Abstract. Objectives. The syndesmosis joint, located between the tibia and fibula, is critical to maintaining the stability and function of the ankle joint. Damage to the ligaments that support this joint can lead to ankle instability, chronic pain, and a range of other debilitating conditions. Understanding the kinematics of a healthy joint is critical to better quantify the effects of instability and pathology. However, measuring this movement is challenging due to the anatomical structure of the syndesmosis joint. Biplane Video Xray (BVX) combined with Magnetic Resonance Imaging (MRI) allows direct measurement of the bones but the accuracy of this technique is unknown. The primary objective is to quantify this accuracy for measuring tibia and fibula bone poses by comparing with a gold standard implanted bead method. Methods. Written informed consent was given by one participant who had five tantalum beads implanted into their distal tibia and three into their distal fibula from a previous study. Three-dimensional (3D) models of the tibia and fibula were segmented (Simpleware Scan IP, Synopsis) from an MRI scan (Magnetom 3T Prisma, Siemens). The beads were segmented from a previous CT and co-registered with the MRI bone models to calculate their positions. BVX (125 FPS, 1.25ms pulse width) was recorded whilst the participant performed level gait across a raised platform. The beads were tracked, and the bone position of the tibia and fibula were calculated at each frame (DSX Suite, C-Motion Inc.). The beads were digitally removed from the X-rays (MATLAB, MathWorks) allowing for blinded image-registration of the MRI models to the radiographs. The mean difference and standard deviation (STD) between bead-generated and image-registered bone poses were calculated for all degrees of freedom (DOF) for both bones. Results. The absolute mean tibia and fibula bone position differences (Table 1) between the bead and BVX poses were found to be less than 0.5 mm for both bones. The bone rotation differences were found to be less than 1° for all axes except for the fibula Z axis rotation which was found to be 1.46°. One study. 1. has reported the kinematics of the syndesmosis joint and reported maximum ranges of motion of 9.3°and translations of 3.3mm for the fibula. The results show that the accuracy of the methodology is sufficient to quantify these small movements. Conclusions. BVX combined with MRI can be used to accurately measure the syndesmosis joint. Future work will look at quantifying the accuracy of the talus to provide further understanding of normal ankle kinematics and to quantify the kinematics across a healthy population to act as a comparator for future patient studies. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

The National Hip Fracture Database (NHFD) is a clinically led web based audit used to inform national policy guidelines. The aim of this audit was to establish the accuracy of completion of NHFD v13.0 theatre collection sheets, identify common pitfalls and areas of good practice, whilst raising awareness of the importance of accuracy of this data and the manner in which it reflects performance of CAH Trauma & Orthopaedic unit in relation to national guidelines. Our aim was to improve completion up to >80% by the operating surgeon and improve overall accuracy. The methodology within both cycles of the audit were identical. It involved reviewing the NHFD V13.0 completed by the operating surgeon and cross-checking their accuracy against clinical notes, operation notes, imaging, anaesthetic charts and A&E admission assessment. Following completion of cycle 1 these results were presented, and education surrounding V13.0 was provided, at the monthly trust audit meeting. At this point we introduced a sticker onto the pre-operative checklist for Hip fractures. This included time of admission and reason for delay. We then completed a re-audit. Cycle-1 included 25 operations, 56% (n=14) had a completed V13.0 form. Of these 21% (n=3) were deemed to be 100% accurate. Cycle-2 included 31 operations (between April – June 21) 81% (n=25) had a completed intra-operative from and showed an increase in accuracy to 56% (n=14). Through raising awareness, education and our interventions we have seen a significant improvement in the completion and accuracy of v13.0. Although 100% accuracy was not achieved its clear that education and intervention will improve compliance over time. Through the interventions that we have implemented we have shown that it is possible to improve completion and accuracy of the NHFD V13.0 theatre collection sheet locally and feel this could be implemented nationally

Currently implemented accuracy metrics in open-source libraries for segmentation by supervised machine learning are typically one-dimensional scores [1]. While extremely relevant to evaluate applicability in clinics, anatomical location of segmentation errors is often neglected. This study aims to include the three-dimensional (3D) spatial information in the development of a novel framework for segmentation accuracy evaluation and comparison between different methods. Predicted and ground truth (manually segmented) segmentation masks are meshed into 3D surfaces. A template mesh of the same anatomical structure is then registered to all ground truth 3D surfaces. This ensures all surface points on the ground truth meshes to be in the same anatomically homologous order. Next, point-wise surface deviations between the registered ground truth mesh and the meshed segmentation prediction are calculated and allow for color plotting of point-wise descriptive statistics. Statistical parametric mapping includes point-wise false discovery rate (FDR) adjusted p-values (also referred to as q-values). The framework reads volumetric image data containing the segmentation masks of both ground truth and segmentation prediction. 3D color plots containing descriptive statistics (mean absolute value, maximal value,…) on point-wise segmentation errors are rendered. As an example, we compared segmentation results of nnUNet [2], UNet++ [3] and UNETR [4] by visualizing the mean absolute error (surface deviation from ground truth) as a color plot on the 3D model of bone and cartilage of the mean distal femur. A novel framework to evaluate segmentation accuracy is presented. Output includes anatomical information on the segmentation errors, as well as point-wise comparative statistics on different segmentation algorithms. Clearly, this allows for a better informed decision-making process when selecting the best algorithm for a specific clinical application

