC growth, but significantly reduced lipid vacuole deposition compared to plastic controls. Together, our studies suggest that BMSCs differentiation into osteogenic and chondrogenic lineages can be enhanced, whereas adipogenic activity is decreased by the culture on engineered ECM. Contribution of specific matrix components and underlying mechanisms need to be further elucidated.

Our studies suggest that the three-lineage differentiation of aged BMSCs can be modulated by culture on hiPSC-engineered ECM. Further studies are aimed at scaling-up to three-dimensional ECM constructs for osteochondral tissue regeneration.

The lateral wall thickness (LWT) in trochanteric femoral fractures is a known predictive factor for postoperative fracture stability. Currently, the AO/OTA classification uses a patient non-specific measure to assess the absolute LWT (aLWT) and distinguish stable A1.3 from unstable A2.1 fractures based on a threshold of 20.5 mm. This approach potentially results in interpatient deviations due to different bone morphologies and consequently variations in fracture stability. Therefore, the aim of this study was to explore whether a patient-specific measure for assessment of the relative LWT (rLWT) results in a more precise threshold for prediction of unstable fractures.

Part 1 of the study evaluated 146 pelvic radiographs to assess left-right symmetry with regard to caput-collum-angle (CCD) and total trochanteric thickness (TTT), and used the results to establish the rLWT measurement technique. Part 2 reevaluated 202 patients from a previous study cohort to analyze their rLWT versus aLWT for optimization purposes.

Findings in Part 1 demonstrated a bilateral symmetry of the femur regarding both CCD and TTT (p ≥ 0.827) allowing to mirror bone's morphology and geometry from the contralateral intact to the fractured femur. Outcomes in Part 2 resulted in an increased accuracy for the new determined rLWT threshold (50.5%) versus the standard 20.5 mm aLWT threshold, with sensitivity of 83.7% versus 82.7% and specificity 81.3% versus 77.8%, respectively.

The novel patient-specific rLWT measure can be based on the contralateral femur anatomy and is a more accurate predictor of a secondary lateral wall fracture in comparison to the conventional aLWT. This study established the threshold of 50.5% rLWT as a reference value for prediction of fracture stability and selection of an appropriate implant for fixation of trochanteric femoral fractures.

To analyse bone stresses in humerus-megaprosthesis construct in response to axial loading under varying implant lengths in proximal humeral replacement following tumour excision.

CT scans of 10 cadaveric humeri were processed in 3D Slicer to obtain three-dimensional (3D) models of the cortical and cancellous bone. Megaprostheses of varying body lengths (L) were modelled in FreeCAD to obtain the 3D geometry. Four FE models: group A consisting of intact bone; groups B (L=40mm), C (L=100mm) and D (L=120mm) comprising of humerus-megaprosthesis constructs were created. Isotropic linear elastic behaviour was assigned for all materials. A tensile load of 200N was applied to the elbow joint surface with the glenohumeral joint fixed with fully bonded contact interfaces. Static analysis was performed in Abaqus. The bone was divided at every 5% bone length beginning distally. Statistical analysis was performed on maximum von Mises stresses in cortical and cancellous bone across each slice using one-way ANOVA (0-45% bone length) and paired t-tests (45-70% bone length). To quantify extent of stress shielding, average percentage change in stress from intact bone was also computed.

Maximum stress was seen to occur distally and anteriorly above the coronoid fossa. Results indicated statistically significant differences between intact state and shorter megaprostheses relative to longer megaprostheses and proximally between intact and implanted bones. Varying levels of stress shielding were recorded across multiple slices for all megaprosthesis lengths. The degree of stress shielding increased with implant lengthening being 2-4 times in C and D compared to B.

Axial loading of the humerus can occur with direct loading on outstretched upper limbs or indirectly through the elbow. Resultant stress shielding effect predicted in longer megaprosthesis models may become clinically relevant in repetitive axial loading during activities of daily living. It is recommended to use shorter megaprosthesis to prevent failure.

Stem cell therapy for the intervertebral disc (IVD) is highly debated but holds great promises. From previous studies, it is known that notochordal cells are highly regenerative and may stimulate other differentiated cells to produce more matrix. Lately, a particular tissue-specific progenitor cell population has been identified in the centre of the intervertebral disc (IVD. The current hope is that these nucleus pulposus progenitor cells (NPPC) could play a particular role in IVD regeneration.

Current evidence confirms the presence of these cells in murine, canine, bovine and in the human fetal/surgical samples. Noteworthy, one of the main markers to identify these cells, i.e., Tie2, is a typical marker for endothelial cells. Thus, it is not very clear what their origin and their role might be in the context of developmental biology. In human surgical specimens, their presence is, even more, obscured depending on the donor's age and the condition of the IVD and other yet unknown factors.

Here, I revisit the recent literature on regenerative cells identified for the IVD in the past decades. Current evidence how these NPPC can be isolated and detected in various species and tissues will be recapitulated. Future directions will be provided on how these progenitor cells could be used for regenerative medicine and tissue engineering.

Osteoarthritis (OA) is a degenerative disease that lacks regenerative treatment options. Current research focuses on mesenchymal stem cells (MSCs) and Platelet-Rich Plasma (PRP) as regenerative therapies, but extracellular vesicles (EVs) have shown to be more advantageous. This study compares the regenerative potential of human umbilical cord MSC-derived EVs (cEVs) and platelet-derived EVs (pEVs) in ex vivo and in vivo OA models.

In the ex vivo study, OA conditions were induced in human cartilage explants, which were then treated either with pEVs or cEVs. Results showed a higher content of DNA and collagen in the pEVs group compared to control and cEVs groups, suggesting that pEVs could be a potential alternative to cEVs.

In the in vivo study, an OA model was established in the knee joints of rats through MIA (monoiodoacetate) injection and then treated either with pEVs or cEVs. Results showed that pEVs-treated knee joints had better subchondral bone integrity and greater OA reversion, particularly in female rats, indicating that pEVs are a viable regeneration treatment for OA and outperform cEVs in terms of efficacy.

Overall, the study demonstrates the potential of EVs as a regenerative treatment for OA, with pEVs showing promising results in both ex vivo and in vivo models. The use of pEVs in clinical practice could provide a faster path to translation due to the established use of platelet concentrates in therapeutics. However, further studies are needed to fully evaluate the potential of pEVs for OA treatment and to elucidate the mechanisms behind their regenerative effects.

Acknowledgments: The authors thank Dr Fernando Hierro (UIB) for their technical contribution with TEM, Mª Trinidad García (UIB) for the access to radioactivity facilities, Aina Arbós (IUNICS) for her contribution in the histology staining, María Tortosa (IdISBa) for her assistance with the animal care and ADEMA School of Dentistry for the access to the cone beam computed tomography (CBCT).

Funding: This research was funded by Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, co-funded by the ESF European Social Fund and the ERDF European Regional Development Fund (MS16/00124; CP16/00124), PROGRAMA JUNIOR del proyecto TALENT PLUS, construyendo SALUD, generando VALOR (JUNIOR01/18), financed by the sustainable tourism tax of the Balearic Islands; the Direcció General d'Investigació and Conselleria d'Investigació, Govern Balear (FPI/2046/2017); the Mecanisme de Recuperació i Resiliència, intended to execute research projects of «Noves polítiques públiques per a un mercat de treball dinàmic, resilient i inclusiu», collected in Pla de Recuperació, Transformació i Resiliència, financed by European Union-Next Generation EU and driven by SOIB and Conselleria de Fons Europeus, Universitat i Cultura i la Conselleria de Model Econòmic, Turisme i Treball (NG0421) and the grant SYN20/03 from IdISBa.

To evaluate the functional outcome of open humerus diaphyseal fractures treated with the Three-stitch technique of antegrade humerus nailing.

This is a retrospective study conducted at the Department of Orthopaedics in D. Y. Patil University, School of Medicine, Navi Mumbai, India. The study included 25 patients who were operated on from January 2019 to April 2021 and follow-ups done till May 2022. Inclusion criteria were adult patients with open humerus diaphyseal fractures (Gustilo-Anderson Classification). All patients with closed fractures, skeletally immature patients, and patients with associated head injury were excluded from the study. All patients were operated on with a minimally invasive Three-stitch technique for antegrade humerus nailing. All patients were evaluated based on DASH score.

Out of the 25 patients included in the study, all patients showed complete union. The mean age of the patients was 40.4 years (range 23–66 years). The average period for consolidation of fracture was 10.56 weeks (range 8–14 weeks). The DASH score ranged from 0 to 15.8 with an average score of 2.96. Five patients reported complications with three patients of post-operative infection and delayed wound healing and two patients with screw loosening. All complications were resolved with proper wound care and the complete union was noted. None of the patients had an iatrogenic neurovascular injury.

Three-stitch antegrade nailing technique is a novel method to treat diaphyseal humerus fractures and provides excellent results. It has various advantages such as minimal invasiveness, minimal injury to the rotator cuff, fewer infection rates, minimal iatrogenic injuries, and good functional outcomes. Therefore, this treatment modality can be effectively used for open humerus diaphyseal fractures.

Low back pain affects 80% of the population with half of cases attributed to intervertebral disc (IVD) degeneration. However, the majority of treatments focus on pain management, with none targeting the underlying pathophysiological causes. PCRX-201 presents a novel gene therapy approach that addresses this issue. PCRX-201 codes for interleukin-1 receptor antagonist (IL-1Ra), the natural inhibitor of the pro-inflammatory cytokine IL-1, which orchestrates the catabolic degeneration of the IVD. Our objective here is to determine the ability of PCRX-201 to infect human nucleus pulposus (NP) cells and tissue to increase the production of IL-1Ra and assess downstream effects on catabolic protein production.

Degenerate human NP cells and tissue explants were infected with PCRX-201 at 0 or 3000 multiplicities of infection (MOI) and subsequently cultured for 5 days in monolayer (n=7), 21 days in alginate beads (n=6) and 14 days in tissue explants (n=5). Cell culture supernatant was collected throughout culture duration and downstream targets associated with pain and degeneration were assessed using ELISA.

IL-1Ra production was increased in NP cells and tissue infected with PCRX-201. The production of downstream catabolic proteins such as IL-1β, IL-6, MMP3, ADAMTS4 and VEGF was decreased in both 3D-cultured NP cells and tissue explants.

Here, we have demonstrated that a novel gene therapy, PCRX-201, is able to infect and increase the production of IL-1Ra in degenerate NP cells and tissue in vitro. The increase of IL-1Ra also resulted in a decrease in the production of a number of pro-inflammatory and catabolic proteins, suggesting PCRX-201 enables the inhibition of IL-1-driven IVD degeneration. At present, no treatments for IVD degeneration target the underlying pathology. The ability of FX201 to elicit anti-catabolic responses is promising and warrants further investigation in vitro and in vivo, to determine the efficacy of this exciting, novel gene therapy.

