Early large treatment effects can arise in small studies, which lessen as more data accumulate. This study aimed to retrospectively examine whether early treatment effects occurred for two multicentre orthopaedic randomized controlled trials (RCTs) and explore biases related to this. Included RCTs were ProFHER (PROximal Fracture of the Humerus: Evaluation by Randomisation), a two-arm study of surgery versus non-surgical treatment for proximal humerus fractures, and UK FROST (United Kingdom Frozen Shoulder Trial), a three-arm study of two surgical and one non-surgical treatment for frozen shoulder. To determine whether early treatment effects were present, the primary outcome of Oxford Shoulder Score (OSS) was compared on forest plots for: the chief investigator’s (CI) site to the remaining sites, the first five sites opened to the other sites, and patients grouped in quintiles by randomization date. Potential for bias was assessed by comparing mean age and proportion of patients with indicators of poor outcome between included and excluded/non-consenting participants.Aims
Methods
The Ponseti method is the gold standard treatment for congenital talipes equinovarus (CTEV), with the British Consensus Statement providing a benchmark for standard of care. Meeting these standards and providing expert care while maintaining geographical accessibility can pose a service delivery challenge. A novel ‘Hub and Spoke’ Shared Care model was initiated to deliver Ponseti treatment for CTEV, while addressing standard of care and resource allocation. The aim of this study was to assess feasibility and outcomes of the corrective phase of Ponseti service delivery using this model. Patients with idiopathic CTEV were seen in their local hospitals (‘Spokes’) for initial diagnosis and casting, followed by referral to the tertiary hospital (‘Hub’) for tenotomy. Non-idiopathic CTEV was managed solely by the Hub. Primary and secondary outcomes were achieving primary correction, and complication rates resulting in early transfer to the Hub, respectively. Consecutive data were prospectively collected and compared between patients allocated to Hub or Spokes. Mann-Whitney U test, Wilcoxon signed-rank test, or chi-squared tests were used for analysis (alpha-priori = 0.05, two-tailed significance).Aims
Methods
Prior to the availability of vaccines, mortality for hip fracture patients with concomitant COVID-19 infection was three times higher than pre-pandemic rates. The primary aim of this study was to determine the 30-day mortality rate of hip fracture patients in the post-vaccine era. A multicentre observational study was carried out at 19 NHS Trusts in England. The study period for the data collection was 1 February 2021 until 28 February 2022, with mortality tracing until 28 March 2022. Data collection included demographic details, data points to calculate the Nottingham Hip Fracture Score, COVID-19 status, 30-day mortality, and vaccination status.Aims
Methods
Ganz’s studies made it possible to address joint deformities on both the femoral and acetabular side brought about by Perthes’ disease. Femoral head reduction osteotomy (FHRO) was developed to improve joint congruency, along with periacetabular osteotomy (PAO), which may enhance coverage and containment. The purpose of this study is to show the clinical and morphological outcomes of the technique and the use of an implemented planning approach. From September 2015 to December 2021, 13 FHROs were performed on 11 patients for Perthes’ disease in two centres. Of these, 11 hips had an associated PAO. A specific CT- and MRI-based protocol for virtual simulation of the corrections was developed. Outcomes were assessed with radiological parameters (sphericity index, extrusion index, integrity of the Shenton’s line, lateral centre-edge angle (LCEA), Tönnis angle), and clinical parameters (range of motion, visual analogue scale (VAS) for pain, Merle d'Aubigné-Postel score, modified Harris Hip Score (mHHS), and EuroQol five-dimension five-level health questionnaire (EQ-5D-5L)). Early and late complications were reported.Aims
Methods
To assess the cost-effectiveness of a two-layer compression bandage versus a standard wool and crepe bandage following total knee arthroplasty, using patient-level data from the Knee Replacement Bandage Study (KReBS). A cost-utility analysis was undertaken alongside KReBS, a pragmatic, two-arm, open label, parallel-group, randomized controlled trial, in terms of the cost per quality-adjusted life year (QALY). Overall, 2,330 participants scheduled for total knee arthroplasty (TKA) were randomized to either a two-layer compression bandage or a standard wool and crepe bandage. Costs were estimated over a 12-month period from the UK NHS perspective, and health outcomes were reported as QALYs based on participants’ EuroQol five-dimesion five-level questionnaire responses. Multiple imputation was used to deal with missing data and sensitivity analyses included a complete case analysis and testing of costing assumptions, with a secondary analysis exploring the inclusion of productivity losses.Aims
Methods
The number of females within the speciality of trauma and orthopaedics (T&O) is increasing. The aim of this study was to identify: 1) current attitudes and behaviours of UK female T&O surgeons towards pregnancy; 2) any barriers faced towards pregnancy with a career in T&O surgery; and 3) areas for improvement. This is a cross-sectional study using an anonymous 13-section web-based survey distributed to female-identifying T&O trainees, speciality and associate specialist surgeons (SASs) and locally employed doctors (LEDs), fellows, and consultants in the UK. Demographic data was collected as well as closed and open questions with adaptive answering relating to attitudes towards childbearing and experiences of fertility and complications associated with pregnancy. A descriptive data analysis was carried out.Aims
Methods
To examine whether natural language processing (NLP) using a clinically based large language model (LLM) could be used to predict patient selection for total hip or total knee arthroplasty (THA/TKA) from routinely available free-text radiology reports. Data pre-processing and analyses were conducted according to the Artificial intelligence to Revolutionize the patient Care pathway in Hip and knEe aRthroplastY (ARCHERY) project protocol. This included use of de-identified Scottish regional clinical data of patients referred for consideration of THA/TKA, held in a secure data environment designed for artificial intelligence (AI) inference. Only preoperative radiology reports were included. NLP algorithms were based on the freely available GatorTron model, a LLM trained on over 82 billion words of de-identified clinical text. Two inference tasks were performed: assessment after model-fine tuning (50 Epochs and three cycles of k-fold cross validation), and external validation.Aims
Methods
Deprivation underpins many societal and health inequalities. COVID-19 has exacerbated these disparities, with access to planned care falling greatest in the most deprived areas of the UK during 2020. This study aimed to identify the impact of deprivation on patients on growing waiting lists for planned care. Questionnaires were sent to orthopaedic waiting list patients at the start of the UK’s first COVID-19 lockdown to capture key quantitative and qualitative aspects of patients’ health. A total of 888 respondents were divided into quintiles, with sampling stratified based on the Index of Multiple Deprivation (IMD); level 1 represented the ‘most deprived’ cohort and level 5 the ‘least deprived’.Aims
Methods
Global literature suggests that female surgical trainees have lower rates of independent operating (operative autonomy) than their male counterparts. The objective of this study was to identify any association between gender and lead/independent operating in speciality orthopaedic trainees within the UK national training programme. This was a retrospective case-control study using electronic surgical logbook data from 2009 to 2021 for 274 UK orthopaedic trainees. Total operative numbers and level of supervision were compared between male and female trainees, with correction for less than full-time training (LTFT), prior experience, and time out during training (OOP). The primary outcome was the percentage of cases undertaken as lead surgeon (supervised and unsupervised) by UK orthopaedic trainees by gender.Aims
Methods
To identify the responsiveness, minimal clinically important difference (MCID), minimal clinical important change (MIC), and patient-acceptable symptom state (PASS) thresholds in the 36-item Short Form Health Survey questionnaire (SF-36) (v2) for each of the eight dimensions and the total score following total knee arthroplasty (TKA). There were 3,321 patients undergoing primary TKA with preoperative and one-year postoperative SF-36 scores. At one-year patients were asked how satisfied they were and “How much did the knee arthroplasty surgery improve the quality of your life?”, which was graded as: great, moderate, little (n = 277), none (n = 98), or worse.Aims
Methods
To compare the cost-utility of removable brace compared with cast in the management of adult patients with ankle fracture. A within-trial economic evaluation conducted from the UK NHS and personnel social services (PSS) perspective. Health resources and quality-of-life data were collected as part of the Ankle Injury Rehabilitation (AIR) multicentre, randomized controlled trial over a 12-month period using trial case report forms and patient-completed questionnaires. Cost-utility analysis was estimated in terms of the incremental cost per quality adjusted life year (QALY) gained. Estimate uncertainty was explored by bootstrapping, visualized on the incremental cost-effectiveness ratio plane. Net monetary benefit and probability of cost-effectiveness were evaluated at a range of willingness-to-pay thresholds and visualized graphically.Aims
Methods
Thresholds of acceptable early migration of the components in total knee arthroplasty (TKA) have traditionally ignored the effects of patient and implant factors that may influence migration. The aim of this study was to determine which of these factors are associated with overall longitudinal migration of well-fixed tibial components following TKA. Radiostereometric analysis (RSA) data over a two-year period were available for 419 successful primary TKAs (267 cemented and 152 uncemented in 257 female and 162 male patients). Longitudinal analysis of data using marginal models was performed to examine the associations of patient factors (age, sex, BMI, smoking status) and implant factors (cemented or uncemented, the size of the implant) with maximum total point motion (MTPM) migration. Analyses were also performed on subgroups based on sex and fixation.Aims
Methods
The cemented Oxford unicompartmental knee arthroplasty (OUKA) features two variants: single and twin peg OUKA. The purpose of this study was to assess the stability of both variants in a worst-case scenario of bone defects and suboptimal cementation. Single and twin pegs were implanted randomly allocated in 12 pairs of human fresh-frozen femora. We generated 5° bone defects at the posterior condyle. Relative movement was simulated using a servohydraulic pulser, and analyzed at 70°/115° knee flexion. Relative movement was surveyed at seven points of measurement on implant and bone, using an optic system.Aims
Methods
Navigation devices are designed to improve a surgeon’s accuracy in positioning the acetabular and femoral components in total hip arthroplasty (THA). The purpose of this study was to both evaluate the accuracy of an optical computer-assisted surgery (CAS) navigation system and determine whether preoperative spinopelvic mobility (categorized as hypermobile, normal, or stiff) increased the risk of acetabular component placement error. A total of 356 patients undergoing primary THA were prospectively enrolled from November 2016 to March 2018. Clinically relevant error using the CAS system was defined as a difference of > 5° between CAS and 3D radiological reconstruction measurements for acetabular component inclination and anteversion. Univariate and multiple logistic regression analyses were conducted to determine whether hypermobile (Aims
Methods
The aim of this study was to assess medium-term improvements following total hip arthroplasty (THA), and to evaluate what effect different preoperative Oxford Hip Score (OHS) thresholds for treatment may have on patients’ access to THA and outcomes. Patients undergoing primary THA at our institution with an OHS both preoperatively and at least four years postoperatively were included. Rationing thresholds were explored to identify possible deprivation of OHS improvement.Aims
Methods
