Introduction. Acetabular bone defects are still challenging to quantify. Numerous classification schemes have been proposed to categorize the diverse kinds of defects. However, these classification schemes are mainly descriptive and hence it remains difficult to apply them in pre-clinical testing, implant development and pre-operative planning. By reconstructing the native situation of a defect pelvis using a Statistical Shape Model (SSM), a more quantitative analysis of the bone defects could be performed. The aim of this study is to develop such a SSM and to validate its accuracy using relevant clinical scenarios and parameters. Methods. An SSM was built on the basis of segmented 66 CT dataset of the pelvis showing no orthopedic pathology. By adjusting the SSM's so called modes of shape variation it is possible to synthetize new 3D pelvis shapes. By fitting the SSM to intact normal parts of an anatomical structure, missing or pathological regions can be extrapolated plausibly. The validity of the SSM was tested by a Leave-one-out study, whereby one pelvis at a time was removed from the 66 pelvises and was reconstructed using a SSM of the remaining 65 pelvises. The reconstruction accuracy was assessed by comparing each original pelvis with its reconstruction based on the root-mean-square (RMS) surface error and five clinical parameters (center of rotation, acetabulum diameter, inclination, anteversion, and volume). The influence of six different numbers of shape variation modes (reflecting the degrees of freedom of the SSM) and four different mask sizes (reflecting different clinical scenarios) was analyzed. Results. The Leave-one-out study showed that the reconstruction errors decreased when the number of shape variation modes included in the SSM increased from 0 to 20, but remained almost constant for higher numbers of shape variation modes. For the SSM with 20 shape variation modes, the RMS of the reconstruction error increased with increasing mask size, whereas the other parameters only increased from Mask_0 to Mask_1, but remained almost constant for Mask_1, Mask_2 and Mask_3. Median reconstruction errors for Mask_1, Mask_2, and Mask_3 were approximately 3 mm in Center of Rotation (CoR) position, 2 mm in Diameter, 3° in inclination and anteversion, as well as 5 ml in volume. Discussion. This is the first study analyzing and showing the feasibility of a quantitative analysis of acetabular bone defects using a SSM-based reconstruction method in the clinical scenario of a defect or implant in both acetabuli and incomplete CT-scans. Validation results showed acceptable reconstruction accuracy, also for clinical scenarios in which less healthy bone remains. Further studies could apply this method on a larger number of defect pelvises to obtain quantitative measures of acetabular bone defects

Aim

In recent years, many studies on revision for infection after arthroplasty have been published. In national arthroplasty registers, revision for infection is defined as surgical debridement, with or without removal or exchange of the entire or parts of the prosthesis due to deep infection, and should be reported to the register immediately after surgery. The diagnosis of infection is made at the surgeon's discretion, based on pre- and perioperative assessment and evaluation, and is not to be corrected to the register based on peroperative bacterial cultures. Due to this lack of validation, the rate of revision for infection will only be an approximation of the true rate of periprosthetic joint infection (PJI). Our aim was to validate the reporting of infection after total hip arthroplasty, and to assess if revisions for infection actually represented true PJI.

As there is currently no evidenced-based and systematic way of prioritising people requiring JRS we aimed to develop a clinically relevant system to improve prioritisation of people who may require JRS. An important challenge in this area is to accurately assign a queue position and improve list management. To identify priority criteria areas eight workshops were held with surgeons and patients. Domains derived were pain, activity limitations, psychosocial wellbeing, economic impact and deterioration. Draft questions were developed and refined through structured interviews with patients and consultation with consultants. 38 items survived critical appraisal and were mailed to 600 patients. Eleven items survived clinimetric and statistical item reduction. Validation then included co-administration with standardised questionnaires (960 patients), verification of patient MAPT scores through clinical interview, examination of concordance with surgeon global ratings and test-retest. Ninety-six Victorian surgeons weighted items using Discrete Choice Experiments (DCEs). The DCE scaling generated a scale, which clearly ranked patients across the disease continuum. The MAPT differentiated people on or not on waiting lists (p<0.001), and was highly correlated with other questionnaires, e.g., unweighted-MAPT vs WOMAC (r=0.78), Oxford Hip/Knee (r=0.86/0.75), Quality of Life (r=0.78), Depression (r=0.64), Anxiety (r=0.60), p<0.001 for all. Test-retest was excellent (ICC=0.89, n=90). Cronbachs reliability was also high 0.85. The MAPT is now routinely administered across all Victorian hospitals undertaking arthroplasty where the response rate is generally above 90%. In the hands of clinicians the MAPT has been used to facilitate fast-tracking of patients with the greatest need, monitoring for deterioration in those waiting for surgery or having a trial of non-operative treatment and deferment of surgery for those that may benefit from further non-operative treatments. The MAPT is short, easy to complete and clinically relevant. It is a specific measure of severity of hip/knee arthritis and assigns priority for surgery. It has excellent psychometric and clinimetric properties evidenced by concordance with standard disease-specific and generic scales and widespread use and endorsement across health services