The e-scooter trial was part of a wider initiative from the Department for Transport in response to COVID pandemic. New emergency legislation was introduced in 2020 to make e-scooters legal in the UK for the first time. This scheme was launched in our county from September 2020. The aim of this case series was to identify the types of Orthopedic injuries resultant from electric scooter transport that presented to our District General Hospital over a 16-month period between September 2020 and December 2021.

This study involved retrospective collection of data from electronic hospital records. Data on demographics, laterality, date of injury, type of injury, treatment, HDU/ITU admissions, mortality, and operating time were collected to characterize the types of e-scooter-related injuries and to investigate the frequency of such injuries over the duration of our search.

A total of 79 orthopedic patients identified with electric scooter injuries between September 2020 and December 2021. 78.5% were males and the mean age was 30.1 years. Summer months accounted for most of the injuries. 17 patients required inpatient care. 23 patients required surgical intervention and a total of 29 surgeries were performed in our hospital. This accounted for a total surgical time of 2088 minutes. One patient admitted with shaft of femur fracture developed pulmonary embolism after the definitive operation and died in HDU.

Electric scooters provide a space efficient, affordable, environmentally friendly mode of transportation which reduce the urban congestion and parking issues. This study demonstrates an increasing frequency of significant orthopedic injury associated with e-scooter use treated at our centre over the course of 16 months. This small series underlines an important problem given that this increase has occurred after the start of the electric scooter trial. Legalization might result in further increase in the incidence of injury.

Pelvic tilt (PT) is always described as the pelvic orientation along the transverse axis, yet four PT definitions were established based on different radiographic landmarks: anterior pelvic plane (PT_a), the centres of femoral heads and sacral plate (PT_m), pelvic outlet (PT_h), and sacral slope (SS). These landmarks quantify a similar concept, yet understanding of their relationships is lacking. Some studies referred to the words “pelvic tilt” for horizontal comparisons, but their PT definitions might differ. There is a demand for understanding their correlations and differences for education and research purposes.

This study recruited 105 sagittal pelvic radiographs (68 males and 37 females) from a single clinic awaiting their hip surgeries. Hip hardware and spine pathologies were examined for sub-group analysis. Two observers annotated four PTs in a gender-dependent manner and repeated it after six months. The linear regression model and intraclass correlation coefficient (ICC) were applied with a 95% significance interval.

The SS showed significant gender differences and the lowest correlations to the other parameters in the male group (−0.3< r <0.2). The correlations of SS in scoliosis (n = 7) and hip implant (female, n = 18) groups were statistically different, yet the sample sizes were too small. PT_m demonstrated very strong correlation to PT_h (r > 0.9) under the linear model PT_m = 0.951 × PT_h - 68.284.

The PT_m and PT_h are interchangeable under a simple linear regression model, which enables study comparisons between them. In the male group, SS is more of a personalised spinal landmark independent of the pelvic anatomy. Female patients with hip implant may have more static spinopelvic relationships following a certain pattern, yet a deeper study using a larger dataset is required. The understanding of different PTs improves anatomical education.

The relationship of degeneration to symptoms has been questioned. MRI detects apparently similar disc degeneration and degenerative changes in subjects both with and without back pain. We aimed to overcome these problems by re-annotating MRIs from asymptomatic and symptomatic groups onto the same grading system.

We analysed disc degeneration in pre-existing large MRI datasets. Their MRIs were all originally annotated on different scales. We re-annotated all MRIs independent of their initial grading system, using a verified, rapid automated MRI annotation system (SpineNet) which reported degeneration on the Pfirrmann (1-5) scale, and other degenerative features (herniation, endplate defects, marrow signs, spinal stenosis) as binary present/absent. We compared prevalence of degenerative features between symptomatics and asymptomatics.

Pfirrmann degeneration grades in relation to age and spinal level were very similar for the two independent groups of symptomatics over all ages and spinal levels. Severe degenerative changes were significantly more prevalent in discs of symptomatics than asymptomatics in the caudal but not the rostral lumbar discs in subjects < 60 years. We found high co-existence of degenerative features in both populations. Degeneration was minimal in around 30% of symptomatics < 50 years.

We confirmed age and disc level are significant in determining imaging differences between asymptomatic and symptomatic populations and should not be ignored. Automated analysis, by rapidly combining and comparing data from existing groups with MRIs and information on LBP, provides a way in which epidemiological and ‘big data’ analysis could be advanced without the expense of collecting new groups.

Prosthetic joint infections represent complications connected to the implantation of biomedical devices, they have high incidence, interfere with osseointegration, and lead to a high societal burden. The microbial biofilm, which is a complex structure of microbial cells firmly attached to a surface, is one of the main issues causing infections. Biofilm- forming bacteria are acquiring more and more resistances to common clinical treatments due to the abuse of antibiotics administration. Therefore, there is increasing need to develop alternative methods exerting antibacterial activities against multidrug-resistant biofilm-forming bacteria. In this context, metal-based coatings with antimicrobial activities have been investigated and are currently used in the clinical practice. However, traditional coatings exhibit some drawbacks related to the insufficient adhesion to the substrate, scarce uniformity and scarce control over the toxic metal release reducing their efficacy. Here, we propose the use of antimicrobial silver-based nanostructured thin films to discourage bacterial infections. Coatings are obtained by Ionized Jet Deposition, a plasma-assisted technique that permits to manufacture films of submicrometric thickness having a nanostructured surface texture, allow tuning silver release, and avoid delamination. To mitigate interference with osseointegration, here silver composites with bone apatite and hydroxyapatite were explored. The antibacterial efficacy of silver films was tested in vitro against gram- positive and gram-negative species to determine the optimal coatings characteristics by assessing reduction of bacterial viability, adhesion to substrate, and biofilm formation. Efficacy was tested in an in vivo rabbit model, using a multidrug-resistant strain of Staphylococcus aureus showing significant reduction of the bacterial load on the silver prosthesis both when coated with the metal only (>99% reduction) and when in combination with bone apatite (>86% reduction). These studies indicate that IJD films are highly tunable and can be a promising route to overcome the main challenges in orthopedic prostheses.

Anterior cruciate ligament reconstruction (ACLR) using a semitendinosus (ST) autograft, with or without gracilis (GR), results in donor muscle atrophy and varied tendon regeneration. The effects of harvesting these muscles on muscle moment arm and torque generating capacity have not been well described. This study aimed to determine between-limb differences (ACLR vs uninjured contralateral) in muscle moment arm and torque generating capacity across a full range of hip and knee motions.

A secondary analysis of magnetic resonance imaging was undertaken from 8 individuals with unilateral history of ST-GR ACLR with complete ST tendon regeneration. All hamstring muscles and ST tendons were manually segmented. Muscle length (cm), peak cross-sectional area (CSA) (cm²), and volume (cm³) were measured in ACLR and uninjured contralateral limbs. OpenSim was used to simulate and evaluate the mechanical consequences of changes in normalised moment arm (m) and torque generating capacity (N.m) between ACLR and uninjured contralateral limbs.

Compared to uninjured contralateral limbs, regenerated ST tendon re-insertion varied proximal (+) (mean = 0.66cm, maximum = 3.44cm, minimum = −2.17cm, range = 5.61cm) and posterior (+) (mean = 0.38cm maximum = 0.71cm, minimum = 0.02cm, range = 0.69cm) locations relative to native anatomical positions. Compared to uninjured contralateral limbs, change in ST tendon insertion point in ACLR limbs resulted in 2.5% loss in peak moment arm and a 3.4% loss in peak torque generating capacity. Accounting for changes to both max isometric force and ST moment arm, the ST had a 14.8% loss in peak torque generating capacity.

There are significant deficits in ST muscle morphology and insertion points following ST-GR ACLR. The ST atrophy and insertion point migration following ACLR may affect force transmission and distribution within the hamstrings and contribute to persistent deficits in knee flexor and internal rotator strength.

Between 2016–2019, 4 patients developed hip infections post-hemiarthroplasty. However, between 2020–2021 (Covid-19 pandemic period), 6 patients developed hip infections following hip hemiarthroplasty.

The purpose of the investigation is to establish the root causes and key learning from the incident and use the information contained within this report to reduce the likelihood of a similar incident in the future. 65 patients presented with a neck of femur fracture during Covid-19 pandemic period between 2020–2021, 26 had hip hemiarthroplasty of which 6 developed hip infections. Medical records, anaesthetic charts and post-hip infections guidelines from RCS and NICE were utilised.

Proteus, Enterococci and Strep. epidermis were identified as the main organisms present causing the hip infection. The average number of ward moves was 4 with 90% of patients developing COVID-19 during their hospital stay. The chance of post-operative wound infection were multifactorial. Having had 5 of 6 patients growing enterococci may suggest contamination of wound either due to potential suboptimal hygiene measures, inadequate wound management /dressing, potential environmental contamination if the organisms (Vancomycin resistant enterococci) are found to be of same types and potential hospital acquired infection due to inadequate infection control measures or suboptimal hand hygiene practices. 3 of the 5 patients grew Proteus, which points towards suboptimal hygiene practices by patients or poor infection control practices by staff.

Lack of maintenance of sterility in post op wound dressings alongside inexperience of the handling of post-operative wound in non-surgical wards; multiple ward transfers exceeding the recommended number according to trust guidelines especially due to pandemic isolation measures and COVID-19 infection itself had resulted in an increased rate of hip infections during the COVID-19 pandemic. Multidisciplinary team education and planned categorisation and isolation strategy is essential to minimise the rate of further hip infections during the pandemic period in future.

Orthopaedic soft tissues, such as tendons, ligaments, and articular cartilage, rely on their unique collagen fiber architectures for proper functionality. When these structures are disrupted in disease or fail to regenerate in engineered tissues, the tissues transform into dysfunctional fibrous tissues. Unfortunately, collagen synthesis in regenerating tissues is often slow, and in some cases, collagen fibers do not regenerate naturally after injury, limiting repair options. One of the research focuses of my team is to develop functional fiber replacements that can promote in vivo repair of musculoskeletal tissues throughout the body. In this presentation, I will discuss our recent advancements in electrowriting 3D printing of natural polymers for creating functional fiber replacements. This manufacturing process utilizes electrical signals to control the flow of polymeric materials through an extrusion nozzle, enabling precise deposition of polymeric fibers with sizes that cannot be achieved using conventional extrusion printing methods. Furthermore, it allows for the formation of fiber organizations that surpass the capabilities of conventional electrospinning processes. During the presentation, I will showcase examples of electrowritten microfiber scaffolds using various naturally-derived polymers, such as gelatin (a denatured form of collagen) and silk fibroin. I will discuss the functional properties of silk-based scaffolds and highlight how they exhibit restored β-sheet and α-helix structures [1]. This restoration results in an elastic response of up to 20% deformation and the ability to withstand cyclic loading without plastic deformation. Additionally, I will present our latest results on the compatibility of this technique with patterning cell-laden fiber structures [2]. This novel biofabrication process allows for the printing of biomimetic microscale architectures with high cell viability, and offers a promising approach to understanding how shear and elongation forces influence cell development of hierarchical (collagen) fibers.