The use of intraoperative navigation and robotic surgery for minimally invasive lumbar fusion has been increasing over the past decade. The aim of this study is to evaluate postoperative clinical outcomes, intraoperative parameters, and accuracy of pedicle screw insertion guided by intraoperative navigation in patients undergoing lumbar interbody fusion for spondylolisthesis. Patients who underwent posterior lumbar fusion interbody using intraoperative 3D navigation since December 2021 were included. Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), and Short Form Health Survey-36 (SF-36) were assessed preoperatively and postoperatively at 1, 3, and 6 months. Screw placement accuracy, measured by Gertzbein and Robbins classification, and facet joint infringement, measured by Yson classification, were assessed by intraoperative Cone Beam CT scans performed at the end of instrumentation. Finally, operation time, intraoperative blood loss, hospital stay, and screw insertion time were evaluated. This study involved 50 patients with a mean age of 63.7 years. VAS decreased from 65.8±23 to 20±22 (p<.01). ODI decreased from 35.4%±15 to 11.8%±14 (p<.01). An increase of SF-36 from 51.5±14 to 76±13 (p<.01) was demonstrated. The accuracy of “perfect” and “clinically acceptable” pedicle screw fixation was 89.5% and 98.4%, respectively. Regarding facet violation, 96.8% of the screws were at grade 0. Finally, the average screw insertion time was 4.3±2 min, hospital stay was 4.2±0.8 days, operation time was 205±53 min, and blood loss was 169±107 ml. Finally, a statistically significant correlation of operation time with hospital stay, blood loss and placement time per screw was found. We demonstrated excellent results for accuracy of pedicle screw fixation and violation of facet joints. VAS, ODI and SF-36 showed statistically significant improvements from the control at one month after surgery. Navigation with intraoperative 3D images represents an effective system to improve operative performance in the surgical treatment of spondylolisthesis

Introduction. Acetabular component orientation is an important determinant of outcome following total hip arthroplasty (THA). Although surgeons aim to achieve optimal cup orientation, many studies demonstrate their inability to consistently achieve this. Factors that contribute are pelvic orientation and the surgeon's ability to correctly orient the cup at implantation. The goal of this study was to determine the accuracy with which surgeons can achieve cup orientation angles. Methods. In this in vitro study using a calibrated left and right sawbone hemipelvis model, participants (n=10) were asked to place a cup mounted on its introducer giving different targets. Measurements of cup orientation were made using a stereophotogrammetry protocol to measure radiographic inclination and operative anteversion (OA). A digital inclinometer was used to measure the intra-operative inclination (IOI) which is the angle of the cup introducer relative to the floor. First, the participant stated his or her preferred IOI and OA and positioned the cup accordingly. Second, the participant had to position the cup parallel to the anteversion of the transverse acetabular ligament (TAL). Third, the participant had to position the cup at IOI angles of 35°, 40° and 45°. Fourth, the participant used the mechanical alignment guide (45° of IOI and 30° of OA) to orient the cup. Each task was analysed separately and subgroup analysis included left versus right side and hip surgeons versus non-hip surgeons. Results. For the first task, hip surgeons preferred smaller IOI and larger OA than non-hip surgeons, but there was no significant difference in accuracy between both groups. When aiming for TAL, both surgeon groups performed similar, but accuracy on the non-dominant side was significantly better compared with the dominant side (mean deviation 0.6° SD 2.4 versus −2.6° SD 2.3) (p=0.004). When aiming for a specific IOI target of 35°, 40° or 45°, non-hip surgeons outperformed hip surgeons (mean deviation form target IOI 1.9° SD 2.7 versus −3.1° SD 3.8) (p<0.0001) with less variance (p=0.03). Contrary to version, accuracy on the dominant side was significantly better compared with the non-dominant side (mean deviation −0.4° SD 3.4 versus −2.1° SD 4.8). When using a mechanical guide, surgeons performed similar (0.6° SD 1.2 versus −0.4° SD 2.1 for inclination p=0.11 and −0.5° SD 2.6 versus −1.8° SD 3.3 for version p=0.22) and these values did not differ significantly from the actual IOI and OA of the mechanical guide. When using a mechanical guide, there was no difference in accuracy between the dominant and non-dominant side. Conclusion. There was no difference in accuracy between hip surgeons and non-hip surgeons when they aimed for their preferred IOI and OA or used a mechanical guide. When aiming for a specific IOI target, non-hip surgeons outperformed hip surgeons. Hip surgeons overestimate IOI and underestimate OA, presumably because this helps to achieve the desired radiographic cup orientation. Regarding accuracy, the non-dominant side was better for version and the dominant side for inclination. When aiming for a specific IOI and OA target, using a mechanical guide is significantly better than freehand cup orientation