Aim

There is growing evidence that bacteria encountered in periprosthetic joint infections (PJI) form surface-attached biofilms on prostheses, as well as biofilm aggregates embedded in synovial fluid and tissues. However, models allowing the investigation of these biofilms and the assessment of their antimicrobial susceptibility in physiologically relevant conditions are currently lacking. To address this, we developed a synthetic synovial fluid (SSF) model and we validated this model in terms of growth, aggregate formation and antimicrobial susceptibility testing, using multiple PJI isolates.

Introduction

Debridement, antibiotics irrigation and implant retention (DAIR) is a common management strategy for hip and knee prosthetic joint infections (PJI). However, failure rates remain high, which has led to the development of predictive tools to help determine success. These tools include KLIC and CRIME80 for acute-postoperative (AP) and acute haematogenous (AH) PJI respectively. We investigated whether these tools were applicable to a Waikato cohort.

Traditional staging systems for high grade osteosarcoma (Enneking, MSTS) are based largely on gross surgical margins and were developed before the widespread use of neoadjuvant chemotherapy. It is now well known that both microscopic margins and chemotherapy are predictors of local recurrence. However, neither of these variables are used in the traditional surgical staging and the precise safe margin distance is debated. Recently, a novel staging system utilizing a 2mm margin cutoff and incorporating precent necrosis was proposed and demonstrated improved prognostic value for local recurrence free survival (LRFS) when compared to the MSTS staging system. This staging system has not been validated beyond the original patient cohort. We propose to analyze this staging system in a cohort of patients with high-grade osteosarcoma, as well as evaluate the ability of additional variables to predict the risk of local recurrence and overall survival.

A retrospective review of a prospectively collected database of all sarcoma patients between 1985 and 2020 at a tertiary sarcoma care center was performed. All patients with high-grade osteosarcoma receiving neo-adjuvant chemotherapy and with no evidence of metastatic disease on presentation were isolated and analyzed. A minimum of two year follow up was used for surviving patients. A total of 225 patients were identified meeting these criteria. Univariate analysis was performed to evaluate variable that were associated with LRFS. Multivariate analysis is used to further analyze factors associated with LRFS on univariate analysis.

There were 20 patients (8.9%) who had locally recurrent disease. Five-year LRFS was significantly different for patients with surgical margins 2mm or less (77.6% v. 93.3%; p=0.006) and those with a central tumor location (67.9 v. 94.4; <0.001). A four-tiered staging system using 2mm surgical margins and a percent necrosis of 90% of greater was also a significant predictor of 5-year LRFS (p=0.019) in this cohort. Notably, percent necrosis in isolation was not a predictor of LRFS in this cohort (p=0.875). Tumor size, gender, and type of surgery (amputation v. limb salvage) were also analyzed and not associated with LRFS. The MSTS surgical margin staging system did not significantly stratify groups (0.066).

A 2mm surgical margin cutoff was predictive of 5-year LRFS in this cohort of patients with localized high-grade osteosarcoma and a combination of a 2mm margin and percent necrosis outperformed the prognostic value of the traditional MSTS staging system. Utilization of this system may improve the ability of surgeons to stage thier patients. Additional variables may increase the value of this system and further validation is required.

The purpose of this study was to develop a quality appraisal tool for the assessment of laboratory basic science biomechanical studies.

Materials andScore development comprised of the following phases: item identification/development, item reduction, content/face/criterion validity, weighting, test-retest reliability and internal consistency. For item identification/development, the panel was asked to independently list criteria and factors they considered important for cadaver study and generate items that should be used to appraise cadaver study quality. For content validity, the content validity ratio (CVR) was calculated. The minimum accepted content validity index (CVI) was set to 0.85. For weighting, equal weight for each item was 6.7% [15 items]. Based on these figures the panel was asked to either upscale or downscale the weight for each item ensuring that the final sum for all items was 100%. Face validity was assessed by each panel member using a Likert scale from 1–7. Strong face validity was defined as a mean score of >5. Test-retest reliability was assessed using 10 randomly selected studies. Criterion validity was assessed using the QUACS scale as standard. Internal consistency was assessed using Cronbach's alpha.

