Negative ulnar variance, lunate shape and increased load transmission are associated with Kienbock’s disease. This may reflect trabecular alignment being more susceptible to shear forces along “fault planes” in Type 1 lunates, causing microfractures and avascular necrosis. The aim of this study was to assess the relationship between lunate bone structure, density and ulnar variance. Standard 90/90 radiographs of 22 cadaveric wrists were taken for ulnar variance and lunate shape. The lunates were harvested and routine CT scans (1mm) were taken in 22/22 in the coronal, sagittal and transverse planes. DICOM files were analysed using Mimics (Materialise, Belgium) to measure Hounsfield units. MicroCT scans (SkyScan, Belgium) (40 μm) were taken in 10/22 in the coronal plane and measured for trabecular angle at the proximal and distal joint surfaces and the ‘tilting angle’ (between scaphoid and radius joint surfaces). Data was anlaysed using one-way ANOVA tests using SPSS for Windows. Negative ulnar variance was noted in 7/22, neutral 10/22 and positive 5/22. Lunate shape according to Zapico was 0/22 Type 1, 18/22 Type 2 and 4/22 Type 3. Lunate bone density was significantly lower in the ulnar positive specimens compared to ulnar negative and neutral (p< 0.001) (fig. 1). The average trabecular angle measured 84.7° (+/− 4.5°) at the proximal and 90.3° (+/− 2.6°) at the distal joint surfaces and tilting angle was 115.7° (+/− 12.0°) (fig. 2). The 50% slice on the microCT correlated best with xray measurements of this angle. This study quantifies the previous finding that load transmission through the lunate and hence lunate bone density is related to ulnar variance and that this is higher in ulnar negative wrists. MicroCT is a useful modality to assess trabecular structure and supports the ‘fault plane’ hypothesis of Kienbock’s Disease

Aims: For planning of Total Hip Arthroplasties (THA) plain X-rays of the pelvis in anterior posterior orientation are used. New methods such as CT scans and intraoperative digitization with navigation devices introduce the third dimension into orthopaedic planning. In order to compare measurements derived from three-dimensional data-acquisition with standard pelvic measurements it is important to estimate the underlying variances of those standards. Methods: 120 patients were investigated and subdivided in 4 groups depending of their age or the condition of their hip joints. The patients were positioned in a supine position on a table and in a standing position. Three landmarks at the patientñs pelvis (left and right anterior superior iliac spine (ASIS) and the pubic tubercle (PT)) were percutaneously digitized with a digitizing arm (Micro-Scribe-3DX, Vizion, Glendale, CA). The pelvic positions in space were calculated in relation to the horizontal and the vertical plane. Results: Despite the anatomical deþnition (0¡), we found an inclination of 4-6¡. There is no signiþcant difference between supine and standing position and no signiþcant difference between the groups and no diffenrence between genders. All patients lyed ßat in supine position without special positioning effort Conclusions: The pelvis orientation ist very stable in standing as well in supine position no matter if the patient is old or young, has coxarthrosis ore none or a THA. Therefore it can be concluded that our knowledge derived from measurements of planar a.-p.x-rays is not inßuenced by a massive variance in pelvic positions

Background: Quantitative sensory testing (QST) conventionally identifies threshold elevation as reflecting sensory deficit. A major disadvantage of the technique is its inability to distinguish organic from feigned sensory deficit, as both are characterized by an elevated threshold. Aim: To distinguish organic from feigned sensory deficit. Method: Vibratory thresholds and their variances were measured, at foot L4, L5 and S1 sites, in 14 patients with low back pain (LBP) suspected of non-organic sensory loss by clinical criteria of Waddell, 14 patient controls with abnormal neurological examination and CT of the low back, and 20 healthy controls. Results: Thresholds of non-organic patients and of patient controls were elevated to a similar extent compared to those of healthy controls. Variances, however, were higher for non-organic patients (6.7–10.5 for the various test sites) than for either patient controls (0.39–0.80, p: 0.001–0.05) or for healthy controls (0.20–0.54, p: 0.001–0.02). Of non-organic patients with high thresholds who would otherwise be identified as pathological, 30–67% were ‘spared’ the misdiagnosis and correctly identified as non-organic because of the inclusion of the variance criterion. Conclusion: Variance evaluation is therefore suggested for inclusion into QST methodology, together with threshold itself, as a quality assurance parameter

