Background. Hip fractures affect 1.6 million people globally per annum, associated with significant morbidity and mortality. A large proportion are extracapsular neck of femur fractures, treated with the dynamic hip screw (DHS). Mechanical failure due to cut-out is seen in up to 7% of DHS implants. The most important predictor of cut-out is the tip-apex distance (TAD), a numerical value of the lag screw”s position in the femoral head. This distance is determined by the psychomotor skills of the surgeon guided by fluoroscopic imaging in theatre. With the current state of surgical training, it is harder for junior trainees to gain exposure to these operations, resulting in reduced practice. Additionally, methods of simulation using workshop bones do not utilise the imaging component due to the associated radiation risks. We present a digital fluoroscopy software, FluoroSim, a realistic, affordable, and accessible fluoroscopic simulation tool that can be used with workshop bones to simulate the first step of the DHS procedure. Additionally, we present the first round of accuracy tests with this software. Methods. The software was developed at the Royal National Orthopaedic Hospital, London, England. Two orthogonally placed cameras were used to track two coloured markers attached to a DHS guide-wire. Affine transformation matrices were used in both the anterior-posterior (AP) and cross table lateral (CTL) planes to match three points from the camera image of the workshop bone to three points on a pre-loaded hip radiograph. The two centre points of each marker were identified with image processing algorithms and utilised to digitally produce a line representing the guide-wire on the two radiographs. To test the accuracy of the system, the software generated 3D guide-wire apex distance (GAD) (from the tip of the guide-wire to a marker at the centre of calibration) was compared to the same distance measured with a digital calliper (MGAD). In addition, the same accuracy value was determined in a simulation scenario, from 406 attempts by 67 medical students. Results. The median absolute inaccuracy of FluoroSim with 270 measurements was 3.35mm (IQR = [1.15mm, 6.53mm]). The absolute inaccuracy showed a graded increase the further away the tip of the guide-wire was from the centre of calibration; MGAD ≤10mm, median absolute inaccuracy = 1.53mm; MGAD 10mm<x≤20mm, median absolute inaccuracy = 4.97mm; MGAD >20mm, median absolute inaccuracy = 7.23mm. Comparison between all three groups reached significance (p < 0.001). In a simulation scenario with medical students, FluoroSim had a significantly greater median absolute inaccuracy of 4.79mm compared to the testing scenario (p < 0.001). Conclusion. FluoroSim is a safe and inexpensive digital imaging adjunct to workshop bones simulation. To our knowledge this technology has not been explored in the context of DHS simulation, and has the potential to be extended to other orthopaedic procedures

Background. Training within surgery is changing from the traditional Halstedian apprenticeship model. There is need for objective assessment of trainees, especially their technical skills, to ensure they are safe to practice and to highlight areas for development. In addition, due to working time restrictions in both the UK and the US, theatre time is being limited for trainees, reducing their opportunities to learn such technical skills. Simulation is one adjunct to training that can be utilised to both assess trainees objectively, and provide a platform for trainees to develop their skills in a safe and controlled environment. The insertion of a dynamic hip screw (DHS) relies on complex psychomotor skills to obtain an optimal implant position. The tip-apex distance (TAD) is a measurement of this positioning, used to predict failure of the implant. These skills can be obtained away from theatre using workshop bone simulation, however this method does not utilise fluoroscopy due to the associated radiation risks. FluoroSim is a novel digital fluoroscopy simulator that can recreate digital radiographs with workshop bone simulation for the insertion of a DHS guide-wire. In this study, we present the training effect demonstrated on FluoroSim. The null hypothesis states that no difference will be present between users with different amounts of exposure to FluoroSim. Methods. Medical students were recruited from three London universities and randomised into a training (n=23) and a control (n=22) cohort. All participants watched a video explanation of the simulator and task and were blinded to their allocation. Training participants completed 10 attempts in total, 5 attempts in week one, followed by a one week wash out period, followed by 5 attempts in week 2. The control group completed a single attempt each week. For each attempt, 5 metrics were recorded; TAD, procedural time, number of radiographs, number of guide-wire retires and cut-out rate (COR). Results. No significant difference was present for any metric between the groups at baseline; randomisation had produced heterogeneous groups minimising selection bias. Intragroup training effect (comparison of initial and last attempt) was significant for all metrics in the training group (p < 0.05) but for no metrics in the control group. The intergroup training effect (comparison of training group attempt ten to control group attempt ten) was present for procedural time, number of radiographs and number of guide-wire retries (p < 0.05). Significance was not reached for TAD and COR. Conclusion. FluoroSim shows skill acquisition with repeat exposure, so the null hypothesis can be rejected. This study has demonstrated the merits of FluoroSim as a training adjunct for psychomotor skill development in a DHS setting