Five items reached a CVI of 1 and 10 items a CVI of 0.875. For weighting five items reached a final weight of 10% and ten items 5%. The mean score for face validity was 5.6. Test-retest reliability ranged from 0.78–1.00 with 9 items reaching a perfect score. Criterion validity was 0.76 and considered to be strong. Cronbach's alpha was calculated to be 0.71 indicating acceptable internal consistency.

The new proposed quality score for basic science studies consists of 15 items and has been shown to be reliable, valid and of acceptable internal consistency. It is suggested that this score should be utilised when assessing basic science studies.

This study aims to implement and assess the inter and intra-reliability of a modernised radiolucency assessment system; the Radiolucency In cemented Stemmed Knee (RISK) arthroplasty classification. Furthermore, we assessed the distribution of regions affected by radiolucency in patients undergoing stemmed cemented knee arthroplasty.

Stemmed knee arthroplasty cases over 7-year period at a single institution were retrospectively identified and reviewed. The RISK classification system identifies five zones in the femur and five zones in the tibia in both the anteroposterior (AP) and lateral planes. Post-operative and follow-up radiographs were scored for radiolucency by four blinded reviewers at two distinct time points four weeks apart. Reliability was assessed using the kappa statistic. A heat map was generated to demonstrate the reported regions of radiolucency.

29 cases (63 radiographs) of stemmed knee arthroplasty were examined radiographically using the RISK system. Intra-reliability (0.83) and Inter-reliability (0.80) scores were both consistent with a strong level of agreement using the kappa scoring system. Radiolucency was more commonly associated with the tibial component (76.6%) compared to the femoral component (23.3%), and the tibial anterior-posterior (AP) region 1 (medial plateau) was the most affected (14.9%).

The RISK classification system is a reliable assessment tool for evaluating radiolucency around stemmed knee arthroplasty using defined zones on both AP and lateral radiographs. Zones of radiolucency identified in this study may be relevant to implant survival and corresponded well with zones of fixation, which may help inform future research.

INTRODUCTION

The restoration of physiological kinematics is one of the goals of a total knee arthroplasty (TKA). Navigation systems have been developed to allow an accurate and precise placement of the implants. But its application to the intraoperative measurement of knee kinematics has not been validated. The hypothesis of this study was that the measurement of the knee axis, femoral rotation, femoral translation with respect to the tibia, and medial and lateral femorotibial gaps during continuous passive knee flexion by the navigation system would be different from that by fluoroscopy taken as reference.

Polyethylene wear represents a significant risk factor for the long-term success of knee arthroplasty [1]. This work aimed to develop and in vivo validate an automated algorithm for accurate and precise AI based wear measurement in knee arthroplasty using clinical AP radiographs for scientifically meaningful multi-centre studies.

Twenty postoperative radiographs (knee joint AP in standing position) after knee arthroplasty were analysed using the novel algorithm. A convolutional neural network-based segmentation is used to localize the implant components on the X-Ray, and a 2D-3D registration of the CAD implant models precisely calculates the three-dimensional position and orientation of the implants in the joint at the time of acquisition. From this, the minimal distance between the involved implant components is determined, and its postoperative change over time enables the determination of wear in the radiographs.

The measured minimum inlay height of 335 unloaded inlays excluding the weight-induced deformation, served as ground truth for validation and was compared to the algorithmically calculated component distances from 20 radiographs.

With an average weight of 94 kg in the studied TKA patient cohort, it was determined that an average inlay height of 6.160 mm is expected in the patient. Based on the radiographs, the algorithm calculated a minimum component distance of 6.158 mm (SD = 81 µm), which deviated by 2 µm in comparison to the expected inlay height.

An automated method was presented that allows accurate and precise determination of the inlay height and subsequently the wear in knee arthroplasty based on a clinical radiograph and the CAD models. Precision and accuracy are comparable to the current gold standard RSA [2], but without relying on special radiographic setups. The developed method can therefore be used to objectively investigate novel implant materials with meaningful clinical cohorts, thus improving the quality of patient care.

