Femoro-acetabular impingement involves a deformity of the hip joint and is associated with hip osteoarthritis. Although 15% of the asymptomatic population exhibits a deformity, it is not clear who will develop symptoms. Current diagnostic imaging measures have either low specificity or low sensitivity and do not consider the dynamic nature of impingement during daily activities. The goal of this study is to determine stresses in the cartilage, subchondral bone and labrum of normal and impinging hips during activities such as walking and sitting down. Quantitative CT scans were obtained of a healthy Control and a participant with a symptomatic femoral cam deformity (‘Bump’). 3D models of the hip were created from automatic segmentation of CT scans. Cartilage layers were added so the articular surface was the mid-line of the joint. Finite element meshes were generated in each region. Bone elastic modulus was assigned element-by-element, calculated from CT intensity converted to bone mineral density using a calibration phantom. Cartilage was modelled as poroelastic, E=0.467 MPa, v=0.167, and permeability 3×10. -16. m. 4. /N s. The pelvis was fixed while rotations and contact forces from Bergmann et al. (2001) were applied to the femur over one load cycle for walking and sitting in a chair. All analyses were performed in FEBio. High shear stresses were seen near the acetabular cartilage-labrum junction in the Bump model, up to 0.12 MPa for walking and were much higher than in the Control. Patient-specific modelling can be used to assess contact and tissue stresses during different activities to better understand the risk of degeneration in individuals, especially for activities that involve high hip flexion. The high stresses at the cartilage labrum interface could explain so-called bucket-handle tears of the labrum

Introduction. With advances in artificial intelligence, the use of computer-aided detection and diagnosis in clinical imaging is gaining traction. Typically, very large datasets are required to train machine-learning models, potentially limiting use of this technology when only small datasets are available. This study investigated whether pretraining of fracture detection models on large, existing datasets could improve the performance of the model when locating and classifying wrist fractures in a small X-ray image dataset. This concept is termed “transfer learning”. Method. Firstly, three detection models, namely, the faster region-based convolutional neural network (faster R-CNN), you only look once version eight (YOLOv8), and RetinaNet, were pretrained using the large, freely available dataset, common objects in context (COCO) (330000 images). Secondly, these models were pretrained using an open-source wrist X-ray dataset called “Graz Paediatric Wrist Digital X-rays” (GRAZPEDWRI-DX) on a (1) fracture detection dataset (20327 images) and (2) fracture location and classification dataset (14390 images). An orthopaedic surgeon classified the small available dataset of 776 distal radius X-rays (Arbeidsgmeischaft für Osteosynthesefragen Foundation / Orthopaedic Trauma Association; AO/OTA), on which the models were tested. Result. Detection models without pre-training on the large datasets were the least precise when tested on the small distal radius dataset. The model with the best accuracy to detect and classify wrist fractures was the YOLOv8 model pretrained on the GRAZPEDWRI-DX fracture detection dataset (mean average precision at intersection over union of 50=59.7%). This model showed up to 33.6% improved detection precision compared to the same models with no pre-training. Conclusion. Optimisation of machine-learning models can be challenging when only relatively small datasets are available. The findings of this study support the potential of transfer learning from large datasets to improve model performance in smaller datasets. This is encouraging for wider application of machine-learning technology in medical imaging evaluation, including less common orthopaedic pathologies

Introduction. Patients (2.7M in EU) with positive cancer prognosis frequently develop metastases (≈1M) in their remaining lifetime. In 30-70% cases, metastases affect the spine, reducing the strength of the affected vertebrae. Fractures occur in ≈30% patients. Clinicians must choose between leaving the patient exposed to a high fracture risk (with dramatic consequences) and operating to stabilise the spine (exposing patients to unnecessary surgeries). Currently, surgeons rely on their sole experience. This often results in to under- or over-treatment. The standard-of-care are scoring systems (e.g. Spine Instability Neoplastic Score) based on medical images, with little consideration of the spine biomechanics, and of the structure of the vertebrae involved. Such scoring systems fail to provide clear indications in ≈60% patients. Method. The HEU-funded METASTRA project is implemented by biomechanicians, modellers, clinicians, experts in verification, validation, uncertainty quantification and certification from 15 partners across Europe. METASTRA aims to improve the stratification of patients with vertebral metastases evaluating their risk of fracture by developing dedicated reliable computational models based on Explainable Artificial Intelligence (AI) and on personalised Physiology-based biomechanical (VPH) models. Result. The METASTRA-AI model is expected to be able to stratify most patients with limited effort end cost, based on parameters extracted semi-automatically from the medical files and images. The cases which are not reliably stratified through the AI model, are examined through a more detailed and personalised biomechanical VPH model. These METASTRA numerical tools are trained through an unprecedentedly large multicentric retrospective study (2000 cases) and validated against biomechanical ex vivo experiments (120 specimens). Conclusion. The METASTRA decision support system is tested in a multicentric prospective observational study (200 patients). The METASTRA approach is expected to cut down the indeterminate diagnoses from the current 60% down to 20% of cases. METASTRA project funded by the European Union, HEU topic HLTH-2022-12-01, grant 101080135