INTRODUCTION. Useful feedback from a Total Knee Replacement (TKR) can be obtained from post-surgery in-vivo assessments. Dynamic Fluoroscopy and 3D model registration using the method of Banks and Hodge (1996) [1] can be used to measure TKR kinematics to within 1° of rotation and 0.5mm of translation, determine tibio-femoral contact locations and centre of rotation. This procedure also provides an accurate way of quantifying natural knee kinematics and involves registering 3D implant or bone models to a series of 2D fluoroscopic images of a dynamic movement. AIM. The aim of this study was to implement a methodology employing the registration methods of Banks and Hodge (1996) [1] to assess the function of different TKR design types and gain a greater understanding of non-pathological (NP) knee biomechanics. METHODS. Knee function was assessed for five subjects with NP knees (4 males and 1 female, 34.8 ± 10.28 years, BMI 25.59 ± 3.35 Kg/m. 2. ) and five subjects 13.2 (± 1.8) months following a TKR (2 males, 3 females, 68 ± 9.86 years, BMI 30 ± 3 Kg/m. 2. ). The TKR types studied included 1 cruciate retaining, 2 cruciate substituting, 1 mobile-bearing (high flex) and 1 medial pivot). Ethical approval was obtained from the South East Wales Local Research Ethics Committee. Each subject's knee was recorded whilst they performed a step up/down task, using dynamic fluoroscopy (Philips). 3D CAD models of each TKR were obtained for the TKR subjects. 3D bone models of the knee, tibia and femur were created for the 5 NP subjects by segmenting MRI scans (3T GE scanner, General Electric Company) using ScanIP (Simpleware, Ltd.). Using the program KneeTrack (S A Banks, USA), each TKR component and bone model was projected onto a series of fluoroscopic images and their 3D pose iteratively adjusted to match the contours on each image. Joint Kinematics were determined from the 3D pose of each 3D model using Cardan/Euler angles [2]. The contact points and centre of rotation of each TKR were also computed. RESULTS. The mean range of motion (ROM) in the sagittal plane was 61° for the NP cohort and 64° for the TKR cohort. The mean frontal plane ROM was 4° for NP knees and 3° for TKR. A greater axial ROM was achieved by the mobile-bearing (7.5°) and medial pivot TKR (7.0°), compared to the cruciate retaining (4.4°) and substituting (3.6°). The Medial Pivot TKR rotated around a medial centre of rotation, whereas the centre of rotation was located laterally for the other TKR types. This has also been found in other studies of stair climbing activities [3]. CONCLUSIONS. This study demonstrates how this method can be used to quantify and compare the kinematics, contact locations and centre of rotation for a range of TKR designs and NP knees in-vivo. Initial analyses have identified functional differences associated with different TKR designs

Background. Hip fractures cause significant morbidity and mortality, affecting 70,000 people in the UK each year. The dynamic hip screw (DHS) is used for the osteosynthesis of extracapsular neck of femur fractures, a procedure that requires complex psychomotor skills to achieve optimal lag screw positioning. The tip-apex distance (TAD) is a measure of the position of the lag screw from the apex of the femoral head, and is the most comprehensive predictor of cut-out (failure of the DHS construct). To develop these skills, trainees need exposure to the procedure, however with the European Working Time Directive, this is becoming harder to achieve. Simulation can be used as an adjunct to theatre learning, however it is limited. FluoroSim is a digital fluoroscopy simulator that can be used in conjunction with workshop bones to simulate the first step of the DHS procedure (guide-wire insertion) using image guidance. This study assessed the construct validity of FluoroSim. The null hypothesis stated that there would be no difference in the objective metrics recorded from FluoroSim between users with different exposure to the DHS procedure. Methods. This multicentre study recruited twenty-six orthopaedic doctors. They were categorised into three groups based on the number of DHS procedures they had completed as the primary surgeon (novice <10, intermediate 10≤x<40 and experienced ≥40). Twenty-six participants completed a single DHS guide-wire attempt into a workshop bone using FluoroSim. The TAD, procedural time, number of radiographs, number of guide-wire retires and cut-out rate (COR) were recorded for each attempt. Results. A significant construct effect was seen for TAD and COR between novice and other users (p < 0.05). The intermediate and experienced users were not significantly different for these metrics. For all other metrics, experienced users had the highest score, contrary to expectation. Conclusion. FluoroSim was able to separate novice users from other cohorts for the two clinically significant outcome metrics. We can therefore partially reject the null hypothesis as construct validity was present for TAD and COR. We have demonstrated that FluoroSim has the potential to be a useful adjunct when learning the psychomotor skills needed for the DHS procedure away from theatre