Distal radius fractures are the most common upper extremity injury, and are increasingly being treated surgically with pre-contoured volar-locking plates. These plates are favored for their low-profile template while allowing for rigid anatomic fixation of distal radius fractures. The geometry of the distal radius is extremely complex, and little evidence within the medical literature suggests that current implant designs are anatomically accurate. The main objective of this study is to determine if anatomic alignment of the distal radii corresponds accurately with modern volar-locking plate designs. Additionally, this study will examine sex-linked differences in morphology of the distal radius.

Segmented CT models of ten female cadaver (mean age, 88.7 ± 4.57 years, range, 82 – 97) arms, and ten male cadaver (mean age, 86 ± 3.59 years, range, 81 – 91) arms were created. Micro CT models were obtained for the DePuy Synthes 2.4mm Extra-articular (EA) Volar Distal Radius Plate (4-hole and 5-hole head), and 2.4mm LCP Volar Column (VC) Distal Radius Plate (8-hole and 9-hole head). Plates were placed onto the distal radii models in a 3D visualization software by a fellowship-trained orthopaedic hand surgeon. The percent contact, volar cortical angle (VCA), border and overlap of the watershed line (WSL) were measured.

Both sexes showed an increase in the average VCA measure from medial to lateral columns which was statistically significant. Female VCA ranged from 28 – 36 degrees, and 38 – 45 degrees for males. WSL overlap ranged from 0 – 34.7629% for all specimens without any statistical significance. The average border distance for females was 2.58571 mm, compared to 3.52411 mm for males, with EA plates having a larger border than VC plates. The border distances had statistically significant differences between the plate types, and was approaching significance between sexes. Lastly, a maximum percent contact of 21.966 % was observed in specimen F4 at a 0.3 mm threshold. No statistical significance between plate or sex populations was observed.

This study investigated the incoherency between the volar cortical angle of the distal radius, and the pre-contoured angle of volar locking plates. It was hypothesized that if the VCA measures between plate and bone were unequal then there would be an increase in watershed line overlap, and decrease in percent contact between the surfaces. Our results agreed with literature, indicating that the VCA of bone was larger than that of the EA and VC pre-contoured plates examined in this study.

With distal radius fracture incidences and prevalence on the rise for elderly female patients, it is a necessity that volar locking plates be re-designed to factor in anatomical features of individual patients with a particular focus on sex differences. New designs should focus on providing smaller head sizes that are more accurately tailored to the natural contours of the volar distal radius. It is recommended that future studies incorporate expertise from multiple surgeons to diversify and further understand plate placement strategies.

Hypotheses:

A subject’s response to commonly used knee assessment scores is variable, even in the presence of a normal knee.

Methods: A group of 150 New Zealand subjects with normal knees were given three commonly used knee assessment questionnaires. There were three age groups with 50 subjects in each group: 20 to 40, 40 to 60 and above 60 years of age. All were examined to determine that each knee was objectively normal. This group was then compared with a similar group of Canadian subjects and the results were analysed.

Results: The results showed significant differences in expectation between the age groups, with the older age group less happy to score maximum points for their ‘normal’ knee. The Hospital for Special Surgery Knee Score scored the lowest followed by the Knee Society Knee Score. In the over 60 years group there was a significant difference between the New Zealand and Canadian subjects with the Canadians tending to score higher in all scores.

Conclusions: These results have implications when trying to compare results of total knee arthroplasty between different countries and age groups. This study has been expanded to include other countries in an attempt to find a mathematical formula to make future comparisons more relevant.

A patient’s response to knee assessment questionnaires is often subjective and linked to age and cultural expectations.

In New Zealand 150 people, split into three groups of ages 20 to 40 years, 40 to 60 years and over 60 years, were given three commonly used knee assessment questionnaires. All were examined objectively to determine that their knees were normal. Scores in these groups were compared to similar groups of Canadian subjects and the results analysed.

The results show significant differences in expectations between the age groups. Older people were reluctant to score maximum points for their normal knees. The Hospital for Special Surgery’s knee score gave the lowest results, followed by the Knee Society score. In the over-60-year group there was a significant difference between scores in New Zealand and Canada, with Canadians tending to score higher in all scores.