Acknowledgements: The author would like to thank the Reprint project (OCENW.XS5.161) and the program “Materials Driven Regeneration” (024.003.013) by the Netherlands Organization for Scientific Research for the financial support.

Osteoarthritis (OA) and diabetis mellitus type 2 (DMT2) are pathogenetically linked. Complement dysregulation contributes to OA and could be involved in DMT2. The inflammatory anaphylatoxin C5a is released during complement activation. This study aims to understand the specific responses of chondrocytes isolated from diabetic and non-diabetic rats exposed to C5a and/or the proinflammatory cytokine TNFα in vitro dependent on the glucose supply. Articular chondrocytes of adult Zucker Diabetic Fatty (ZDF) rats (homozygous: fa/fa, diabetic, heterozygous: fa/+, lean controls) were exposed to 10 ng/mL TNFα and 25 ng/mL C5a alone or in combination, both, under normo- (NG, 1 g/L glucose) and hyperglycemic (HG, 4.5 g/L glucose) conditions (4 or 24 h). Chondrocyte survival, metabolic activity and gene expression of collagen type 2, suppressors of cytokine signaling (SOCS)1, −3 and anti-oxidative hemoxygenase-1 (HMOX1) were assessed. The complement regulatory protein CD46 and cell nuclei sizes were analyzed. Chondrocyte vitality remained unaffected by the treatment. Metabolic activity was impaired in chondrocytes of non-diabetic rats under HG conditions. Collagen type 2 transcription was suppressed by TNFα under HG condition in chondrocytes from nondiabetic donors and under both conditions in those of DMT2 rats (24 h)

Except for DMT2 chondrocytes under HG (4 h), HMOX1 was generally induced by TNFα +/- C5a (NG, HG). C5a elevated HMOX1 only in chondrocytes of controls. The SOCS1/3 genes were increased by TNFα (NG, diabetic, non diabetic, 4 and 24 h). This could also be observed in chondrocytes of diabetic, but not of lean rats (24 h, HG). At 4 h, C5a induced SOCS1 only in non diabetic chondrocytes (NG, HG). Cytoprotective CD46 protein was suppressed by TNFα under NG condition. Nuclear volumes of chondrocyte were lower in chondrocytes from DMT2 rats compared to those from controls. The differential response suggests that chondrocytes are irreversibly compromised by DMT2.

Achnowledgement: The authors are grateful for the support by the “Stiftung Edoprothetik (S 04/21)”

Intraoperative fractures although rare are one of the complications known to occur while performing a total hip arthroplasty (THA). However, due to lower incidence rates there is currently a gap in this area of literature that systematically reviews this important issue of complications associated with THA.

Method: We looked into Electronic databases including PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), the archives of meetings of orthopaedic associations and the bibliographies of included articles and asked experts to identify prospective studies, published in any language that evaluated intra-operative fractures occurring during total hip arthroplasty from the year 1950-2020. The screening, data extraction and quality assessment were carried out by two researchers and if there was any discrepancy, a third reviewer was involved.

Fourteen studies were identified. The reported range of occurrence of fracture while performing hip replacement surgery was found to be 0.4-7.6%. Major risk factors identified were surgical approaches, Elderly age, less Metaphyseal-Diaphyseal Index score, change in resistance while insertion of the femur implants, inexperienced surgeons, uncemented femoral components, use of monoblock elliptical components, implantation of the acetabular components, patients with ankylosing spondylitis, female gender, uncemented stems in patients with abnormal proximal femoral anatomy and with cortices, different stem designs, heterogeneous fracture patterns and toothed design.

Intraoperative fractures during THA were managed with cerclage wire, femoral revision, intramedullary nail and cerclage wires, use of internal fixation plates and screws for management of intra operative femur and acetabular fractures.

The main reason for intraoperative fracture was found to be usage of cementless implants but planning and timely recognition of risk factors and evaluating them is important in management of intraoperative fractures. Adequate surgical site exposure is critical especially during dislocation of hip, reaming of acetabulum, impaction of implant and preparing the femoral canal for stem insertion. Eccentric and increased reaming of acetabulum to accommodate a larger cup is to be avoided, especially in females and elderly patients as the acetabulum is thinner. However, this area requires more research in order to obtain more evidence on effectiveness, safety and management of intraoperative fractures during THA.

This study aims to compare the biomechanical properties of the “Double Lasso-Loop” suture anchor (DLSA) technique with the commonly performed interference screw (IS) technique in an ex vivo ovine model.

Fourteen fresh sheep shoulder specimens were used in this study. Dissection was performed leaving only the biceps muscle attached to the humerus and proximal radius before sharply incised to simulate long head of biceps tendon (LHBT) tear. Repair of the LHBT tear was performed on all specimens using either DSLA or IS technique. Cyclical loading of 500 cycles followed by load to failure was performed on all specimens. Tendon displacement due to the cyclical loading at every 100 cycles as well as the maximum load at failure were recorded and analysed. Stiffness was also calculated from the load displacement graph during load to failure testing.

No statistically significant difference in tendon displacement was observed from 200 to 500 cycles. Statistically significant higher stiffness was observed in IS when compared with DSLA (P = .005). Similarly, IS demonstrated significantly higher ultimate failure load as compared with DSLA (P = .001). Modes of failure observed for DSLA was mostly due to suture failure (7/8) and anchor pull-out (1/8) while IS resulted in mostly LHBT (4/6) or biceps (2/6) tears. DSLA failure load were compared with previous studies and similar results were noted.

After cyclical loading, tendon displacement in DLSA technique was not significantly different from IS technique. Despite the higher failure loads associated with IS techniques in the present study, absolute peak load characteristics of DLSA were similar to previous studies. Hence, DLSA technique can be considered as a suitable alternative to IS fixation for biceps tenodesis.

Bone defects require implantable graft substitutes, especially porous and biodegradable biomaterial for tissue regeneration. The aim of this study was to fabricate and assess a 3D-printed biodegradable hydroxyapatite/calcium carbonate scaffold for bone regeneration.

Conventional 3D printing by itself is incapable of creating pores on a micro scale within deposited filaments throughout 3D scaffolds. These pores and hence larger surface areas are needed for cells to be adhered, proliferated, and differentiated. The aim of this work was to fabricate 3D polycaprolactone (PCL) scaffolds with internal multiscale porosity by using two different 3D printing techniques (ink/pellet of polymer-salt composite in low/high temperature printing) combined with salt leaching to improve cell adhesion, and cell proliferation besides to change degradation rate of PCL scaffolds:

1. Non-solvent phase separation integrated 3D printing of polymer-salt inks with various salt content (i.e., low temperature ink-based printing, LT).

2. FDM printing of composite polymer-salt pellets which will be obtained by casting and evaporating of prepared ink (i.e., high temperature composite-pellet-based printing, HT).

Further, the two approaches were followed by post salt leaching. Stem cells were able to attach on the surface and grow up to 14 days based on increasing cellular activities.

Depletion of Scleraxis-lineage (ScxLin) cells in adult tendon recapitulates age-related decrements in cell density, ECM organization and composition. However, depletion of ScxLin cells improves tendon healing, relative to age-matched wildtype mice, while aging impairs healing. Therefore, we examined whether ScxLin depletion and aging result in comparable shifts in the tendon cell environment and defined the intrinsic programmatic shifts that occur with natural aging, to define the key regulators of age-related healing deficits.

ScxLin cells were depleted in 3M-old Scx-Cre+; Rosa-DTRF/+ mice via diphtheria toxin injections into the hindpaw. Rosa-DTRF/+ mice were used as wildtype (WT) controls. Tendons were harvested from 6M-old ScxLin depleted and WT mice, and 21-month-old (21M) C57Bl/6 mice (aged). FDL tendons (n=6) were harvested for single-cell RNAseq, pooled, collagenase digested, and sorted for single cell capture. Data was processed using Cell Ranger and then aligned to the annotated mouse genome (mm10). Filtering, unsupervised cell clustering, and differential gene expression (DEG) analysis were performed using Seurat.

Following integration and sub-clustering of the tenocyte populations, five distinct subpopulations were observed. In both ScxLin depletion and aging, ‘ECM synthesizers’ and ‘ECM organizers’ populations were lost, consistent with disruptions in tissue homeostasis and altered ECM composition. However, in ScxLin depleted mice retention of a ‘specialized ECM remodeler’ population was observed, while aging tendon cells demonstrated inflammatory skewing with retention of a ‘pro-inflammatory tenocyte population’. In addition, enrichment of genes associated with protein misfolding clearance were observed in aged tenocytes. Finally, a similar inflammatory skewing was observed in aged tendon-resident macrophages, with this skewing not observed in ScxLin depleted tendons.

These data suggest that loss of ‘ECM synthesizer’ populations underpins disruptions in tendon homeostasis. However, retention of ‘specialized remodelers’ promotes enhanced healing (ScxLin depletion), while inflammatory skewing may drive the impaired healing response in aged tendons.

Source of the study: University of Auckland, Auckland, New Zealand and University of Otago, Christchurch, New Zealand

Outcomes following knee arthroplasty are typically defined as implant survivorship at defined timepoints, or revision incidence over time. These estimates are difficult to conceptualise, and lack context for younger patients with more remaining years of life. We therefore aimed to determine a ‘lifetime’ risk of revision as a more useful metric for total (TKA) and unicompartmental knee arthroplasty (UKA).

The New Zealand Joint Registry was used to identify 96,497 primary TKAs and 13,481 primary UKAs performed between 1999 and 2019. Patient mortality and revision incidence were also extracted. Estimates of lifetime risk were calculated using an actuarial lifetable method. The estimates were stratified by age and gender. Reasons for revision were categorised using previously published standardised definitions.

The lifetime risk of UKA revision was two-fold higher than TKA across all age groups (range 3.7-40.4% UKA, 1.6-22.4% TKA). Revision risk was higher for males with TKA (range 3.4%-25.2% males, 1.1%-20% females), but higher for females with UKA (range 4.3%-43.4% vs. 2.9%-37.4% for males). Revision due to infections were higher for TKA (1.5% males, 0.7% females) compared with UKA (0.4% males, 0.1% females). The increased risk in younger UKA patients was associated with higher incidence of aseptic loosening (UKA 2%, TKA 1%) and ‘unexplained pain’ (UKA 2%, TKA 0.2%).

The risk for UKA was two-fold higher than TKA, and this was partially explained by a higher proportion of revisions due to ‘unexplained pain’. For TKA, males had higher risk of revision, in contrast to UKA where females had higher risk; this gender difference was associated with higher incidence of infections with TKA. Younger age, gender and higher ASA status were also associated with increased lifetime risk of UKA revision. Lifetime risk of revision can provide a meaningful measure of arthroplasty outcomes to aid patient counselling.

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.

Ankle fractures are among the most common types of fractures. If surgery is not performed within 12 to 24 hours, ankle swelling is likely to develop and delay the operative fixation. This leads to patients staying longer in the ward waiting and increased hospital occupancy. This prolonged stay has significant financial implication as well as it is frustrating for both patients and health care professionals.