Abstract. Objectives. Investigate Magnetic Resonance Imaging (MRI) as an alternative to Computerised Tomography (CT) when calculating kinematics using Biplane Video X-ray (BVX) by quantifying the accuracy of a combined MRI-BVX methodology by comparing with results from a gold-standard bead-based method. Methods. Written informed consent was given by one participant who had four tantalum beads implanted into their distal femur and proximal tibia from a previous study. Three-dimensional (3D) models of the femur and tibia were segmented (Simpleware Scan IP, Synopsis) from an MRI scan (Magnetom 3T Prisma, Siemens). Anatomical Coordinate Systems (ACS) were applied to the bone models using automated algorithms. 1. The beads were segmented from a previous CT and co-registered with the MRI bone models to calculate their positions. BVX (60 FPS, 1.25 ms pulse width) was recorded whilst the participant performed a lunge. The beads were tracked, and the ACS position of the femur and tibia were calculated at each frame (DSX Suite, C-Motion Inc.). The beads were digitally removed from the X-rays (MATLAB, MathWorks) allowing for blinded image-registration of the MRI models to the radiographs. The mean difference and standard deviation (STD) between bead-generated and image-registered bone poses were calculated for all degrees of freedom (DOF) for both bones. Using the principles defined by Grood and Suntay. 2. , 6 DOF kinematics of the tibiofemoral joint were calculated (MATLAB, MathWorks). The mean difference and STD between these two sets of kinematics were calculated. Results. The absolute mean femur and tibia ACS position differences (Table 1) between the bead and image-registered poses were found to be within 0.75mm for XYZ, with all STD within ±0.5mm. Mean rotation differences for both bones were found to be within 0.2º for XYZ (Table 1). The absolute mean tibiofemoral joint translations (Table 1) were found to be within ±0.7mm for all DOF, with the smallest absolute mean in compression-distraction. The absolute mean tibiofemoral rotations were found to be within 0.25º for all DOF (Table 1), with the smallest mean was found in abduction-adduction. The largest mean and STD were found in internal-external rotation due to the angle of the X-rays relative to the joint movement, increasing the difficulty of manual image registration in that plane. Conclusion. The combined MRI-BVX method produced bone pose and tibiofemoral kinematics accuracy similar to previous CT results. 3. This allows for confidence in future results, especially in clinical applications where high accuracy is needed to understand the effects of disease and the efficacy of surgical interventions. Acknowledgements: This research was supported by the Engineering and Physical Sciences Research Council (EPSRC) doctoral training grant (EP/T517951/1). Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Introduction and Objective. After anterior cruciate ligament reconstruction one of the risk factors for graft (re-)rupture is an increased posterior tibial slope (PTS). The current treatment for PTS is a high tibial osteotomy (HTO). This is a free-hand method, with 1 degree of tibial slope correction considered to be equal to 1 or even 1.67 mm of the anterior wedge resection. Error rates in the frontal plane reported in literature vary from 1 – 8.6 degrees, and in the sagittal plane outcomes in a range of 2 – 8 degrees are reported when planned on PTSs of 3 – 5 degrees. Therefore, the free-hand method is considered to have limited accuracy. It is expected that HTO becomes more accurate with patient specific saw guides (PSGs), with an accuracy margin reported in literature of 2 degrees. This proof of concept porcine cadaver case study aimed to investigate whether the use of PSGs improves the accuracy of HTO to less than 2 degrees. Secondly, the reproducibility of tibial slope measurement was evaluated. Materials and Methods. Preoperative MRI images of porcine cadaver knees (n = 3) were used to create 3D anatomical bone models (Mimics, Materialise, Belgium). These 3D models were subsequently used to develop PSGs (3-Matic, Materialise, Belgium) to correct all tibias for 3 degrees PTS and 4 degrees varus. The PSG mediated HTOs were performed by an experienced orthopaedic surgeon, after which postoperative MRI images were obtained. 3D anatomical models of postoperative tibias were created, and tibial slopes were assessed on both pre- and postoperative tibias. The tibial slope was defined as the angle between the mechanical axis and 3D tibial reference plane in the frontal and sagittal plane. The accuracy of the PSG mediated HTO (median and range) was defined as the difference in all possible combinations of the preoperatively planned and postoperatively obtained tibial slopes. To ensure reproducibility, the pre- and postoperative tibial slopes were measured thrice by one observer. The intra-class correlation coefficients (ICCs) were subsequently calculated to assess the intra-rater reliability (SPSS, IBM Corp., Armonk, N.Y., USA). Results. An accuracy within 2 degrees was achieved in all three cases. The median and range in accuracy for each specimen were +0.46 (−0.57 – 1.45), +0.60 (−1.07 – 1.00), and +0.45 (−0.16 – 0.71) degrees in the frontal plane, and −0.45 (−1.97 – 1.22), −0.80 (−2.42 – 1.77), and 0.00 (−2.19 – 1.93) degrees in the sagittal plane. The pre- and postoperatively planned tibial slopes in the frontal and sagittal plane were measured with a good up to excellent reproducibility. The ICCs of the preoperative planned tibial slopes were 0.82 (95% CI, 0.11 – 1.0), and 0.77 (95% CI, 0.17 – 1.0) for the frontal and sagittal plane, respectively. Postoperative, the ICC for the frontal plane was 0.92 (95% CI, 0.43 – 1.0), and 0.67 (95% CI, −0.06 – 0.99) for the sagittal plane. Conclusions. This proof of concept porcine case study showed an accuracy for the PSG mediated HTO within 2 degrees for each specimen. Moreover, the tibial slopes were measured with a good up to excellent reproducibility. Therefore, the PSG mediated HTO seems to be accurate and might be better than the current used free-hand HTO method. These results offer perspective for implementation of PSG mediated HTO to correct PTS and metaphyseal varus