These findings have implications when it comes to comparing results of total knee arthroplasty in different countries and age groups. This study has been expanded to include other countries in an attempt to find a mathematical formula that will make future comparisons more relevant.

Objectives/background: Flexion Stability and Patella tracking after Total Knee Replacement is mainly influenced from the rotational alignment of the femoral component. Different implant philosophies use different landmarks for rotational alignment, as the epicondylar line, the posterior condyles or the anteroposterior line. An individual variation of the different landmarks is known from manual implantation an cadaver and CT studies. The purpose of this study was to measure the variation of three different lines for femoral rotational alignment to show the possible difference and check the so far used values in manual instrumentation technique. Design/methods: Using the Navitrack Navigation system we performed 100 consecutive TKRs. The landmarks for the 3 most common lines for rotational alignment of the femoral component has been probed. The software calculated the position of the lines and the 3-dimensional ankle between the lines. Intraoperative snapshots were taken to postoperative data analysis of the numeric data. Results: The mean difference between the ECL and the PCL was –0,96 (SD 3,64; range −10.7 − 5,9). In varus knees −0,2 (−6 −4,5) in valgus knees 1,4 (–10,7 – 5,9). ECL to the APC was in mean 88,83 (SD 7,23; range 100,8 – 71,9). In varus knees 91,3 (99 – 76,2) in valgus knees 83,8 (100,8 – 71,9). Conclusions: Using a navigation system it is easy to perform an individual, intraoperative measurement of the relationship of different anatomical landmarks for rotational alignment of the femoral component. But the range of values shows that in the manual technique with fixed rotational alignment given by the instruments, there is a high risk for femoral rotational malalignment. The results depended on preoperative deformity could only be seen as a bias for higher variance in valgus knees. For the navigation procedures there is not one universal landmark which can be used. Furthermore the systems must be developed for intraoperative functional analysis, with integration of soft tissue balancing, to improve functional and long-term outcome in TKR

Aims. Patients with A1 and A2 trochanteric hip fractures represent a substantial proportion of trauma caseload, and national guidelines recommend that sliding hip screws (SHS) should be used for these injuries. Despite this, intramedullary nails (IMNs) are routinely implanted in many hospitals, at extra cost and with unproven patient outcome benefit. We have used data from the National Hip Fracture Database (NHFD) to examine the use of SHS and IMN for A1 and A2 hip fractures at a national level, and to define the cost implications of management decisions that run counter to national guidelines. Methods. We used the NHFD to identify all operations for fixation of trochanteric fractures in England and Wales between 1 January 2021 and 31 December 2021. A uniform price band from each of three hip fracture implant manufacturers was used to set cost implications alongside variation in implant use. Results. We identified 18,156 A1 and A2 trochanteric hip fractures in 162 centres. Of these, 13,483 (74.3%) underwent SHS fixation, 2,352 (13.0%) were managed with short IMN, and 2,321 (12.8%) were managed with long IMN. Total cost of IMN added up to £1.89 million in 2021, and the clinical justification for this is unclear since rates of IMN use varied from 0% to 97% in different centres. Conclusion. Most trochanteric hip fractures are managed with SHS, in keeping with national guidelines. There is considerable variance between hospitals for implant choice, despite the lack of evidence for clinical benefit and cost-effectiveness of more expensive nailing systems. This suggests either a lack of awareness of national guidelines or a choice not to follow them. We encourage provider units to reassess their practice if outwith the national norm. Funding bodies should examine implant use closely in this population to prevent resource waste at a time of considerable health austerity. Cite this article: Bone Jt Open 2022;3(10):741–745