An objective technological solution for tracking adherence to at-home shoulder physiotherapy is important for improving patient engagement and rehabilitation outcomes, but remains a significant challenge. The aim of this research was to evaluate performance of machine-learning (ML) methodologies for detecting and classifying inertial data collected during in-clinic and at-home shoulder physiotherapy exercise. A smartwatch was used to collect inertial data from 42 patients performing shoulder physiotherapy exercises for rotator cuff injuries in both in-clinic and at-home settings. A two-stage ML approach was used to detect out-of-distribution (OOD) data (to remove non-exercise data) and subsequently for classification of exercises. We evaluated the performance impact of grouping exercises by motion type, inclusion of non-exercise data for algorithm training, and a patient-specific approach to exercise classification. Algorithm performance was evaluated using both in-clinic and at-home data.Aims
Methods
Studies on long-term patient-reported outcomes after open surgery for triangular fibrocartilage complex (TFCC) are scarce. Surgeons and patients would benefit from self-reported outcome data on pain, function, complications, and satisfaction after this surgery to enhance shared decision-making. The aim of this study is to determine the long-term outcome of adults who had open surgery for the TFCC. A prospective cohort study that included patients with open surgery for the TFCC between December 2011 and September 2015. In September 2020, we sent these patients an additional follow-up questionnaire, including the Patient-Rated Wrist Evaluation (PRWE), to score satisfaction, complications, pain, and function.Aims
Methods
In total knee arthroplasty (TKA), blood loss continues internally after surgery is complete. Typically, the total loss over 48 postoperative hours can be around 1,300 ml, with most occurring within the first 24 hours. We hypothesize that the full potential of tranexamic acid (TXA) to decrease TKA blood loss has not yet been harnessed because it is rarely used beyond the intraoperative period, and is usually withheld from ‘high-risk’ patients with a history of thromboembolic, cardiovascular, or cerebrovascular disease, a patient group who would benefit greatly from a reduced blood loss. TRAC-24 was a prospective, phase IV, single-centre, open label, parallel group, randomized controlled trial on patients undergoing TKA, including those labelled as high-risk. The primary outcome was indirect calculated blood loss (IBL) at 48 hours. Group 1 received 1 g intravenous (IV) TXA at the time of surgery and an additional 24-hour postoperative oral regime of four 1 g doses, while Group 2 only received the intraoperative dose and Group 3 did not receive any TXA.Aims
Methods
Little guidance exists in the current literature regarding which patient recorded outcome measures (PROMs) are most clinically appropriate following anterior cruciate ligament reconstruction (ACL) surgery, and what results surgeons should expect or accept. Many PROMs have been validated, but their “ideal” results have not been published, limiting a surgeon's ability to compare their patients’ outcomes with those of their colleagues. We undertook a systematic review of PROMs for ACL to look at common usage and outcomes. After appropriate paper selection, we then undertook a pragmatic meta-analysis (i.e., including all papers that fulfilled the selection criteria, regardless of CONSORT status) and calculated weighted mean outcome scores and
Patients may be able to return to higher level activities following hip arthroplasty with modern techniques and prostheses, but the Oxford hip score, the standard PROM used by the NJS exhibits severe skew and kurtosis. The commonest score is 48/48. Most patients score above 40 preventing any discrimination between approaches or prostheses. We therefore sought both subjective and objective metrics which were relevant and valid without skew or high kurtosis in postoperative patients. The Metabolic Equivalent of Task (MET) reports energy usage in kcal/min burnt across a range of activities, condensed into a score of 0–25. A MET over 8 is considered ‘conditioning exercise’ tethered to life expectancy. A 2 point difference in average MET is considered a clinically relevant difference. Walking speed is a simple valid metric tethered to life expectancy, with a 0.1m/sec difference in walking speed equates to a clinically important difference. Oxford Hip Score (OHS), and the MET were prospectively recorded in 221 primary hip arthroplasty procedures pre-operatively and at 1-year using a web based application. Pre and postoperative Gait analysis was undertaken on a subgroup of 34 patients, in comparison with age and sex matched controls. Post-operatively, the OHS demonstrated significant skewed distributions with ceiling effects of 41% scoring 48/48. The MET was normally distributed around a mean of 10.3, with a
Utility score is a preference-based measure of general health state – where 0 is equal to death, and 1 is equal to perfect health. To understand a patient's smallest perceptible change in utility score, the minimal clinically important difference (MCID) can be calculated. However, there are multiple methods to calculate MCID with no consensus about which method is most appropriate. The aim of this study is to calculate MCID values for the Veterans-RAND 12 (VR12) utility score using varying methods. Our hypothesis is that different methods will yield different MCID values. A tertiary institutional registry (SMART) was used as the study cohort. Patients who underwent unilateral TKA for osteoarthritis from January 2012 to January 2020 were included. Utility score was calculated from VR12 responses using the standardised Brazier's method. Distribution and anchor methods were used for the MCID calculation. For distribution methods, 0.5
Successful estimation of postoperative PROMs prior to a joint replacement surgery is important in deciding the best treatment option for a patient. However, estimation of the outcome is associated with substantial noise around individual prediction. Here, we test whether a classifier neural network can be used to simultaneously estimate postoperative PROMs and uncertainty better than current methods. We perform Oxford hip score (OHS) estimation using data collected by the NJR from 249,634 hip replacement surgeries performed from 2009 to 2018. The root mean square error (RMSE) of the various methods are compared to the
Bone age is a radiographical assessment used in pediatric medicine due to its relative objectivity in determining biological maturity compared to chronological age and size.1 Currently, Greulich and Pyle (GP) is one of the most common methods used to determine bone age from hand radiographs.2–4 In recent years, new methods were developed to increase the efficiency in bone age analysis like the shorthand bone age (SBA) and the automated artificial intelligence algorithms. The purpose of this study is to evaluate the accuracy and reliability of these two methods and examine if the reduction in analysis time compromises their accuracy. Two hundred thirteen males and 213 females were selected. Each participant had their bone age determined by two separate raters using the GP (M1) and SBA methods (M2). Three weeks later, the two raters repeated the analysis of the radiographs. The raters timed themselves using an online stopwatch while analyzing the radiograph on a computer screen. De-identified radiographs were securely uploaded to an automated algorithm developed by a group of radiologists in Toronto. The gold standard was determined to be the radiology report attached to each radiograph, written by experienced radiologists using GP (M1). For intra-rater variability, intraclass correlation analysis between trial 1 (T1) and trial 2 (T2) for each rater and method was performed. For inter-rater variability, intraclass correlation was performed between rater 1 (R1) and rater 2 (R2) for each method and trial. Intraclass correlation between each method and the gold standard fell within the 0.8–0.9 range, highlighting significant agreement. Most of the comparisons showed a statistically significant difference between the two new methods and the gold standard; however it may not be clinically significant as it ranges between 0.25–0.5 years. A bone age is considered clinically abnormal if it falls outside 2
The functional pelvic tilt when standing and sitting forward of 7402 cases on the OPS, Optimized Ortho, Australia Data Base were reviewed. All patients had undergone lateral radiographs when standing simulating extension of the hip, and sitting forward when the hip is near full flexion. Pelvic tilt was measured as the angle of the Anterior Pelvic Plane to the vertical Sagittal Plane, rotation anteriorly being given a positive value. Pelvises that had rotated more than 13 degrees anteriorly (+ve) when sitting forward or posteriorly (-ve) when standing were considered to place the hip at increased risk of dislocation or edge loading when flexed or extending respectively. This degree of rotation has the effect of changing the acetabular version by approximately10. 0. Most safe zones that have been described have given a range of anteversion of 20. 0. as safe. A change of 10. 0. would potentially place the acetabular orientation outside this range. Further, clinical studies have supported this concept. All lateral radiographs were reviewed to confirm that 281 had undergone instrumented spinal fusion at some level between T12 and S1. There was a large variability in the number and the levels arthrodesed. The range of pelvic mobility in the non-arthrodesed group in extension was −37. 0. to 31. 0. (mean −0.9. 0. ,
Aims. Radiological residual acetabular dysplasia (RAD) has been reported in up to 30% of children who had successful brace treatment of infant developmental dysplasia of the hip (DDH). Predicting those who will resolve and those who may need corrective surgery is important to optimize follow-up protocols. In this study we have aimed to identify the prevalence and predictors of RAD at two years and five years post-bracing. Methods. This was a single-centre, prospective longitudinal cohort study of infants with DDH managed using a published, standardized Pavlik harness protocol between January 2012 and December 2016. RAD was measured at two years’ mean follow-up using acetabular index-lateral edge (AI-L) and acetabular index-sourcil (AI-S), and at five years using AI-L, AI-S, centre-edge angle (CEA), and acetabular depth ratio (ADR). Each hip was classified based on published normative values for normal, borderline (1 to 2
INTRODUCTION. Determining proper joint tension in reverse total shoulder arthroplasty (rTSA) can be a challenging task for shoulder surgeons. Often, this is a subjective metric learned by feel during fellowship training with no real quantitative measures of what proper tension encompasses. Tension too high can potentially lead to scapular stress fractures and limitation of range of motion (ROM), whereas tension too low may lead to instability. New technologies that detect joint load intraoperatively create the opportunity to observe rTSA joint reaction forces in a clinical setting for the first time. The purpose of this study was to observe the differences in rTSA loads in cases that utilized two different humeral liner sizes. METHODS. Ten different surgeons performed a total of 37 rTSA cases with the same implant system. During the procedure, each surgeon reconstructed the rTSA implants to his or her own preferred tension. A wireless load sensing humeral liner trial (VERASENSE for Equinoxe, OrthoSensor, Dania Beach, FL) was used in lieu of a traditional plastic humeral liner trial to provide real-time load data to the operating surgeon during the procedure. Two humeral liner trial sizes were offered in 38mm and 42mm curvatures and were selected each case based on surgeon preference. To ensure consistent measurements between surgeons, a standardized ROM assessment consisting of four dynamic maneuvers (maximum internal to external rotation at 0°, 45°, and 90° of abduction, and a maximum flexion/extension maneuver) and three static maneuvers (arm overhead, across the body, and behind the back) was completed in each case. Deidentified load data in lbf was collected and sorted based on which size liner was selected. Differences in means for minimum and maximum load values for the four dynamic maneuvers and differences in means for the three static maneuvers were calculated using 2-tailed unpaired t-tests. RESULTS. No significant differences were observed for the flexion/extension maneuver between the 38mm and 42mm liner sizes, but a significant difference was observed for every internal/external rotation assessment at 0°, 45°, and 90° of abduction. No significant differences were observed for the across the body and overhead maneuvers, but a significant difference was observed for the behind the back maneuver (p = 0.015).