High tibial osteotomy (HTO) is an effective surgical treatment for isolated medial compartment knee osteoarthritis; however, widespread adoption is limited due to difficulty in achieving the planned correction, and patient dissatisfaction due to soft tissue irritation. A new HTO system – Tailored Osteotomy Knee Alignment (TOKA®, 3D Metal Printing Ltd, Bath, UK) could potentially address these barriers having a custom titanium plate and titanium surgical guides featuring a unique mechanism for precise osteotomy opening as well as saw cutting and drilling guides. The aim of this study was to assess the accuracy of this novel HTO system using cadaveric specimens; a preclinical testing stage ahead of first-in-human surgery according to the ‘IDEAL-D’ framework for device innovation. Local ethics committee approval was obtained. The novel opening wedge HTO procedure was performed on eight cadaver leg specimens. Whole lower limb CT scans pre- and post-operatively provided geometrical assessment quantifying the discrepancy between pre-planned and post-operative measurements for key variables: the gap opening angle and the patient specific surgical instrumentation positioning and rotation - assessed using the implanted plate. The average discrepancy between the pre-operative plan and the post-operative osteotomy correction angle was: 0.0 ± 0.2°. The R2 value for the regression correlation was 0.95. The average error in implant positioning was −0.4 ± 4.3 mm, −2.6 ± 3.4 mm and 3.1 ± 1.7° vertically, horizontally, and rotationally respectively. This novel HTO surgery has greater accuracy and smaller variability in correction angle achieved compared to that reported for conventional or other patient specific methods with published data available. This system could potentially improve the accuracy and reliability of osteotomy correction angles achieved surgically

Magnetic resonance imaging (MRI) is the gold standard for the diagnosis of the pathologies affecting the glenohumeral joint and the rotator cuff diseases. MRI allows to highlight anatomic discontinuities of both muscles and tendons. However, MRI diagnostic accuracy has not proven to be highly sensitive in distinguishing between a partial-thickness tear and a full-thickness rotator cuff tear. The purpose of this study was to determine if MRI under axial traction can be helpful in increasing MRI sensitivity to identify partial-thickness rotator cuff tears. The study included 10 patients (4 males and 6 females) who had clinical examination and MRI suggesting a partial-thickness rotator cuff tear. They were candidates for shoulder arthroscopy because of persistent symptoms after at least three months of conservative treatment. The patients underwent a new MRI (under axial traction: MRI-AT) with a 4-kg weight applied to the affected arm. Then the patients underwent arthroscopy to confirm the diagnosis. Patients with a suspected full-thickness rotator cuff tear were excluded from the study. Patients’ average age was 52.4 years, and the dominant side was affected in 77.7% of the cases. Preoperative Constant-Murley Score was 57. MRI-AT showed that 3 patients were affected by a complete tear of the rotator cuff, 3 patients by a partial-thickness rotator cuff tear and 4 patients had no lesion. The analysis of data showed that: under axial traction the subacromial space increased by 0,2 mm (P value = 0,001075), the superior glenohumeral space decreased by 2.4 mm (P value = 0,07414), the inferior glenohumeral space increased by 0.3 mm (P value = 0,02942), the acromial angle decreased by 1.9° (P value = 0,0002104) and the acromion-glenohumeral angle decreased by 0.3° (P-value = 0,01974). Two experienced evaluators analyzed previous standard MRI and MRI-AT scans in a double-blinded fashion, with inter-rater evaluation of all the images and measures. Intraclass correlation coefficient (ICC) has been utilized to assess the reliability of the measures performed by different operators. ICC always resulted in more than 0.7, showing a high concordance among values in the same group. A comparative evaluation between standard MRI and MRI-AT has been conducted to highlight possible discrepancies and this has been compared to intraoperative findings. Concordance of the values was 89% between standard MRI and MRI-AT and 100% between MRI under axial traction and intraoperative findings. This study showed a high correlation between the diagnosis achieved with MRI-AT and the intraoperative arthroscopic findings. The use of MRI-AT in clinical practice may improve the diagnostic sensitivity of this method to detect a partial-thickness rotator cuff tear

Driven by increasing emphasis on problem-based and self-directed learning, medical students and doctors in orthopedic specialty training rely increasingly on the internet as learning resource. As students or residents performance on physical examination may be less supervised in comparison to other clinical skills (for example surgical competence), online videos may provide a valuable source for education of physical examination skills. Cognitive psychological research has shown that videos can help viewers to understand techniques and manage the sequential steps of physical examination and approach to patients. YouTube is the largest open-access video platform available and provides access to thousands of educational videos on orthopedics-related topics. VuMedi, G9MD, and Orthobullets are examples of online platforms requiring user-registration with video content that is more directly focused on orthopedic topics. The objective of this study was to investigate the accuracy and quality of instructional videos on the physical examination of the elbow and identify factors influencing the educational usefulness. A YouTube, VuMedi, Orthobullets, and G9MD search was performed on October 7, 2018 for videos on the physical examination of the elbow. We included both basic examination and disease specific tests. The included videos were rated for accuracy and quality by two independent authors using a modified version of a validated scoring system. Inter-rater reliability was analyzed using mean difference and intra-class correlation coefficient. Twenty-three out of 126 videos were indicated as useful for educational purposes. Accuracy, quality and total scores were statistically significant higher for videos from specialized platforms compared to YouTube: 16.5 (95% CI 16 to 17) vs. 12.816 (95% CI 12.3 to 13.3) respectively. Video accuracy and quality were highly variable and did not correlate. The number of days online, views, and likes showed no or weak correlation with accuracy and quality. For the total score, our assessment tool showed excellent inter-rater reliability of 0.93 (95% CI 0.09–0.95) and a mean difference of 0.024 point between the two observers (p=0.871). There is considerable variation in accuracy and quality of online available videos on the physical examination of the elbow. We indicated 23 educationally useful videos and provided an assessment method. This assessment method can be useful for both viewers to assess reliability of a video and educators interested in creating videos