Knee ligament injury is one of the most frequent sport injuries and ligament reconstruction has been used to restore the structural stability of the joint. Cycling exercises have been shown to be safe for anterior cruciate ligament (ACL) reconstruction and are thus often prescribed in the rehabilitation of patients after ligament reconstruction. However, whether it is safe for posterior cruciate ligament (PCL) reconstruction remains unclear. Considering the structural roles of the PCL, backward cycling may be more suitable for rehabilitation in PCL reconstruction. However, no study has documented the differences in the effects on the knee kinematics between forward and backward pedaling. Therefore, the current study aimed to measure and compare the arthrokinematics of the tibiofemoral joint between forward and backward pedaling using a biplane fluoroscope-to- computed tomography (CT) registration method. Eight healthy young adults participated in the current study with informed written consent. Each subject performed forward and backward pedaling with an average resistance of 20 Nm, while the motion of the left knee was monitored simultaneously by a biplane fluoroscope (ALLURA XPER FD, Philips) at 30 fps and a 14-camera stereophotogrammetry system (Vicon, OMG, UK) at 120 Hz. Before the motion experiment, the knee was CT and magnetic resonance scanned, which enabled the reconstruction of the bones and articular cartilage. The bone models were registered to the fluoroscopic images using a volumetric model-based fluoroscopy-to-CT registration method, giving the 3-D poses of the bones. The bone poses were then used to calculate the rigid-body kinematics of the joint and the arthrokinematics of the articular cartilage. In this study, the top dead center of the crank was defined as 0° so forward pedaling sequence would begin from 0° to 360°. Compared with forward pedaling, for crank angles from 0° to 180°, backward pedaling showed significantly more tibial external rotation. Moreover, both the joint center and contact positions in the lateral compartment were more anterior while the contact positions in the medial compartment was more posterior, during backward pedaling. For crank angles from 180° to 360°, the above-observed phenomena were generally reversed, except for the anterior-posterior component of the contact positions in the medial compartment. Forward and backward pedaling displayed significant differences in the internal/external rotations while the rotations in the sagittal and frontal planes were similar. Compared with forward cycling, the greater tibial external rotation for crank angles from 0° to 180° during backward pedaling appeared to be the main reason for the more anterior contact positions in the lateral compartment and more posterior contact positions in the medial compartment. Even though knee angular motions during forward and backward pedaling were largely similar in the sagittal and frontal planes, significant differences existed in the other components with different contact patterns. The current results suggest that different pedaling direction may be used in rehabilitation programs for better treatment outcome in future clinical applications

Total knee replacement (TKR) design aims to restore normal kinematics with emphasis on flexion range. The survivorship of a TKR is dependent on the kinematics in six-degrees-of-freedom (6-DoF). Stepping up, such as stair ascent is a kinematically demanding activity after TKR. The debate about design choice has not yet been informed by 6-DoF in vivo kinematics. This prospective randomised controlled trial (RCT) compared kneeling kinematics in three TKR designs. 68 participants were randomised to receive either cruciate retaining (CR-FB), rotating platform (CR-RP) or posterior stabilised (PS-FB) prostheses. Image quality was sufficient for 49 of these patients to be included in the final analysis following a minimum 1-year follow-up. Patients completed a step-up task while being imaged using single-plane fluoroscopy. Femoral and tibial computer-aided design (CAD) models for each of the TKR designs were registered to the fluoroscopic images using bespoke software OrthoVis to generate six-degree-of-freedom kinematics. Differences in kinematics between designs were compared as a function of flexion. There were no differences in terminal extension between the groups. The CR-FB was further posterior and the CR-RP was more externally rotated at terminal extension compared to the other designs. Furthermore, the CR-FB designs was more posteriorly positioned at each flexion angle compared to both other designs. Additionally, the CR-RP design had more external femoral rotation throughout flexion when compared with both fixed bearing designs. However, there were no differences in total rotation for either step-up or down. Visually, it appears there was substantial variability between participants in each group, indicating unique patient-specific movement patterns. While use of a specific implant design does influence some kinematic parameters, the overall patterns are similar. Furthermore, there is high variability indicating patient-specific kinematic patterns. At a group level, none of these designs appear to provide markedly different step-up kinematic patterns. This is important for patient expectations following surgery. Future work should aim to better understand the unique patient variability

Introduction. A long nail is often recommended for treatment of complex trochanteric fractures but requires longer surgical and fluoroscopy times. A possible solution could be a nail with an appropriate length which can be locked in a minimally invasive manner by the main aiming device. We aimed to determine if such a nail model* offers similar structural stability on biomechanical testing on artificial bone as a standard long nail when used to treat complex trochanteric fractures. Method. An artificial osteoporotic bone model was chosen. As osteosynthesis material two cephalomedullary nails (CMN) were chosen: a superior locking nail (SL-Nail) which can be implanted with a singular targeting device, and a long nail (long-nail) with distal locking using free-hand technique. AO31-A2.2 fractures were simulated in a standardized manner. The insertion of the nail was strictly in accordance with the IFU and surgical manual of the manufacturer. The nail was locked dynamically proximally and statically distally. Axial height of the construct, varus collapse, and rotational deformity directly after nail insertion were simulated. A Universal Testing Machine was used. Measurements were made with a stereo-optic tracking system. Reactive movements were recorded and evaluated in all six degrees of freedom. A comparative analysis provided information about the stability and deformation of the assemblies to be compared. Result. There was a detectable difference in the axial fracture movement resulting in narrowing of the fracture gap. The load displacement was 1.7mm higher for the SL-Nail. There was no difference in varus collapse or rotational deformity between the nail variants. Conclusion. We conclude that there are small differences which are clinically insignificant and that a superior locking nail can safely be used to manage complex trochanteric fractures. *DCN SL nail, SWEMAC, Linköping, Sweden. Funding: no funding

