Objectives. Computed tomography (CT) plays an important role in evaluating wear and periacetabular osteolysis (PAO) in total hip replacements. One concern with CT is the high radiation exposure since standard pelvic CT provides approximately 3.5 millisieverts (mSv) of radiation exposure, whereas a planar radiographic examination with three projections totals approximately 0.5 mSv. The objective of this study was to evaluate the lowest acceptable radiation dose for dual-energy CT (DECT) images when measuring wear and periacetabular osteolysis in uncemented metal components. Materials and Methods. A porcine pelvis with bilateral uncemented hip prostheses and with known linear wear and acetabular bone defects was examined in a third-generation multidetector DECT scanner. The examinations were performed with four different radiation levels both with and without iterative reconstruction techniques. From the high and low peak kilo voltage acquisitions, polychrmoatic images were created together with virtual monochromatic images of energies 100 kiloelectron volts (keV) and 150 keV. Results. We could assess wear and PAO while substantially lowering the effective radiation dose to 0.7 mSv for a total pelvic view with an accuracy of around 0.5 mm for linear wear and 2 mm to 3 mm for PAO. Conclusion. CT for detection of prosthetic wear and PAO could be used with clinically acceptable accuracy at a radiation exposure level equal to plain radiographic exposures. Cite this article: B. Sandgren, M. Skorpil, P. Nowik, H. Olivecrona, J. Crafoord, L. Weidenhielm, A. Persson. Assessment of wear and periacetabular osteolysis using dual energy computed tomography on a pig cadaver to identify the lowest acceptable radiation dose. Bone Joint Res 2016;5:307–313. DOI: 10.1302/2046-3758.57.2000566

Loosening is a serious problem in total arthroplasty and early detection of bone loss in the vicinity of an implant would help in its investigation. We present a method for the objective evaluation of bone adjacent to metallic implants in which a modified technique of quantitative computed tomography (QCT) is used to reconstruct cross-sectional images with few artefacts. We have used this technique in 19 patients with knee arthroplasties to monitor the changes in bone density around the tibial stem of the prosthesis. In the first weeks after operation all patients showed a decrease in bone density ranging from 0.4% to 3.6% per month. One year after arthroplasty bone density had stabilised and only minor changes were observed. Our work indicates that modified QCT is a sensitive method for the long-term monitoring of the anchorage of implants and allows the early detection of osteolytic changes

Surgeons need to be able to measure angles and distances in three dimensions in the planning and assessment of knee replacement. Computed tomography (CT) offers the accuracy needed but involves greater radiation exposure to patients than traditional long-leg standing radiographs, which give very little information outside the plane of the image.

There is considerable variation in CT radiation doses between research centres, scanning protocols and individual scanners, and ethics committees are rightly demanding more consistency in this area.

By refining the CT scanning protocol we have reduced the effective radiation dose received by the patient down to the equivalent of one long-leg standing radiograph. Because of this, it will be more acceptable to obtain the three-dimensional data set produced by CT scanning. Surgeons will be able to document the impact of implant position on outcome with greater precision.

Introduction

Up to 16% of scaphoid fractures are radiologically occult; failure to diagnose scaphoid fractures may lead to delayed union, nonunion or avascular necrosis. Fractures may take weeks to be excluded and many patients are unnecessarily immobilised increasing work absence, clinical reviews and cost. The use of CT early in the management of suspected occult scaphoid fractures has been evaluated.

Our study evaluated the accuracy of an image-guided total knee replacement system based on CT with regard to preparation of the femoral and tibial bone using nine limbs from five cadavers. The accuracy was assessed by direct measurement using an extramedullary alignment rod without radiographs.

The mean angular errors of the femur and tibia, which represent angular gaps from the real mechanical axis in the coronal plane, were 0.3° and 1.1°, respectively. The CT-based system, provided almost perfect alignment of the femoral component with less than 1° of error and excellent alignment with less than 3° of error for the tibial component. Our results suggest that standardisation of knee replacement by the use of this system will lead to improved long-term survival of total knee arthroplasty.

We compared the usefulness of radiography, CT and MRI in 25 children with spinal tuberculosis. Radiography provided most of the information necessary for diagnosis and treatment. Axial CT was the most accurate method for visualising the posterior bony elements. Sagittal MRI best showed the severity and content of extradural compression and helped to differentiate between an abscess and fibrous tissue. The main value of CT and MRI is in the preoperative evaluation of the small proportion of patients who require surgical treatment for paraplegia.

Objective

The aim of the study was to evaluate inter observer reliability and intra observer reproducibility between the three column classification using 3D CT reconstruction models and schatzker classification systems using 2D CT models.

Aims

This study aimed to investigate the incidence of ≥ 5 mm asymmetry in lower and whole leg lengths (LLs) in patients with unilateral osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH-OA) and primary hip osteoarthritis (PHOA), and the relationship between lower and whole LL asymmetries and femoral length asymmetry.