The aim was to formulate a pathway for the ankle fracture patients coming to the emergency department, outpatients and planned for operative intervention. To identify whether pre-operative hospital admissions of stable ankle fracture patients are reduced with the implementation of the pathway. We formulated an ankle fracture fixation pathway, which was approved for use in December 2020. A retrospective analysis of 6 months hospital admissions of ankle fracture patients in the period between January to June 2020. The duration from admission to the actual surgery was collected to review if some admissions could have been avoided and patients brought directly on the surgery day.

A total of 23 patients were included. Mean age was 60.5 years and SD was 17years. 94% of patients were females. 10 patients were appropriately discharged.7 Patients were appropriately admitted. 6 Patients were unnecessarily admitted. These 6 patients were admitted on presentation to ED. Retrospective analysis of this audit showed that this cohort of patients met the safe discharge criteria and could have been discharged. Duration of unnecessary stay ranged from 1 to 11 days (21 days in total). Total saving could have been £6300.

Standards were met in 74% of cases. Preoperative hospital admission could be reduced with the proposed pathway. It is a valuable tool to be used and should be implemented to reduce unnecessary hospital admissions.

The Royal College of Surgeons of England (RCS) Good Surgical Practice guidance identifies essential criteria for surgical operation note documentation. The current quality improvement project aims to identify if using pre-templated operation notes for documenting fractured neck of femur surgery results in improved documentation when compared to free hand orthopaedic operation notes.

A total of fourteen categories were identified from the RCS guidance as required across all the operations identified in this study. All operations for the month of October 2021 were identified and the operation notes analysed. Pre-templated operation notes were compared to free hand operation notes.

97 cases were identified, of which 74 were free hand operation notes and 23 were pre-templated fractured neck of femur operation notes. All fourteen categories were completed in 13 (57%) of the templated operation notes vs 0 (0%) in the free hand operation notes (odds ratio 0.0052, 95% CI 0.0003 to 0.0945, p < 0.001). The median total number of completed categories was significantly higher in the templated op-note group compared to the free hand op-note group (templated median 14, range 12-14, vs. free hand median 11, range 9 to 13, p < 0.001). Logistic regression analysis of operation notes written by Registrars or Consultants identified Registrars as more likely to document the antibiotic prophylaxis given (p = 0.025).

Use of pre-templated operation notes results in significantly improved documentation. Adoption of generic pre-templated operation notes to improve surgical documentation should be considered across all operations.

Nuclear factor erythroid 2–related factor 2 (Nrf2)/antioxidant response element (ARE) pathway is key in maintaining redox homeostasis and the pathogenesis of osteoarthritis (OA) involves oxidative distress. We thus investigated whether Nrf2/ARE signaling may control expression of key chondrogenic differentiation and hyaline cartilage maintenance factor SOX9.

In human C-28/I2 chondrocytes SOX9 expression was measured by RT–qPCR after shRNA-mediated knockdown of Nrf2 or its antagonist the Kelch-like erythroid cell-derived protein with cap “n” collar homology-associated protein 1 (Keap1). Putative ARE-binding sites in the proximal SOX9 promoter region were inactivated, cloned into pGL3, and co-transfected with phRL–TK for dual-luciferase assays to verify whether Nrf2 transcriptionally regulates SOX9. SOX9 promoter activity without and with Nrf2-inducer methysticin were analyzed. Sox9 expression in articular chondrocytes was correlated to cartilage thickness and degeneration in wild-type (WT) and Nrf2-knockout mice. Data were analyzed by one-way ANOVA, a Student's t-test, or Wilcoxon rank-sum test, according to the normal distribution. Statistical significance was set to p < 0.05.

While Keap1-specific RNAi increased SOX9 expression, Nrf2-specific RNAi significantly decreased it. Putative ARE sites (ARE₁, ARE₂) were identified in the SOX9 promoter region. ARE₂ mutagenesis significantly reduced SOX9 promoter activity, while truncation of ARE₁ did not. A functional ARE₂ site was thus essential for methysticin-mediated induction of SOX9 promoter activity. Knee cartilage of young Nrf2-knockout mice further revealed significantly fewer Sox9-positive chondrocytes as compared to old Nrf2-knockout animals, which further showed thinner cartilage and more severe cartilage erosion.

Our data suggest that SOX9 expression in articular cartilage is directly Nrf2-dependent and that pharmacological Nrf2 activation may hold potential to diminish age-dependent osteoarthritic changes in knee cartilage through improving protective SOX9 expression.

Electrospinning is an advantageous technique for cartilage tissue engineering (CTE) applications due to its ability to produce nanofibers recapitulating the size and alignment of the collagen fibers present within the articular cartilage superficial zone. Moreover, coaxial electrospinning allows the fabrication of core-shell fibers able to encapsulate and release bioactive molecules in a sustained manner. Kartogenin (KTG) is a small heterocyclic molecule, which was demonstrated to promote the chondrogenic differentiation of human bone marrow-derived mesenchymal stem/stromal cells(hBMSCs)[1].

In this work, we developed and evaluated the biological performance of core-shell poly(glycerol sebacate)(PGS)/poly(caprolactone)(PCL) aligned nanofibers (core:PGS/shell:PCL) mimicking the native articular cartilage extracellular matrix(ECM) and able to promote the sustained release of the chondroinductive drug KTG[2].

The produced coaxial aligned PGS/PCL scaffolds were characterized in terms of their structure and fiber diameter, chemical composition, thermal properties, mechanical performance under tensile testing and in vitro degradation kinetics, in comparison to monoaxial PCL aligned fibers and respective non-aligned controls. KTG was incorporated into the core PGS solution to generate core-shell PGS-KTG/PCL nanofibers and its release kinetics was studied by HPLC analysis. KTG-loaded electrospun aligned scaffolds capacity to promote hBMSCs chondrogenic differentiation was evaluated by assessing cell proliferation, typical cartilage-ECM production (sulfated glycosaminiglycans(sGAG)) and chondrogenic marker genes expression in comparison to non-loaded controls. All the scaffolds fabricated showed average fiber diameters within the nanometer-scale and the core-shell structure of the fibers was clearly confirmed by TEM. The coaxial PGS-KTG/PCL nanofibers evidenced a more sustained drug release over 21 days. Remarkably, in the absence of the chondrogenic cytokine TGF-β3, KTG-loaded nanofibers promoted significantly the proliferation and chondrogenic differentiation of hBMSCs, as suggested by the increased cell numbers, higher sGAG amounts and up-regulation of the chondrogenic genes COL2A1, Sox9, ACAN and PRG4 expression. Overall, our results highlight the potential of core-shell PGS-KTG/PCL aligned nanofibers for the development of novel MSC-based CTE strategies.

Acknowledgements: The authors thank FCT for funding through the project InSilico4OCReg (PTDC/EME-SIS/0838/2021) and to institutions iBB (UID/BIO/04565/2020) and Associate Laboratory I4HB (LA/P/0140/2020).

Conventional proximal tibial osteotomy is a widely successful joint-preserving treatment for osteoarthritis; however, conventional procedures do not adequately control the posterior tibial slope (PTS). Alterations to PTS can affect knee instability, ligament tensioning, knee kinematics, muscle and joint contact forces as well as range of motion.

This study primarily aimed to provide a comprehensive investigation of the variables influencing PTS during high tibial osteotomy using a 3D surgical simulation approach. Secondly, it aimed to provide a simple means of implementing the findings in future 3D pre-operative planning and /or clinically.

The influence of two key variables: the gap opening angle and the hinge axis orientation on PTS was investigated using three independent approaches: (1) 3D computational simulation using CAD software to perform virtual osteotomy surgery and simulate the post-operative outcome. (2) Derivation of a closed-form mathematical solution using a generalised vector rotation approach (3) Clinical assessment of synthetically generated x-rays of osteoarthritis patients (n=28; REC reference: 17/HRA/0033, RD&E NHS, UK) for comparison against the theoretical/computational approaches.

The results from the computational and analytical assessments agreed precisely. For three different opening angles (6°, 9° and 12°) and 7 different hinge axis orientations (from −30° to 30°), the results obtained were identical. A simple analytical solution for the change in PTS, ΔP_s, based on the hinge axis angle, α, and the osteotomy opening angle, θ, was derived:

ΔP_s=sin^-1(sin α sin θ)

The clinical assessment demonstrated that the absolute values of PTS, and changes resulting from various osteotomies, matched the results from the two relative prediction methods.

This study has demonstrated that PTS is impacted by the hinge axis angle and the extent of the osteotomy opening angle and provided computational evidence and analytical formula for general use.

Titanium alloys are one of the most used for orthopaedic implants and the fabrication of them by 3D printing technology is a raising technology, which could effectively resolve existing challenges. Surface modification of Ti surfaces is often necessary to improve biocorrosion resistance, especially in inflammatory conditions. Such modification can be made by coatings based on hydrogels, like alginate (Alg) - a naturally occurring anionic polymer. The properties of the hydrogel can be further enhanced with calcium phosphates like octacalcium phosphate (OCP) as a precursor of biologically formed hydroxyapatite. Formed Alg-OCP matrices have a high potential in wound healing, delivery of bioactive agents etc. but their effect on 3D printed Ti alloys performance was not well known.

In this work, Alg-OCP coated 3D printed samples were studied with electrochemical measurements and revealed significant variations of corrosion resistance vs. composition of the coating. The potentiodynamic polarization test showed that the Alg-OCP-coated samples had lower corrosion current density than simple Alg-coated samples. Electrochemical impedance spectroscopy indicated that OCP incorporated hydrogels had also a high value of the Bode modulus and phase angle. Hence Alg-OCP hydrogels could be highly beneficial in protecting 3D printed Ti alloys especially when the host conditions for the implant placement are inflammatory.

AcThis work was supported by the European Union Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Actions GA860462 (PREMUROSA). The authors also acknowledge the access to the infrastructure and expertise of the BBCE – Baltic Biomaterials Centre of Excellence (European Union Horizon 2020 programme under GA857287).

A major obstacle in biofabrication is replicating the organization of the extracellular matrix and cellular patterns found in anisotropic tissues within bioengineered constructs. While magnetically-assisted 3D bioprinting techniques have the potential to create scaffolds that mimic natural biological structures, they currently lack the ability to accurately control the dispersion of magnetic substances within the bioinks without compromising the fidelity of the intended composite. To overcome this dichotomy, the concepts of magnetically- and matrix-assisted 3D bioprinting are combined here. This method preserves the resolution of printed structures by keeping low viscosity bioinks uncrosslinked during printing, which allows for the arrangement of magnetically-responsive microfibers without compromising the structural integrity of the design. Solidification is induced after the microfibers are arranged in the desired pattern. Furthermore, the precise design of these magnetic microfillers permits the utilization of low levels of inorganic materials and weak magnetic field strengths, which reduces the potential risks that may be associated with their use. The effectiveness of this approach is evaluated in the context of tendon tissue engineering, and the results demonstrate that combining the tendons like anisotropic fibrous microstructure with remote magneto-mechanical stimulation during in vitro maturation provides both biochemical and biophysical cues that effectively guide human adipose-derived stem cells towards a tenogenic phenotype In summary, the developed strategy allows the fabrication of anisotropic high-resolution magnetic composites with remote stimulation functionalities, opening new horizons for tissue engineering applications.