Many factors have been reported to affect the functional survival of OCA transplants, including chondrocyte viability at time of transplantation, rate and extent of allograft bone integration, transplantation techniques, and postoperative rehabilitation protocols and adherence. The objective of this study was to determine the optimal subchondral bone drilling technique by evaluating the effects of hole diameter on the material properties of OCAs while also considering total surface area for potential biologic benefits for cell and vascular ingrowth. Using allograft tissues that would be otherwise discarded in combination with deidentified diagnostic imaging (MRI and CT), a model of a large shell osteochondral allograft was recreated using LS-PrePost and FEBio based on clinically relevant elastic material properties for cortical bone, trabecular bone, cartilage, and hole ingrowth tissue. The 0.8 mesh size model consisted of 4 mm trabecular bone, 4 mm cortical bone, and 3 mm cartilage sections that summed to a cross-sectional area of 1600 mm2 (40 mm x 40 mm). Holes were modeled to be 4mm deep in relation to clinical practice where holes are drilled from the deep margin of subchondral trabecular bone to the cortical subchondral bone plate. To test the biomechanic variations between drill hole sizes, models with hole sizes pertinent to standard-of-care commercially available orthopaedic drill sizes of 1.1mm, 2.4 mm, or 4.0 mm holes were loaded across the top surface over a one second duration and evaluated for effective stress, effective strain, 1st principal strain, and 3rd principal strain in compressive conditions. Results measured effective stress and strain and 1st and 3rd principal strain increased with hole depth. The results of the present FEA modeling study indicate that the larger 4.0 mm diameter holes were associated with greater stresses and strains within OCA shell graft, which may render the allograft at higher risk for mechanical failure. Based on these initial results, the smaller diameter 2.4 mm and 1.1 mm holes will be further investigated to determine optimal number, configuration, and depth of subchondral drilling for OCA preparation for transplantation

Menisci are crucial structures for knee homeostasis: they provide increase of congruence between the articular surfaces of the distal femur and tibial plateau, bear loading, shock absorption, lubrication, and proprioception. After a meniscal lesion, the golden rule, now, is to save as much meniscus as possible: only the meniscus tissue which is identified as unrepairable should be excised and meniscal sutures find more and more indications. Several different methods have been proposed to improve meniscal healing. They include very basic techniques, such as needling, abrasion, trephination and gluing, or more complex methods, such as synovial flaps, meniscal wrapping, or the application of fibrin clots. Basic research of meniscal substitutes has also become very active in the last decades. The features needed for a meniscal scaffold are: promotion of cell migration, it should be biomimetic and biocompatible, it should resist forces applied and transmitted by the knee, it should slowly biodegrade and should be easy to handle and implant. Several materials have been tested, that can be divided into synthetic and biological. The first have the advantage to be manufactured with the desired shapes and sizes and with precise porosity dimension and biomechanical characteristics. To date, the most common polymers are polylactic acid (PGA); poly-(L)-lactic acid (PLLA); poly- (lactic-co-glycolic acid) (PLGA); polyurethane (PU); polyester carbon and polycaprolactone (PCL). The possible complications, more common in synthetic than natural polymers are poor cell adhesion and the possibility of developing a foreign body reaction or aseptic inflammation, leading to alter the joint architecture and consequently to worsen the functional outcomes. The biological materials that have been used over time are the periosteal tissue, the perichondrium, the small intestine submucosa (SIS), acellular porcine meniscal tissue, bacterial cellulose. Although these have a very high biocompatibility, some components are not suitable for tissue engineering as their conformation and mechanical properties cannot be modified. Collagen or proteoglycans are excellent candidates for meniscal engineering, as they maintain a high biocompatibility, they allow for the modification of the porosity texture and size and the adaptation to the patient meniscus shape. On the other hand, they have poor biomechanical characteristics and a more rapid degradation rate, compared to others, which could interfere with the complete replacement by the host tissue. An interesting alternative is represented by hydrogel scaffolds. Their semi-liquid nature allows for the generation of scaffolds with very precise geometries obtained from diagnostic images (i.e. MRI). Promising results have been reported with alginate and polyvinyl alcohol (PVA). Furthermore, hydrogel scaffolds can be enriched with growth factors, platelet-rich plasma (PRP) and Bone Marrow Aspirate Concentrate (BMAC). In recent years, several researchers have developed meniscal scaffolds combining different biomaterials, to optimize the mechanical and biological characteristics of each polymer. For example, biological polymers such as chitosan, collagen and gelatin allow for excellent cellular interactions, on the contrary synthetic polymers guarantee better biomechanical properties and greater reliability in the degradation time. Three-dimensional (3D) printing is a very interesting method for meniscus repair because it allows for a patient-specific customization of the scaffolds. The optimal scaffold should be characterized by many biophysical and biochemical properties as well as bioactivity to ensure an ECM-like microenvironment for cell survival and differentiation and restoration of the anatomical and mechanical properties of the native meniscus. The new technological advances in recent years, such as 3D bioprinting and mesenchymal stem cells management will probably lead to an acceleration in the design, development, and validation of new and effective meniscal substitutes