The Banff Patellofemoral Instability Instrument 2.0 (BPII 2.0) is a patient-reported disease-specific quality of life (QOL) outcome measure used to assess patients with recurrent lateral patellofemoral instability (LPI) both pre- and post-operatively. The purpose of this study was to compare the BPII 2.0 to four other relevant patient reported outcome measures (PROMs): the Tampa Scale-11 for kinesiophobia (TSK-11), the pain catastrophizing scale (PCS), a general QOL (EQ-5D-5L), and a return to sport index (ACL-RSI). This concurrent validation sought to compare and correlate the BPII 2.0 with these other measures of physical, psychological, and emotional health. The psychological and emotional status of patients can impact recovery and rehabilitation, and therefore a disease-specific PROM may be unable to consistently identify patients who would benefit from interventions encompassing a holistic and person-focused approach in addition to disease-specific treatment.

One hundred and ten patients with recurrent lateral patellofemoral instability (LPI) were assessed at a tertiary orthopaedic practice between January and October 2021. Patients were consented into the study and asked to complete five questionnaires: the BPII 2.0, TSK-11, PCS, EQ-5D-5L, and the ACL-RSI at their initial orthopaedic consultation. Descriptive demographic statistics were collected for all patients. A Pearson's r correlation coefficient was employed to examine the relationships between the five PROMs. These analyses were computed using SPSS 28.0 © (IBM Corporation, 2021).

One hundred and ten patients with a mean age of 25.7 (SD = 9.8) completed the five PROMs. There were 29 males (26.3%) and 81 females (73.6%) involving 50% symptomatic left knees and 50% symptomatic right knees. The mean age of the first dislocation was 15.4 years (SD = 7.3; 1-6) and the mean BMI was 26.5 (SD = 7.3; range = 12.5-52.6) The results of the Pearson's r correlation coefficient demonstrated that the BPII 2.0 was statistically significantly related to all of the assessed PROM's (p

There was significant correlation evident between the BPII 2.0 and the four other PROMs assessed in this study. The BPII 2.0 does not explicitly measure kinesiophobia or pain catastrophizing, however, the significant statistical relationship of the TSK-11 and PCS to the BPII 2.0 suggests that this information is being captured and reflected. The preliminary results of this concurrent validation suggest that the pre-operative data may offer predictive validity. Future research will explore the ability of the BPII 2.0 to predict patient quality of life following surgery.

Aim

In vivo biofilm models play major role to study biofilm development, morphology, and regulatory molecules involve in biofilm. Due to ethical restrictions, the use mammalian models are replaced with other alternative models in basic research. Recently, we have developed insect infection model G. mellonella larvae to study implant associated biofilm infections. This model organism is easy to handle, cheap and ethical restriction free and could be used for the high through put screening of antimicrobial compounds to treat biofilm. To promote the use of this model in basic research we aimed to validate this based on the typical biofilm features such as less susceptible to the antibiotics, complexity of the biofilm structure and gene expression profile of biofilms.

Acute spinal cord injury (SCI) is most often secondary to trauma, and frequently presents with associated injuries. A neurological examination is routinely performed during trauma assessment, including through Advanced Trauma Life Support (ATLS). However, there is no standard neurological assessment tool specifically used for trauma patients to detect and characterize SCI during the initial evaluation. The International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) is the most comprehensive and popular tool for assessing SCI, but it is not adapted to the acute trauma patients such that it is not routinely used in that setting. Therefore, the objective is to develop a new tool that can be used routinely in the initial evaluation of trauma patients to detect and characterize acute SCI, while preserving basic principles of the ISNCSCI.

The completion rate of the ISCNSCI during the initial evaluation after an acute traumatic SCI was first estimated. Using a modified Delphi technique, we designed the Montreal Acute Classification of Spinal Cord Injuries (MAC-SCI), a new tool to detect and characterize the completeness (grade) and level of SCI in the polytrauma patient. The ability of the MAC-SCI to detect and characterize SCI was validated in a cohort of 35 individuals who have sustained an acute traumatic SCI. The completeness and neurological level of injury (NLI) were assessed by two independent assessors using the MAC-SCI, and compared to those obtained with the ISNCSCI.

Only 33% of patients admitted after an acute traumatic SCI had a complete ISNCSCI performed at initial presentation. The MAC-SCI includes 53 of the 134 original elements of the ISNCSCI which is 60% less. There was a 100% concordance between the severity grade derived from the MAC-SCI and from the ISNCSCI. Concordance of the NLI within two levels of that obtained from the ISNCSCI was observed in 100% of patients with the MAC-SCI and within one level in 91% of patients. The ability of the MAC-SCI to discriminate between cervical (C0 to C7) vs. thoracic (T1 to T9) vs. thoraco-lumbar (T10 to L2) vs. lumbosacral (L3 to S5) injuries was 100% with respect to the ISNCSCI.