Functional outcomes are commonly reported in studies of musculoskeletal oncology patients undergoing limb salvage surgery; however, interpretation requires knowledge of the smallest amount of improvement that is important to patients – the minimally important difference (MID). We established the MIDs for the Musculoskeletal Tumor Society Rating Scale (MSTS) and Toronto Extremity Salvage Score (TESS) in patients with bone tumors undergoing lower limb salvage surgery. This study was a secondary analysis of the recently completed PARITY (Prophylactic Antibiotic Regimens in Tumor Surgery) study. This data was used to calculate: (1) the anchor-based MIDs using an overall function scale and a receiver operating curve analysis, and (2) the distribution-based MIDs based on one-half of the
Successful estimation of postoperative PROMs prior to a joint replacement surgery is important in deciding the best treatment option for a patient. However, estimation of the outcome is associated with substantial noise around individual prediction. Here, we test whether a classifier neural network can be used to simultaneously estimate postoperative PROMs and uncertainty better than current methods. We perform Oxford hip score (OHS) estimation using data collected by the NJR from 249,634 hip replacement surgeries performed from 2009 to 2018. The root mean square error (RMSE) of the various methods are compared to the
Cam-type femoroacetabular impingement is caused by bone excess on the femoral neck abutting the acetabular rim. This can cause cartilage and labral damage due to increased contact pressure as the cam moves into the acetabulum. However, the damage mechanism and the influence of individual mechanical factors (such as sliding distance) are poorly understood. The aim of this study was to identify the cam sliding distance during impingement for different activities in the hip joint. Motion data for 12 different motion activities from 18 subjects, were applied to a hip shape model (selected as most likely to cause damage, anteriorly positioned with a maximum alpha angle of 80°). The model comprised of a pointwise representation of the acetabular rim and points on the femoral head and neck where the shape deviated from a sphere (software:Matlab). The movement of each femoral point was tracked in 3D while an activity motion was applied, and impingement recorded when overlap between a cam point and the acetabular rim occurred. Sliding distance was recorded during impingement for each relevant femoral point. Angular sliding distances varied for different activities. The highest mean (±SD) sliding distance was for leg-crossing (42.62±17.96mm) and lowest the trailing hip in golf swing (2.17±1.11mm). The high
Background. The use of a knotless TightRope for the stabilisation of a syndesmotic injury is a well-recognised mode of fixation. It has been described that the device can be inserted using a “closed” technique. This presents a risk of saphenous nerve entrapment and post-operative pain. Aim. We aimed to establish the actual risk of injury to the Saphenous Nerve using a “closed” technique for the insertion of a TightRope. Method. 20 TightRopes were inserted into Fresh Frozen Cadavers. This was done using the senior authors preferred technique of divergent tightropes with the distal implant directed slightly anterior to the fibula-tibia axis and the proximal implant slightly posterior in order to simulate the greatest risk to the nerve. This was done under image Intensifier guidance to simulate an intraoperative environment. The medial side of the distal tibia was then dissected to directly record and measure the relationship of the TightRope to the Saphenous Nerve. Measurements were taken using digital calipers from the centre of the button on the medial side of the TightRope to the centre of the nerve at the point of closest proximity. Results. 12 TightRopes were found to exit posterior to the nerve, 7 anterior and 1 penetrated through the centre of the nerve. The mean distance from the centre of the button to the nerve was 6.99mm (range 0.72–14.52mm,
Abstract. Background. Aim of this study is to determine the difference between re-operation rates after conventional Methods of fixation of patella fractures using Metallic implants and novel technique of all suture fixation using Ethibond or fiber tape. Methods. This is a retrospective comparative analysis involving 62 patients who had a transverse patellar fracture and underwent surgery between January 2013 to December 2021. Selected patients were divided, based on different fixation methods used, into four groups - TBW group, CC screw group, Encirclage group and Suture Fixation Group. Patients were followed till bone union was evident on radiographs. Number of patients in Metallic implant group undergoing repeat operation were compared with the patients who underwent patella fracture fixation using all suture technique. Mean and
In this RCT the primary aim was to assess whether a short (125mm) Exeter V40 stem offered an equivalent hip specific function compared to the standard (150mm) stem when used for cemented total hip arthroplasty (THA). Secondary aims were to evaluate health-related quality of life (HRQoL), patient satisfaction, stem height and alignment, radiographic loosening, and complications between the two stems. A prospective multicentre double-blind randomised control trial was conducted. During a 15-month period, 220 patients undergoing THA were randomised to either a standard (n=110) or short (n=110) stem Exeter. There were no significant (p≥0.065) differences in preoperative variables between the groups. Functional outcomes and radiographic assessment were undertaken at 1- and 2-years. There were no differences (p=0.428) in hip specific function according to the Oxford hip score at 1-year (primary endpoint) or at 2-years (p=0.767) between the groups. The short stem group had greater varus angulation (0.9 degrees, p=0.003) when compared to the standard group and were more likely (odds ratio 2.42, p=0.002) to have varus stem alignment beyond one
Introduction. Recent technological advancements have led to the introduction of robotic-assisted total knee arthroplasty to improve the accuracy and precision of bony resections and implant position. However, the in vivo accuracy is not widely reported. The primary objective of this study is to determine the accuracy and precision of a cut block positioning robotic arm. Method. Seventy-seven patients underwent total knee arthroplasty with various workflows and alignment targets by three arthroplasty-trained surgeons with previous experience using the ROSA® Knee System. Accuracy and precision were determined by measuring the difference between various workflow time points, including the final pre-operative plan, validated resection angle, and post-operative radiographs. The mean difference between the measurements determined accuracy, and the
Femoroacetabular Impingement (FAI) syndrome, characterised by abnormal hip contact causing symptoms and osteoarthritis, is measured using the International Hip Outcome Tool (iHOT). This study uses machine learning to predict patient outcomes post-treatment for FAI, focusing on achieving a minimally clinically important difference (MCID) at 52 weeks. A retrospective analysis of 6133 patients from the NAHR who underwent hip arthroscopic treatment for FAI between November 2013 and March 2022 was conducted. MCID was defined as half a
Current treatment options for displaced acetabular fractures in elderly patients include non-surgical management, surgical fixation and surgical fixation with simultaneous hip replacement, the so-called “fix-and-replace”™. There remains a paucity of evidence to guide surgeons in decision making for these difficult injuries. The aim of this study was to assess the feasibility of performing an appropriately powered RCT between treatment options for acetabular fractures in older patients. This was an NIHR funded feasibility triple-arm RCT with participation from 7 NHS MTCs. Patients older than 60 were recruited if they had an acetabular fracture deemed sufficiently displaced for the treating surgeon to consider surgical fixation. Randomisation was performed on a 1:1:1 basis. The three treatment arms were non-surgical management, surgical fixation and fix-and-replace. Feasibility was assessed by willingness of patients to participate and clinicians to recruit, drop out rate, estimates of
Background. There are many different procedures described for the correction of hallux valgus deformity. Minimally invasive surgery has become increasingly popular, with clinical and radiological outcomes comparable to traditional open osteotomy approaches. There is increasing interest in hallux valgus deformity correction using third-generation minimally invasive chevron akin osteotomy (MICA) technique. Objective. To assess the radiographic correction and 2 year clinical outcomes of third-generation MICA using validated outcome measures. Methods. This is a prospective single-surgeon case series of 420 consecutive feet undergoing MICA surgery between July 2014 and November 2018. Primary clinical outcome measures included the Manchester-Oxford Foot Questionnaire (MOXFQ), EQ-5D, and the Visual Analogue Pain Scale. Secondary outcome measures included radiographic parameters, and complication rates. Results. Pre-operative and 2 year post-operative patient reported outcomes were collected for 334 feet (79.5%). At minimum 2 year follow-up, the MOXFQ scores (mean ±
The angle of acetabular inclination is an important measurement in total hip replacement (THR) procedures. Determining the acetabular component orientation intra-operatively remains a challenge. An increasing number of innovators have described techniques and devices to achieve it. This paper describes a mechanical inclinometer design to measure intra-operative acetabular cup inclination. Then, the mechanical device is tested to determine its accuracy. The aim was to design an inclinometer to measure inclination without existing instrumentation modification. The device was designed to meet the following criteria: 1. measure inclination with acceptable accuracy (+/− 5o); 2. easy to use intra-operatively (handling & visualization); 3. adaptable and useable with majority of instrumentation kits without modification; 4. sterilizable by all methods; 5. robust/reusable. The prototype device was drafted by computer aided design (CAD) software. Then a prototype was constructed using a 3D printer to establish the final format. The final device was CNC machined from SAE 304 stainless steel. The design uses an eccentrically weighted flywheel mounted on two W16002-2RS ball bearings pressed into symmetrical housing components. The weighted wheel is engraved with calibrated markings relative to its mass centre. Device functioning is dependent on gravity maintaining the weighted wheel in a fixed orientation while the housing can adapt to the calibration allowing for determining the corresponding measurement. The prototype device accuracy was compared to a digital device. A digital protractor was used to create an angle. The mechanical inclinometer (user blinded to digital reading) was used to determine the angle and compared to the digital reading. The accuracy of the device compared to the standard freehand technique was assessed using a saw bone pelvis fixed in a lateral decubitus position. 18 surgeons (6 expert, 6 intermediate, 6 novice) were asked to place an uncemented acetabular cup in a saw bone pelvis to a target of 40 degrees. First freehand then using the inclinometer. The inclination was determined using a custom-built inertial measurement unit with the user blinded to the result. Comparison between the mechanical and digital devices showed that the mechanical device had an average error of −0.2, a
Critical-sized bone defects can result from trauma, inflammation, and tumor resection. Such bone defects, often have irregular shapes, resulting in the need for new technologies to produce suitable implants. Bioprinting is an additive manufacturing method to create complex and individualised bone constructs, which can already include vital cells. In this study, we established an extrusion-based printing technology to produce osteoinductive scaffolds based on polycaprolactone (PCL) combined with calcium phosphate, which is known to induce osteogenic differentiation of stem cells. The model was created in python based on the signed distance functions. The shape of the 3D model is a ring with a diameter of 20 mm and a height of 10 mm with a spongiosa-like structure. The interconnected irregular pores have a diameter of 2 mm +/− 0.2 mm
Background. Lateral lumbar spine statistical shape models (SSM) have been used previously to describe associations with osteoarthritis and back pain. However, associations with factors such as osteoporosis, menopause and parity have not been explored. Methods and Results. A 143-point SSM, describing L1 to the top of L5, was applied to lateral spine iDXA scans from UK Biobank. Associations with self-reported osteoporosis, menopause, parity and back pain and the first 10 modes of variation were examined using adjusted binary logistic regression or linear regression (adjusted for age, height, weight and total spine BMD). We report odds ratios with 95% confidence intervals for each
Previous studies have highlighted differences in the risk of periprosthetic fracture between tapered slip (TS) and composite beam (CB) stems. This biomechanical study explored periprosthetic fractures around these stems and the effect of adding a 16-gauge calcar or diaphyseal wire to TS stems on their resistance to torque. A power analysis determined a sample size of 7 specimens per group, assuming a
Background. Artificial total knee designs have revolutionized over time, yet 20% of the population still report dissatisfaction. The standard implants fail to replicate native knee kinematic functionality due to mismatch of condylar surfaces and non-anatomically placed implantation. (Daggett et al 2016; Saigo et al 2017). It is essential that the implant surface matches the native knee to prevent Instability and soft tissue impingement. Our goal is to use computational modeling to determine the ideal shapes and orientations of anatomically-shaped components and test the accuracy of fit of component surfaces. Methods. One hundred MRI scans of knees with early osteoarthritis were obtained from the NIH Osteoarthritis Initiative, converted into 3D meshes, and aligned via an anatomic coordinate system algorithm. Geomagic Design X software was used to determine the average anterior-posterior (AP) length. Each knee was then scaled in three dimensions to match the average AP length. Geomagic's least-squares algorithm was used to create an average surface model. This method was validated by generating a statistical shaped model using principal component analysis (PCA) to compare to the least square's method. The averaged knee surface was used to design component system sizing schemes of 1, 3, 5, and 7 (fig 1). A further fifty arthritic knees were modeled to test the accuracy of fit for all component sizing schemes.
To investigate whether anterior pelvic plane-pelvic tilt (APP-PT) is associated with distinct hip pathomorphologies, we asked: (1) Is there a difference in APP-PT between symptomatic young patients eligible for joint preservation surgery and an asymptomatic control group? (2) Does APP-PT vary between distinct acetabular and femoral pathomorphologies? (3) Does APP-PT differ in symptomatic hips based on demographic factors?. IRB-approved, single-center, retrospective, case-control, comparative study in 388 symptomatic hips (357) patients (mean age 26 ± 2 years [range 23 to 29], 50% females) that presented to our tertiary center for joint preservation over a five year-period. Patients were allocated to 12 different morphologic subgroups. The overall study group was compared to a control group of 20 asymptomatic hips (20 patients). APP-PT was assessed in all patients based on AP pelvis X-rays using the validated HipRecon software. Values between overall and control group were compared using an independent samples t-test. Multiple regression analysis was performed to examine the influences of diagnoses and demographic factors on APP-PT. Minimal clinically important difference (MCID) of APP-PT was defined as >1