Knee swelling is common after injury or surgery, resulting in pain, restricted range of movement and limited mobility. Accurately measuring knee swelling is critical to assess recovery. However, current measurement methods are either unreliable or expensive [1,2]. Therefore, a new measurement method is developed. This wearable (the ‘smart brace’) has shown the ability to distinguish a swollen knee from a not swollen knee using multi-frequency-bio impedance analysis (MF-BIA) [3]. This study aimed to determine the accuracy of this smart brace. The study involved 25 usable measurements on patients treated for unilateral knee osteoartritis with a 5mL injection of Lidocaïne + DepoMedrol (1:4). MF-BIA measurements were taken before and after the injection, both on the treated and untreated knee. The smart brace accurately measured the effect of the injection by a decrease in resistance of up to 2.6% at 100kHz (p<0.01), where commonly used gel electrodes were unable to measure the relative difference. Remarkably, both the smart brace and gel electrodes showed a time component in the MF-BIA measurements. To further investigate this time component, 10 participants were asked to lie down for 30 minutes, with measurements taken every 3 minutes using both gel electrodes and the smart brace on both legs. The relative change between each time step was calculated to determine changes over time. The results showed presence of a physiological aspect (settling of knee fluids), and for the brace also a mechanical aspect (skin-electrode interface) [4]. The mechanical aspect mainly interfered with reactance values. Overall, the smart brace is a feasible method for quantitatively measuring knee swelling as a relative change over time. However, the skin-electrode interface should be improved for reliable measurements at different moments in time. The findings suggest that the smart brace could be a promising tool for monitoring knee swelling during rehabilitation

The aim of this project is to test the parameters of Patient Specific Instruments (PSIs) and measuring accuracy of surgical cuts using sawblades with different depths of PSI cutting guide slot. Clear operative oncological margins are the main target in malignant bone tumour resections. Novel techniques like patient specific instruments (PSIs) are becoming more popular in orthopaedic oncology surgeries and arthroplasty in general with studies suggesting improved accuracy and reduced operating time using PSIs compared to conventional techniques and computer assisted surgery. Improved accuracy would allow preservation of more natural bone of patients with smaller tumour margin. Novel low-cost technology improving accuracy of surgical cuts, would facilitate highly delicate surgeries such as Joint Preserving Surgery (JPS) that improves quality of life for patients by preserving the tibial plateau and muscle attachments around the knee whilst removing bone tumours with adequate tumour margins. There are no universal guidelines on PSI designs and there are no studies showing how specific design of PSIs would affect accuracy of the surgical cuts. We hypothesised if an increased depth of the cutting slot guide for sawblades on the PSI would improve accuracy of cuts. A pilot drybone experiment was set up, testing 3 different designs of a PSI with changing cutting slot depth, simulating removal of a tumour on the proximal tibia. A handheld 3D scanner (Artec Spider, Luxembourg) was used to scan tibia drybones and Computer Aided Design (CAD) software was used to simulate osteosarcoma position and plan intentioned cuts. PSI were designed accordingly to allow sufficient tumour. The only change for the 3 designs is the cutting slot depth (10mm, 15mm & 20mm). 7 orthopaedic surgeons were recruited to participate and perform JPS on the drybones using each design 2 times. Each fragment was then scanned with the 3D scanner and were then matched onto the reference tibia with customized software to calculate how each cut (inferior-superior-vertical) deviated from plan in millimetres and degrees. In order to tackle PSI placement error, a dedicated 3D-printed mould was used. Comparing actual cuts to planned cuts, changing the height of the cutting slot guide on the designed PSI did not deviate accuracy enough to interfere with a tumour resection margin set to maximum 10mm. We have obtained very accurate cuts with the mean deviations(error) for the 3 different designs were: [10mm slot: 0.76 ± 0.52mm, 2.37 ± 1.26°], [15 mm slot: 0.43 ± 0.40 mm, 1.89 ± 1.04°] and [20 mm: 0.74 ± 0.65 mm, 2.40 ± 1.78°] respectively, with no significant difference between mean error for each design overall, but the inferior cuts deviation in mm did show to be more precise with 15 mm cutting slot (p<0.05). Simulating a cut to resect an osteosarcoma, none of the proposed designs introduced error that would interfere with the tumour margin set. Though 15mm showed increased precision on only one parameter, we concluded that 10mm cutting slot would be sufficient for the accuracy needed for this specific surgical intervention. Future work would include comparing PSI slot depth with position of knee implants after arthroplasty, and how optimisation of other design parameters of PSIs can continue to improve accuracy of orthopaedic surgery and allow increase of bone and joint preservation