Among the advanced technology developed and tested for orthopaedic surgery, the Rizzoli (IOR) has a long experience on custom-made design and implant of devices for joint and bone replacements. This follows the recent advancements in additive manufacturing, which now allows to obtain products also in metal alloy by deposition of material layer-by-layer according to a digital model. The process starts from medical image, goes through anatomical modelling, prosthesis design, prototyping, and final production in 3D printers and in case post-production. These devices have demonstrated already to be accurate enough to address properly the specific needs and conditions of the patient and of his/her physician. These guarantee also minimum removal of the tissues, partial replacements, no size related issues, minimal invasiveness, limited instrumentation. The thorough preparation of the treatment results also in a considerable shortening of the surgical and of recovery time. The necessary additional efforts and costs of custom-made implants seem to be well balanced by these advantages and savings, which shall include the lower failures and revision surgery rates. This also allows thoughtful optimization of the component-to-bone interfaces, by advanced lattice structures, with topologies mimicking the trabecular bone, possibly to promote osteointegration and to prevent infection. IOR's experience comprises all sub-disciplines and anatomical areas, here mentioned in historical order. Originally, several systems of Patient-Specific instrumentation have been exploited in total knee and total ankle replacements. A few massive osteoarticular reconstructions in the shank and foot for severe bone fractures were performed, starting from mirroring the contralateral area. Something very similar was performed also for pelvic surgery in the Oncology department, where massive skeletal reconstructions for bone tumours are necessary. To this aim, in addition to the standard anatomical modelling, prosthesis design, technical/technological refinements, and manufacturing, surgical guides for the correct execution of the osteotomies are also designed and 3D printed. Another original experience is about en-block replacement of vertebral bodies for severe bone loss, in particular for tumours. In this project, technological and biological aspects have also been addressed, to enhance osteointegration and to diminish the risk of infection. In our series there is also a case of successful custom reconstruction of the anterior chest wall. Initial experiences are in progress also for shoulder and elbow surgery, in particular for pre-op planning and surgical guide design in complex re-alignment osteotomies for severe bone deformities. Also in complex flat-foot deformities, in preparation of surgical corrections, 3D digital reconstruction and 3D printing in cheap ABS filaments have been valuable, for indication, planning of surgery and patient communication; with special materials mimicking bone strength, these 3D physical models are precious also for training and preparation of the surgery. In Paediatric surgery severe multi planar & multifocal deformities in children are addressed with personalized pre-op planning and custom cutting-guides for the necessary osteotomies, most of which require custom allografts. A number of complex hip revision surgeries have been performed, where 3D reconstruction for possible final solutions with exact implants on the remaining bone were developed. Elective surgery has been addressed as well, in particular the customization of an original total ankle replacement designed at IOR. Also a novel system with a high-tibial-osteotomy, including a custom cutting jig and the fixation plate was tested. An initial experience for the design and test of custom ankle & foot orthotics is also in progress, starting with 3D surface scanning of the shank and foot including the plantar aspect. Clearly, for achieving these results, multi-disciplinary teams have been formed, including physicians, radiologists, bioengineers and technologists, working together for the same goal

Introduction and Objective. Forced external rotation is hypothesized as the key mechanism of syndesmotic ankle injuries. This complex trauma pattern ruptures the syndesmotic ligaments and induces a three-dimensional deviation from the normal distal tibiofibular joint configuration. However, current diagnostic imaging modalities are impeded by a two-dimensional assessment, without taking into account ligamentous stabilizers. Therefore, our aim is two-fold: (1) to construct an articulated statistical shape model of the normal ankle with inclusion of ligamentous morphometry and (2) to apply this model in the assessment of a clinical cohort of patients with syndesmotic ankle injuries. Materials and Methods. Three-dimensional models of the distal tibiofibular joint were analyzed in asymptomatic controls (N= 76; Mean age 63 +/− 19 years), patients with syndesmotic ankle injury (N = 13; Mean age 35 +/− 15 years), and their healthy contralateral equivalent (N = 13). Subsequently, the statistical shape model was generated after aligning all ankles based on the distal tibia. The position of the syndesmotic ligaments was predicted based on previously validated iterative shortest path calculation methodology. Evaluation of the model was described by means of accuracy, compactness and generalization. Canonical Correlation Analysis was performed to assess the influence of syndesmotic lesions on the distal tibiofibular joint congruency. Results. Our presented model contained an accuracy of 0.23 +/− 0.028 mm. Mean prediction accuracy of ligament insertions was 0.53 +/− 12 mm. A statistically significant difference in anterior syndesmotic distance was found between ankles with syndesmotic lesions and healthy controls (95% CI [0.32, 3.29], p = 0.017). There was a significant correlation between presence of syndesmotic injury and the morphological distal tibiofibular configuration (r = 0.873, p <0,001). Conclusions. In this study, we constructed a bony and ligamentous statistical model representing the distal tibiofibular joint Furthermore, the presented model was able to detect an elongation injury of the anterior inferior tibiofibular ligament after traumatic syndesmotic lesions in a clinical patient cohort