Restoration a joint's articular surface following degenerative or traumatic pathology to the osteochondral unit pose a significant challenge. Recent advances have shown the utility of collagen-based scaffolds in the regeneration of osteochondral tissue. To provide these collagen scaffolds with the appropriate superstructure novel techniques in 3D printing have been investigated. This study investigates the use of polyɛ-caprolactone (PCL) collagen scaffolds in a porcine cadaveric model to establish the stability of the biomaterial once implanted. This study was performed in a porcine cadaveric knee model. 8mm defects were created in the medial femoral trochlea and repaired with a PCL collagen scaffold. Scaffolds were secured by one of three designs; Press Fit (PF), Press Fit with Rings (PFR), Press Fit with Fibrin Glue (PFFG). Mobilisation was simulated by mounting the pig legs on a continuous passive motion (CPM) machine for either 50 or 500 cycles. Biomechanical tensile testing was performed to examine the force required to displace the scaffold. 18 legs were used (6 PF, 6 PFR, 6 PFFG). Fixation remained intact in 17 of the cohort (94%). None of the PF or PFFG scaffolds displaced after CPM cycling. Mean peak forces required to displace the scaffold were highest in the PFFG group (3.173 Newtons,
To characterize the microstructural organization of collagen fibers in human medial menisci and the response to mechanical loading in relation to age. We combine high resolution imaging with mechanical compression to visualize the altered response of the tissue at the microscale. Menisci distribute the load in the knee and are predominantly composed of water and specifically hierarchically arranged collagen fibers. Structural and compositional changes are known to occur in the meniscus during aging and development of osteoarthritis. However, how microstructural changes due to degeneration affect mechanical performance is still largely unknown [1]. Fresh frozen 4 mm Ø plugs of human medial menisci (n=15, men, 20-85 years) with no macroscopic damage nor known diseases from the MENIX biobank at Skåne University Hospital were imaged by phase contrast synchrotron tomography at the TOMCAT beamline (Paul Scherrer Institute, CH). A rheometer was implemented into the beamline to perform in-situ stress relaxation (2 steps 15% and 30% strain) during imaging (21 keV, 2.75μm pixel size). 40s scans were acquired before and after loading, while 14 fast tomographs (5s acquisitions) were taken during relaxation. The fiber 3D orientations and structural changes during loading were determined using a structure tensor approach (adapting a script from [1]). The 3D collagen fiber orientation in menisci revealed alternating layers of fibers. Two main areas are shown: surfaces and bulk. The surface layers are a mesh of randomly oriented fibers. Within the bulk 2-3 layers of fibers are visible that alternate about 30° to each other. Structural degeneration with age is visible and is currently being quantified. During stress-relaxation all menisci show a similar behavior, with samples from older donors being characterized by larger
Abstract. Introduction. Tibial tubercle osteotomy (TTO) is a complex surgical procedure with a significant risk of complications, which include nonunion and tibial fracture. To determine whether an additional suture tape augmentation can provide better biomechanical stability compared with standard screw fixation. Methods. Five matched pairs of human cadaveric knees were divided into 2 groups: the first group underwent standard TTO fixation with 2 parallel screws. The second group underwent a novel fixation technique, in which a nonabsorbable suture tape (FiberTape) in a figure-of-8 construct was added to the standard screw fixation. Tubercular fragment migration of >50% of the initial distalization length was defined as clinical failure Tubercular fragment displacement during cyclic loading and pull-to-failure force were recorded and compared between the 2 groups. Results. The augmented group showed less cyclic tubercular fragment displacement after every load level compared with the standard group, with statistically significant differences starting from 500 N (P < .05; power > 0.8). Mean ±
Whilst lateral ankle sprain is often considered a benign injury it represents between 3–5% of all A&E visits in the UK. The mechanical characteristics of ankle ligaments under sprain-like conditions are scarcely reported. The lateral collateral ankle ligaments were dissected from n=6 human cadaveric specimens to produce individual bone-ligament-bone specimens. An Instron Electropuls E10000 was used to uni-axially load the ankle ligaments in tension. The ligaments were first preconditioned between 2 N and a load value corresponding to 3.5% strain for 15 cycles and then strained to failure at a rate of 100%/s. The mean ultimate failure loads and their
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
Introduction. Achieving high flexion after total knee arthroplasty is very important for patients in Asian countries where deep flexion activities are an important part of daily life. The Bi-Surface Total Knee System (Japan Medical Material, Kyoto, Japan), which has a unique ball-and-socket mechanism in the mid-posterior portion of the femoral and tibial components, was designed to improve deep knee flexion and long-term durability after total knee arthroplasty (Figure 1). The purpose of this study was to determine the in vivo three dimensional kinematics of Bi-Surface Total Knee System in order to evaluate and analyze the performance of this system with other conventional TKA designs currently available in the market today. Materials and Methods. Three dimensional kinematics were evaluated during a weight-bearing deep knee bend activity using fluoroscopy and a 2D-to-3D registration technique for 66 TKA. Each knee was analyzed to determine femorotibial kinematics, including weight-bearing range of motion, anterior/posterior contact position, and tibio-femoral rotation. Results. The average weight-bearing range of motion for the entire group was 125.5∗∗∗∗∗. Forty three of sixty six knees had greater range of motion than 120∗∗∗∗∗. At full extension, the average contact positions were −0.5mm (range, from −12.2mm to 6.8mm;
Introduction. Removal of primary components during revision TKA procedure can damage underlying bone, resulting in defects that may need filled for stability of the revision reconstruction. Special revision components including cones and/or augments are often used to compensate for the missing bones. Little work has been done to characterize metaphyseal geometry in the vicinity of the knee joint, however, in order to motivate proper size and shape of cones and augments. The objective of this study was to use statistical shape modelling to evaluate variation in endosteal anatomy for revision TKA. Methods. Digital models of the femur and tibia were generated through segmentation of computed tomography scans, for the femur and the tibia (n∼500). Custom software was used to perform virtual surgery and statistical shape analysis of the metaphyseal geometry. A representative and appropriately sized revision femoral component was placed on each bone, assuming anterior referencing with an external rotation of 3 degrees from the posterior condyle axis. The outer and inner boundaries of the cortical bone were determined at the resection level and at 5 mm increments proximally, up to 40 mm. Similar analyses were performed on the tibia, using a typical revision resection (0 degrees medial and posterior slope), with outer and inner boundaries of the cortical bone were determined in 5 mm increments up to 40mm distal to the resection. Metaphyseal contours were exported relative to the central fixation feature of the implant, and average geometries were calculated based on size, and across the entire cohort. Principal Component Analysis (PCA) was used to quantify the variability in shape, specifically to evaluate the +/− 1 and 2
Decreasing the chance of local relapse or infection after surgical excision of bone metastases is a main goals in orthopedic oncology. Indeed, bone metastases have high incidence rate (up to 75%) and important cross-relations with infection and bone regeneration. Even in patients with advanced cancer, bone gaps resulting from tumor excision must be filled with bone substitutes. Functionalization of these substitutes with antitumor and antibacterial compounds could constitute a promising approach to overcome infection and tumor at one same time.
Here, for the first time, we propose the use of nanostructured zinc-bone apatite coatings having antitumor and antimicrobial efficacy. The coatings are obtained by Ionized Jet Deposition from composite targets of zinc and bovine-derived bone apatite.
Antibacterial and antibiofilm efficacy of the coatings is demonstrated in vitro against S. Aureus and E. Coli. Anti-tumor efficacy is investigated against MDA- MB-231 cells and biocompatibility is assessed on L929 and MSCs. A microfluidic based approach is used to select the optimal concentration of zinc to be used to obtain antitumor efficacy and avoid cytotoxicity, exploiting a custom gradient generator microfluidic device, specifically designed for the experiments. Then, coatings capable of releasing the desired amount of active compounds are manufactured. Films morphology, composition and ion-release are studies by FEG- SEM/EDS, XRD and ICP. Efficacy and biocompatibility of the coatings are verified by investigating MDA, MSCs and L929 viability and morphology by Alamar Blue, Live/Dead Assay and FEG-SEM at different timepoints. Statistical analysis is performed by SPSS/PC + Statistics TM 25.0 software, one-way ANOVA and post-hoc Sheffe? test. Data are reported as Mean ±
Hip Osteoarthritis (HOA) is the most common joint disorder and a major cause of disability in the adult population, leading to total hip replacement (THR). Recently, evidence has mounted for a prominent etiologic role of femoroacetabular impingement (FAI) in the development of early OA in the non-dysplastic hip. FAI is a pathological mechanical process, caused by abnormalities of the acetabulum and/or femur leading to damage the soft tissue structures. FAI can determine chondro-labral damage and groin pain in young adults and can accelerate HOA progression in middle-aged adults. The aim of the study was to determine if the presence of calcium crystal in synovial fluid (SF) at the time of FAI surgery affects the clinical outcomes to be used as diagnostic and predictive biomarker. 49 patients with FAI undergoing arthroscopy were enrolled after providing informed consent; 37 SFs were collected by arthrocentesis at the time of surgery and 35 analyzed (66% males), median age 35 years with
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
Infection in orthopedics is a challenge, since it has high incidence (rates can be up to 15-20%, also depending on the surgical procedure and on comorbidities), interferes with osseointegration and brings severe complications to the patients and high societal burden. In particular, infection rates are high in oncologic surgery, when biomedical devices are used to fill bone gaps created to remove tumors. To increase osseointegration, calcium phosphates coatings are used. To prevent infection, metal- and mainly silver-based coatings are the most diffused option. However, traditional techniques present some drawbacks, including scarce adhesion to the substrate, detachments, and/or poor control over metal ions release, all leading to cytotoxicity and/or interfering with osteointegration. Since important cross-relations exist among infection, osseointegration and tumors, solutions capable of addressing all would be a breakthrough innovation in the field and could improve clinical practice. Here, for the first time, we propose the use antimicrobial silver-based nanostructured thin films to simultaneously discourage infection and bone metastases. Coatings are obtained by Ionized Jet Deposition, a plasma-assisted technique that permits to manufacture films of submicrometric thickness having a nanostructured surface texture. These characteristics, in turn, allow tuning silver release and avoid delamination, thus preventing toxicity. In addition, to mitigate interference with osseointegration, here silver composites with bone apatite are explored. Indeed, capability of bone apatite coatings to promote osseointegration had been previously demonstrated in vitro and in vivo. Here, antibacterial efficacy and biocompatibility of silver-based films are tested in vitro and in vivo. Finally, for the first time, a proof-of-concept of antitumor efficacy of the silver-based films is shown in vitro. Coatings are obtained by silver and silver-bone apatite composite targets. Both standard and custom-made (porous) vertebral titanium alloy prostheses are used as substrates. Films composition and morphology depending on the deposition parameters are investigated and optimized. Antibacterial efficacy of silver films is tested in vitro against gram+ and gram- species (E. coli, P. aeruginosa, S. aureus, E. faecalis), to determine the optimal coatings characteristics, by assessing reduction of bacterial viability, adhesion to substrate and biofilm formation. Biocompatibility is tested in vitro on fibroblasts and MSCs and, in vivo on rat models. Efficacy is also tested in an in vivo rabbit model, using a multidrug resistant strain of S. aureus (MRSA, S. aureus USA 300). Absence of nanotoxicity is assessed in vivo by measuring possible presence of Ag in the blood or in target organs (ICP-MS). Then, possible antitumor effect of the films is preliminary assessed in vitro using MDA-MB-231 cells, live/dead assay and scanning electron microscopy (FEG-SEM). Statistical analysis is performed and data are reported as Mean ±
The widely used Fracture Risk Assessment Tool (FRAX) estimates a 10-year probability of major osteoporotic fracture (MOF) using age, sex, body mass index, and seven clinical risk factors, including prior history of fracture. Prior fracture is a binary variable in FRAX, although it is now clear that prior fractures affect future MOF risk differently depending on their recency and site. Risk of MOF is highest in the first two years following a fracture and then progressively decreases with time – this is defined as imminent risk. Therefore, the FRAX tool may underestimate true fracture risk and result in missed opportunities for earlier osteoporosis management in individuals with recent MOF. To address this, multipliers based on age, sex, and fracture type may be applied to baseline FRAX scores for patients with recent fractures, producing a more accurate prediction of both short- and long-term fracture risk. Adjusted FRAX estimates may enable earlier pharmacologic treatment and other risk reduction strategies. This study aimed to report the effect of multipliers on conventional FRAX scores in a clinical cohort of patients with recent non-hip fragility fractures. After obtaining Research Ethics Board approval, FRAX scores were calculated both before and after multiplier adjustment, for patients included in our outpatient Fracture Liaison Service who had experienced a non-hip fragility fracture between June 2020 and November 2021. Patients age 50 years or older, with recent (within 3 months) forearm (radius and/or ulna) or humerus fractures were included. Exclusion criteria consisted of patients under the age of 50 years or those with a hip fracture. Age- and sex-based FRAX multipliers for recent forearm and humerus fractures described by McCloskey et al. (2021) were used to adjust the conventional FRAX score. Low, intermediate and high-risk of MOF was defined as less than 10%, 10-20%, and greater than 20%, respectively. Data are reported as mean and