Introduction. Subacromial corticosteroid injection is widely used in the treatment of Subacromial Impingement Syndrome (SIS). There is increasing interest in using ultrasound (US) to improve the accurate placement of injections. This study investigated whether the accuracy of placement of US-guided subacromial corticosteroid injections influences patients' outcome of pain and function. Method. Secondary analysis of data from a 2−2 factorial randomised controlled trial investigating exercise and corticosteroid injection for pain and function in SIS. US-guided injections were delivered according to a pre-defined protocol. Video images were reviewed to categorise accuracy of injection into the subacromial bursa into 3 accuracy groups using pre-defined criteria: 1) not in the subacromial bursa; 2) probably in the subacromial bursa; and 3) definitely in the subacromial bursa. The primary outcome measure was the self-reported Shoulder Pain and Disability Index (SPADI) total score, compared at 6 weeks and 6 months. Secondary outcomes included SPADI pain and function subscales and participant global rating of overall change from baseline. A mixed effects model was used to compare accuracy groups' outcomes at 6 weeks and 6 months, adjusted for baseline covariates. Results. US-guided injection accuracy data were available for 114 participants; with 22 participants in group 1, 21 in group 2 and 71 in group 3. There were no significant differences in mean SPADI scores among the three injection accuracy groups at 6 weeks (group 2 vs. 1: 8.22 (95% CI −4.01, 20.50); group 3 vs. 1: −0.57 (−10.27, 9.13)) and 6 months (group 2 vs. 1: 12.38 (−5.34, 30.10); group 3 vs. 1: 3.10 (−11.04, 17.23)). Similarly, no differences between accuracy groups were seen in SPADI pain, SPADI function or participant global rating of change. Conclusion. The accuracy of US-guided subacromial corticosteroid injection in SIS does not influence clinical response to the injection, questioning the need for guided injections. Larger, adequately powered studies are required to explore this further

Background. Biomechanical joint contact pressure distribution measurements have proven to be a very valuable tool in orthopaedic research to investigate the influence of surgical techniques such as total knee arthroplasty (TKA) on the human knee joint. Quantification of the in vitro tibiofemoral and patellofemoral contact pressure distribution before and after the intervention are an important measure to evaluate the impact of the surgery. The K scan pressure sensor from Tekscan (South Boston USA) is a commonly reported device for these in vitro pressure measurements. Despite the large interest in the sensor, the effective measurement accuracy for in vitro biomechanical joint contact measurement still remains a big question and therefore the reliability of these measurements should be questioned. Methods. Reliable contact pressure measurements can only be done if the sensor behaviour is fully understood. Therefore, a tailored multi-axial testing machine has been designed to profoundly investigate and characterise the sensor behaviour. This test setup is unique through its ability to apply a predefined tangential force or sliding velocity to the sensor's interface next to a normal force. Dynamic effects occurring in knee joint motion can thus be simulated while evaluating the effect on the contact pressure measurements. Results. The change in contact friction coefficient by insertion of the sensor in the joint is quantified. Different interface conditions (dry, lubricated with PTFE spray, lubricated with surgical lubricant) have been evaluated to obtain the best sliding conditions and to minimise the undesired sensor accuracy deteriorating effects. Conclusion. An optimal calibration procedure is put forward and side-effects that deteriorate the measurement accuracy are quantified. The provided knowledge facilitates orthopaedic biomechanics researchers to optimally perform joint contact measurements and to estimate the effective measurement accuracy. In addition, the presented rig provides the opportunity to study the inherent knee kinematics and prosthesis shape optimisation through the inherent degrees of freedom in the rig

Summary Statement. Pedicle screws provide robust fixation and rigid immobilization. There has been no attempt to correlate the anatomic dimensions of thoracic and lumbar pedicles with the accuracy of navigated insertion. This study demonstrates that comparable accuracy using this technique. Introduction. Pedicle screws provide robust mechanical fixation, which makes their use attractive; their use enables fixation of the three spinal columns. There remains concern about the potential both for misplacement; various investigators have studied the accuracy of pedicle screw insertions, comparing different techniques. What is not clear, however, is whether there is any relation between the variables of pedicles’ anatomic dimensions, screw dimensions and accuracy. This study aims to elucidate the relationship between these variables. Patients & Methods. We conducted a retrospective review of consecutive pedicle screws that were inserted in the thoracic and lumbar spine at our institution. Screws were inserted using the navigated method (Stealth Station® TREON™, Medtronic, Louisville, CO). The accuracy of the screw insertion was measured using the classification system developed by Gertzbein and Robbins; pedicle dimensions were measured from post-operative computed tomography scans. The corresponding pre-operative scans were then used to measure the pedicle dimensions at the other levels. The magnitude of a cortical breach in the pedicle was represented by a letter: A (no breach), B (<2mm), C (>2mm, <4mm), D (>4mm, <6mm) and E (>6mm). In addition, measurements were made of the anatomic dimensions of the pedicles. The combination of these two measures allowed for direct correlation to be made between the accuracy of screw insertion, screw dimensions and pedicle anatomy. We then computed the proportion of each pedicle (width) occupied by a screw. Results. A total of 765 screws were reviewed, 493 were in the thoracic spine and 272 in the lumbar spine. Of the screws in the thoracic spine, 472 (96%) were either fully in the pedicle or less than 2mm beyond the cortex (within the A+B classification); when considered separately, 323 (66%) were completely within the pedicle (A) and 149 (30%) were less than 2mm beyond the cortex. A total of 21 (4%) screws were beyond 2mm but within 6mm (C+D). In the lumbar spine, 270 (99%) were either completely within the cortex or less than 2mm exposed (classified as A or B). The nadir of pedicle width was at T4. From L1 to L5, measured pedicle width also rose. This pattern was followed, although it was less profound, when screw diameter was measured in the lumbar spine (and even less so in the thoracic vertebrae). The height of pedicles was noted to progressively increase, peaking at the thoraco-lumbar junction. The mid thoracic region was associated with screws occupying the greatest proportion of pedicle diameter. Discussion/Conclusion. The use of pedicle screws in the thoracic and lumbar spine remains relatively safe. The accuracy of navigated insertion was found to compare well to previous series’. Although there is some association between the anatomical dimensions of pedicles and the dimensions of screws, this doesn't seem to be a strong association. Based on the findings in this series, future studies that relate the long term outcome (e.g. failure or screw loosening) with proportion of pedicle diameter taken up by a screw may be warranted