Objectives

Current studies on the additional benefit of using computed tomography (CT) in order to evaluate the surgeons’ agreement on treatment plans for fracture are inconsistent. This inconsistency can be explained by a methodological phenomenon called ‘spectrum bias’, defined as the bias inherent when investigators choose a population lacking therapeutic uncertainty for evaluation. The aim of the study is to determine the influence of spectrum bias on the intra-observer agreement of treatment plans for fractures of the distal radius.

Introduction

Malrotation following total knee replacement is directly related to poor outcome. The knowledge of proximal and distal rotational axes and angles of the femur is therefore of high importance. The aim of the study was to determine whether the most used proximal and distal femoral angles; femoral anteversion angle (FAA) and posterior condylar angle (PCA) were different within individuals, between right, left and gender. As well, we studied whether the “inferior condylar angle” is correlated to the PCA and therefore useful in determining the rotation of the distal femur.

Orthopaedic injuries in the knee are often associated with vascular injury. When these vascular injuries are missed devastating there are devastating outcomes like limb ablation. Pulse examination in these patients is not sensitive to exclude vascular injuries. That often lead to clinicians opting for Computed Tomography Angiogram (CTA) to exclude vascular. this usually leads to a burden in Radiology Department. This study aimed to evaluate the prevalence of vascular injury in patient with orthopaedic injury in the knee. The computed tomography (CT) done in patients with distal femur fracture, knee dislocation and proximal tibia fractures were retrieved from the picture archiving and comunication system (PACS). The CTs were done between June 2017 and June 2022. The computed tomography angiogram (CTA) reports were reviewed to determine cases that vascular injury. A sample size of 511 cases was collected. 386 cases were done CTA and 125 cases were not done CTA. There were 218 tibial plateau fractures, 79 knee dislocations, 72 distal metaphyseal femur fractures, 61 floating knees, 55 distal femure intraarticular and 26 proximal metaphyseal tibia fractures. The mechanisms of injury in these were gunshot, fall from standing height, fall from height, MVA, MBA, PVA and sports. Prevalance was 9.17% (47) of the total injuries in the knee. Prevalance in patients who were sent for CTA was 12.08%. Routine CTA in patients with injuries in the knee is not recomended. The use of ankle brachial index may decrease the number of CTA done

Introduction: Optimal component position in all planes and well balanced soft tissues lead to a good clinical outcome and long-term survival after total knee arthroplasty. We investigated the implantation accuracy of navigated total knee arthroplasty at 3 months followup and the influence on the clinical outcome at 2 years followup. Patients and Methods: Forty-four patients (44 procedures) were enrolled in our prospective study. One half of the surgeries were performed using a computed tomography based navigation system, and one half of the surgeries were performed without computed tomography navigation. Outcomes were based on the Insall knee score parameters, anterior knee pain, patient satisfaction, feeling of instability, and step test. The radiographic parameters were the mechanical axis, tibial slope, lateral distal femoral angle, and medial proximal tibial angle. Results: The radiographic measurements showed no differences between both groups (patients within ± 3° inaccuracy range in computed tomography based/computed tomography free groups; mechanical axis 86%/81%, tibial slope 95%/91%, lateral distal femoral angle 95%/91%, medial proximal tibial angle 91%/95%). The cumulative error of alignment showed no difference between the study groups. Seventeen of 21 (81%) patients fulfilled four criteria in the CT based group, and 15 of 21 (71.4%) patients fulfilled four criteria in the comparison group. Nineteen of 21 (90.5%) patients in both groups achieved three criteria in an optimal manner. An increased (p < 0.001) Insall knee score was found for changes over time in both study groups; however, there were no differences between the CT based or CT free patient groups. The postoperative ROM in both groups showed no difference at the 3-month and 2-year followup examinations. Both groups had an increase (p ≤ 0.002) in ROM between the 3-month and 2-year followup examinations. The examination of ligament balancing in full extension showed a higher rate of a stable soft tissue situation in the CT free navigation group but the difference was not significant. In 30° of flexion we detected a better (p = 0.004) ligament situation medially and laterally in the CT free group. The anterior drawer test showed a better (p = 0.035) stability in the CT free navigation group. Discussion: The computed tomography free system provided equal radiographic results, but we found improved ligament balancing in the computed tomography free group. The computed tomography based module has an optimal preoperative planning procedure, but is more expensive and time consuming