Statistical shape modeling (SSM) and statistical density modeling (SDM) are tools capable of describing the main modes of deviation in the shape and density distribution of the shoulder using a set of uncorrelated variables called principal components (PCs). We hypothesize that the first PC of the SDM, which scales overall density up/down, will be inversely correlated with age and will, on average, be greater for males than females. We also hypothesize that there is a correlation between some PCs of shape and density. SSM and SDM were developed for scapulae and humeri by segmenting surface meshes from computed tomographic images of 75 cadaveric shoulders. Bones were co-registered and defined by the same surface mesh. Volumetric tetrahedral meshes were defined for one of the specimens serving as base meshes for SDM. Base meshes were morphed to each individual bone's surface and superimposed upon the corresponding CT data to determine image intensity in Hounsfield units at each node. Principal component analysis was performed on the exterior shape and internal density distribution of bones. T-tests were performed to find any differences in PC scores between males and females, and Pearson correlation coefficients were calculated for age and PC scores. Finally, correlation coefficients between each of the PCs of the shape and density models were calculated. For the humerus, the first three PCs of the SDM were significantly correlated with age (ρ = 0.40, −0.46, and 0.36, all p ≤ 0.007). For the scapula, the first and ninth PCs showed such correlation (ρ = −0.31, and −0.32, all p ≤ 0.02). Statistically significant differences due to sex were found for the second to sixth SDM PCs of the humerus, with differences in average PC scores of 1, 1, −0.7, −0.8, and −0.6
Abstract. Introduction. Ultrasonic cutting in surgery has great potential. However, a key limitation is heat created by friction between the bone and the blade. Bone has poor thermal conductivity which hinders the dissipation of heat, causing cell death near the cut site In addition, ultrasonic vibration may create microcracks. It was hypothesised that these effects on bone would vary with the frequency and displacement of the ultrasonically powered blade. Therefore varying frequencies and displacements of the tip of the blade were studied to find the combination with fewest microcracks and lowest temperature rise at the bone-tool interface. Aim. To explore the effect of different frequencies and tip displacements of ultrasonic cutting devices on the amount of thermal and mechanical damage. Methods. In vitro tests were conducted on fresh rat femoral shafts using two different frequencies; 20kHz and 35kHz.Two displacement amplitudes of two different frequencies were used: 23.9 μm (p-p) and 7.5 μm (p-p) both at 20kHz and 18.7 μm (p-p) and 27 μm (p-p) both at 35kHz and. Cooling was used to emulate clinical conditions. Histological examination (H & E and TUNEL) was performed to identify live and dead cells. Further rat femoral shafts (n=6) were exposed to the same number of cuts by each tool to identify any micro-damage induced by different electrical currents using Micro-CT and confocal Laser scanning microscope. All experimental data were expressed as mean ±
Abstract. Objectives. Ultrasound speckle tracking is a safe and non-invasive diagnostic tool to measure soft tissue deformation and strain. In orthopaedics, it could have broad application to measure how injury or surgery affects muscle, tendon or ligament biomechanics. However, its application requires custom tuning of the speckle-tracking algorithm then validation against gold-standard reference data. Implementing an experiment to acquire these data takes months and is expensive, and therefore prohibits use for new applications. Here, we present an alternative optimisation approach that automatically finds suitable machine and algorithmic settings without requiring gold-standard reference data. Methods. The optimisation routine consisted of two steps. First, convergence of the displacement field was tested to exclude the settings that would not track the underlying tissue motion (e.g. frame rates that were too low). Second, repeatability was maximised through a surrogate optimisation scheme. All settings that could influence the strain calculation were included, ranging from acquisition settings to post-processing smoothing and filtering settings, totalling >1,000,000 combinations of settings. The optimisation criterion minimised the normalised
Abstract. Objective. This study assesses the prevalence of major and minor discordance between hip and spine T scores using Radiofrequency Echographic Multi-spectrometry (REMS). REMS is a novel technology that uses ultrasound and radiofrequency analysis to measure bone density and bone fragility at the hip and lumbar spine. The objective was to compare the results with the existing literature on Dual-Energy X-ray Absorptiometry (DEXA) the current “gold standard” for bone densitometry. REMS and DEXA have been shown to have similar diagnostic accuracy, however, REMS has less human input when carrying out the scan, therefore the rates of discordance might be expected to be lower than for DEXA. Discordance poses a risk of misclassification of patients’ bone health status, causing diagnostic ambiguity and potentially sub-optimal management decisions. Reduction of discordance rates therefore has the potential to significantly improve treatment and patient outcomes. Methods. Results from 1,855 patients who underwent REMS investigations between 2018 and 2022 were available. Minor discordance is defined as a difference of one World Health Organisation (WHO) diagnostic classification (Normal / Osteopenia or Osteopenia / Osteoporosis). Major discordance is defined as a difference of two WHO diagnostic classifications (Normal / Osteoporosis). The results were compared with reported DEXA discordance rates. Results. 1,732 individuals had both hip and spine T scores available for analysis. There were 267 cases of discordance. No instances of major discordance were observed. The minor discordance rate was 15.4%. 6.5% of the REMS scans with minor discordance showed > 1.0
Aims. While preoperative bloodwork is routinely ordered, its value in determining which patients are at risk of postoperative readmission following total knee arthroplasty (TKA) and total hip arthroplasty (THA) is unclear. The objective of this study was to determine which routinely ordered preoperative blood markers have the strongest association with acute hospital readmission for patients undergoing elective TKA and THA. Methods. Two population-based retrospective cohorts were assembled for all adult primary elective TKA (n = 137,969) and THA (n = 78,532) patients between 2011 to 2018 across 678 North American hospitals using the American College of Surgeons National Quality Improvement Programme (ACS-NSQIP) registry. Six routinely ordered preoperative blood markers - albumin, haematocrit, platelet count, white blood cell count (WBC), estimated glomerular filtration rate (eGFR), and sodium level - were queried. The association between preoperative blood marker values and all-cause readmission within 30 days of surgery was compared using univariable analysis and multivariable logistic regression adjusted for relevant patient and treatment factors. Results. The mean TKA age was 66.6 years (SD 9.6) with 62% being females (n = 85,163/137,969), while in the THA cohort the mean age was 64.7 years (SD 11.4) with 54% being female (n = 42,637/78,532). In both cohorts, preoperative hypoalbuminemia (< 35 g/l) was associated with a 1.5- and 1.8-times increased odds of 30-day readmission following TKA and THA, respectively. In TKA patients, decreased eGFR demonstrated the strongest association with acute readmission with a standardized odds ratio of 0.75 per two
Abstract. Objectives. Neonatal motor development transitions from initially spontaneous to later increasingly complex voluntary movements. A delay in transitioning may indicate cerebral palsy (CP). The general movement optimality score (GMOS) evaluates infant movement variety and is used to diagnose CP, but depends on specialized physiotherapists, is time-consuming, and is subject to inter-observer differences. We hypothesised that an objective means of quantifying movements in young infants using motion tracking data may provide a more consistent early diagnosis of CP and reduce the burden on healthcare systems. This study assessed lower limb kinematic and muscle force variances during neonatal infant kicking movements, and determined that movement variances were associated with GMOS scores, and therefore CP. Methods. Electromagnetic motion tracking data (Polhemus) was collected from neonatal infants performing kicking movements (min 50° knee extension-flexion, <2 seconds) in the supine position over 7 minutes. Tracking data from lower limb anatomical landmarks (midfoot inferior, lateral malleolus, lateral knee epicondyle, ASIS, sacrum) were applied to subject-scaled musculoskeletal models (Gait2354_simbody, OpenSim). Inverse kinematics and static optimisation were applied to estimate lower limb kinematics (knee flexion, hip flexion, hip adduction) and muscle forces (quadriceps femoris, biceps femoris) for isolated kicks. Functional principal component analysis (fPCA) was carried out to reduce kicking kinematic and muscle force waveforms to PC scores capturing ‘modes’ of variance. GMOS scores (lower scores = reduced variety of movement) were collected in parallel with motion capture by a trained operator and specialised physiotherapist. Pearson's correlations were performed to assess if the
Abstract. Objectives. There is renewed interest in bi-unicondylar arthroplasty (Bi-UKA) for patients with medial and lateral tibiofemoral osteoarthritis, but a spared patellofemoral compartment and functional cruciate ligaments. The bone island between the two tibial components may be at risk of tibial eminence avulsion fracture, compromising function. This finite element analysis compared intraoperative tibial strains for Bi-UKA to isolated medial unicompartmental arthroplasty (UKA-M) to assess the risk of avulsion. Methods. A validated model of a large, high bone-quality tibia was prepared for both UKA-M and Bi-UKA. Load totalling 450N was distributed between the two ACL bundles, implant components and collateral ligaments based on experimental and intraoperative measurements with the knee extended and appropriately sized bearings used. 95th percentile maximum principal elastic strain was predicted in the proximal tibia. The effect of overcuts/positioning for the medial implant were studied; the magnitude of these variations was double the
The purpose of this randomized controlled trial was to evaluate serum metal ion levels in patients undergoing THA with either a standard or modular dual-mobility bearing. Patients undergoing primary THA for osteoarthritis were randomized to receive either a modular dual-mobility or a standard polyethylene bearing. All patients received the same titanium acetabular and femoral component and a ceramic femoral head. Only patients without a prior history of metal implants in their body were eligible for inclusion, thus isolating serum metal ions to the prosthesis itself. Serum metal ion levels were drawn pre-operatively and at 1 year postoperatively. Power analysis determined that 40 patients (20 in each group) were needed to identify a clinically relevant difference in serum cobalt of 0.35 ng/ml (ppb) at 90% power assuming a pooled
Introduction: The Scarf osteotomy for the treatment of hallux valgus is achieving popularity, but no comparative study has proven the efficacy of this procedure over other first metatarsal osteotomies. We present a retrospective comparative review of the radiological outcomes of Chevron and Scarf with Akin osteotomy in the treatment of hallux valgus. Materials and Methods: The radiological outcomes of 40 first metatarsal osteotomies, 20 Chevron and 20 Scarf with Akin are presented. The radiological parameters studied included hallux valgus angle, hallux inter-phallangeus, intermetatarsal angle, sesamoid station and foot width. Results: The mean post-operative hallux valgus angles (HVA’s) were: Chevron mean HVA 17.90,
Abstract. Objectives. The objective of this proof of concept study was to explore whether some total hip arthroplasty (THA) patients with well-functioning implants achieve normal sagittal plane hip kinematics during walking gait. Methods. Sagittal plane hip kinematics were recorded in eleven people with well-functioning THA (71 ± 8 years, Oxford Hip Score = 46 ± 3) and ten healthy controls (61 ± 5 years) using a three-dimensional motion capture system as they walked over-ground at a self-selected velocity. THA patients were classified as high- or low-functioning (HF and LF, respectively) depending on whether the mean absolute difference between their sagittal plane hip kinematics was within one
Three distal femoral axes have been described to aid in alignment of the femoral component; the Trans Epicondylar Axis (TEA), the Posterior Condylar Axis (PCA) and the Antero Posterior (AP) axis. Our aim was to identify if there was a reproducible relationship between the axes which would aid alignment of the femoral component. This is the first study compare all three distal femoral axes with each other using magnetic resonance imaging (MRI) in a Caucasian population. Our sample group represents real life patients awaiting total knee arthroplasty (TKA), as opposed non-arthritic or cadaveric knees. We identified the relationship between these rotational axes by performing MRI scans on 89 patients awaiting TKA with patient-specific instrumentation. Measurements were taken by two observers. Patients had a mean age of 62.5 years (range 32–91). 51 patients were female. The mean angle between the TEA and the AP axis was 92.78° with a
Congenital talipes equinovarus (CTEV), also known as club foot or talipes is a common congenital disorder. Parents are using the Internet more and more as a source of information about health care. Unfortunately, the quality of health care information on the Internet varies. This study looked at information available to parents using two instruments for judging the equality of information on the internet. The top five search engines were searched on Google. Three of these were also included in the top 50 sites in Ireland so these 3 sites were used. The phrases CTEV and club foot were searched from all 3 platforms. Websites were then scrutinized using the HON code and the DISCERN tool. 54 organic sites were found for the 3 search engines using the key word club foot. For the key word CTEV 55 matches were returned for the three search engines. 4 websites displayed the HON code. Using the discern tool CTEV websites had a mean score of 60 with a
Introduction. External fixators are attached to bones with percutaneous pins and wires inserted through soft tissues and bone increasing the risk of infections. Such infections compromise patient outcomes e.g., through pin loosening or loss, failure of fixator to stabilise the fracture, additional surgery, increased pain, and delayed mobilisation. These infections also impact the healthcare system for example, increased OPD visits, hospitalisations, treatments, surgeries and costs. Nurses have a responsibility in the care and management of patients with external fixators and ultimately in the prevention of pin-site infection. Yet, evidence on best practices in the prevention of pin-site infection is limited and variation in pin-site management practices is evident. Various strategies are used for the prevention of pin-site infection including the use of different types of non-medicated and medicated wound dressings. The aim of this retrospective study was to investigate the use of dry gauze or iodine tulle dressings for the prevention of pin-site infections in patients with lower limb external fixators. Methodology. A retrospective study of patients with lower limb external fixators who attended the research site between 2015–2022. Setting & Sample: The setting was the outpatient's (OPD) orthopaedic clinic in a University Teaching Hospital in Dublin, Ireland. Eligibility Criteria:. Over the age of 16, treated with an Ilizarov, Taylor Spatial frame (TSF) or Limb Reconstruction System (LRS) external fixators on lower limbs,. Pin-sites dressed with dry gauze or iodine tulle,. Those with pre-existing infected wounds close to the pin site and/or were on long term antibiotics were excluded. Follow Up Period: From time of external fixator application to first pin-site infection or removal of external fixator. Outcome Assessment: The primary outcome was pin-site infection, secondary outcomes included but were not limited to frequency of pin-site infection according to types of bone fixation, frequency of pin/wire removal and hospitalisation due to infection. Data analysis: IBM SPSS Version 25 was used for statistical analysis. Descriptive and inferential statistics were conducted as appropriate. Categorical data were analysed by counting the frequencies (number and percentages) of participants with an event as opposed to counting the number of episodes for each event. Differences between groups were analysed using Chi-square test or Fisher's exact test, where appropriate. Continuous variables were reported using mean and