Acknowledgments: ERC Grant CoG MagTendon nr 772817, BioChips PoC project nr 10106930, (PD/BD/129403/2017), (CEECIND/01375/2017), (2020.03410.CEECIND), (2022.05526.PTDC), (ED481B2019/025).

Introduction

Virtual fracture clinics (VFC's) aim to reduce the number of outpatient appointments while improving the clinical effectiveness and patients experience through standardisation of treatment pathways. With 4.6% of ED admissions due to trauma the VFC prevents unnecessary face to face appointments providing a cost savings benefit to the NHS.

Re-rupture rates after rotator cuff repair remain high because of inadequate biological healing at the tendon-bone interface. Single-growth factor therapies to augment healing at the enthesis have so far yielded inconsistent results. An emerging approach is to combine multiple growth factors over a spatiotemporal distribution that mimics normal healing. We propose a novel combination treatment of insulin-like growth factor 1 (IGF-1), transforming growth factor β1 (TGF-β1) and parathyroid hormone (PTH) incorporated into a controlled-release tyraminated poly-vinyl-alcohol hydrogel to improve healing after rotator cuff repair. We aimed to evaluate this growth factor treatment in a rat chronic rotator cuff tear model.

A total of 30 male Sprague-Dawley rats underwent unilateral supraspinatus tenotomy. Delayed rotator cuff repairs were then performed after 3 weeks, to allow tendon degeneration that resembles the human clinical scenario. Animals were randomly assigned to: [1] a control group with repair alone; or [2] a treatment group in which the hydrogel was applied at the repair site. All animals were euthanized 12 weeks after rotator cuff surgery and the explanted shoulders were analyzed for biomechanical strength and histological quality of healing at the repair site.

In the treatment group had significantly higher stress at failure (73% improvement, P=0.003) and Young's modulus (56% improvement, P=0.028) compared to the control group. Histological assessment revealed improved healing with significantly higher overall histological scores (10.1 of 15 vs 6.55 of 15, P=0.032), and lower inflammation and vascularity.

This novel combination growth factor treatment improved the quality of healing and strength of the repaired enthesis in a chronic rotator cuff tear model. Further optimization and tailoring of the growth factors hydrogel is required prior to consideration for clinical use in the treatment of rotator cuff tears. This novel treatment approach holds promise for improving biological healing of this clinically challenging problem.

Osteochondromas are benign chondrogenic lesions arising on the external surface of the bone with aberrant cartilage (exostosis) from the perichondral ring that may contain a marrow cavity also. In a few cases, depending on the anatomical site affected, different degrees of edema, redness, paresthesia, or paresis can take place due to simple contact or friction. Also, depending on their closeness to neurovascular structures, the procedure of excision becomes crucial to avoid recurrence. We report a unique case of recurrent osteochondroma of the proximal humerus enclosing the brachial artery which makes for an important case and procedure to ensure that no relapse occurs.

We report a unique case of a 13-year-old female who had presented with a history of pain and recurrent swelling for 5 years. The swelling size was 4.4 cm x 3.7 cm x 4 cm with a previous history of swelling at the same site operated in 2018. CT reports were suggestive of a large well defined broad-based exophytic diaphyseal lesion in the medial side of the proximal humerus extending posteriorly. Another similar morphological lesion measuring approximately 9 mm x 7 mm was noted involving the posterior humeral shaft. The minimal distance between the lesion and the brachial artery was 2 mm just anterior to the posterio-medial growth. Two intervals were made, first between the tumor and the neurovascular bundle and the other between the anterior tumor and brachial artery followed by exostosis and cauterization of the base.

Proper curettage and excision of the tumor was done after dissecting and removing the soft tissue, blood vessels, and nerves so that there were very less chances of relapse. Post-operative X-ray was done and post 6 months of follow-up, there were no changes, and no relapse was observed. Thus, when presented with a case of recurrent osteochondroma of the proximal humerus, osteochondroma could also be in proximity to important vasculature as in this case enclosing the brachial artery. Thus, proper curettage and excision should be done in such cases to avoid recurrence.

Currently, the consensus regarding subscapularis tendon repair during a reverse total shoulder arthroplasty (rTSA) is to do so if it is possible. Repair is thought to decrease the risk of dislocation and improve internal rotation but may also increase stiffness and improvement in internal rotation may be of subclinical benefit. Aim is to retrospectively evaluate the outcomes of rTSA, with or without a subscapularis tendon repair.

We completed a retrospective review of 51 participants (25 without and 26 with subscapularis repair) who received rTSR by a single-surgeon using a single-implant. Three patient reported outcome measures (PROM) were assessed pre-operatively and post-operative at twelve months, as well as range of movement (ROM) and plain radiographs. Statistical analysis utilized unpaired t tests for parametric variables and Mann-Whitney U test for nonparametric variables.

External Rotation ROM pre-operatively was the only variable with a significance difference (p=0.02) with the subscapularis tendon repaired group having a greater range. Pre- and post-operative abduction (p=0.72 & 0.58), forward flexion (p=0.67 & 0.34), ASES (p=0.0.06 & 0.78), Oxford (p=0.0.27 & 0.73) and post-operative external rotation (p=0.17)

Greater external rotation ROM pre-operatively may be indicative of the ability to repair the subscapularis tendon intra-operatively. However, repair does not seem to improve clinical outcome at 12 months.

There was no difference of the PROMs and AROMs between the subscapularis repaired and not repaired groups for any of the variables at the pre-operative or 12 month post operative with the exception of the external rotation ROM pre-operatively. We can conclude that from PROM or AROM perspective there is no difference if the tendon is repaired or not in a rTSR and indeed the patients without the repair may have improved outcomes at 12 months.

The June 2023 Oncology Roundup³⁶⁰ looks at: A size-based criteria for flap reconstruction after thigh-adductor soft-tissue sarcoma resection; Surgical treatment of infected massive endoprostheses implanted for musculoskeletal tumours; Free vascularized fibula for proximal humerus oncological reconstruction in children; The national incidence of chondrosarcoma of bone; a review; Bone sarcoma follow-up: when do events happen?; Osteosarcomas in older adults: a report from the Cooperative Osteosarcoma Study Group

The April 2023 Spine Roundup³⁶⁰ looks at: Percutaneous transforaminal endoscopic discectomy versus microendoscopic discectomy; Spine surgical site infections: a single debridement is not enough; Lenke type 5, anterior, or posterior: systematic review and meta-analysis; Epidural steroid injections and postoperative infection in lumbar decompression or fusion; Noninferiority of posterior cervical foraminotomy versus anterior cervical discectomy; Identifying delays to surgical treatment for metastatic disease; Cervical disc replacement and adjacent segment disease: the NECK trial; Predicting complication in adult spine deformity surgery.

The April 2023 Research Roundup³⁶⁰ looks at: Ear protection for orthopaedic surgeons?; Has arthroscopic meniscectomy use changed in response to the evidence?; Time to positivity of cultures obtained for periprosthetic joint infection; Bisphosphonates for post-COVID-19 osteonecrosis of the femoral head; Missing missed fractures: is AI the answer?; Congenital insensitivity to pain and correction of the knee; YouTube and paediatric elbow injuries.

The February 2023 Children’s orthopaedics Roundup³⁶⁰ looks at: Trends in management of paediatric distal radius buckle fractures; Pelvic osteotomy in patients with previous sacral-alar-iliac fixation; Sacral-alar-iliac fixation in patients with previous pelvic osteotomy; Idiopathic toe walking: an update on natural history, diagnosis, and treatment; A prediction model for treatment decisions in distal radial physeal injuries: a multicentre retrospective study; Angular deformities after percutaneous epiphysiodesis for leg length discrepancy; MRI assessment of anterior coverage is predictive of future radiological coverage; Predictive scoring for recurrent patellar instability after a first-time patellar dislocation.

The February 2023 Wrist & Hand Roundup³⁶⁰ looks at: ‘Self-care’ protocol for minimally displaced distal radius fractures; Treatment strategies for acute Seymour fractures in children and adolescents: including crushed open fractures; Routinely collected outcomes of proximal row carpectomy; Moving minor hand surgeries in the office-based procedure room: a population-based trend analysis; A comparison between robotic-assisted scaphoid screw fixation and a freehand technique for acute scaphoid fracture: a randomized, controlled trial; Factors associated with conversion to surgical release after a steroid injection in patients with a trigger finger; Two modern total wrist arthroplasties: a randomized comparison; Triangular fibrocartilage complex suture repair reliable even in ulnar styloid nonunion.

The August 2023 Children’s orthopaedics Roundup³⁶⁰ looks at: DDH: What can patients expect after open reduction?; Femoral head deformity associated with hip displacement in non-ambulatory cerebral palsy; Bony hip reconstruction for displaced hips in patients with cerebral palsy: is postoperative immobilization indicated?; Opioid re-prescriptions after ACL reconstruction in adolescents are associated with subsequent opioid use disorder; Normative femoral and tibial lengths in a modern population of USA children; Retrospective analysis of associated anomalies in 636 patients with operatively treated congenital scoliosis; Radiological hip shape and patient-reported outcome measures in healed Perthes’ disease; Significantly displaced adolescent posterior sternoclavicular joint injuries.

The August 2023 Wrist & Hand Roundup360 looks at: Complications and patient-reported outcomes after trapeziectomy with a Weilby sling: a cohort study; Swelling, stiffness, and dysfunction following proximal interphalangeal joint sprains; Utility of preoperative MRI for assessing proximal fragment vascularity in scaphoid nonunion; Complications and outcomes of operative treatment for acute perilunate injuries: a systematic review; The position of the median nerve in relation to the palmaris longus tendon at the wrist: a study of 784 MR images; Basal fractures of the ulnar styloid? A randomized controlled trial; Proximal row carpectomy versus four-corner arthrodesis in SLAC and SNAC wrist; Managing cold intolerance after hand injury: a systematic review.

The December 2022 Foot & Ankle Roundup³⁶⁰ looks at: Evans calcaneal osteotomy and multiplanar correction in flat foot deformity; Inflammatory biomarkers in tibialis posterior tendon dysfunction; Takedown of ankle fusions and conversion to total ankle arthroplasty; Surgical incision closure with three different materials; Absorbable sutures are not inferior to nonabsorbable sutures for tendo Achilles repair; Zadek’s osteotomy is a reliable technique for treating Haglund’s syndrome; How to best assess patient limitations after acute Achilles tendon injury; Advances in the management of infected nonunion of the foot and ankle.