Aims. This is a multicentre, prospective assessment of a proportion of the overall orthopaedic trauma caseload of the UK. It investigates theatre capacity, cancellations, and time to surgery in a group of hospitals that is representative of the wider population. It identifies barriers to effective practice and will inform system improvements. Methods. Data capture was by collaborative approach. Patients undergoing procedures from 22 August 2022 and operated on before 31 October 2022 were included. Arm one captured weekly caseload and theatre capacity. Arm two concerned patient and injury demographics, and time to surgery for specific injury groups. Results. Data was available from 90 hospitals across 86 data access groups (70 in England, two in Wales, ten in Scotland, and four in Northern Ireland). After exclusions, 709 weeks' of data on theatre capacity and 23,138 operations were analyzed. The average number of cases per operating session was 1.73. Only 5.8% of all theatre sessions were dedicated day surgery sessions, despite 29% of general trauma patients being eligible for such pathways. In addition, 12.3% of patients experienced at least one cancellation. Delays to surgery were longest in Northern Ireland and shortest in England and Scotland. There was marked variance across all fracture types. Open fractures and fragility hip fractures, influenced by guidelines and performance renumeration, had short waits, and varied least. In all, nine hospitals had 40 or more patients waiting for surgery every week, while seven had less than five. Conclusion. There is great variability in operative demand and list provision seen in this study of 90 UK hospitals. There is marked variation in nearly all injuries apart from those associated with performance monitoring. There is no evidence of local network level coordination of care for orthopaedic trauma patients. Day case operating and pathways of care are underused and are an important area for service improvement. Cite this article: Bone Jt Open 2023;4(6):463–471

Aims. To assess the incidence of radiological lateral osteoarthritis (OA) at 15 years after medial unicompartmental knee arthroplasty (UKA) and assess the relationship of lateral OA with symptoms and patient characteristics. Methods. Cemented Phase 3 medial Oxford UKA implanted by two surgeons since 1998 for the recommended indications were prospectively followed. A 15-year cumulative revision rate for lateral OA of 5% for this series was previously reported. A total of 163 unrevised knees with 15-year (SD 1) anterior-posterior knee radiographs were studied. Lateral joint space width (JSW. L. ) was measured and severity of lateral OA was classified as: nil/mild, moderate, and severe. Preoperative and 15-year Oxford Knee Scores (OKS) and American Knee Society Scores were determined. The effect of age, sex, BMI, and intraoperative findings was analyzed. Statistical analysis included one-way analysis of variance and Kruskal-Wallis H test, with significance set at 5%. Results. The mean age was 80.6 years (SD 8.3), with 84 females and 79 males. The mean JSW. L. was 5.6 mm (SD 1.4), and was not significantly related to age, sex, or intraoperative findings. Those with BMI > 40 kg/m. 2. had a smaller JSW. L. than those with a ‘normal’ BMI (p = 0.039). The incidence of severe and moderate lateral OA were both 4.9%. Overall, 2/142 (1.4%) of those with nil/mild lateral OA, 1/8 (13%) with moderate, and 2/8 (25%) with severe subsequently had a revision. Those with severe (mean OKS 35.6 (SD 9.3)) and moderate OA (mean OKS 35.8 (SD 10.5)) tended to have worse outcome scores than those with nil/mild (mean OKS 39.5 (SD 9.2)) but the difference was only significant for OKS-Function (p = 0.044). Conclusion. This study showed that the rate of having severe or moderate radiological lateral OA at 15 years after medial UKA was low (both 4.9%). Although patients with severe or moderate lateral OA had a lower OKS than those with nil/mild OA, their mean scores (OKS 36) would be classified as good. Cite this article: Bone Jt Open 2023;4(3):210–218

Aims. The aim of this study was to determine whether total hip arthroplasty (THA) for chronic hip pain due to unilateral primary osteoarthritis (OA) has a beneficial effect on cognitive performance. Methods. A prospective cohort study was conducted with 101 patients with end-stage hip OA scheduled for THA (mean age 67.4 years (SD 9.5), 51.5% female (n = 52)). Patients were assessed at baseline as well as after three and months. Primary outcome was cognitive performance measured by d2 Test of Attention at six months, Trail Making Test (TMT), FAS-test, Rivermead Behavioural Memory Test (RBMT; story recall subtest), and Rey-Osterrieth Complex Figure Test (ROCF). The improvement of cognitive performance was analyzed using repeated measures analysis of variance. Results. At six months, there was significant improvement in attention, working speed and concentration (d2-test; p < 0.001), visual construction and visual memory (ROCF; p < 0.001), semantic memory (FAS-test; p = 0.009), verbal episodic memory (RBMT; immediate recall p = 0.023, delayed recall p = 0.026), as well as pain (p < 0.001) with small to large effect sizes. Attention, concentration, and visual as well as verbal episodic memory improved significantly with medium effect sizes over η. 2. partial. = 0.06. In these cognitive domains the within-group difference exceeded the minimum clinically important difference. Conclusion. THA is associated with clinically relevant postoperative improvement in the cognitive functions of attention, concentration, and memory. These data support the concept of a broad interaction of arthroplasty with central nervous system function. Cite this article: Bone Joint J 2022;104-B(3):331–340