Introduction. With many stakeholders, healthcare decisions are complex. However, patient interests should be prioritized. This maximizes healthcare value (quality divided by cost), simultaneously minimizing costs (objective) and maximizing quality (subjective). Unfortunately, even ‘high value’ procedures like total knee arthroplasty (TKA) suffer from recovery assessment subjectivity (i.e. high assessment variability) and increasing costs. High TKA costs and utilization yield high annual expenditures (∼$22B), including postoperative physical therapy (PT) accounting for ∼10% of total costs (∼$2.3B annually). Post-TKA PT is typically homogenous across subjects ensuring most recover, however recent work shows outcomes unimpacted by PT. Accordingly, opportunities exist improving healthcare value by simultaneously reducing unnecessary PT expenditures and improving outcomes. However, discerning recovery completion relies on discrete ROM measures captured clinically and subjective clinician experience (i.e. intuition about recovery). Accordingly, our goal was developing objective post-TKA performance assessment methods utilizing gait knee ROM and statistical analyses to categorize patient recovery (‘accelerated,’ ‘delayed,’ or ‘normal’). Methods. We first established statistical reasons for current post-TKA rehabilitation including risk-reward tradeoffs between incorrectly ascribing ‘poor recovery’ to well-recovering patients (T1 error) or ‘good recovery’ to poorly-recovering patients (T2 error) using methods described by Mudge et al. and known TKA volumes/rehabilitation costs. Next, previously captured gait ROM data from well-healed patients was utilized establishing standard recovery curves. These were then utilized to assess newly captured patient recovery. Following IRB approval, we prospectively captured gait ROM from 10 TKA patients (3M, 69±13 years) 1-week pre-TKA and 6-weeks immediately post-TKA. Performance was compared to recovery curves via control charts/Shewhart rules (daily performance) as well as
Introduction and Objective. An important subset of patients is dissatisfied after total joint arthroplasty (TJA) due to residual functional impairment. This study investigated the assessment of objectively measured step-up performance following TJA, to identify patients with poor functional improvement after surgery, and to predict residual functional impairment during early postoperative rehabilitation. Secondary, longitudinal changes of block step-up (BS) transfers were compared with functional changes of subjective patient reported outcome measures (PROMs) following TJA. Materials and Methods. Patients with end stage hip or knee osteoarthritis (n = 76, m/f = 44/32; mean age = 64.4
Patellofemoral arthroplasty (PFA) has higher revision rates than total knee arthroplasty (TKA) [Van der List, 2015; Dy, 2011]. Some indications for revision include mechanical failure, patellar mal-tracking, implant malalignment, disease progression and persistent pain or stiffness [Dy, 2011; Turktas, 2015]. Implant mal-positioning can lead to decreased patient satisfaction and increased revision rates [Turktas, 2015]. Morphological variability may increase the likelihood of implant mal-positioning. This study quantifies the morphological variability of the anterior-posterior (AP) and medial-lateral (ML) aspects of the patellofemoral compartment using a database of computed tomography (CT) scans. The analysis presented here used the custom CT based program SOMA (SOMA V.4.3.3, Stryker, Mahwah, NJ). SOMA contains a large database of 3D models created from CT scans. Anatomic analysis and implant fitting tools are also integrated into SOMA to perform morphometric analyses. A coordinate system is established from the femoral head center, the intercondylar notch, and a morphological flexion axis (MFA). The MFA is created by iteratively fitting circles to the posterior condyles and creating and axis through the circles' centers. The sagittal plane is created normal to this axis and through the notch. A coronal plane is created from the femoral head center and the flexion axis. The AP measurement is taken normal to the coronal plane from the anterior cortex sulcus to the intercondylar notch (Figure 1). A 5°-flexed anterior resection is created to run-out at the anterior cortex sulcus. The ML measurement is taken normal to the sagittal plane from the most medial to the most lateral points of the anterior resection (Figure 1). The ML measurements are broken down into medial and lateral components divided by a sagittal plane through the trochlea. Means and
The objective of our study is to evaluate the accuracy of an X-ray based image segmentation system for patient specific instrument (PSI) design or any other surgical application that requires 3D modeling of the knee. The process requires two bilateral short film X-ray images of knee and a standing long film image of the leg including the hip and ankle. The short film images are acquired with an X-ray positioner device that is embedded with fiducial markers to correct for setup variation in source and cassette position. An automated image segmentation algorithm, based on a statistical model that couples knee bone shape and radiographic appearance, calculates 3D surface models of the knee from the bi-lateral short films (Imorphics, Manchester UK) (Figure 1). Surface silhouettes are used to inspect and refine the automatically generated segmentation; the femur and tibia mechanical axes are then calculated using automatically generated surface model landmarks combined with user-defined markups of the hip and ankle center from the standing long film (Figure 2). The accuracy of the 2D/3D segmentation system was evaluated using simulated X-ray imagery generated from one-hundred osteoarthritic, lower limb CT image samples using the Insight Toolkit (Kitware, Inc.). Random, normally distributed variations in source and cassette positions were included in the dataset. Surface accuracy was measured using root-mean-square (RMS) point-to-surface (P2S) distance calculations with respect to paired benchmark CT segmentations. Landmark accuracy was calculated by measuring angular differences between the 2D/3D generated femur and tibia mechanical tibia with respect to paired CT-generated landmark data. The paired RMS sample mean and
Abstract. Objectives. Additive manufacturing (AM) enables fine control over the architecture of porous lattice structures, and the resulting mechanical performance. Orthopaedic implants may benefit from the tailored stiffness/elastic modulus of these AM biomaterials, as the stiffness can be made to closer match the properties of the replaced trabecular bone. Methods. This study used laser powder bed fusion (PBF) to create stochastic porous lattice structures in stainless steel (SS316L) and titanium alloy (Ti6Al4V), with modifications that aimed to overcome PBF manufacturing limitations of build angles. The structures were tested in uni-axial compression (n = 5) in 10 load orientations relative to the structure, including the three orthogonal axes. Results. The testing verified that no hidden peaks in elastic modulus existed in the stochastic structure. The
Aims. Accurate placement of acetabular and femoral stem components in total hip arthroplasty (THA) is an important factor in the success of the procedure. A variety of free hand or navigated techniques is reported. Survivorship and complications have been shown to be directly related to implant position during THA. The aim of this cadaver study was to assess the accuracy of the placement of the components in THA using patient specific instruments (PSI) in combination with a 3D planning software and the direct anterior approach. Method. Patient specific instruments (PSI) were developed to guide the surgeon during THA that were 3D printed with their bone models following a 3D software planning protocol (LPH software V2.5.1, Onefit-Medical, Eos Imaging Company, Besancon, France). Acetabular guides: cup, offset and straight reamer handle and impactor, femoral- and chisel guides were used in each THA (Fig. 1). To define anatomic bone landmarks and to generate a 3D model of each hip joint CT scans were performed preoperatively. The planning of component position was done by one surgeon (AZ) preop. Surgery was performed by two experienced surgeons (AZ, SD) on cadaver specimen with 4 hips in two separate series. A total of 8 hip replacements were evaluated pre- and postoperatively using CT-scans of each hip joint to compare planned to achieved results. Mechanical simulations of the guides were carried out to verify that there were no conflicts between the different instruments. To meet the ISO standard 16061: 2015 the compatibility of the instruments with the guides has been checked. Parameters were evaluated in 3D pelvic and femoral planes: center cup position, inclination angle, anteversion angle, cutting height and plan orientation, anteversion angle, flexion/extension angle, varus/valgus angle, anatomical and functional leg length, offset. Acceptance criteria: postop. parameters evaluated must not have a deviation of more than 5 degrees, 2,5 mm according to preop. planning. For every THA the test protocol has been completely realized. Results. The difference between the preop. and postop. measures in the first series of 4 hips revealed 2 outliers because of fractures of the acetabulum in 2 cases, related to bad cadaver quality. In the second series we found satisfactory results comparing the planned preop and postop component position (Fig. 2). For example difference of leg length showed a mean absolute of 1,58 mm,
Aims. Cementless total knee arthroplasty (TKA) offers the potential for strong biological fixation compared with cemented TKA where fixation is achieved by the mechanical integration of the cement. Few mid-term results are available for newer cementless TKA designs, which have used additive manufacturing (3D printing). The aim of this study was to present mid-term clinical outcomes and implant survivorship of the cementless Stryker Triathlon Tritanium TKA. Methods. This was a single institution registry review of prospectively gathered data from 341 cementless Triathlon Tritanium TKAs at four to 6.8 years follow-up. Outcomes were determined by comparing pre- and postoperative Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) scores, and pre- and postoperative 12-item Veterans RAND/Short Form Health Survey (VR/SF-12) scores. Aseptic loosening and revision for any reason were the endpoints which were used to determine survivorship at five years. Results. At mid-term follow-up, the mean KOOS JR score improved significantly from 33.14 (0 t0 85,
Aims. We aim to objectively assess the impact of COVID-19 on mean total operative cases for all indicative procedures (as outlined by the Joint Committee on Surgical Training (JCST)) experienced by orthopaedic trainees in the deanery of the Republic of Ireland. Subjective experiences were reported for each trainee using questionnaires. Methods. During the first four weeks of the nationwide lockdown due to COVID-19, the objective impact of the pandemic on each trainee’s surgical caseload exposure was assessed using data from individual trainee logbook profiles in the deanery of the Republic of Ireland. Independent predictor variables included the trainee grade (ST 3 to 8), the individual trainee, the unit that the logbook was reported from, and the year in which the logbook was recorded. We used the analysis of variance (ANOVA) test to assess for any statistically significant predictor variables. The subjective experience of each trainee was captured using an electronic questionnaire. Results. The mean number of total procedures per trainee over four weeks was 36.8 (7 to 99;
Introduction. Cup malposition in hip arthroplasty and hip resurfacing is associated with instability, accelerated wear, and the need for revision. A recent study measuring cup orientation on conventional radiodiographs demonstrated an incidence of cup malpositioning of 50% according to the safe zone that they defined 1,2. A prior study of 105 conventionally placed cups using CT demonstrated a cup malpositioning incidence of 74%3. The current study similarly assesses the variation in cup position using conventional techniques as measured by CT. Methods. CT studies of 123 hips in 119 patients with total hip arthroplasties performed using conventional techniques were used for this study. The indications for the CT studies were for CT-based surgical navigation of the contralateral side or for assessment of periprosthetic osteolysis. An application specific software modules was developed to measure cup orientation using CT (HipSextant Research Application 1.0.13 Surgical Planning Associates Inc., Boston, Massachusetts). The cup orientation was determined by first identifying Anterior Pelvic Plane Coordinate system landmarks on a 3D surface model. A multiplanar reconstruction module then allowed for the creation of a plane parallel with the opening plane of the acetabulum. The orientation of the cup opening plane in the AP Plane coordinate space was calculated according to Murray's definitions of operative anteversion and operative inclination. Since these studies including images through the femoral condyles, femoral anteversion could be measured on these hips as well (Osirix v5.6, Pixmeo SARL, Bernex, Switzerland). Results. Cup orientation for the 123 hips is shown in Figure 1. Operative anteversion averaged 29.7 degrees with a
Purpose: To calculate a clinically relevant and intra-operatively accessible measure of olecranon length that could be reliably applied by the operating surgeon to optimise comminuted olecranon fracture fixation. Materials: One hundred normal adult anteroposterior and lateral radiographs of the elbow were studied with respect to the proximal olecranon width (OW), greater sigmoid notch width (SW) on lateral views, trans-epicondylar distance (TED), and trochlear width distance (TWD) on AP views. The mean ratios of TWD/SW and TED/SW and an index OW X SW/TED along with their
Aims. The removal of the cruciate ligaments in total knee arthroplasty (TKA) has been suggested as a potential contributing factor to patient dissatisfaction, due to alteration of the in vivo biomechanics of the knee. Bicruciate retaining (BCR) TKA allows the preservation of the cruciate ligaments, thus offering the potential to reproduce healthy kinematics. The aim of this study was to compare in vivo kinematics between the operated and contralateral knee in patients who have undergone TKA with a contemporary BCR design. Methods. A total of 29 patients who underwent unilateral BCR TKA were evaluated during single-leg deep lunges and sit-to-stand tests using a validated computer tomography and fluoroscopic imaging system. In vivo six-degrees of freedom (6DOF) kinematics were compared between the BCR TKA and the contralateral knee. Results. During single-leg deep lunge, BCR TKAs showed significantly less mean posterior femoral translation (13 mm;
Clinical laxity tests are frequently used for assessing knee ligament injuries and for soft tissue balancing in total knee arthroplasty (TKA). Current routine methods are highly subjective with respect to examination technique, magnitude of clinician-applied load and assessment of joint displacement. Alignment measurements generated by computer-assisted technology have led to the development of quantitative TKA soft tissue balancing algorithms. However to make the algorithms applicable in practice requires the standardisation of several parameters: knee flexion angle should be maintained to minimise the potential positional variation in ligament restraining properties; hand positioning of the examining clinician should correspond to a measured lever arm, defined as the perpendicular distance of the applied force from the rotational knee centre; accurate measurement of force applied is required to calculate the moment applied to the knee joint; resultant displacement of the knee should be quantified. The primary aim of this study was to determine whether different clinicians could reliably assess coronal knee laxity with a standardised protocol that controlled these variables. Furthermore, a secondary question was to examine if the experience of the clinician makes a difference. We hypothesised that standardisation would result in a narrow range of laxity measurements obtained by different clinicians. Six consultant orthopaedic surgeons, six orthopaedic trainees and six physiotherapists were instructed to assess the coronal laxity of the right knee of a healthy volunteer. Points were marked over the femoral epicondyles and the malleoli to indicate hand positioning and give a constant moment arm. The non-invasive adaptation of a commercially available image-free navigation system enabled real-time measurement of coronal and sagittal mechanical femorotibial (MFT) angles. This has been previously validated to an accuracy of ±1°. Collateral knee laxity was defined as the amount of angular displacement during a stress manoeuvre. Participants were instructed to maintain the knee joint in 2° of flexion whilst performing a varus-valgus stress test using what they perceived as an acceptable load. They were blinded to the coronal MFT angle measurements. A hand-held force application device (FAD) was then employed to allow the clinicians to apply a moment of 18Nm. This level was based on previous work to determine a suitable subject tolerance limit. They were instructed to repeat the test using the device in the palm of their right hand and to apply the force until the visual display and an auditory alarm indicated that the target had been reached. The FAD was then removed and participants were asked to repeat the clinical varus-valgus stress test, but to try and apply the same amount of force as they had been doing with the device. Maximum MFT angular deviation was automatically recorded for each stress test and the maximum moment applied was recorded for each of the tests using the FAD. Means and