The December 2022 Children’s orthopaedics Roundup³⁶⁰ looks at: Immobilization of torus fractures of the wrist in children (FORCE): a randomized controlled equivalence trial in the UK; Minimally invasive method in treatment of idiopathic congenital vertical talus: recurrence is uncommon; “You’re O.K. Anaesthesia”: closed reduction of displaced paediatric forearm and wrist fractures in the office without anaesthesia; Trunk range of motion and patient outcomes after anterior vertebral body tethering versus posterior spinal fusion: comparison using computerized 3D motion capture technology; Selective dorsal rhizotomy for individuals with spastic cerebral palsy; Scheuermann’s kyphosis and posterior spinal fusion; All-pedicle-screw constructs in skeletally immature patients with severe idiopathic early-onset scoliosis; Proximal femoral screw hemiepiphysiodesis in children with cerebral palsy.

The objectives of our study were to compare patient reported outcome measures between manual and robotic-assisted total hip arthroplasty.

Between 1st May 2021 and 31st August 2022, 539 consecutive patients who underwent 564 primary total hip arthroplasties were identified from the local registry database. Data were prospectively collected, and included patient demographics, American Society of Anaesthesiologists (ASA) grade, surgical approach, robotic-assistance, Oxford Hip Score (OHS), EQ-5D-3L and EQ-VAS pre-operatively and at twelve months.

Robotic-assistance, compared against manual total hip arthroplasty, was associated with an enhanced median (interquartile range) OHS (46 [42 – 48] vs 43 [36 – 47], p-value < 0.001), EQ-5D-3L (5 [5 – 7] vs 6 [5 – 8], p-value 0.002), and EQVAS (90 [75 – 95] vs 80 [70 – 90], p-value 0.003) at twelve months after surgery. Robotic-assistance was confirmed to be an independent predictor of a greater OHS at twelve months on a multivariate linear regression analysis (p-value 0.001).

Robotic assistance was superior to manual total hip arthroplasty in enhancing patient reported outcomes at twelve months after surgery.

The April 2023 Knee Roundup³⁶⁰ looks at: Does bariatric surgery reduce complications after total knee arthroplasty?; Mid-flexion stability in total knee arthroplasties implanted with kinematic alignment: posterior-stabilized versus medial-stabilized implants; Inflammatory response in robotic-arm-assisted versus conventional jig-based total knee arthroplasty; Journey II bicruciate stabilized (JII-BCS) and GENESIS II total knee arthroplasty: the CAPAbility, blinded, randomized controlled trial; Lifetime risk of revision and patient factors; Platelet-rich plasma use for hip and knee osteoarthritis in the USA; Where have the knee revisions gone?; Tibial component rotation in total knee arthroplasty: CT-based study of 1,351 tibiae.

The February 2023 Foot & Ankle Roundup³⁶⁰ looks at: Joint inflammatory response in ankle and pilon fractures; Tibiotalocalcaneal fusion with a custom cage; Topical application of tranexamic acid can reduce blood loss in calcaneal fractures; Risk factors for failure of total ankle arthroplasty; Pain catastrophizing: the same as pain forecasting?.

Introduction

Schatzker V & VI tibial plateau fractures are serious life-changing injuries often resulting in significant complications including post-traumatic arthritis. Reported incidence of secondary TKA following ORIF of all tibial plateau fractures is 7.3% and 13% for Schatzker V & VI tibial. This study reports a 15-year single centre experience of CEF of Schatzker V & VI fractures including PROMs and incidence of secondary TKA. This study was approved by the local Institutional board.

Introduction

Coronal malalignment and leg length discrepancies (LLD) are frequently associated. Temporary hemiepiphysiodesis (tHED) is commonly employed for the correction of limb malalignment in skeletally immature patients. For treatment of LLD greater than 2 cm, lengthening with intramedullary legnthening nails is a safe and reliable technique. However, the combined application of these approaches in skeletally immature patients has not yet been investigated.

Introduction

Circular external frames (CEF) are commonly used for a wide variety of indications, often when other devices are not appropriate. Circular frames are particularly associated with pin-site infection (PSI). Currently there is a gap in the available literature surrounding the risk of frame use with in-situ prosthetic joints. This retrospective study investigated the incidence of prosthetic joint infection (PJI) in a series of patients with in-situ arthroplasties treated with CEF.

Introduction

The management of fracture-related infection has undergone radical progress following the development of international guidelines. However, there is limited consideration to the realities of healthcare in low-resource environments due to a lack of available evidence in the literature from these settings. Initial antimicrobial suppression to support fracture union is frequently used in low- and middle-income countries despite the lack of published clinical evidence to support its practice. This study aimed to evaluate the outcomes following initial antimicrobial suppression to support fracture union in the management of fracture-related infection.

The benefits of cell salvage autotransfusion are well reported. There is a common non-evidenced belief amongst revision arthroplasty surgeons that auto-transfusion is potentially contraindicated in infected revisions.

The aim is to study the immediate and delayed outcomes of using cell saver on patients undergoing PJI surgery.

Prospective cohort service evaluation registered with the local audit department. 20 PJI cases in 18 patients where cell saver was used over a period of 4 years. Intraoperative fluid and tissue samples were taken for culture. Blood culture from salvaged blood pre and post leucodepletion filter were sent for microbiological analysis. Data on type of surgery, blood loss, further allogenic transfusion and SIRS response was collected. Success of infection clearance was assessed using 2019 MSIS ORT. Five patients receiving autologous blood in non-infection cases were used as controls.

Mean age for the PJI group was 67.7 years, 67% female. 11 patients (67%) had 1st stage surgery and 5 (25%) underwent 2nd stage whereas 4 patients had single stage surgery. The mean calculated blood loss was 1398 mls (range 400–3000mls). 6 Patients required further allogenic transfusion. 16 patients received blood via a leuco-depletion filter. The same organism grown from tissues was identified in post-filter blood in 8/17 patients (47%).

2/20 have grown a different organism in post-filtered blood, _P.Acne._

2 patients developed SIRS upon auto-transfusion, however one was thought to be secondary to cementing. The control group had 443 mls mean amount of blood loss and 1 patient developed a SIRS response.

14/20 (70%) patients had successful clearance of infection (tier 1) 2 patients died prior to undergoing 2nd stage.

Using cell saver did not impact main outcome of infection clearance in PJI surgery. We would advocate its routine usage whilst avoiding direct collection of heavily contaminated blood.

Following the establishment of regional Major Trauma Networks in England in 2012, there were concerns that pressures regarding resource allocation in Major Trauma Centres (MTCs) may have a detrimental impact on the care of patients with hip fractures in these hospitals. This study aimed to compare outcomes in hip fracture care between MTCs and trauma units (TUs).

National Hip Fracture Database data was extracted from 01/01/2015 to 31/12/2022 for all hospitals in England. Outcome measures included perioperative medical and physiotherapy assessments, time to surgery, consultant supervision in theatre, Best Practice Tariff (BPT) compliance, discharge to original residence, and mortality. Data was pooled and weighted for MTCs and remaining hospitals (TUs).

A total of 487,089 patients with hip fractures were included from 167 hospitals (23 MTCs and 144 TUs). MTCs achieved marginally higher rates of orthogeriatrician assessment within 72 hours of admission (91.1% vs 90.4%, p<0.001) and mobilisation out of bed by first postoperative day (81.9% vs 79.7%, p<0.001). A lower proportion of patients underwent surgery by the day after admission in MTCs (65.2% vs 69.7%, p<0.001). However, there was significantly higher consultant surgeon and anaesthetist supervision rates during surgery in MTCs (71.8% vs 61.6%, p<0.001). There was poorer compliance with BPT criteria in MTCs (57.3% vs 60.4%, p<0.001), and proportionately fewer MTC patients were discharged to their original residence (63.5% vs 60.4%, p<0.001). There was no difference between MTCs and TUs in 30-day mortality (6.8% vs 6.8%, p=0.825).

This study demonstrates that MTCs have greater difficulty in providing prompt surgery to hip fracture patients. However, their marginally superior perioperative care outcomes appear to compensate for this, as their mortality rates are similar to TUs. These findings suggest that the regionalisation of major trauma in England has not significantly compromised the overall care of hip fracture patients.

The purpose of this modified Delphi study was to obtain consensus on wound closure (including best practices for each tissue layer of closure) and dressing management in total hip arthroplasty (THA), using an evidence-based approach.

The Delphi panel included 20 orthopedic surgeons from Europe and North America. Eighteen statements were identified (14 specific to THA and 4 relating to both THA and total knee arthroplasty) using a targeted literature review. Consensus was developed on the statements with up to three rounds of anonymous voting per topic. Panelists ranked their agreement with each statement on a five-point Likert scale. An a priori threshold of 75% was required for consensus.

In Round 1, 15 of 18 statements achieved consensus via a structured electronic questionnaire. In Round 2, the 3 statements that did not achieve consensus were revised during a virtual face to face meeting. An additional 2 statements were edited for clarity. In Round 3, the 5 revised statements achieved consensus via a structured electronic questionnaire. Wound closure related interventions that were recommended for use in THA included: 1) barbed sutures over non-barbed sutures (shorter closing times and overall cost savings); 2) subcuticular sutures over skin staples (lower risk of infections and higher patient preference); 3) mesh-adhesives over silver-impregnated dressings (lower rate of wound complications); 4) negative pressure wound therapy over other dressings (lower wound complications and reoperations and fewer dressing changes); 5) triclosan coated sutures (lower risk of surgical site infection).

Using a modified Delphi approach, a panel of 20 orthopedic surgeons achieved consensus on 18 statements pertaining to multi-layer wound closure and dressing management in THA. This study forms the basis for identifying critical evidence gaps within wound management to help reduce variability in outcomes during THA.

Arthroplasty in patients who are intravenous drug abusers presents a complex challenge, frequently requiring intervention at a younger age. The cohort suffer increased complication rates due to significant co-morbidities and poor engagement in medical services, in comparison to other patients undergoing lower limb arthroplasty. Multiple small studies show arthroplasty in this patient cohort is associated with high complication and mortality rates.

A search of electronic databases were undertaken with the assistance of the library services from the Rotherham NHS Foundation Trust, including Chocraine, SCOPUS and PubMed.

Abstracts were reviewed and relevant studies extracted for full review. Full text articles were reviewed based on strict inclusion and exclusion criteria.

Searches identified Two thousand and forty-four papers; twenty-seven studies were identified for full review of the paper based on the inclusion criteria above. From this, nine studies were deemed appropriate to for data extraction.

These nine papers present one hundred and thirty-two cases of lower limb arthroplasty, fifty nine Total Knee Arthroplasty and seventy three Total Hip Arthroplasty. From this the authors examined incidences of implant failure due to infection, revision, mortality, dislocation, aseptic loosening, peri-prosthetic fracture, or other causes. Of these, 58% of patients (n = 77) with a history of intravenous drug abuse suffered some form of significant complication; 4% of this cohort (n = 5) were lost to follow up. Infection was reported in 32% of cases and a mortality rate of 4.7%.

The rising demand of lower limb arthroplasty for intra-venous drug abusers presents a very real problem for the modern Orthopaedic surgeon. Within the studies examined, more than half report implant failure. This study synthesises the available literature regarding treatment of these patients to help facilitate decision making and informed consent.