The rate of completion of the ISNCSCI is low at initial presentation after an acute traumatic SCI. The MAC-SCI is a streamlined tool proposed to detect and characterize acute SCI in polytrauma patients, that is specifically adapted to the acute trauma setting. It is accurate for determining the completeness of the SCI and localize the NLI (cervical vs. thoracic vs. lumbar). It could be implemented in the initial trauma assessment protocol to guide the acute management of SCI patients.

Acute spinal cord injury (SCI) is most often secondary to trauma, and frequently presents with associated injuries. A neurological examination is routinely performed during trauma assessment, including through Advanced Trauma Life Support (ATLS). However, there is no standard neurological assessment tool specifically used for trauma patients to detect and characterize SCI during the initial evaluation. The International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) is the most comprehensive and popular tool for assessing SCI, but it is not adapted to the acute trauma patients such that it is not routinely used in that setting. Therefore, the objective is to develop a new tool that can be used routinely in the initial evaluation of trauma patients to detect and characterize acute SCI, while preserving basic principles of the ISNCSCI.

The completion rate of the ISCNSCI during the initial evaluation after an acute traumatic SCI was first estimated. Using a modified Delphi technique, we designed the Montreal Acute Classification of Spinal Cord Injuries (MAC-SCI), a new tool to detect and characterize the completeness (grade) and level of SCI in the polytrauma patient. The ability of the MAC-SCI to detect and characterize SCI was validated in a cohort of 35 individuals who have sustained an acute traumatic SCI. The completeness and neurological level of injury (NLI) were assessed by two independent assessors using the MAC-SCI, and compared to those obtained with the ISNCSCI.

Only 33% of patients admitted after an acute traumatic SCI had a complete ISNCSCI performed at initial presentation. The MAC-SCI includes 53 of the 134 original elements of the ISNCSCI which is 60% less. There was a 100% concordance between the severity grade derived from the MAC-SCI and from the ISNCSCI. Concordance of the NLI within two levels of that obtained from the ISNCSCI was observed in 100% of patients with the MAC-SCI and within one level in 91% of patients. The ability of the MAC-SCI to discriminate between cervical (C0 to C7) vs. thoracic (T1 to T9) vs. thoraco-lumbar (T10 to L2) vs. lumbosacral (L3 to S5) injuries was 100% with respect to the ISNCSCI.

The rate of completion of the ISNCSCI is low at initial presentation after an acute traumatic SCI. The MAC-SCI is a streamlined tool proposed to detect and characterize acute SCI in polytrauma patients, that is specifically adapted to the acute trauma setting. It is accurate for determining the completeness of the SCI and localize the NLI (cervical vs. thoracic vs. lumbar). It could be implemented in the initial trauma assessment protocol to guide the acute management of SCI patients.

Acute spinal cord injury (SCI) is most often secondary to trauma, and frequently presents with associated injuries. A neurological examination is routinely performed during trauma assessment, including through Advanced Trauma Life Support (ATLS). However, there is no standard neurological assessment tool specifically used for trauma patients to detect and characterize SCI during the initial evaluation. The International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) is the most comprehensive and popular tool for assessing SCI, but it is not adapted to the acute trauma patients such that it is not routinely used in that setting. Therefore, the objective is to develop a new tool that can be used routinely in the initial evaluation of trauma patients to detect and characterize acute SCI, while preserving basic principles of the ISNCSCI.

The completion rate of the ISCNSCI during the initial evaluation after an acute traumatic SCI was first estimated. Using a modified Delphi technique, we designed the Montreal Acute Classification of Spinal Cord Injuries (MAC-SCI), a new tool to detect and characterize the completeness (grade) and level of SCI in the polytrauma patient. The ability of the MAC-SCI to detect and characterize SCI was validated in a cohort of 35 individuals who have sustained an acute traumatic SCI. The completeness and neurological level of injury (NLI) were assessed by two independent assessors using the MAC-SCI, and compared to those obtained with the ISNCSCI.