Aims

Manual impaction, with a mallet and introducer, remains the standard method of installing cementless acetabular cups during total hip arthroplasty (THA). This study aims to quantify the accuracy and precision of manual impaction strikes during the seating of an acetabular component. This understanding aims to help improve impaction surgical techniques and inform the development of future technologies.

Aims

Tissue adhesives (TAs) are a commonly used adjunct to traditional surgical wound closures. However, TAs must be allowed to dry before application of a surgical dressing, increasing operating time and reducing intraoperative efficiency. The goal of this study is to identify a practical method for decreasing the curing time for TAs.

Aims

Within healthcare, several measures are used to quantify and compare the severity of health conditions. Two common measures are disability weight (DW), a context-independent value representing severity of a health state, and utility weight (UW), a context-dependent measure of health-related quality of life. Neither of these measures have previously been determined for developmental dysplasia of the hip (DDH). The aim of this study is to determine the DW and country-specific UWs for DDH.

Aims

The aim of this study was to explore the genetic correlation and causal relationship between blood plasma proteins and rheumatoid arthritis (RA).

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 standard deviation (SD) of kinematic and muscle force waveform PC scores, representing the intra-subject variance of movement or muscle activation, were associated with the GMOS scores. Results. The study compared GMOS scores, kinematics, and muscle force variances from a total of 26 infants with a mean corrected gestational age of 39.7 (±3.34) weeks and GMOS scores between 21 and 40. There was a significant association between the SD of the PC scores for knee flexion and the GMOS scores (PC1: R = 0.59, p = 0.002; PC2: R = 0.49, p = 0.011; PC3: R = 0.56, p = 0.003). The three PCs captured variances of the overall flexion magnitude (66% variance explained), early-to-late kick knee extension (20%), and continual to biphasic kicking (6%). For hip flexion, only the SD of PC1 correlated with GMOS scores (PC1: R = 0.52, p = 0.0068), which captured the variance of the overall flexion magnitude (81%). For the biceps femoris, the SD of PC1 and PC3 associated with GMOS scores (PC1: R = 0.50, p = 0.002; PC3: R = 0.45, p = 0.03), which captured the variance of the overall bicep force magnitude (79%) and early-to-late kick bicep activation (8%). Conclusions. Infants with reduced motor development as scored in the GMOS displayed reduced variances of knee and hip flexion and biceps femoris activation across kicking cycles. These findings suggest that combining objectively measured movement variances with existing classification methods could facilitate the development of more consistent and accurate diagnostic tools for early detection of CP. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