Introduction. In tissue engineering, the establishment of sufficient vascularization is essential for tissue viability and functionality. Inadequate vascularization disrupts nutrients and oxygen supply. Nonetheless, regenerating intricate vascular networks represents a significant challenge. Consequently, research efforts devoted to preserving and regenerating functional vascular networks in engineered tissues are of paramount importance. The present work aims to validate a decellularisation process with preservation of the vascular network and extracellular matrix (ECM) components in fasciocutaneous flaps. Method. Five vascularized fasciocutaneous flaps from cadaveric donors were carefully harvested from the anterolateral thigh (ALT), preserving the main perforator of the fascia lata. The entire ALT flap underwent decellularization by perfusion using a clinically validated chemical protocol. Fluoroscopy and computed tomography (CT) were used to analyze the persistence of the vascular network within the flap, pre- and post-decellularization. Histological analysis, including hematoxylin and eosin staining, and quantitative DNA assessment evaluated decellularization efficacy. Further qualitative (immunohistochemistry, IHC) and quantitative analyses were conducted to assess the preservation of ECM components, such as collagen, glycosaminoglycans, and elastin. Result. On average, the ALT flap maintains 82% of the perfusion area (p = 0.094) post-treatment. Histological analysis confirmed decellularization efficacy and revealed structural rearrangement. Paired analysis revealed a significant decrease in DNA levels (<14.8 ng/mg of dry weight, p****< 0.0001) and well-maintained ECM. IHC indicated the persistence of elastine, collagen IV and laminin. Quantitative analysis confirmed elastin (p = 0.44) and collagen persistence (+74%, p*** = 0.001, albeit with a decrease in matrix glycosaminoglycans (-41%, p*** = 0.01). Conclusion. Decellularization effectively removed cells, while preserving the ECM overall and maintaining some vascular network integrity. Yet, further study is needed to validate these findings, involving microCT examination of the vascular network and its ability to support cell colonization and viability

Increasing incidence of osteoporosis, obesity and an aging population have led to an increase in low energy hip fractures in the elderly. Perceived lower blood loss and lower surgical time, media coverage of minimal invasive surgery and patient expectations unsurprisingly have led to a trend towards intramedullary devices for fixation of extracapsular hip fractures. This is contrary to the Cochrane review of random controlled trials of intramedullary vs extramedullary implants which continues recommends the use of a sliding hip screw (SHS) over other devices. Furthermore, despite published literature of minimally invasive surgery (MIS) of SHS citing benefits such as reduced soft tissue trauma, smaller scar, faster recovery, reduced blood loss, reduced analgesia needs; the uptake of these approaches has been poor. We describe a novel technique one which remains minimally invasive, that not only has a simple learning curve but easily reproducible results. All patients who underwent MIS SHS fixation of extracapsular fractures were included in this study. Technique is shown in Figure 1. We collated data on all intertrochanteric hip fractures that were treated by a single surgeon series during period Jan 2014 to July 2015. Data was collected from electronic patient records and radiographs from Picture Archiving and Communication System (PACS). Surgical time, fluoroscopy time, blood loss, surgical incision length, post-operative transfusion, Tip Apex Distance (TAD) were analyzed. There were 10 patients in this study. All fractures were Orthopaedic Trauma Association (OTA) type A1 or A2. Median surgical time was 36 minutes (25–54). Mean fluoroscopy time was similar to standard incision sliding hip screw fixation. Blood loss estimation with MIS SHS can be undertaken safely and expeditiously for extracapsular hip fractures

Total knee replacements (TKR) have been the main choice of treatment for alleviating pain and restoring physical function in advanced degenerative osteoarthritis of the knee. Recently, there has been a rising interest in minimally invasive surgery TKR (MIS-TKR). However, accurate restoration of the knee axis presents a great challenge. Patient-specific-instrumented TKR (PSI-TKR) was thus developed to address the issue. However, the efficacy of this new approach has yet to be determined. The purpose of the current study was thus to measure and compare the 3D kinematics of the MIS-TKR and PSI-TKR in vivo during sit-to-stand using a 3D fluoroscopy technology. Five patients each with MIS-TKR and PSI-TKR participated in the current study with informed written consent. Each subject performed quiet standing to define their own neutral positions and then sit-to-stand while under the surveillance of a bi-planar fluoroscopy system (ALLURA XPER FD, Philips). For the determination of the 3D TKR kinematics, the computer-aided design (CAD) model of the TKR for each subject was obtained from the manufacturer including femoral and tibial components and the plastic insert. At each image frame, the CAD model was registered to the fluoroscopy image via a validated 2D-to-3D registration method. The CAD model of each prosthesis component was embedded with a coordinate system with the origin at the mid-point of the femoral epicondyles, the z-axis directed to the right, the y-axis directed superiorly, and the x-axis directed anteriorly. From the accurately registered poses of the femoral and tibial components, the angles of the TKR were obtained following a z-x-y cardanic rotation sequence, corresponding to flexion/extension, adduction/abduction and internal/external rotation. During sit-to-stand the patterns and magnitudes of the translations were similar between the MIS-TKR and PSI-TKR groups, with posterior translations ranging from 10–20 mm and proximal translations from 29–31mm. Differences in mediolateral translations existed between the groups but the magnitudes were too small to be clinically significant. For angular kinematics, both groups showed close-to-zero abduction/adduction, but the PSI-TKR group rotated externally from an internally rotated position (10° of internal rotation) to the neutral position, while the MIS-TKR group maintained at an externally rotated position of less than 5° during the movement. During sit-to-stand both groups showed similar patterns and magnitudes in the translations but significant differences in the angular kinematics existed between the groups. While the MIS-TKR group maintained at an externally rotated position during the movement, the PSI-TKR group showed external rotations during knee extension, a pattern similar to the screw home mechanism in a normal knee, which may be related to more accurate restoration of the knee axis in the PSI-TKR group. A close-to-normal angular motion may be beneficial for maintaining a normal articular contact pattern, which is helpful for the endurance of the TKR. The current study was the first attempt to quantify the kinematic differences between PSI and non-PSI MIS. Further studies to include more subjects will be needed to confirm the current findings. More detailed analysis of the contact patterns is also needed