The Revision Hip Complexity Classification (RHCC) was developed by modified Delphi system in 2022 to provide a comprehensive, reproducible framework for the multidisciplinary discussion of complex revision hip surgery. The aim of this study was to assess the validity, intra-relater and inter-relater reliability of the RHCC.

Radiographs and clinical vignettes of 20 consecutive patients who had undergone revision of Total Hip Arthroplasty (THA) at our unit during the previous 12-month period were provided to observers. Five observers, comprising 3 revision hip consultants, 1 hip fellow and 1 ST3-8 registrar were familiarised with the RHCC. Each revision THA case was classified on two separate occasions by each observer, with a mean time between assessments of 42.6 days (24–57). Inter-observer reliability was assessed using the Fleiss™ Kappa statistic and percentage agreement. Intra-observer reliability was assessed using the Cohen Kappa statistic. Validity was assessed using percentage agreement and Cohen Kappa comparing observers to the RHCC web-based application result.

All observers were blinded to patient notes, operation notes and post-operative radiographs throughout the process.

Inter-observer reliability showed fair agreement in both rounds 1 and 2 of the survey (0.296 and 0.353 respectively), with a percentage agreement of 69% and 75%.

Inter-observer reliability was highest in H3-type revisions with kappa values of 0.577 and 0.441.

Mean intra-observer reliability showed moderate agreement with a kappa value of 0.446 (0.369 to 0.773).

Validity percentage agreement was 44% and 39% respectively, with mean kappa values of 0.125 and 0.046 representing only slight agreement.

This study demonstrates that classification using the RHCC without utilisation of the web-based application is unsatisfactory, showing low validity and reliability. Reliability was higher for more complex H3-type cases. The use of the RHCC web app is recommended to ensure the accurate and reliable classification of revision THA cases.

Subtrochanteric femoral fractures are a subset of hip fractures generally treated with cephalomedullary nail fixation\[1\]. Single lag screw devices are most commonly-used, but integrated dual screw constructs have become increasingly popular\[2,3\]. The aim of this study was to compare outcomes of fixation of subtrochanteric femoral fractures using a single lag screw (Gamma3 nail, GN) with a dual screw device (InterTAN nail, IN). The primary outcome was mechanical failure, defined as lag screw cut-out, back-out, nail breakage or peri-implant fracture.

Consecutive adult patients (18yrs) with subtrochanteric femoral fracture treated in a single centre were retrospectively identified using electronic records. Patients that underwent surgical fixation using either a long GN (2010–2017) or IN (2017–2022) were included. Medical records and radiographs were reviewed to identify complications of fixation. Cox regression analysis was used to determine the risk of mechanical failure and secondary outcomes by implant design. Multivariable regression models were used to identify predictors of mechanical failure.

The study included 622 patients, 354 in the GN group (median age 82yrs, 72% female) and 268 in the IN group (median age 82yrs, 69% female). The risk of any mechanical failure was increased two-fold in the GN group (HR 2.44 \[95%CI 1.13 to 5.26\]; _p=0.024_). Mechanical failure comprising screw cut-out (_p=0.032_), back-out (_p=0.032_) and nail breakage (_p=0.26_) was only observed in the GN group. Technical predictors of failure included varus >5° for cut-out (OR 19.98 \[2.06 to 193.88\]; _p=0.01_), TAD;25mm for back-out (8.96 \[1.36 to 58.86\]; p=0.022) and shortening 1cm for peri-implant fracture (7.81 \[2.92 to 20.91\]; _p=<0.001_).

Our results demonstrate that an intercalated screw construct is associated with a lower risk of mechanical failure compared with the a single lag screw device. Intercalated screw designs may reduce the risk of mechanical complications for patients with subtrochanteric femoral fractures.

Arthroplasties are widely performed to improve mobility and quality of life for symptomatic knee/hip osteoarthritis patients. With increasing rates of Total Joint Replacements in the United Kingdom, predicting length of stay is vital for hospitals to control costs, manage resources, and prevent postoperative complications. A longer Length of stay has been shown to negatively affect the quality of care, outcomes and patient satisfaction. Thus, predicting LOS enables us to make full use of medical resources.

Clinical characteristics were retrospectively collected from 1,303 patients who received TKA and THR. A total of 21 variables were included, to develop predictive models for LOS by multiple machine learning (ML) algorithms, including Random Forest Classifier (RFC), K-Nearest Neighbour (KNN), Extreme Gradient Boost (XgBoost), and Na¯ve Bayes (NB). These models were evaluated by the receiver operating characteristic (ROC) curve for predictive performance. A feature selection approach was used to identify optimal predictive factors. Based on the ROC of Training result, XgBoost algorithm was selected to be applied to the Test set.

The areas under the ROC curve (AUCs) of the 4 models ranged from 0.730 to 0.966, where higher AUC values generally indicate better predictive performance. All the ML-based models performed better than conventional statistical methods in ROC curves. The XgBoost algorithm with 21 variables was identified as the best predictive model. The feature selection indicated the top six predictors: Age, Operation Duration, Primary Procedure, BMI, creatinine and Month of Surgery.

By analysing clinical characteristics, it is feasible to develop ML-based models for the preoperative prediction of LOS for patients who received TKA and THR, and the XgBoost algorithm performed the best, in terms of accuracy of predictive performance. As this model was originally crafted at Ashford and St. Peters Hospital, we have naturally named it as THE ASHFORD OUTCOME.

Hip dysplasia is a common cause of hip pain in young adults. Pelvic osteotomy (PO) techniques are the gold standard for treating symptomatic patients, albeit technically demanding. This study aimed to (1) evaluate the 90-day complication rate, and (2) investigate the reasons, frequency and timing of reoperations following primary PO procedures.

We retrospectively analysed the National Hospital Episode Statistics database, examining all patients aged over 14 who underwent PO in NHS England hospitals from 2010 to 2023. We identified index procedures and reoperations using relevant OPCS-4 codes. We analysed patient demographics, 90-day complications, and readmission rates for ipsilateral metalwork removal, revision PO, hip arthroscopy (HA), and THR conversion, and calculated the mean time to reoperations.

This study included 1,348 PO cases (mean age: 28.7±9.1 years, 89.5% female). The mean hospital stay was 5.4±3.9 days, with a 90-day readmission rate of 0.52% at a mean of 51.0±17.2 days. The most common causes were infection (0.22%) and reoperation (0.15%). The 90-day rate of pulmonary embolism and deep vein thrombosis was 0.074%. One patient died within 90 days.

Overall, 810 patients (60.1%) were readmitted for a subsequent hip procedure at a mean of 2.12±1.90 years following their primary PO. Metalwork removal was required in 616 patients (45.7%) at a mean of 1.70±1.19 years. Readmission rates for revision PO, HA, and THR, were 4.23% (mean time: 2.89±0.82 years), 4.15% (mean time: 2.91±2.28 years) and 6.01% (mean time: 5.24±3.08 years) respectively.

This study highlights a low 90-day complication rate following primary PO, but a high reoperation rate, mainly for metalwork removal. We provide the most up-to-date report of revision PO, HA and THR conversion rates in England. These findings provide valuable insight that can facilitate informed decision-making, expectation-setting, and post-operative planning, also establishing a benchmark for future quality improvement.

Hip arthroscopy (HA) and pelvic osteotomy (PO) are surgical procedures used to treat a variety of hip pathology affecting young adults, including femoroacetabular impingement and hip dysplasia respectively. This study aimed to investigate the trends and regional variation in the provision of HA and PO across England from 2010 to 2023 to inform healthcare resource allocation.

We analysed the National Hospital Episode Statistics database for all HA and PO procedures in NHS England using specific OPCS-4 codes: HA: ‘W83+Z843’ or ‘W84+Z843’; PO: ‘X222+Z75’. We collected patient demographics, age, sex, and region of treatment. We performed descriptive and regression analyses to evaluate temporal trends in PO volume, age, sex and regional variation.

22,401 HAs and 1,348 POs were recorded between 2010 and 2023. The annual number of HAs declined by 28.4%, whilst the number of POs increased by 64% (p<0.001). Significantly more females underwent PO vs HA (90% vs 61.3%) and were older than males undergoing the same procedure (PO: 29.0±8.7 vs 25.8±9.2 years; HA: 36.8±12.0 years vs 35.8±11.2 years, p<0.001). For HA, the mean age of both sexes decreased by 3.3 and 2.9 years respectively (p<0.001), whereas the age of PO patients did not change significantly over the study period. There were significant regional variations with a mean incidence of 1.60/100,00 for HA (ranging from 0.70–2.66 per 100,000) and 0.43/100,000 for PO (ranging from 0.08–2.07 per 100,000).

We have observed a decline in HA volume in England, likely due to improved patient selection and the impact of COVID-19, whilst PO volume has significantly increased, with regional variation persisting for both procedures. These trends highlight the need for equitable HA and PO access to improve patient outcomes and call for strategic healthcare planning and resource allocation to reduce disparities and improve training opportunities.

This large UK multicentre study evaluates clinical outcomes and identifies factors associated with local complication following PFR for non-oncological conditions.

132 patients across four UK centres underwent PFR from 01/08/2004-28/03/2023 with median follow-up of 1.9 (Q10.5-Q34.2) years. 75 (56.8%) patients were female and the mean age was 74.0 (SD 11.7) years. 103 (78%) patients had Charleston Comorbidity Index ≥3. ASA class was III or IV in 66.6%. Indications were infected revision (39, 29.5%), periprosthetic fracture (36, 27.3%), acute trauma (30, 22.7%), aseptic revision (17, 12.9%), failed trauma (nine, 6.8%) and complex primary arthroplasty (one, 0.8%). The primary outcome was the local complication rate. Secondary outcomes were systemic complications, reoperation and mortality rates. Comparisons were made with t-tests and Chi2 tests to investigate patient and surgical factors associated with local complication. Statistical significance was p<0.05.

There were 37(28.0%) local complications. These were 18 (13.6%) dislocations, eight (6.1%) prosthetic joint infections, four (3.0%) haematomas, three (2.3%) superficial infections, one (0.8%) wound dehiscence, one (0.8%) sciatic nerve palsy and one (0.8%) femoral perforation. Dislocation mostly occurred in conventional articulations (12, 9.1%) followed by dual-mobility cups (three, 2.3%), constrained cups (two, 1.5%) and hemiarthroplasty (one, 0.8%). Median time to local complication was 30 (Q14-Q3 133) days. Seven (5.3%) patients developed a systemic complication. Thirty-three (25.0%) patients underwent reoperation. Thirty-day and one-year mortality rates were 3.8% and 12.1%, respectively. Longer surgical waiting times (7.9 \[SD 16.9) versus 2.6 \[SD 4.4\] days, p<0.001) and longer operating times (212.5 \[SD 71.8\] versus 189.4 \[SD 59.3\] mins, p=0.0450) were associated with local complication.