Introduction and Objective. Medial Knee Osteoarthritis (MKO) is associated with abnormal knee varism, this resulting in altered locomotion and abnormal loading at tibio-femoral condylar contacts. To prevent end-stage MKO, medial compartment decompression is selectively considered and, when required, executed via High Tibial Osteotomy (HTO). This is expected to restore normal knee alignment, load distribution and locomotion. In biomechanics, HTO efficacy may be investigated by a thorough analysis of the ground reaction forces (GRF), whose orientation with respect to patient-specific knee morphology should reflect knee misalignment. Although multi-instrumental assessments are feasible, a customized combination of medical imaging and gait analysis (GA), including GRF data, rarely is considered. The aim of this study was to report an original methodology merging Computed-Tomography (CT) with GA and GFR data in order to depict a realistic patient-specific representation of the knee loading status during motion before and after HTO. Materials and Methods. 25 MKO-affected patients were selected for HTO. All patients received pre-operative clinical scoring, and radiological/instrumental assessments; so far, these were also executed post-operatively at 6-month follow-up on 7 of these patients. State-of-the-art GA was performed during walking and more demanding motor tasks, like squatting, stair-climbing/descending, and chair-rising/sitting. An 8-camera motion capture system, combined with wireless electromyography, and force platforms for GRF tracking, was used together with an own established protocol. This marker-set was enlarged with 4 additional skin-based non-collinear markers, attached around the tibial-plateau rim. While still wearing these markers, all analyzed patients received full lower-limb X-ray in standing posture a CT scan of the knee in weight-bearing Subsequently, relevant DICOMs were segmented to reconstruct the morphological models of the proximal tibia and the additional reference markers, for a robust anatomical reference frame to be defined on the tibia. These marker trajectories during motion were then registered to the corresponding from CT-based 3D reconstruction. Relevant registration matrices then were used to report GRF data on the reconstructed tibial model. Intersection paths of GRF vectors with respect to the tibial-plateau plane were calculated, together with their centroids. Results. Pre-operative clinical and radiological scoring confirmed MKO and associated abnormal varism. The morphological characterization of GRF was successfully achieved pre- and post- HTO on patient-specific tibial plateau. Pre-operative GFR patterns and peaks, including those related to knee joint moments, were observed medially on the knee, as expected. In post-HTO, these resulted lateralized and much closer to the tibial plateau spine, as desired. In detail, when post- is compared to pre-op, the difference of the centroids were, on average, 54.6±18.1 mm (min÷max: 36.7÷72.8 mm) more lateral during walking and 52.5±28.5 mm (24.7÷87.6 mm) during stair climbing. When reported in % of the tibial plateau width, these values became 69.2±20.1 (46.1÷81.4) and 78.1±30.1 (43.4÷98.0), respectively. Post-op also clinical scores and GA revealed a considerable overall improvement, especially in functional performances. Conclusions. The reported novel approach allows a combination of motion data, including GFR, and tibial-plateau morphology. Relevant pre- and post-operative routine application offer a quantification of the effect of the original deformity and executed joint realignment, and an assistance for surgical planning in case of HTO as well as ideally in other orthopedic treatments