Aims. The aim of this study was to assess the feasibility of conducting a full-scale, appropriately powered, randomized controlled trial (RCT) comparing internal fracture fixation and distal femoral replacement (DFR) for distal femoral fractures in older patients. Patients and Methods. Seven centres recruited patients into the study. Patients were eligible if they were greater than 65 years of age with a distal femoral fracture, and if the surgeon felt that they were suitable for either form of treatment. Outcome measures included the patients’ willingness to participate, clinicians’ willingness to recruit, rates of loss to follow-up, the ability to capture data, estimates of
The aim of this study was to. describe the measurements of range of circumduction in normal volunteers and develop summaries of the data,. develop the rate and rhythm of circumduction of the wrist with the use of Biometric electrogoniometer,. reproducibility, reliability and accuracy of these measures of circumduction. Forty healthy subjects with a mean age of 42.6 years were assessed with flexible biaxial electrogoniometry in standard 90° pronated position of wrist for kinematic assessment of movement in orthogonal planes. Functional range of flexion-extension, ulnar-radial deviation and circumduction was measured and analysis of the digital output produced a visual display of the results as Lissajous's figures. This also allowed measurement of the total range of circumduction as two-dimensional area under the curve measurement. The rate and rhythm of movements were mathematically calculated and displayed over the two dimensional circumduction curves. The average arc of uniplanar flexion and extension is greater than the flexion and extension component of the circumduction curve but mean uniplanar radial ulnar deviation arc is similar to the radial-ulnar deviation component of the circumduction curve. The area of circumduction and circumference of the circumduction curve was used to measure the total range of circumduction. The four quadrants for the velocity of circumduction showed that the rate was faster in the deviation components as compared to flexion and extension. Quadrant analysis showed the changes in the rhythm was less in the deviation components compared to flexion and extension. The accuracy for measuring uniplanar movements showed a
Introduction. The purpose of this study was to demonstrate the feasibility of passively collecting objective data from a commercially available smartphone-based care management platform (sbCMP) and robotic assisted total knee arthroplasty (raTKA). Methods. Secondary data analysis was performed using de-identified data from a commercial database that collected metrics from a sbCMP combined with intraoperative data collection from raTKA. Patients were included in this analysis if they underwent unilateral raTKA between July 2020 and February 2021, and were prescribed the sbCMP (n=131). The population consisted of 76 females and 55 males, with a mean age of 64 years (range, 43 – 81). Pre-operative through six-week post-operative data included step counts from the sbCMP, as well as administration of the KOOS JR. Intraoperative data included surgical times, the hip-knee-ankle angle (HKA), and medial and lateral laxity assessments from the robotic assessment. Data are presented using descriptive statistics. Comparisons were performed using a paired samples t-test, or Wilcoxon Signed-rank test, with significance assessed at p<0.05. A minimal detectable change (MDC) in the KOOS JR score was considered ½
Introduction. The purpose of this study was to characterize the recovery of physical activity following knee arthroplasty by means of step counts and flight counts (flights of stairs) measured using a smartphone-based care platform. Methods. This is a secondary data analysis on the treatment cohort of a multicenter prospective trial evaluating the use of a smartphone-based care platform for primary total and unicondylar joint arthroplasty. Participants in the treatment arm that underwent primary total or unicondylar knee arthroplasty and had at least 3 months of follow-up were included (n=367). Participants were provided the app with an associated smart watch for measuring several different health measures including daily step and flight counts. These measures were monitored preoperatively, and the following postoperative intervals were selected for review: 2–4 days, 1 month, 1.5 month, 3 months and 6 months. The data are presented as mean,
Introduction. Model-based radiostereometric analysis (MBRSA) allows the in vivo measurement of implant loosening (i.e. migration) from a host bone by acquiring a pair of biplanar radiographs of the patient's implant over time. Focusing on total knee replacement patients, the accuracy of MBRSA in calculating tibial baseplate migration depends on the accuracy in registering a 3D model onto the biplanar radiographs; thus, the shape of the baseplate and its orientation relative to the imaging planes is pertinent. Conventionally, the baseplate coordinate system is aligned with the laboratory coordinate system, however, this reference orientation is unnecessary and may hide unique baseplate features resulting in less accurate registration (Figure 1). Therefore, the primary objective of this study was to determine the optimal baseplate orientation for improving accuracy during MBRSA, and an acceptable range of orientations for clinical use. A second objective was to demonstrate that a custom knee positioning guide repeatably oriented the baseplate within the acceptable range of orientations. Materials and Methods. A tibia phantom consisting of a baseplate rigidly fixed to a sawbone was placed in 24 orientations (combination of six rotations about X (i.e. knee flexion) and four rotations about Z (i.e. hip abduction)) with three pairs of radiographs acquired at each orientation. The radiographs were processed in MBRSA software, and the mean maximum total point motion (MTPM), an indicator of bias error during model registration, was plotted as a function of the two rotations to determine the optimal orientation and a range of acceptable orientations (Figure 2). A custom knee positioning guide was manufactured with the goal of orienting the baseplate close to the optimal orientation and within the acceptable range of orientations (Figure 3). Ten independent pairs of biplanar radiographs were acquired by repeatedly placing a knee model in the knee positioning guide, and the images were processed in MBRSA software to determine the baseplate orientation. Results and Discussion. Results showed an 85% decrease in bias error between the reference orientation (i.e. no rotation) and the optimal orientation (10° rotation about X and 5° rotation about Z). An acceptable range of orientations from 5° − 20° rotation about an axis perpendicular to the sagittal imaging plane and from 5° − 15° rotation about an axis perpendicular to the coronal imaging plane was defined as these orientations decreased the bias error by more than 50%. Additionally, the custom knee positioning guide controlled the mean orientation ± one
Background. There have been multiple techniques described to determine hindfoot alignment radiographically. The 2-dimensional nature of radiographs fails to take into account the contribution of the remainder of the foot to overall alignment. A new radiographic technique has been published in which the hindfoot alignment is calculated using the Ground Reaction Force Calcanea Offset. This technique accounts for the individual forefoot contribution to alignment, but is still limited by it´s 2-dimensional nature. The purpose of this study was to compare the hindfoot moment arm (HMA) described by Saltzman and the hindfoot alignment angle (HAA) described by Williamson, with a technique determining the ground reaction force calcaneal offset (GRF-CT) using 3-dimensional weight bearing CT Scans. Methods. The HMA, HAA, and GRF-CT 3-D weight bearing CT scans were measured by three different investigators. Each of these measurements were calculated twice on separate occasions by each investigator to determine the intra- and inter-observer reliability. Results. 104 patients underwent weight bearing hindfoot alignment radiographs and 3-dimensional weight bearing CT scans including 33 patients with varus and 71 patients with valgus hindfoot deformities. There was excellent intra- and inter-observer reliability with all three measurement techniques (P< 0.01), however the GRF-CT showed the best intra- and inter-observer reliability with the lowest
A technical goal in total knee arthroplasty is the production of a neutral coronal plane mechanical axis. Errors may produce large mechanical axis deviations precipitating early implant failure. This study sought to test if measured distal femoral resection produced more accurate and consistent coronal alignment than arbitrarily set distal femoral resection. Data from a cohort of 255 consecutive unselected primary total knee arthroplasties undertaken by the senior author (PM) was collected prospectively and independently assessed. In the first 167 cases distal femoral resection was arbitrarily set to 5 degrees of valgus. In the remaining 88 cases the distal femoral resection angle was determined on a preoperative long leg standing AP radiograph. Postoperative coronal alignment was measured on long leg standing AP radiograph in all cases. The measured distal femoral valgus angle was between 4 and 7 degrees. An equal number measured either 5 or 6 degrees and accounted for 85% of the total number. Statistically insignificant improvements in mean axis and
It is unclear why ACL rupture increases osteoarthritis risk, regardless of ACL reconstruction. Our aims were: 1) to establish the reliability and accuracy of a direct method of determining tibiofemoral contact in vivo with UO-MRI, 2) to assess differences in knees with ACL rupture treated nonoperatively versus operatively, and 3) to assess differences in knees with ACL rupture versus healthy knees. We recruited a convenience sample of patients with prior ACL rupture. Inclusion criteria were: 1) adult participants between 18–50 years old; 2) unilateral, isolated ACL rupture within the last five years; 3) if reconstructed, done within one year from injury; 4) intact cartilage; and 5) completed a graduated rehabilitation program culminating in return to sport or recreational activities. Participants were excluded if they had other ligament ruptures, osteoarthritis, an incompletely rehabilitated injury, were prohibited from undergoing MRI, or had a history of ACL re-rupture. Using the UO-MRI, we investigated tibiofemoral contact area, centroid location, and six degrees of freedom alignment under standing, weightbearing conditions with knees extended. We compared patients with ACL rupture treated nonoperatively versus operatively, and ACL ruptured knees versus healthy control knees. We assessed reliability using the intra-class correlation coefficient, and accuracy by comparing UO-MRI contact area with a 7Tesla MRI reference standard. We used linear mixed-effects models to test the effects of ACL rupture and ACL reconstruction on contact area. We used a paired t test for centroid location and alignment differences in ACL ruptured knees versus control knees, and the independent t test for differences between ACL reconstruction and no reconstruction. Analyses were performed using R version 3.5.1. We calculated sample size based on a previous study that showed a contact area
Aims. The primary aim of this study was to quantify the improvement in patient-reported outcome measures (PROMs) following total hip arthroplasty (THA), as well as the extent of any deterioration through the seven-year follow-up. The secondary aim was to identify predictors of PROM improvement and deterioration. Patients and Methods. A total of 976 patients were enrolled into a prospective, international, multicentre study. Patients completed a battery of PROMs prior to THA, at three months post-THA, and at one, three, five, and seven-years post-THA. The Harris Hip Score (HHS), the 36-Item Short-Form Health Survey (SF-36) Physical Component Summary (PCS), the SF-36 Mental Component Summary (MCS), and the EuroQol five-dimension three-level (EQ-5D) index were the primary outcomes. Longitudinal changes in each PROM were investigated by piece-wise linear mixed effects models. Clinically significant deterioration was defined for each patient as a decrease of one half of a
Introduction. An understanding of anatomic variability can help guide the surgeon on intervention strategies. Well-functioning thumb metacarpophalangeal joints (MCPJ) are essential for carrying out typical daily activities. However, current options for arthroplasty are limited. This is further hindered by the lack of a precise understanding of the geometric variation present in the population. In this paper, we offer new insight into the major modes of geometric variation in the thumb MCP using Statistical Shape Modelling. Methods. Ten participants free from hand or wrist disease or injury were recruited for CT imaging (Ethics Ref:14/LO/1059). 1. Participants were sex matched with mean age 31yrs (range 27–37yrs). Metacarpal (MC1) and proximal phalanx (PP1) bone surfaces were identified in the CT volumes using a greyscale threshold, and meshed. The ten MC1 and ten PP1 segmented bones were aligned by estimating their principal axes using Principal Component Analysis (PCA), and registration was performed to enable statistical comparison of the position of each mesh vertex. PCA was then used again, to reduce the dimensionality of the data by identifying the main ‘modes’ of independent size and shape variation (principal components, PCs) present in the population. Once the PCs were identified, the variation described by each PC was explored by inspecting the shape change at two
Aim: Component positioning may be adversely affected by minimally invasive approach in total hip replacement due to restricted visualization. Problems with proper alignement are suggested to concern anteversion more than inclination and occur particulary in the lateral position. Method: 53 patients were enrolled prospectively randomised to each group. First group (standard group, n= 30pts) underwent conventional total hip replacement in supine position and transgluteal approach and second group (MIS group, n= 23pts) underwent THR using minimally invasive anterior approach in lateral decubitus position Every group was operated on by two experienced senior surgeons. Desired cup position was 40°–45°inclination and 15–20° anteversion for the MIS group and 45°inclination and 15 ° anteversion for standard group. Postoperatively all patients had pelvic CT scan. Inclination and anteversion were determined by an independent observer using a 3-D model and planning software, the operative definition was used according to Murray. Results: Mean inclination/anteversion in the MIS group was 39°(26°–50°)/25°(10°–47°), and 44°(29°–57°)/22°(1°–53°) within the standard group.