Introduction. Femoral periprosthetic fractures above TKA are commonly treated with retrograde intramedullary nailing (IMN). This study determined if TKA design and liner type affect the minimum knee flexion required for retrograde nailing through a TKA. Methods. Twelve cadaveric specimens were prepared for six single radius (SR) TKAs and six asymmetric medial pivot (MP) TKAs. Trials with 9mm polyethylene liners were tested with cruciate retaining (CR), cruciate substituting (CS) and posterior stabilizing (PS) types. The knee was extended to identify the minimum knee flexion required to allow safe passage of the opening reamer while maintaining an optimal fluoroscopic starting point for retrograde nailing. Furthermore, the angle of axis deviation between the reamer and the femoral shaft was calculated from fluoroscopic images. Results. In all specimens, the reamer entry point was posterior to Blumensaat's line. In the SR TKA, the average flexion required was 70, 71 and 82 degrees for CR, CS and PS respectively. The required flexion in PS was significantly greater than the other designs (p=0.03). In the MP TKA, the average flexion required was 74, 84 and 123 degrees for CR, CS and PS respectively. The required flexion was significantly greater in CS and PS designs (p<0.0001). Femoral component size did not affect the minimum flexion required. Furthermore, the entry reamer required 9.2 (SR) and 12.5 (MP) degrees of posterior axis deviation from the femur. Conclusions. Our study illustrates four novel factors to consider when performing retrograde nailing through TKA. First, significant knee flexion is required to obtain an ideal radiographic starting point when retaining the liner. Second, PS implants require more flexion with both TKA designs. Third, femoral component size does not affect the flexion required. Fourth, there is a consistent posterior axis deviation of the entry reamer from the femoral shaft, explaining the commonly created extension deformity

Objectives. Intra-articular injections of local anaesthetics (LA), glucocorticoids (GC), or hyaluronic acid (HA) are used to treat osteoarthritis (OA). Contrast agents (CA) are needed to prove successful intra-articular injection or aspiration, or to visualize articular structures dynamically during fluoroscopy. Tranexamic acid (TA) is used to control haemostasis and prevent excessive intra-articular bleeding. Despite their common usage, little is known about the cytotoxicity of common drugs injected into joints. Thus, the aim of our study was to investigate the effects of LA, GC, HA, CA, and TA on the viability of primary human chondrocytes and tenocytes in vitro. Methods. Human chondrocytes and tenocytes were cultured in a medium with three different drug dilutions (1:2; 1:10; 1:100). The following drugs were used to investigate cytotoxicity: lidocaine hydrochloride 1%; bupivacaine 0.5%; triamcinolone acetonide; dexamethasone 21-palmitate; TA; iodine contrast media; HA; and distilled water. Normal saline served as a control. After an incubation period of 24 hours, cell numbers and morphology were assessed. Results. Using LA or GC, especially triamcinolone acetonide, a dilution of 1:100 resulted in only a moderate reduction of viability, while a dilution of 1:10 showed significantly fewer cell counts. TA and CA reduced viability significantly at a dilution of 1:2. Higher dilutions did not affect viability. Notably, HA showed no effects of cytotoxicity in all drug dilutions. Conclusion. The toxicity of common intra-articular injectable drugs, assessed by cell viability, is mainly dependent on the dilution of the drug being tested. LA are particularly toxic, whereas HA did not affect cell viability. Cite this article: P. Busse, C. Vater, M. Stiehler, J. Nowotny, P. Kasten, H. Bretschneider, S. B. Goodman, M. Gelinsky, S. Zwingenberger. Cytotoxicity of drugs injected into joints in orthopaedics. Bone Joint Res 2019;8:41–48. DOI: 10.1302/2046-3758.82.BJR-2018-0099.R1