Adductor strain is a common injury among football players. The adductor muscle group contains the three adductor muscles. (adductor longus, magnus and brevis) Adductor longus muscle is a triangular-shaped long muscle. This muscle originates from the superior ramus of the pubic bone and inserted into the middle part of the linea aspera. Adductor longus muscle is the most commonly injured muscle of adductors. Sudden acceleration, jumping, stretching, and kicking the ball are common causes of an adductor injury. Adductor muscle strains can result in missed playing time for football players. We present a 26-year-old man soccer player with pain in the left groin and proximal thigh. The symptoms had started during training and after kicking the ball with left foot (dominant side), he felt an acute pain in the groin region and proximal thigh. Despite the injury, he managed to finish the training. The team physician examined the patient immediately after training. The range of motion of both hip joints was in normal ranges and mild pain with adduction. There was a palpable mass at the inner proximal thigh during contraction of adductor muscles. There was no history of groin pain or adductor problems before this injury. Conventional radiographs showed no osseous abnormalities. 36 hours after the injury, MRI revealed acute grade IIB strain in the left adductor longus muscle, including both superior and inferior parts of the muscle. A hematoma was observed in the superior part of the left adductor muscle, with a craniocaudal length of 42 millimeters. There was an adductor muscle strain with hyperintensity extending for a craniocaudal length of approximately 12 centimeters involving more than 50% crosses sectional diameter of the muscle belly. Conservative treatment started immediately, consisting of cold therapy and soft tissue massage. Compression of the injured tissue using a 15-cm elastic bandage roll is done to limit bleeding and provide support. Iced water machine (Game Ready) was used. The team physician examined the player every day and prescribed physiotherapy protocol daily. Additionally, short interval follow-up MRI is used to evaluate the injury. (After 7 and 14 days of the injury) No injection was performed. The player is able to return to play immediately, despite MRI's strain images. The player started straight running 5 days later and joined to team training 8 days later and played 90 minutes-league-match 12 days after injury without any pain. No injection was performed. The player is able to return to play immediately, despite MRI's strain images. The player started straight running 5 days later and joined to team training 8 days later and played 90 minutes-league-match 12 days after injury without any pain. MRI is a useful technique in diagnosing trauma in football players presenting with groin pain. In this case, to estimate time-to-return-to-play, MRI alone is not strong evidence. MRI is a good option for follow up, but anamnesis and clinical examination is not inferior to diagnostic imaging

Summary. Coagulase-negative staphylococci, including S. epidermidis, have emerged as the leading pathogens of hospital-acquired biomaterial-related infections. These infections can be clinically indolent and challenging also for diagnostic imaging. In the current model of catheter-related infections, . 68. Ga-labeled Siglec-9 PET/CT imaging was able to detect peri-implant S. epidermidis bone infections. Introduction. Coagulase-negative staphylococci, including S. epidermidis, have emerged as the leading pathogen of nosocomial (hospital-acquired) biomaterial-related infections, including periprosthetic infections and intravascular catheter-related bloodstream infections. Pathogenic S. epidermidis strains exhibit robust attachment to implant surfaces and subsequent biofilm formation. By nature, the clinical picture of periprosthetic S. epidermidis infections can be indolent with vague signs of infection. These infections are also highly challenging for diagnostic imaging and microbiologic studies. Our recent experimental study of . 18. F-FDG-PET/CT confirmed that subacute peri-implant S. epidermidis infections, reflecting limited inflammatory reaction, are characterised by low . 18. F-FDG uptake. Vascular adhesion protein-1 (VAP-1) is an inflammation inducible endothelial protein, which controls leukocyte migration to sites of inflammation and infection. Siglec-9 is a leukocyte ligand of VAP-1. We hypothesised that . 68. Ga-labeled Siglec-9, developed for PET imaging of inflammation and cancer, could be a novel tracer also for early defection of S. epidermidis peri-implant bone infections. Material & Methods. Thirty adult male Sprague-Dawley rats were randomised into three groups (n=10/group). A clinical intravenous polymer catheter was introduced into the medullary cavity of the left tibia followed by injections of a clinical isolate of S. epidermidis (T-54580, 3 × 10. 8. CFU/mL) and an adjunct sodium morrhuate. In the positive control group, a clinical isolate of S. aureus (52/52A/80, 3 × 10. 5. CFU/mL) with sodium morrhuate was injected. In the negative control group, equal amount of sterile saline was injected via the catheter. The catheter, cut at the level of tibial tuberosity, was left in situ to serve as the implant. Two weeks after surgery, PET imaging with . 68. Ga-DOTA-Siglec-9 was performed with quantitative analysis of the standardised uptake value (SUV) in the region of interests both in vivo and ex vivo. SUV ratio between the operated and contralateral intact tibia was calculated. The presence of infections and the absence of contamination in the negative control group were verified by separate microbiological analyses of bone samples and retrieved implants. The presence of microbial biofilms on catheters was verified ex vivo with fluorescence microscope. Histologic inflammatory reaction was graded using a scoring system. Intergroup differences were tested by means of ANOVA with a post-hoc test. Results. Both staphylococcal strains caused histologically acute osteomyelitic changes. In . 68. Ga-DOTA-Siglec-9 PET/CT imaging of the negative control group, there was a significant difference (29.5%, p<0.001) in the SUV ratio of the operated and contralateral tibia, demonstrating aseptic inflammatory reaction to catheter implantation. The corresponding SUV ratio values were 58.1% in the S. epidermidis group and 41.7% in the S. aureus group. The uptake in the S. epidermidis group was significantly (p=0.009) higher than in the negative control group. Discussion/Conclusion. The animal model was reproducible in creation of culture-positive biomaterial-related infections. . 68. Ga-labeled Siglec-9 PET/CT imaging was able to demonstrate aseptic inflammation in the negative control group and the tracer also detected peri-implant bone infections caused by S. epidermidis