Background and Objectives. Triangular fibrocartilaginous complex (TFCC) tears are common sources of ulna sided wrist pain and resultant functional disability. Diagnosis is based on history, clinical examination and radiological evidence of a TFCC central perforation or radial/ulna tear. The purpose of this study is therefore to evaluate the diagnostic accuracy of Magnetic Resonance Imaging (MRI) and Magnetic Resonance Arthrography (MRA) in the detection of TFCC injury in the adult population. Methods. Published and unpublished literature databases were systematically review independently by two researchers. Two-by-two tables were constructed to calculate the sensitivity and specificity of MRI or MRA investigations against arthroscopic outcomes. Pooled sensitivity and specificity values and summary Receiver Operating Characteristic curve (sROC) evaluations were performed. Methodological quality of each study was assessed using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies) tool. Results. Twenty one studies were eligible, including 910 wrists. On meta-analysis, MRA was superior to MRI in the investigation of complete TFCC tears with a pooled sensitivity of 0.75 (95% Confidence Interval (CI): 0.70, 0.79) and specificity of 0.81 (95% CI: 0.76, 0.86), compared to MRAs 0.84 (95% CI: 0.79, 0.89), and 0.95 (95% CI: 0.92, 0.98) respectively. MRA and MRI performed at greater field strengths reported greater sensitivity and specificity findings. For 3.0 Tesla (T) MRI, the meta-analysis indicated a sensitivity of 0.86 (95% CI: 0.65, 0.97), and specificity of 1.00 (0.87, 1.00). In comparison, the pooled sensitivity for the 1.5T MRI assessment was 0.70 (95% CI: 0.64, 0.75) and specificity of 0.79 (95% CI: 0.72, 0.85). This trend was repeated for MRA where 3.0T MRA exhibited a sensitivity was 1.00 (95% CI: 0.79, 1.00) and specificity of 1.00 (95% CI: 0.82, 1.00), whilst pooled analysis 1.5T MRA demonstrated a sensitivity of 0.83 (95% CI: 0.78, 0.89) and specificity of 0.95 (95% CI: 0.91, 0.98). There was insufficient data to assess the diagnostic test accuracy of partial TFCC lesions. Conclusions. Given its acceptable diagnostic test accuracy, it is recommended that in cases where there are questions over the diagnosis and subsequent management of patients with ulna wrist pain, a MRA should be undertaken rather than MRI

Details of orthopaedic implants in Scotland are recorded on a national database. The results are used by the Scottish Arthroplasty Project to record survival and complication rates for both knee and hip replacements. The aim of our study was to assess the accuracy of recorded data for unicompartmental knee replacements in the West of Scotland. The national database was searched for all unicompartmental knee replacements carried out in the West of Scotland between March 2000 to October 2004. All patient data was then crosschecked with hospital theatre records and case notes for confirmation of accuracy. A total of 88 cases were coded as unicompartment joint replacements in the study period. 63 cases were confirmed as being accurate (71.6%) and 6 as being inaccurate (6.8%). 19 patient details were not available for review either from notes or theatre records (21.6%). Of those coded inaccurately, five were total knee replacements, one cemented hip hemiarthroplasty and one shoulder replacement. One case of miscoding could be accounted for as an error in documentation while in six cases no cause could be identified. Of the 63 knees confirmed as unicompartmental, seven knees had been revised within 5 years, giving a 5 year survival rate of 87.7%. The current system used by the Scottish Arthroplasty Project in Scotland has at least a 6.8% inaccuracy rate when recording unicompartmental knee replacements