Only 33% of patients admitted after an acute traumatic SCI had a complete ISNCSCI performed at initial presentation. The MAC-SCI includes 53 of the 134 original elements of the ISNCSCI which is 60% less. There was a 100% concordance between the severity grade derived from the MAC-SCI and from the ISNCSCI. Concordance of the NLI within two levels of that obtained from the ISNCSCI was observed in 100% of patients with the MAC-SCI and within one level in 91% of patients. The ability of the MAC-SCI to discriminate between cervical (C0 to C7) vs. thoracic (T1 to T9) vs. thoraco-lumbar (T10 to L2) vs. lumbosacral (L3 to S5) injuries was 100% with respect to the ISNCSCI.

The rate of completion of the ISNCSCI is low at initial presentation after an acute traumatic SCI. The MAC-SCI is a streamlined tool proposed to detect and characterize acute SCI in polytrauma patients, that is specifically adapted to the acute trauma setting. It is accurate for determining the completeness of the SCI and localize the NLI (cervical vs. thoracic vs. lumbar). It could be implemented in the initial trauma assessment protocol to guide the acute management of SCI patients.

Aim

Kingella kingae seems to be the most common cause of osteoarticular infections (OAI) in children under 48 months of age (1). Recent studies had shown that K. kingae is poorly susceptible to anti-staphylococcal penicillin and some isolates produce beta-lactamase (2). This led to the need for new treatment guidelines for OAI in populations in which K. kingae is frequent. Our study aimed to design a model which could predict K. kingae OAI in order to initiate appropriate empirical treatment on hospital admission.

Background

The anatomy of the human knee is very different than the tibiofemoral surface geometry of most modern total knee replacements (TKRs). Many TKRs are designed with simplified articulating surfaces that are mediolaterally symmetrical, resulting in non-natural patterns of motion of the knee joint [1]. Recent orthopaedic trends portray a shift away from basic tibiofemoral geometry towards designs which better replicate natural knee kinematics by adding constraint to the medial condyle and decreasing constraint on the lateral condyle [2]. A recent design concept has paired this theory with the concept of guided kinematic motion throughout the flexion range [3]. The purpose of this study was to validate the kinematic pattern of motion of the surface-guided knee concept through in vitro, mechanical testing.

Robotic-assisted technology in total knee arthroplasty (TKA) aims to increase implantation accuracy, with real-time data being used to estimate intraoperative component alignment. Postoperatively, Perth computed tomography (CT) protocol is a valid measurement technique in determining both femoral and tibial component alignments. The aim of this study was to evaluate the accuracy of intraoperative component alignment by robotic-assisted TKA through CT validation. A total of 33 patients underwent TKA using the MAKO robotic-assisted TKA system. Intraoperative measurements of both femoral and tibial component placements, as well as limb alignment as determined by the MAKO software were recorded. Independent postoperative Perth CT protocol was obtained (n.29) and compared with intraoperative values. Mean absolute difference between intraoperative and postoperative measurements for the femoral component were 1.17 degrees (1.10) in the coronal plane, 1.79 degrees (1.12) in the sagittal plane, and 1.90 degrees (1.88) in the transverse plane. Mean absolute difference between intraoperative and postoperative measurements for the tibial component were 1.03 degrees (0.76) in the coronal plane and 1.78 degrees (1.20) in the sagittal plane. Mean absolute difference of limb alignment was 1.29 degrees (1.25), with 93.10% of measurements within 3 degrees of postoperative CT measurements. Overall, intraoperatively measured component alignment as estimated by the MAKO robotic-assisted TKA system is comparable to CT-based measurements.

Aim

There have been many attempts to define the criteria by which prosthetic joint infection (PJI) is diagnosed. Our aim is to validate the 2021 European Bone and Joint Infection Society (EBJIS) definition of PJI.

Introduction and Aims

Sensor technology is seeing increased utility in joint arthroplasty, guiding surgeons in assessing the soft tissue envelope intra-operatively (OrthoSensor, FL, USA). Meanwhile, surgical navigation systems are also transforming, with the recent introduction of inertial measurement unit (IMU) based systems no longer requiring optical trackers and infrared camera systems in the operating room (i.e. OrthAlign, CA, USA). Both approaches have now been combined by embedding an IMU into an intercompartmental load sensor. As a result, the alignment of the tibial varus/valgus cut is now measured concurrently with the mediolateral tibiofemoral contact load magnitudes and locations. The wireless sensor is geometrically identical to the tibial insert trial and is placed on the tibial cutting plane after completing the proximal tibial cut. Subsequently, the knee is moved through a simple calibration maneuver, rotating the tibia around the heel. As a result, the sensor provides a direct assessment of the obtained tibial varus/valgus alignment. This study presents the validation of this measurement.