Introduction. Aseptic loosening of the acetabular cup in total hip replacement (THR) remains a major problem. Current diagnostic imaging techniques are ineffective at detecting early loosening, especially for the acetabular component. The aim of this preliminary study was to assess the viability of using a vibration analysis technique to accurately detect acetabular component loosening. Methods. A simplified acetabular model was constructed using a Sawbones foam block into which an acetabular cup was fitted. Different levels of loosening were simulated by the interposition of thin layer of silicon between the acetabular component and the Sawbones block. This included a simulation of a secure (stable) fixation and various combinations of cup zone loosening. A constant amplitude sinusoidal excitation with a sweep range of 100–1500 Hz was used. Output vibration from the model was measured using an accelerometer and an ultrasound probe. Loosening was determined from output signal features such as the number and relative strength of the observed harmonic frequencies. Results. Both measurement methods were capable of measuring the output vibration. Preliminary findings show different patterns in the output signal spectra were visible when comparing the stable cup with the 1mm of simulated spherical loosening at driving frequencies 1050 Hz, 1100 Hz and 1150 Hz (p < 0.05) using the accelerometer, whereas for ultrasound at frequencies 950 Hz and 1350 Hz (p < 0.05). Conclusions. Experimental testing showed that vibration analysis could be used as a potential detection method for acetabular cup component loosening using either an accelerometer or ultrasound probe to detect the vibration. However, the capacity of ultrasound to overcome the attenuating effect of the surrounding soft tissues and its high signal to noise ratio suggest it has the best potential for clinical use

Background. The anterior-posterior (AP) pelvis radiograph is crucial for diagnosis of neck of femur (NOF) fractures, especially as this is one of the commonest fractures in the elderly population. Anecdotally we found that initial AP pelvis radiographs for these suspected fractures did not always exhibit the bones sufficiently. Repeat radiographs were needed, leading to delays in diagnosis, treatment, and repeated radiation exposure. Missed diagnoses can have significant consequences for this patient group. We assessed how many initial AP pelvis radiographs taken for suspected NOF fracture fitted criteria for adequate diagnostic imaging. Methods. A retrospective study was carried out assessing the initial AP pelvis radiograph done for each patient presenting to our dedicated NOF unit with suspected NOF fracture for 1st June – 31st July 2014. European Guidelines for Diagnostic Imaging were used as the benchmark. Each radiograph was scored out of six, one for each criteria fulfilled. Guidelines deemed images scoring ≤3 as inadequate. Results. 76 images were assessed with mean patient age 85 years. 51.3% of images scored ≤3 and mean score was 3.59. The least-met criterion was “sharp reproduction of sacrum and vertebral foramina” (26.3%). Crucially only 52.6% achieved “visually sharp reproduction of spongiosa, trochanters and corticalis of both femurs”, important in diagnosis of NOF fractures. Conclusion. More than half initial AP pelvis radiographs taken for suspected NOF fracture were inadequate based on European Guidelines at a dedicated NOF unit. Part of the difficulty can be attributed to challenging patient demographics, however adequate initial radiographs should be aimed for, as repeat radiographs can lead to delays in diagnosis and treatment as well as repeated radiation exposure. Missed diagnoses can have significant consequences for this patient group; we particularly recommend care to be taken to sharply visualise the trochanters and proximal femora to avoid missing subtle fractures