Summary. Bi-plane Image matching method is very useful technique to evaluate the loaded 3D motion of each cervical level. Introduction. Cervical orthoses are commonly used to regulate the motion of cervical spines for conservative treatment of injuries and for post-operative immobilization. Previous studies have reported the efficacy of orthoses for 2D flex-extension or 3D motions of the entire cervical spine. However, the ability of cervical orthoses to reduce motion might be different at each intervertebral level and for different types of motion (flexion-extension, rotation, lateral bending). The effectiveness of immobilizing orthoses at each cervical intervertebral level for 3D motions has not been reported. The purpose of this study is to evaluate the effectiveness of the Philadelphia collar to each level of cervical spines with 3D motion analysis under loading condition. Patients & Methods. Patient Sample: Four asymptomatic volunteer subjects were recruited and provided informed consent. Approval of the experimental design by the institutional review board was obtained. These 4 individuals were without any history of cervical diseases or procedures. The presence of any symptoms, spinal disorders and anatomical abnormalities in fluoroscopic images or CT was a criterion of exclusion from this study. Outcome Measures: To evaluate the efficacy of the Philadelphia collar, ANOVA was used to compare the range of motion with and without collar at the C3/4, C4/5, C5/6 and C6/7 intervertebral levels for each motion. The level of statistical significance was set at p<0.05. When a statistical difference was detected, post hoc Tukey tests were performed. Methods. Three-dimensional models of the C3-C7 vertebrae were developed from CT scans of each subject using commercial software. Two fluoroscopy systems were positioned to acquire orthogonal images of the cervical spine. The subject was seated within the view of the dual fluoroscopic imaging system. Pairs of images were taken in each of 7 positions: neutral posture, maximum flexion and extension, maximum left and right lateral bending, and maximum left and right rotation. The images and 3D vertebral models were imported into biplane 2D-3D registration software, where the vertebral models were projected onto the pair of digitised images and the 3D bone pose was adjusted to match its radiographic projection in each image. Relative motions between each vertebral body were calculated from body-fixed coordinate systems using a flexion-lateral bending-axial rotation Cardan angle sequence. Results. Flexion range was significantly reduced with the collar at each cervical level. Extension range was significantly reduced at the C3/4 level. Rotation and lateral bending were reduced for C3/4, C4/5, C5/6 levels with the collar. Discussion/Conclusion. The Philadelphia Collar significantly reduces cervical motion at C3/4, C4/5 and C5/6 levels in almost all motions (except for extension). At the C6/7 level, this type of collar has limited effectiveness reducing cervical motion. We used 3D radiographic measurements to quantify the effectiveness of the Philadelphia collar for reducing cervical motion. Bi-plane 2D-3D registration method is useful technique to evaluate 3D motion of cervical spines

Intra-operative fluoroscopy in thumb metacarpophalangeal joint arthrodesis has been recommended as a means of achieving optimal alignment more consistently. This is not our current practice. A patient attending dissatisfied with an arthrodesis in excessive flexion performed outwith our unit highlighted the potential for problems, and we therefore elected to review our own outcomes. An evaluation of the alignment achieved in thumb metacarpophalangeal joint arthrodeses, to determine if current outcomes satisfactory or if fluoroscopic assistance should be considered. Radiological review of alignment of thumb metacarpophalangeal joint arthodeses carried out by two Consultant Surgeons with specialist interests in upper limb surgery in a District General hospital. Cases were predominantly identified retrospectively from sequential review of operating lists. The radiological images were, or had been taken, as part of routine follow-up and were not standardised. The alignment was also assessed independently by a junior doctor with no involvement in the patient's surgical treatment and no knowledge of the intended alignment. Recommended positions for arthrodesis have covered a range from 0 to 30 degrees, so for the purposes of analysis that range was considered acceptable. 14 cases had an average fusion position of 18 degrees flexion (range 6 to 30 degrees). 6 underwent concurrent ipsilaterel trapeziectomy. The series achieved satisfactory alignment radiologically without the routine use of intra-operative fluoroscopy

One of the main surgical goals when performing a total knee replacement (TKR) is to ensure the implants are properly aligned and correctly sized; however, understanding the effect of alignment and rotation on the biomechanics of the knee during functional activities is limited. Cardiff University has unique access to a group of local patients who have relatively high frequency of poor alignment, and early failure. This provides a rare insight into how malalignment of TKR's can affect patients from a clinical and biomechanical point of view to determine how to best align a TKR. This study aims to explore relationship clinical surgical measurements of Implant alignment with in-vivo joint kinematics. 28 patient volunteers (with 32 Kinemax (Stryker) TKR's were recruited. Patients undertook single plane video fluoroscopy of the knee during a step-up and step-down task to determine TKR in-vivo kinematics and centre of rotation (COR). Joint Track image registration software (University of Florida, USA) was used to match CAD models of the implant to the x-ray images. Hip-Knee-Ankle (HKA) was measured using long-leg radiographs to determine frontal plane alignment. Posterior tibial slope angle was calculated using radiographs. An independent sample t-test was used to explore differences between neutral (HKA:-2° to 2°), varus (≥2°) and valgus alignment (≤-2°) groups. Other measures were explored across the whole cohort using Pearson's correlations (SPSS V23). There was found to be no statistical difference between groups or correlations for HKA. The exploratory analysis found that tibial slope correlated with Superior/Inferior translation ROM during step up (r=−0.601, p<0.001) and step down (r=−.512, p=0.03) the position of the COR heading towards the lateral (r=−.479, p=0.006) during step down. Initial results suggest no relationship between frontal plane alignment and in-vivo. Exploratory analyses have found other relationships that are worthy of further research and may be important in optimizing function