Aims. The first death in the UK caused by COVID-19 occurred on 5 March 2020. We aim to describe the clinical characteristics and outcomes of major trauma and orthopaedic patients admitted in the early COVID-19 era. Methods. A prospective trauma registry was reviewed at a Level 1 Major Trauma Centre. We divided patients into Group A, 40 days prior to 5 March 2020, and into Group B, 40 days after. Results. A total of 657 consecutive trauma and orthopaedic patients were identified with a mean age of 55 years (8 to 98;
The condylopatellar notch (CPN) represents the border between the patellofemoral articulation and the tibiofemoral articulation [Pao, 2001]. This could be a valuable landmark for establishing the boundaries of unicompartmental knee replacements. Its location on the distal femur has been described radiographically, but it has not, to our knowledge, been quantified with respect to anatomic landmarks [Hoffelner, 2015]. This study seeks to leverage a large database of computed tomography (CT) scans to quantify the location of the CPN with respect to well established anatomic landmarks of the knee. The analysis presented here used the custom CT based program SOMA (SOMA V.4.3.3, Stryker, Mahwah, NJ). SOMA contains a large database of 3D models created from CT scans. Anatomic analysis and implant fitting tools were also integrated into SOMA to perform morphometric analyses. 986 healthy distal femurs were analyzed. A coordinate system was established from the femoral head center, the intercondylar notch, and a morphological flexion axis (MFA). The MFA was created by iteratively fitting circles to the posterior condyles and creating and axis through the circles' centers. The sagittal plane was created normal to this axis and through the notch. A plane was created from the femoral head center and the flexion axis. A coronal plane was created from this plane and a point on the anterior cortex sulcus. Points were placed on a template bone model in the medial and lateral extents of the surface depressions of both the medial and lateral aspect of the CPN, where the depression of the CPN is most distinct. These points were then mapped to each of the 986 femoral specimens via a shape correspondence model. A line is created between the pairs of points representing the medial and lateral CPN's. The coordinates of the points are measured with respect to sagittal and coronal planes (Figure 1). Means and
The trabecular metal Monoblock TKR is comprised of a porous tantalum base plate with the polyethylene liner embedded directly in the porous metal. An alternative design, the trabecular metal Modular TKR, allows polyethylene liner insertion into the locking base plate after base plate implantation, but removes the low modulus of elasticity that was inherent in the Monoblock design. The purpose of this study was to compare the fixation of the Monoblock and Modular trabeucular metal base plates in a randomised controlled trial. Fifty subjects (30 female) were randomly assigned to receive the uncemented trabecular metal Monoblock or uncemented trabecular metal Modular knee replacement. A standard procedure of tantalum marker insertion in the proximal tibial and polyethylene liner was followed with uniplanar radiostereometric analysis (RSA) examinations immediately post-operatively and at 6 week, 3 month, 6 month, and 12 month follow-ups. The study was approved by the Research Ethics Board and all subjects signed an Informed Consent Form. Twenty-one subjects received Monoblock components and 20 received Modular components. An intra-operative decision to use cemented implants occurred in 5 cases and 4 subjects did not proceed to surgery after enrollment. The clinical precision of implant migration measured as maximum total point motion (MTPM) was 0.13 mm (upper limit of 95% confidence interval of double exams). Implant migration at 12 months was 0.88 ± 0.64 mm (mean and
1. The histories of 149 patients, coming to the Hospital for Sick Children within the first three years of life with congenital dislocation of the hip (191 dislocated hips), and treated by conservative methods, have been reviewed. 2. The patients with unilateral dislocations (107) have been divided into three groups, according to the angle of slope of the opposite acetabulum. This angle was measured on the first radiograph and related to the mean value for age and sex. 3. The opposite hip was classed as "normal" if the acetabular angle was below or within one
Surgical fixation of tibial plateau fractures in elderly patients with open reduction and internal fixation (ORIF) provides inferior outcomes compared to younger patients. Primary total knee arthroplasty (TKA) may be of benefit in patients with pre-existing arthritis, marked osteopenia, or severe fracture comminution. Rationale for primary TKA includes allowing early mobility in hopes of reducing associated complications such as deconditioning, postoperative pneumonia, or venous thromboembolism, and reducing post-traumatic arthritis which occurs in 25% to 45% of patients and requires revision TKA in up to 15%. Subsequent revision TKA has been shown to have significantly worse outcomes than TKA for primary osteoarthritis. This systematic review sought to elicit the clinical outcomes and peri-operative complication rates following primary TKA for tibial plateau fractures. A comprehensive search of MEDLINE, Embase, and PubMed databases from inception through March 2018 was performed in accordance with PRISMA guidelines. Two reviewers independently screened papers for inclusion and identified studies featuring perioperative complications and clinical outcomes following primary TKA for tibial plateau fractures. Studies were included for final data analysis if they met the following criteria: (1) studies investigating TKA as the initial treatment for tibial plateau fractures, (2) patients must be ≥ 18 years old, (3) have a minimum ≥ 24-month follow-up, and (4) must be published in the English language. Case series, cohort, case-control, and randomized-control trials were included. Weighted means and
Model-based Roentgen Stereophotogrammetric Analysis (RSA) measures micromotion of an orthopaedic implant with respect to its surrounding bone, without the use of markers on the implant. In previous studies with a total knee prosthesis, Model-based RSA showed to be very accurate. In this study, Model-based RSA is validated in a phantom experiment of a total hip prosthesis. A metal backed, elliptical shaped EP-FIT PLUS ®cup was used in combination with a SL-PLUS ® hip-stem from PLUS Endoprothetik AG. In vivo conditions were simulated by using sawbones and perspex plates to mimic the bones and soft tissue. Virtual projections of the CAD models of the implant were fitted on the automatically detected contours in nine RSA radiographs and the error inmigration calculation was determined. The
Dynamic 2D sonography of the infant hip is a commonly used clinical procedure for developmental dysplasia of the hip (DDH) screening. It however has been found to be unreliable with some studies reporting associated misdiagnosis rates of up to 29%. In a recent systematic review, Charlton et al. examined dynamic ultrasound (US) screening for hip instability in the first six weeks after birth and found current best practices for such early screening techniques to be divergent between international institutions in terms of clinical scanning protocols. Such protocols include: the appropriate scanning plane and US probe position (e.g. coronal, transverse, lateral, anterior), DDH diagnostic metrics (e.g. femoral head coverage, alpha angle), appropriate patient age when scanning, and follow up procedures. To improve reliability of diagnosis and to help in standardizing diagnosis across different raters and health-centers, we propose an automated method for dynamically assessing hip instability using 3D US. 38 infant hips from 19 patients were scanned with B-mode 3D US by a paediatric orthopaedic surgeon and two technologists from the radiology department at a paediatric tertiary care centre. To quantify hip assessment, we proposed the use of femoral head coverage variability (ΔFHC3D) within 3D US volumes collected during a sequence of US scans (one at rest, and another with posterior stress applied to the joint as maneuvered during a dynamic assessment). We used phase symmetry image features to localize the ilium's vertical cortex and a random forest classifier to identify the location of the femoral head. The proposed ΔFHC3D provided good repeatability with an average test-retest ICC measure of 0.70 (95% confidence interval: 0.35 to 0.87, F(21,21) = 7.738, p<.001). The mean difference of ΔFHC3D measurements was 0.61% with a SD of 4.05%. Since the observed changes in ΔFHC3D start near 0% and range up to about 18% from stable to mildly unstable hips in this cohort, the mean difference and
Purpose: We tested the reliability of a digitalised x-ray reading system, Imagika(r), used to measure linear wear of total hip arthroplasy on the AP view of the pelvis. Material and methods: Wear measurements were taken for total hip arthroplasties without cement (n=20) and with cement (n=19) using the distance between the centre of the acetabular cup and the femoral ball. The system delivered measures in hundredths of millimetres that were rounded off to the nearest tenth millimetre. For non-cemented implants, the centre of the acetabular cup was found automatically on the digitalised radiograms using the contour of the metal socket. For cemented cups, the centre of the cup was determined from five points situated on the metallic ellipse included in the polyethylene circumference. The software placed the point clicked by the reader on the adjacent intermediary zone showing the greatest contrast. Five observers read the radiograms twice at 15 day intervals. The observers were a young resident, a senior traumatology surgeon,and a senior surgeon specialised in hip surgery. Results were compared to determine inter- and intra- observer variability. Results: Intra-observer variability was low since the
Articulation of the polyethylene (PE) insert between the metal femoral and tibial components in total knee replacements (TKR) results in wear of the insert which can necessitate revision surgery. Continuous PE advancements have improved wear resistance and durability increasing implant longevity. Keeping up with these material advancements, this study utilises model-based radiostereometric analysis (mbRSA) as a tool to measure in vivo short-term linear PE wear to thus predict long-term wear of the insert. Radiographic data was collected from the QEII Health Sciences Centre in Halifax, NS. Data consisted of follow-up RSA examinations at post-operative, six-, 12-, and 24-month time periods for 72 patients who received a TKR. Implanted in all patients were Stryker Triathlon TKRs with a fixed, conventional PE bearing of either a cruciate retaining or posterior stabilised design. Computer-aided design (CAD) implant models were either provided by the manufacturer or obtained from 3D scanned retrieved implants. Tibial and femoral CAD models were used in mbRSA to capture pose data in the form of Cartesian coordinates at all follow-ups for each patient. Coordinate data was manually entered into a 3D modeling software (Geomagic Studio) to position the implant components in virtual space as presented in the RSA examinations. PE wear was measured over successive follow-ups as the linear change in joint space, defined as the shortest distance between the tibial baseplate and femoral component, independently for medial and lateral sides. A linear best-fit was applied to each patient's wear data; the slope of this line determined the annual wear rate per individual patient. Wear rates were averaged to provide a mean rate of in vivo wear for the Triathlon PE bearing. Mean linear wear per annum across all 72 patients was 0.088mm/yr (SD: 0.271 mm/yr) for the medial condyle and 0.032 mm/yr (SD: 0.230 mm/yr) for the lateral condyle. Cumulative linear wear at the 2-year follow-up interval was 0.207mm (SD: 0.565mm) and 0.068mm (SD: 0.484mm) for the medial and lateral condyles, respectively. Linear PE wear measurements using mbRSA and Geomagic Studio resulted in 0.056mm/yr additional wear on the medial condyle than the lateral condyle. Large