Due to its high complication rate, PFR should be a salvage option when performed for non-oncological indications. Conventional articulations should be avoided. PFR should be delivered in a timely manner and ideally as dual-consultant cases to reduce operating time.

Current advice regarding implant choice is based on estimates of cost-benefit derived from implant survival to an endpoint of revision. Current estimates do not account for many implant failures which are treated with non-revision surgery and may not be accurate. The aim of this study was to estimate survival of major stem implant design groups to an endpoint of reoperation.

Primary total hip replacement and linked revision form the National Joint Registry (NJR) and Hospital Episode Statistics (HES) data linked by unique identifier were used. Survival of femoral implant groups (cemented stainless steel polished taper [PTSS], cemented cobalt chrome polished taper [PTCC], cemented composite beam [CB], collarless cementless [NCOL] and collared cementless [COL]) was estimated using Kaplan-Meier method.

809,832 patients with valid NJR and HES data from England, were included. Cumulative failure at ten years for PTSS increased overall from 2.9% (95%CI 2.8–2.9) to 3.6% (95%CI 3.6–3.7) after inclusion of reoperations. Cumulative failure at ten years for PTSS increased from 2.5% (95%CI 2.5–2.6) to 3.3% (95%CI 3.2–3.4), for PTCC increased from 3.8% (95%CI 3.5–4.0) to 5.4% (95%CI 5.1–5.6), for CB increased from 3.1% (95%CI 2.9–3.3) to 4.1% (95%CI 3.8–4.3), for NCOL increased from 3.4% (95%CI 3.3–3.5) to 3.9% (95%CI 3.8–4.0), and for COL increased from 2.5% (95%CI 2.4–2.6) to 3.1% (95%CI 2.9–3.2), after inclusion of reoperations.

Re-operation for internal fixation is as significant life event for the patient as revision. When a more inclusive metric is used, the patient and clinician's perspective on what constitutes a GIRFT implant may not be the same. Further work is required to update implant selection guidance in view of the change in implant performance.

As patient data continues to grow, the importance of efficient and precise analysis cannot be overstated. The employment of Generative Artificial Intelligence (AI), specifically Chat GPT-4, in the realm of medical data interpretation has been on the rise. However, its effectiveness in comparison to manual data analysis has been insufficiently investigated.

This quality improvement project aimed to evaluate the accuracy and time-efficiency of Generative AI (GPT-4) against manual data interpretation within extensive datasets pertaining to patients with orthopaedic injuries.

A dataset, containing details of 6,562 orthopaedic trauma patients admitted to a district general hospital over a span of two years, was reviewed. Two researchers operated independently: one utilised GPT-4 for insights via prompts, while the other manually examined the identical dataset employing Microsoft Excel and IBM® SPSS® software. Both were blinded on each other's procedures and outcomes. Each researcher answered 20 questions based on the dataset including injury details, age groups, injury specifics, activity trends and the duration taken to assess the data.

Upon comparison, both GPT-4 and the manual researcher achieved consistent results for 19 out of the 20 questions (95% accuracy). After a subsequent review and refined prompts (prompt engineering) to GPT-4, the answer to the final question aligned with the manual researcher's findings. GPT-4 required just 30 minutes, a stark contrast to the manual researcher's 9-hour analytical duration.

This quality improvement project emphasises the transformative potential of Generative AI in the domain of medical data analysis. GPT-4 not only paralleled the accuracy of manual analysis but also achieved this in significantly less time. For optimal accurate results, data analysis by AI can be enhanced through human oversight. Adopting AI-driven approaches, particularly in orthopaedic data interpretation, can enhance efficiency and ultimately improve patient care. We recommend future investigations on large and more varied datasets to reaffirm these outcomes.

The reliable production of _in vitro_ chondrocytes that faithfully recapitulate _in vivo_ development would be of great benefit for orthopaedic disease modelling and regenerative therapy(1,2). Current efforts are limited by off-target differentiation, resulting in a heterogeneous product, and by the lack of comparison to human tissue, which precludes detailed evaluation of _in vitro_ cells(3,4).

We performed single-cell RNA-sequencing of long bones dissected from first-trimester fetal limbs to form a detailed ‘atlas’ of endochondral ossification. Through 100-gene in-situ sequencing, we placed each sequenced cell type into its anatomical context to spatially resolve the process of endochondral ossification. We then used this atlas to perform deconvolution on a series of previously published bulk transcriptomes generated from _in vitro_ chondrogenesis protocols to evaluate their ability to accurately produce chondrocytes.

We then applied single-nuclear RNA-sequencing to cells from the best performing protocol collected at multiple time points to allow direct comparison between the differentiation of _in vitro_ and _in vivo_ cells.

We captured 275,000 single fetal cells, profiling the development of chondrocytes from multipotent mesenchymal progenitors to hypertrophic cells at full transcriptomic breadth. Using this atlas as the ground truth for evaluating _in vitro_ cells, we found substantial variability in cell states produced by each protocol, with many showing little similarity to _in vivo_ cells, and all exhibiting off-target differentiation.

Trajectory alignment between _in vivo_ and _in vitro_ single-cell data revealed key differences in gene expression dynamics between _in vitro_ and _in vivo cells,_ with several osteoblastic transcription factors erroneously unregulated _in vitro,_ including _FOXO1._

Using this information, we inhibited _FOXO1_ in culture to successfully increase chondrocyte yield _in vitro._

This study presents a new framework for evaluating tissue engineering protocols, using single-cell data to drive improvement and bring the prospect of true engineered cartilage closer to reality.

Different techniques have been described to address massive bone loss of the acetabulum in revision hip surgery. aMace has gained popularity as it provides customization aiming to restore hip centre and provide good initial stability in cases of large non-contained defects. It takes into account quality of host bone. Its porous defect filling scaffold provides an excellent surface for osteointegration.

Our aim was to assess the short and mid-term outcomes of patients who underwent revision surgery using aMace system.

Ethical approval was obtained. A retrospective study included all patients who had aMace between June 2013 and October 2022 allowing for a minimum of 12-months follow-up. Patients’ demographics, indication, bone-loss severity, reconstruction details, re-operation, complications, mortality, pain and function were assessed.

52 cases were performed by 13 surgeons with median 51 months follow-up. Median age was 72.7 years. 86.5% were female. Average BMI was 25.3. Average ASA grade was 3.

65% were classified as Paprosky IIIB and 32% were IIIA.

73% were found to have poor bone quality on CT. Main indication for aMace was massive bone loss/discontinuity secondary to aseptic loosening in 88.5%.

77% underwent single-stage revision. 53.8% had 2 or more previous revisions. 71% underwent stem revision in the same setting. 77% received a dual mobility bearing.

Re-operation rate was 5.7% for instability and femoral PPF. LLD was reported in 9.6%.

Permanent Sciatic nerve palsy occurred in 3.8% of the cases.

30-days mortality was 1.9%.

Statistically significant post-op improvements in pain and mobility were reported (p<0.001). None of the acetabular components have been revised.

Our study shows satisfactory surgical outcomes with a relatively low complication rate and significant pain and mobility improvements in the early to mid-term stages.

We recommend these costly cases to be done in highly specialist centres adopting MDT approach.

The primary treatment goal for patients with femoroacetabular impingement syndrome, a common hip condition in athletes, is to improve pain and function. In selected patients, in the short term following intervention, arthroscopic hip surgery is superior to a pragmatic NHS- type physiotherapy programme. Here, we report the three-year follow-up results from the FemoroAcetabular Impingement Trial (FAIT), comparing arthroscopic hip surgery with physiotherapy in the management of patients with femoroacetabular impingement (FAI) syndrome.

Two-group parallel, assessor-blinded, pragmatic randomised controlled study across seven NHS England sites. 222 participants aged 18 to 60 years with FAI syndrome confirmed clinically and radiologically were randomised (1:1) to receive arthroscopic hip surgery (n = 112) or physiotherapy and activity modification (n = 110). We previously reported on the hip outcome score at eight months. The primary outcome measure of this study was minimum Joint Space Width (mJSW) on Anteroposterior Radiograph at 38 months post randomisation. Secondary outcome measures included the Hip Outcome Score and Scoring Hip Osteoarthritis with MRI (SHOMRI) score.

Minimum Joint Space Width data were available for 101 participants (45%) at 38 months post randomisation. Hip outcome score and MRI data were available for 77% and 62% of participants respectively. mJSW was higher in the arthroscopy group (mean (SD) 3.34mm (1.01)) compared to the physiotherapy group (2.99mm (1.33)) at 38 months, p=0.017, however this did not exceed the minimally clinically important difference of 0.48mm. SHOMRI score was significantly lower in the arthroscopy group (mean (SD) 9.22 (11.43)) compared to the physiotherapy group (22.76 (15.26)), p-value <0.001. Hip outcome score was higher in the arthroscopy group (mean (SD) 84.2 (17.4)) compared with the physiotherapy group (74.2 (21.9)), p-value < 0.001).

Patients with FAI syndrome treated surgically may experience slowing of osteoarthritisprogression and superior pain and function compared with patients treated non- operatively.

Alcohol hand rubs, endorsed by WHO and NICE guidelines, are integral to modern surgical practices. Our objective was to assess how different scrubbing methods impact overall water usage by the surgical team, shedding light on variations among team members and their environmental implications.

Over three consecutive arthroplasty lists spanning a week, water usage during scrubbing was observed for the operating team. Blinding all team members, including the anesthetist, consultant surgeon, orthopaedic registrar, orthopaedic SHO, and scrub nurse, during water usage calculations was implemented. Automated taps, using motion sensors, posed a challenge due to variable water quantity, necessitating water flow calculations per sensor movement. The senior surgeon, with over 20 years of experience, follows a traditional approach, starting with a morning prescrub and using an alcohol tub for each case, except when hands are soiled.

We observed a total of 14 cases of lower limb primary arthroplasty. The cumulative water usage for scrubbing by the entire team was 193 liters, yielding a mean of 13.8 liters (±1.85) per case. The anaesthetist demonstrated the most conservative water usage, utilizing a total of 11.85 liters with a mean of 0.84 liters per case. Notably, alcohol rub was employed for half of the observed time, contributing to this efficient use. The senior operating surgeon used a total of 15.6 liters, averaging 1.1 liters per case. In contrast, the SHO and the registrar exhibited the highest water consumption, totaling 121.6 liters and yielding a mean of 5.7 liters per case. The nurses’ collective water usage for scrubbing amounted to 44.8 liters.

Adopting alcohol rub, as endorsed by WHO, results in a remarkable 10-fold reduction in water usage, aligning with global health guidelines. This highlights significant potential for resource conservation in surgical procedures, presenting a practical and environmentally conscious approach to surgical scrubbing practices.

Introduction

Early clinical examination combined with MRI following a high ankle sprain allows accurate diagnosis of syndesmosis instability. However, patients often present late, and for chronic injuries clinical assessment is less reliable. Furthermore, in many centres MRI may be not be readily available. The aims of the current study were to define MRI characteristics associated with syndesmosis instability, and to determine whether MRI patterns differed according to time from injury.