The anatomy of the femur shows a high inter-patient variability, making it challenging to design standard prosthetic devices that perfectly adapt to the geometry of each individual. Over the past decade, Statistical Shape Models (SSMs) have been largely used as a tool to represent an average shape of many three-dimensional objects, as well as their variation in shape. However, no studies of the morphology of the residual femoral canal in patients who have undergone an amputation have been performed. The aim of this study was therefore to evaluate the main modes of variation in the shape of the canal, therefore simulating and analysing different levels of osteotomy. To assess the variability of the femoral canal, 72 CT-scans of the lower limb were selected. A segmentation was performed to isolate the region of interest (ROI), ranging from the lesser tip of the trochanter to the 75% of the length of the femur. The canals were then sized to scale, aligned, and 16 osteotomy levels were simulated, starting from a section corresponding to 25% of the ROI and up to the distal section. For each level, the main modes of variations of the femoral canal were identified through Principal Component Analysis (PCA), thus generating the mean geometry and the extreme shapes (±2 stdev) of the principal modes of variation. The shape of the canals obtained from these geometries was reconstructed every 10 mm, best- fitted with an ellipse and the following parameters were evaluated: i) ellipticity, by looking at the difference between axismax and axismin; ii) curvature of the canal, calculating the arc of circumference passing through the shapes’ centroids; iii) conicity, by looking at the maximum/minimum diameter; iv) mean diameter. To understand the association between the main modes and the shape variance, these parameters were compared, for each level of osteotomy, between the two extreme geometries of the main modes of variation. Results from PCA pointed out that the first three PCs explained more than the 87% of the total variance, for each level of simulated osteotomy. By analysing the extreme geometries for a distal osteotomy (e.g. 80% of the length of the canal), the first PC was associated to a combination of ROC (var%=41%), conicity (var%=28%) and ellipticity (var%=7%). PC2 was still associated with the ROC (var%=16%), while PC3 turned out to be associated with the diameter (var%=38%). Through the SSM presented in this study, a quantitatively evaluation of the deformation of the intramedullary canal has been made possible. By analysing the extreme geometries obtained from the first three modes of variance, it is clear that the first three PCs accounted for the variations in terms of curvature, conicity, ellipticity and diameter of the femoral canal with a different weight, depending on the level of osteotomy. Through this work, it was also possible to parametrize these variations according to the level of excision. The results given for the segment corresponding to the 80% of the length of the canal showed that, at that specified level, the ROC, conicity and ellipticity were the anatomical parameters with the highest range of variability, followed by the variation in terms of diameter. Therefore, the analysis carried out can provide information about the relevance of these parameters depending on the level of osteotomy suffered by the amputee. In this way, optimal strategies for the design and/or customization of osteo-integrated stems can be offered depending on the patient's residual limb

Distal radius fractures (DRFs) are common injuries that represent 17% of all adult upper extremity fractures. Some fractures deemed appropriate for nonsurgical management following closed reduction and casting exhibit delayed secondary displacement (greater than two weeks from injury) and require late surgical intervention. This can lead to delayed rehabilitation and functional outcomes. This study aimed to determine which demographic and radiographic features can be used to predict delayed fracture displacement. This is a multicentre retrospective case-control study using radiographs extracted from our Analytics Data Integration, Measurement and Reporting (DIMR) database, using diagnostic and therapeutic codes. Skeletally mature patients aged 18 years of age or older with an isolated DRF treated with surgical intervention between two and four weeks from initial injury, with two or more follow-up visits prior to surgical intervention, were included. Exclusion criteria were patients with multiple injuries, surgical treatment with fewer than two clinical assessments prior to surgical treatment, or surgical treatment within two weeks of injury. The proportion of patients with delayed fracture displacement requiring surgical treatment will be reported as a percentage of all identified DRFs within the study period. A multivariable conditional logistic regression analysis was used to assess case-control comparisons, in order to determine the parameters that are mostly likely to predict delayed fracture displacement leading to surgical management. Intra- and inter-rater reliability for each radiographic parameter will also be calculated. A total of 84 age- and sex-matched pairs were identified (n=168) over a 5-year period, with 87% being female and a mean age of 48.9 (SD=14.5) years. Variables assessed in the model included pre-reduction and post-reduction radial height, radial inclination, radial tilt, volar cortical displacement, injury classification, intra-articular step or gap, ulnar variance, radiocarpal alignment, and cast index, as well as the difference between pre- and post-reduction parameters. Decreased pre-reduction radial inclination (Odds Ratio [OR] = 0.54; Confidence Interval [CI] = 0.43 – 0.64) and increased pre-reduction volar cortical displacement (OR = 1.31; CI = 1.10 – 1.60) were significant predictors of delayed fracture displacement beyond a minimum of 2-week follow-up. Similarly, an increased difference between pre-reduction and immediate post reduction radial height (OR = 1.67; CI = 1.31 – 2.18) and ulnar variance (OR = 1.48; CI = 1.24 – 1.81) were also significant predictors of delayed fracture displacement. Cast immobilization is not without risks and delayed surgical treatment can result in a prolong recovery. Therefore, if reliable and reproducible radiographic parameters can be identified that predict delayed fracture displacement, this information will aid in earlier identification of patients with DRFs at risk of late displacement. This could lead to earlier, appropriate surgical management, rehabilitation, and return to work and function