Total Shoulder Arthroplasty (TSA) is a solution to fixing shoulder complications and restoring normal shoulder functionality. Shoulder arthritis is one of the common indicators of TSA. Studies suggest that 15% and 7% of the total Rheumatoid Arthritis (RA) and Osteoarthritis (OA) patients respectively, in sub-Saharan Africa, have degenerated shoulders. These patients are implanted with a Total Shoulder Prosthesis (TSP). There are limited literature available on the morphometric features of African shoulders. Previous studies have indicated that differences in shoulder surface geometry of the European and African populations, exists. This study aims at identifying the structural differences of the humeral articulating surfaces between South African and Swiss data sets. The South African data set included the Computerised Tomography (CT) scans of cadavers sourced from the University of Cape Town and the Swiss data set included the cadaver CT scans obtained from the SICAS Medical Image Repository. Sixty reconstructed models of humerus were generated from these scans of 30 (bilateral) healthy cadavers (15 South African and 15 Swiss) using Mimics®. The humeral articulating surfaces were separated from the shaft by performing in-silico surgery using SOLIDWORKS®, according to the guidelines provided orthopaedic surgeons. A Matlab code was generated to determine the superior-inferior (S-I) and the anterior-posterior (A-P) circular diameter and the peak points (PPs) of the articulating surfaces. The PPs were defined as the highest point on the articulating surface, which is most likely to be in contact with the glenoid. The S-I diameter was found to be significantly greater (p<0.01) than the A-P diameter for both the data sets (average difference = 5.02mm). Both the average A-P and S-I diameter for the Swiss data set were significantly larger (p = 0.02 and p = 0.03) than the South African data set by 2.36 mm and 2.70 mm respectively. The PPs were found to lie at an off-set from the origin. in case of the Swiss data set the average PP lie on the superior-posterior (S-P) quadrant and for the South African data set the average PP was found to lie on the anterior-inferior (A-I) quadrant. The A-P variation on the position of PP was highly significant (p = 0.003). The results obtained in this study sheds light on the observed morphological variations between the South African and Swiss data sets. The observed circular diameter values are similar to the literature. The observed results suggest that the average TSP needed for the Swiss data set would have been larger than the ones needed for the South African data set. PP is a novel feature which has not been studied extensively. The fact that the average Swiss data set PP lie in the S-P quadrant might suggest that these humeral heads are more retroverted and superiorly tilted when compared to the South African data set. These morphometric variations can play a major role in post-TSA kinematics. The future scope of this study is to highlight other morphometric variations, if any, for the gleno-humeral articulating surfaces

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

Purpose and background. Whether to order an MRI scan or not for patients with low back and leg pain (LBP). Resources are limited. Waiting for diagnostic imaging impacts time to treatment and may be critical to the “18 week target”. We have looked into devising a system in which we can ordered MRI scans for patients with LBP pre-clinical assessment based on questionnaire and accessing their referral letter. Methods and results. 49 patient's referrals were looked into (randomly picked). 23 had a questionnaire filled by either themselves or their GPs. the rests had MRI scans ordered based on their referral letters. MRI scans were requested pre-clinical assessment for patients with symptoms spreading beyond their knees and willing to consider interventional treatments (injections or operations). We considered MRI positive if the report mentioned stenosis or disc prolapse causing nerve root or cauda compression. 7 out of the 23 fitted the criteria for MRI. 6 (85%) of them had positive results. 26 of the GP referrals letters had MRI out of those 16 (61%) had positive results. In total out of 33 MRI, 22 (66.7%) were positive. Conclusion. Our study showed that pre-clinic MRI scanning for patients with LBP is an effective method to find surgically treatable pathology. Using the questionnaire was more advantageous than the referral letter in order to identify patients who would benefit from pre-clinic MRI scanning. With the small numbers this is not statistically significant. We propose that rather than a blanket scanning, it would be reasonable to scan patients based on their referral letter. No Conflict of interest. No funding obtained. This abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting

Summary Statement. Computational models are the primary tools for efficient design-phase exploration of knee replacement concepts before in vitro testing. To improve design-phase efficiency, a subject-specific computational platform was developed that allows designers to assess devices in realistic conditions by directly integrating subject-specific experimental data in these models. Introduction. Early in the design-phase of new implant design, numerous in vitro tests would be desirable to assess the influence of design parameters or component alignment on the performance of the device. However, cadaveric testing of knee replacement devices is a costly and time-consuming procedure, requiring manufacture of parts, preparation of cadaveric specimens, and personnel to carry of the experiments. Validated computational models are ideally suited for pre-clinical, high-volume design evaluation. Initial development of these models requires substantial time and expertise; once developed, however, computational simulations may be applied for comparative evaluation of devices in an extremely efficient manner [Baldwin et al. 2012]. Still, computational models are complementary of experimental testing and for this reason, computational models tuned with subject-specific experimental data, e.g. soft tissue parameters, could bring even more efficiency in the design phase. The objective of the current study was to develop a platform of tools that easily allows for subject-specific knee simulations. The system integrates with commercially available medical imaging and finite element software to allow for direct, efficient comparison of designs and surgical alignment under a host of different boundary conditions. Patients & Methods. MRI image was acquired, and 3D bone models were generated using the Mimics Innovation Suite® (Materialise NV, Leuven, Belgium). The two models (1) tibiofemoral (TF) joint laxity including ligamentous constraint and (2) whole joint (TF and patellofemoral (PF)) mechanics during dynamic activities of daily living (e.g. gait, squat, chair-rise), developed in Abaqus/Explicit (SIMULIA, Providence, RI), were then be adapted with integrated subject-specific attachment sites. Results. The suite of tools provides a platform for baseline evaluation of design factors, comparison of new implant designs with predicate devices, and assessment of robustness to surgical alignment. This platform is currently capable of taking into account subject-specific factors in order to provide realistic results in relation with experimental data. Implant material properties, ligament properties and initial conditions can be varied, and results compared, to evaluate the influence of a host of design and surgical factors on implant performance. The interface allows users without complex finite element expertise to setup, analyze and compare devices and interpret results. Discussion/Conclusion. A platform which allows implant designers to evaluate their design ideas in realistic conditions integrating subject-specific parameters and to compare with predicate devices has the potential to substantially decrease the development time for new devices. Designers can perform iterative modification to their devices to focus on an optimal design solution prior to in vitro testing, reducing the number of pre-clinical cadaveric experiments that may be required, and ultimately improving TKR mechanics in the patient population