The purpose of this study is to evaluate accuracy of tibia cutting and tibia implantation in UKA which used navigation system for tibia cutting and tibia component implantation, and to evaluate clinical results. We performed 72 UKAs using navigation system from November, 2012. This study of 72 knees included 56 females and 16 males with an average operation age of 74.2 years and an average body mass index (BMI) of 24.8 kg/m2. The diagnosis was osteoarthritis (OA) in 67 knees and osteonecrosis (ON) in 5 knees. The UKA (Oxford partial knee microplasty, Biomet, Warsaw, IN) was used all cases. We evaluated patients clinically using the Japanese orthopaedic association (JOA) score, range of motion (ROM), operation time, the amount of bleeding and complications. Patients were evaluated clinically at preoperation and final follow up in JOA score and ROM. As an radiologic examination, we evaluated preoperative and postoperative lower limb alignment in FTA (femoro-tibial angle) by weightbearing long leg antero-posterior alignment view X-rays. Also we evaluated a tibial component implantation angle by postoperative CT, and tibia cutting angle by intraoperative navigation system. We defined the tibial angle which a tibia functional axis and the tibia component made in coronal plane, also tibial posterior slope angle which a tibia axis and tibia component made in sagittal plane by CT. We measured tibial angle and tibial posterior slope angle by 3D template system. We performed UKA in all cases mini-midvastus approach. At first we performed osteotomy of the proximal medial tibia using CT-Free navigation. At this procedure we performed osteotomy to do re-cut if check did cutting surface in navigation, and there was cutting error (>3°), and then to do check again in navigation. Next we did not use navigation and went the osteotomy of the distal femur with an IM rod and drill guide of microplasty system. And then we performed a trial and decided bearing gap and moved to cementing. At first we went cementing of the tibia component. At this procedure we went to drive implant again if check did implant surface in navigation, and there was implantation error(>3°), and to do check. We checked did tibia cutting, tibia implantation carefully in navigation. In addition, We sterilize a clips and use it came to be in this way possible for the check of the first osteotomy side exactly. ROM was an average of 122.7° of preoperation became an average of 128.2° at final follow up, and JOA score was an average of 50.5 points of preoperation improved an average of 86.6 points at final follow up after UKA. An average of the operation time was 94 minutes, an average of the amount of bleeding was 137.7ml, and complications were one proximal type deep venous thrombosis (DVT) and one pin splinter joining pain by navigation, .Asetic loosening(tibial component) was one case, and this conversed the TKA. In the radiologic evaluation, FTA was an average of 182.1° of preoperation corrected an average of 175.9°after UKA. In other words, an average of 6.2° were corrected by UKA. The tibia component implantation angle was an average of 90.18° in a measurement by the CT after UKA, intoraoperative tibia component implantation angle was an average of 90.32° in a measurement by the navigation system. These two differences did not accept the significant difference at an average of 1.33°.(P=0.5581). Similarly, the posterior slope angle were as follow; average of 5.65°by CT and average of 5.75°by navigation. These two differences did not accept the significant difference at an average of 1.33°. (P=0.6475). Discussion: We performed UKA using navigation and evaluated the implantation accuracy for tibia osteotomy, tibia implantation. They were good alignment with an average of 90.18°, and outliers more than 3° were two cases(2.8%). It will be necessary to examine long-term progress including clinical results complications in future. We are performed UKA now in femur side using PSI(patient specific instruments) and tbia side using Navigation

Our aim was to determine whether tantalum markers improved the accuracy and/or precision of methods for the measurement of migration in total hip replacement based on conventional measurements without mathematical correction of the data, and with Ein Bild Roentgen Analyse – Femoral Component Analysis (EBRA-FCA) which allows a computerised correction. Three observers independently analysed 13 series of roentgen-stereophotogrammetric-analysis (RSA)-compatible radiographs (88). Data were obtained from conventional measurements, EBRA-FCA and the RSA method and all the results were compared with the RSA data. Radiological evaluation was also used to quantify in how many radiographs the intraosseous position of the bone markers had been simulated. The results showed that tantalum markers improve reliability whereas they do not affect accuracy for conventional measurements and for EBRA-FCA. Because of the danger of third-body wear their implantation should be avoided unless they are an integral part of the method

The role of digital radiography has evolved in recent years. In many hospitals, radiographs have been completely digitised and moved to Picture Archiving and Communications System (PACS). Pre-operative templating for arthroplasty has been a major problem as a result. We investigate the accuracy of Orthoview™ software in templating for hip and knee arthroplasty. A retrospective review of 20 Stryker-Exter hip and 20 Biomet-Vanguard knee arthroplasties was conducted. Anonymised preoperative radiographs were reviewed by experienced orthopaedic surgeons. Templated component sizes were compared with actual implanted component sizes. All radiographs were digitised on Kodak Carestream PACS. Five surgeons were asked to separately review the radiographs to avoid intra-observer error. In templating for hip arthroplasty, Orthoview™ was 80% accurate in predicting the femoral stem size within one size of the actual component used. It predicted the offset with 100% accuracy. In 90% of patients, the actual head implant was within one size of the templated head. The system was able to predict the acetabular component size in only 30%. In knee arthroplasty, Orthoview™ was 80% accurate within one size of the actual component used for the femur and 90% for the tibia. Orthoview™ enables the flexibility of digitised films to be used for pre-operative templating. It is reasonably accurate in prediction of femoral sizing in both hip and knee arthroplasty and tibial size in knee arthroplasty. It is considerably less useful for acetabular sizing. Surgeons should keep this variability in mind until more accurate systems are available