Bi-cruciate stabilized (BCS) TKA is the prosthesis that aims to substitute bi-cruciate ligament with post-cam engagement. We estimated to describe the in vivo kinematics during deep knee bending in BCS and Cruciate retaining (CR) TKA with the same articular geometry. We analyzed 26 knees who agreed to the current investigation under institutional review board approval. 17 knees were implanted with BCS (Journey ∥BCS, Smith & Nephew. Memphis, US) and 9 knees with CR (Journey∥CR). Each patient was asked to perform deep knee bending under weight-bearing condition. To estimate the spatial position and orientation of the TKA, 2D/3D registration technique with single fluoroscopy was used. We evaluated anteroposterior (AP) translation of the nearest point from femoral component to tibial axial plane for medial and lateral sides, femoral external rotation relative to tibial component and post-cam engagement in BCS. Measurement results were analyzed using Wilcoxon test. Values of P<0.05 were considered statistically significant. Medial AP translation indicated 11.7±5.1% posterior movement in BCS and 4.0±6.6% anterior movement in CR from minimum flexion to 130°. Lateral AP translation indicated 28.9±11.4% posterior movement in BCS and 18.3±6.2% posterior movement in CR from minimum flexion to 130°. Femoral external rotation were observed in both group and the amount of rotation were 5.2°±4.5° in BCS and 8.2°±4.0° in CR. Anterior post-cam engagement was not observed in all cases (76.5%). But medial AP translation in BCS was anteriorly in shallow flexion angles compared to CR. It suggested that anterior post-cam engagement couldn't work in valid

Study Purpose. A preliminary study to compare continuous sagittal plane lumbar inter-vertebral kinematics in 10 healthy volunteers in recumbent and weight bearing configurations using quantitative fluoroscopy. Background. There are no direct in-vivo comparisons between continuous weight bearing and non-weight bearing inter-vertebral kinematics in the same healthy individuals. This information will advance our knowledge of spine mechanics and provide reference values for clinical studies. Methods. Ten male healthy control volunteer subjects aged between 30 and 50 underwent a recumbent bending procedure during fluoroscopy. All participants repeated this in weight bearing. Trunk motion was controlled for range and velocity. Digital image sequences (DICOM) of these movements were captured at 15 fps and analysed using automated frame to frame image registration codes in MATLAB (Mathworks). Inter-vertebral motion characteristics, including inter-vertebral angular range of rotation and attainment rate (Laxity), were calculated. Results. These results are the preliminary output of an ongoing study to create a reference database for normal spine kinematics. Comparisons of the motion patterns within and between participants will be demonstrated along with preliminary statistical analysis of range of motion and speed of attainment (laxity) of the angular range within the first 10° of trunk motion after the inter-vertebral motion starts. Laxity is proposed as a new in vivo proxy for the neutral zone where force is replaced by trunk motion near the neutral position. Conclusion. These preliminary comparisons demonstrate the feasibility of establishing a reference database of lumbar spine kinematics to which patient populations can be compared, potentially allowing these to emerge as outcome measures. No conflicts of interest. Sources of funding: PhD studentship: School of Design Engineering and Computing, Bournemouth University. This abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting

Summary. Practitioners should maintain a high suspicion of concurrent carpal fractures in patients who present with a distal radius fracture after a fall onto an outstretched hand, particularly if forearm rotation is involved. Introduction. Simultaneous scaphoid and distal radius fractures, and the importance of their identification, have been previously described in multiple reports. However, few studies have investigated the incidence of carpal fractures, in general, occurring concurrently with distal radius fractures after a common mechanism of wrist injury. The purpose of this study is to investigate the incidence and characteristics of carpal fractures occurring simultaneously with distal radius fractures after a fall onto an outstretched hand. We hope to determine whether different fall parameters, such as hand position and forearm rotation, influence the frequency of this injury. Methods. Baseline MRI scans and fluoroscopic images of the wrist were obtained for two sets of 24 fresh frozen cadaveric arms. All of the arms were transected 18 cm proximal to Lister's tubercle and then mounted at 80° of wrist extension and full pronation. In the first set of 24 arms, eight were mounted perpendicular to the MTS table top, eight were radially deviated 10–15°, and eight were ulnarly deviated 10–15°. In the second set of 24 arms, twelve underwent 5 N-m of external forearm rotation, with six of the arms perpendicular to the MTS table top and the other six ulnarly deviated 10–15°. The last twelve arms underwent 5 N-m of internal forearm rotation, with six of the arms perpendicular to the MTS table top and the other six radially deviated 10–15°. The arms were then loaded on an MTS machine and axially displaced 2.5 cm at a compression rate of 5 cm/sec. Post injury fluoroscopic images and MRI scans of the wrist were obtained and analyzed. The MRI scans were scrutinised by one of us (EAO) – a board certified orthopaedic surgeon. Results. All of the arms sustained a distal radius fracture. Post-stress MRI revealed that 17 (35%) of the wrists also sustained at least one carpal bone fracture. The most common carpal bone injured was the scaphoid, which was fractured in 15 of the 17 arms with concurrent carpal fractures, or 31% of the arms overall. Moreover, lunate fractures were present in 6 of the wrists, triquetral fractures in 4 of the wrists, capitate fractures in 3 of the wrists, and one hamate fracture was present. Of the 17 arms with concurrent fractures, 15 had been subjected to a rotational force during MTS testing. Discussion. The incidence of carpal fractures occurring simultaneously with distal radius fractures after a fall onto an outstretched hand comprised a substantial proportion of the arms examined. While the type of carpal fracture does not appear to correlate with a specific hand position, it is evident that forearm rotation is more likely to result in concomitant injury. Early wrist motion—now the standard of care—after immobilization of a patient with a distal radius fracture may result in non-union if a missed carpal fracture is also present

Summary. Increased lateral ulnotrochlear joint space due to improper sizing in radial head arthroplasty may result in medial collateral ligament laxity, leading to increased osteophytes and arthritis. Introduction. Radial head (RH) arthroplasty is a common response to comminuted RH fractures. Typical complications include improper sizing, leading to changes in joint kinematics. Evidence of these changes should be visible through fluoroscopic images of affected joints. The two examined changes in this study are the ulnar deviation from distal radial translation (DRT), and the widening of the lateral ulnotrochlear joint space (LUT). Methods. Eight fresh-frozen cadaver arms were used. Initial images were taken with the native RH intact. The Kocher approach exposed the radiocapitellar (RC) joint capsule, preserving all ligaments. The RH was excised and Integra Katalyst CoCr (Plainsboro, NJ) telescoping, bipolar, RH inserted. Images were taken with implant sizings: −2mm, 0mm, +2mm, and +4mm, (from native) using 1mm washers preventing implant bipolarity. AP fluoroscopic images of the elbow were taken at full extension. Joint spaces were measured using image analysis, normalised using known radio-opaque lengths. Four LUT measurements were made, two medially and two laterally, and normalised by measuring the RH implant diameter. Each set (medial and lateral) were averaged together and the resulting value used for all comparisons. Images of distal ulnar deviation at the wrist were taken with the wrist in supination, the hand rotated medially. Measurements were from the distal medial radial tip to the distal lateral ulnar tip. Images were normalised by placing a scalpel in the same plane as measurement. Results. DRT values were difference paired for each arm using the 0mm values as baselines. One-way ANOVA of the paired values resulted in significant DT with sizing increases (p<0.01). The quotient of DRT and sizing determined comparative impact with the LUT increase. LUT joint gap measurements were percentage paired, with natives as the baseline, and One-way ANOVA used. A significant increase in LUT spacing occurred with increased sizings (p<0.01). Discussion. Increased ulnar deviation can increase loading on the TFCC, leading to possible TFCC tear, increased articular cartilage wear from carpal misalignment, and eventual wrist instability and arthritis. The percentage of the radial lengthening is represented in DRT. Over-sizing results in small percentages of increased radial length at the wrist, therefore deviation at the elbow must take place, either through rotation of the ulna, or translation. Either of these can be seen through LUT measurements. Previous measurements of the LUT space were made by Frank (2009), with similar results. This was being used as a method of improper sizing detection using radiographs. The percentage difference of LUT space for corresponding sizing: there is an increase in LUT space for every sizing; maybe due to loosening of the soft tissue from arthroplasty. Increased LUT space indicates the medial translation of proximal ulna. This can result in Medial Collateral Ligament laxity, leading to increased osteophytes, and arthritis. Use and non-treatment, can create a chronic, painful, disorder

Intra-articular punctures and injections are performed routinely on patients with injuries to and chronic diseases of joints, to release an effusion or haemarthrosis, or to inject drugs. The purpose of this study was to investigate the accuracy of placement of the needle during this procedure. A total of 76 cadaver acromioclavicular joints were injected with a solution containing methyl blue and subsequently dissected to distinguish intra- from peri-articular injection. In order to assess the importance of experience in achieving accurate placement, half of the injections were performed by an inexperienced resident and half by a skilled specialist. The specialist injected a further 20 cadaver acromioclavicular joints with the aid of an image intensifier. The overall frequency of peri-articular injection was much higher than expected at 43% (33 of 76) overall, with 42% (16 of 38) by the specialist and 45% (17 of 38) by the resident. The specialist entered the joint in all 20 cases when using the image intensifier. Correct positioning of the needle in the joint should be facilitated by fluoroscopy, thereby guaranteeing an intra-articular injection