Abstract. OBJECTIVES. Dual mobility (DM) total hip replacements (THRs) were introduced to reduce the risk of hip dislocation in at-risk patients. DM THRs have shown good overall survivorship and low rates of dislocation, however, the mechanisms which describe how these bearings function in-vivo are not fully understood. This is partly due to a lack of suitable characterisation methodologies which are appropriate for the novel geometry and function of DM polyethylene liners, whereby both surfaces are subject to articulation. This study aimed to develop a novel semi-quantitative geometric characterisation methodology to assess the wear/deformation of DM liners. METHODS. Three-dimensional coordinate data of the internal and external surfaces of 14 in-vitro tested DM liners was collected using a Legex 322 coordinate measuring machine. Data was input into a custom Matlab script, whereby the unworn reference geometry was determined using a sphere fitting algorithm. The analysis method determined the geometric variance of each point from the reference surface and produced surface deviation heatmaps to visualise areas of wear/deformation. Repeatability of the method was also assessed. RESULTS. Semi-quantitative analysis of the surface deviation heatmaps revealed circumferential damage patterns similar to those reported in the literature. Additionally, the location of the damaged regions corresponded between the internal and external surfaces. Comparing five repeat measurements of the same liner, the maximum geometric variance of each surface varied by 1 µm (standard deviation) suggesting a high repeatability of the method. CONCLUSIONS. This study presents an effective and highly repeatable characterisation methodology to semi-quantitatively assess the wear/deformation of in-vitro tested DM liners. This method is suitable for the analysis of retrieved DM liners whereby no pre-service information is available, which may provide information about the complex in-vivo kinematics and mechanical failure mechanisms of these bearings

Early mobilization within the first 12 hours (day zero) of total joint arthroplasty (TJA) has been shown to reduce length of stay (LoS) without risking clinical outcomes, patient safety or satisfaction. The purpose of this study was to investigate associations between the degree of mobilization on day zero (i.e., standing at the bedside versus walking in the hallway) and LoS in TJA patients. In addition, we investigated predictors of LoS and day zero mobilization. A retrospective cohort study was undertaken of the health records of patients in a community hospital setting who had an elective unilateral primary TJA between June 2015 and May 2017 and had mobilized on day zero. The total sample was 283 patients (184 TKA and 99 THA) across four mobilization categories: Sat on beside (n = 76), Stood by bed/marched in place (n = 83), Walked in the room (n = 79), and Walked in hall (n = 45). Analysis of variance found no significant group differences in age, ASA score, Charlson Comorbidity Index score, anesthesia, surgeon, procedure type, pain medication, and patient reported symptoms recorded by physiotherapists. Significantly more women were in the Sat group and significantly more men were in the Hall group (p < .001). Patient reported symptoms of nausea and drowsiness were significantly greater for the Sat group (p < .001). LoS was also significantly different across the groups. Post hoc Tukey comparisons found the Walked Hall group had significantly shorter LoS (M = 2.7 days) than the Sat group (M = 3.9, p < .001), Stood group (M = 3.4, p = .011), and the Walked Room group (M = 3.5, p = .004). A hierarchical regression was performed to determine predictors of LoS. Block 1 consisted of demographic, medical status, and patient reported symptoms as variables. Mobilization was entered in Block 2. The first model was significant (p < .001) and explained 24% of variance in LoS. The final model was also significant (p < .001), accounting for a total of 26% of the variance in LoS. Thus, block 2 (i.e., mobilization) accounted for a small but significant 2% incremental variance (p = .008) beyond the block 1 variables in the prediction of LoS. With mobilization added, only male gender (p = .002), lower BMI (p = .026), and lower ASA scores (p = .006) remained significant predictors of shorter LoS, and the predictive ability of several of the block 1 variables were reduced to non-significant levels. A simultaneous regression model was then used to predict degree of mobilization. The model accounted for 24% of the variance in mobilization (p < .001). Variables significantly associated with a greater degree of mobilization included: younger age, male gender, lower BMI, and fewer symptoms, namely nausea, numbness, lightheadedness, and drowsiness. This study found length of stay was shorter when patients mobilized farther on the day of surgery. Some factors predictive of mobilization may be modifiable. Focusing on symptom management could increase opportunities for farther mobilization on the day of surgery, and thus decrease length of stay