Summary Statement. The current study introduced the effects of projection errors on ankle morphological measurements using CT-based simulated radiographs by correlation analysis between 2D/3D dimensions and reliability analysis with randomised perturbations while measuring planar parameters on radiographs. Introduction. Clinical success of total ankle arthroplasty (TAA) depends heavily on the available anatomy-based information of the morphology for using implants of precisely matched sizes. Among the clinically available medical imaging modalities, bi-planar projective radiographs are commonly used for this purpose owing to their convenience, low cost, and low radiation dose compared with other modalities such as MRI or CT. However, the intrinsic articular surface of the ankle joint is not symmetrical and oblique which implies that it is difficult to describe all the anatomical dimensions in detail with only one radiograph, thereby hindering the determination of accurate ankle morphometric parameters. The purposes of this study were to compare the measurements of ankle morphology using 3D CT images with those on planar 2D images; and to quantify the repeatability of the 2D measurements under simulated random perturbations. Patients & Methods. Fifty-eight fresh frozen cadaveric ankle specimens were used in the current study. Each specimen was fixed in the neutral position with a plastic frame. After fixation, the specimen-fixation construct was scanned using a 16-slice spiral CT scanner (GE BrightSpeed 16, C&G Technologies, USA) with a slice thickness of 0.625 mm. A global coordinate system was embedded in the ankle specimen with the origin at the geometric center of the talus, the anteroposterior (A/P) axis in parallel to the base-plate, the superoinferior (S/I) axis perpendicular to the base-plate, and the mediolateral (M/L) axis as the line perpendicular to both the A/P and S/I axes. Fourteen 3D morphological parameters were automatically determined using a house-developed program in MATLAB R2010a (The MathWorks, Inc., USA). A simulated standard digital radiography system, in which the X-ray focus was 1 meter away from the image plane, was also introduced to determine the planar 2D morphological parameters for comparing with those determined in 3D. Reliability with randomised perturbations during measurements was also assessed in terms of the intra-class correlation coefficients using a 2-way mixed-effects average model (ICC3, k) for intra-examiner assessments. All statistical analysis was performed using SPSS 13.0 (SPSS Inc., USA). Results. Most of the morphological parameters had high correlation and reliability, except for the maximal tibial thickness (MTiTh), distance between most vertex of tibial mortise to the level of MTiTh (MDV) and radius of trochlea tali (TaR) had moderate to low correlation which were 0.54, 0.37 and 0.09 respectively. The ICC coefficients indicated that the MDV, talus width (TaW) and inclination angle between two most vertex points of trochlea tali (MLATa) had moderate and poor reliability which were 0.59, 0.49 and 0.07 respectively. Discussion/Conclusion. The current study introduced the effects of projection errors on ankle morphological measurements using CT-based simulated radiographs by correlation analysis between 2D/3D dimensions and reliability analysis with randomised perturbations while measuring planar parameters on radiographs. MTiTh and MDV are the important parameters to help surgeon pre-surgical decision-making. TaW is one of the critical parameters for choosing accurate sise of TAA implant. It implies that the respectively accurate pose of ankle is critical during bi-planar radiography

Objectives

Mesenchymal stem cells have the ability to differentiate into various cell types, and thus have emerged as promising alternatives to chondrocytes in cell-based cartilage repair methods. The aim of this experimental study was to investigate the effect of bone marrow derived mesenchymal stem cells combined with platelet rich fibrin on osteochondral defect repair and articular cartilage regeneration in a canine model.

We have designed a prospective study to evaluate the usefulness of prolonged incubation of cultures from sonicated orthopaedic implants. During the study period 124 implants from 113 patients were processed (22 osteosynthetic implants, 46 hip prostheses, 54 knee prostheses, and two shoulder prostheses). Of these, 70 patients had clinical infection; 32 had received antibiotics at least seven days before removal of the implant. A total of 54 patients had sonicated samples that produced positive cultures (including four patients without infection). All of them were positive in the first seven days of incubation. No differences were found regarding previous antibiotic treatment when analysing colony counts or days of incubation in the case of a positive result. In our experience, extending incubation of the samples to 14 days does not add more positive results for sonicated orthopaedic implants (hip and knee prosthesis and osteosynthesis implants) compared with a conventional seven-day incubation period.

Cite this article: Bone Joint J 2013;95-B:1001–6.