Introduction. A staging system has been developed to revise the 1994 ARCO classification for ONFH. The final consensus resulted in the following 4-staged system: stage I—X-ray is normal, but either magnetic resonance imaging or bone scan is positive; stage II—X-ray is abnormal (subtle signs of osteosclerosis, focal osteoporosis, or cystic change in the femoral head) but without any evidence of subchondral fracture, fracture in the necrotic portion, or flattening of the femoral head; stage III—fracture in the subchondral or necrotic zone as seen on X-ray or computed tomography scans. This stage is further divided into stage IIIA (early, femoral head depression ≤2 mm) and stage IIIB (late, femoral head depression >2 mm); and stage IV—X-ray evidence of osteoarthritis with accompanying joint space narrowing, acetabular changes, and/or joint destruction. Radiographs, magnetic resonance imaging (MRI), and computed tomography (CT) scans may all be involved in diagnosing ONFH; however, the optimal diagnostic modality remains unclear. The purpose of this study was to identify: 1) how ONFH is diagnosed at a single academic medical center, and 2) if CT is a necessary modality for diagnosing/staging OFNH. Methods. The EMR was queried for the diagnosis of ONFH between 1/1/2008–12/31/2018 at a single academic medical center. CT and MRI scans were reviewed by the senior author and other contributors. The timing and staging quality of the diagnosis of ONFH were compared between MRI and CT to determine if CT was a necessary component of the ONFH work-up. Results. There were 803 patients with ONFH over the 10 years of study. 382 had CT only, 166 had MRI only, and 255 had both a CT and MRI. Of the 255 patients who had both CT and MRI, 228 actually had ONFH after inspection. A diagnosis of ONFH was made by MRI only in 57% (129/228) while another 21% (48/228) used MRI and CT simultaneously. 22% (51/228) of cases were diagnosed by CT scan first. 94% (48/51) of these cases involved a cancer (CA) diagnoses, the CT scans were used for CA staging and were not helpful with ARCO staging of ONFH. The other 3 cases identified asymptomatic ONFH. MRI scans performed after diagnosis with CT in symptomatic patients were then utilized for staging. Conclusion. Although CT scan was a useful adjunct for diagnosing ONFH during a staging workup for CA, it was not useful for ARCO staging of ONFH and treatment decisions. Based on this retrospective study, CT scan is not necessary when using the Revised ARCO Staging System

Sarcopenia has been observed to be a predictor of mortality in international studies of patients with metastatic disease of the spine. This study aimed to validate sarcopenia as a prognostic tool in a New Zealand setting. A secondary aim of this study was to assess the intra-observer reliability of measurements of psoas and vertebral body cross sectional areas on computed tomography imaging. A cohort of patients who had presented to Waikato Hospital with secondary neoplasia in the spinal column from 2014 to 2018 was selected. Cross sectional psoas and vertebral body areas were measured at the mid-pedicle L3 level, followed by calculation of the psoas to vertebral body cross sectional area ratio. Psoas to vertebral body cross sectional area ratio was compared with survivorship. The strength of the correlation between sarcopenia and survivorship was compared with the correlation between serum albumin and survivorship, as well as the correlation between the Metastatic Spine Risk Index (MSRI) and survivorship. A total of 110 patients who received operative (34) and non-operative (76) were included. The results demonstrate that psoas to vertebral body cross sectional area ratio is not statistically significantly correlated with survivorship (p=0.53). Serum albumin is significantly correlated with survivorship (p<0.0001), as was the MSRI. There is good intra-observer and inter-observer reliability for measurements of psoas to vertebral body cross sectional area. This study failed to demonstrate the utility for the psoas to vertebral body cross sectional area ratio that other studies have demonstrated in estimating survivorship. Serum albumin levels remain a useful prognostic indicator in patients with secondary tumours in the vertebral column

The painful hip without obvious clinical or radiographic signs of complications is a well-known scenario for surgeons. The clinical tools we have access to currently lack a dynamic test for detecting early signs of motion between implant and bone. A new software, Sectra IMA, has a potential to facilitate diagnosis of early implant loosening by analysis of paired CT exams. In clinical practise the two scans are acquired by endpoint of a possible motion, “a provocation CT”, for example maximal external and internal rotation in a CT hip examination. 20 years of research by Olivecrona and Weidenhielm is the scientific background for the technique. Early results are presented by Sandberg et al 2022. To further validate and create clinical evidence more extensive clinical studies is needed. A proposal for a multicentric, global clinical study will be presented for further discussion. A new technique for diagnosis of acetabular cup loosening using computed tomography: preliminary experience in 10 patients. Henrik Olivecrona, Lotta Olivecrona, Lars Weidenhielm, Marilyn E Noz, Jocelyn Kardos, Gerald Q Maguire Jr, Michael P Zeleznik, Peter Aspelin. Acta Orthop. 2008 Jun;79(3):346-53. doi: 10.1080/17453670710015247. Inducible displacement CT increases the diagnostic accuracy of aseptic loosening in primary total hip arthroplasty. Sandberg O, Carlsson S, Harbom E, Cappelen V, Tholén S, Olivecrona H, Wretenberg P. Acta Orthop. 2022 Oct 31;93:831-836. doi: 10.2340/17453674.2022.5240.PMID: 36314542

A number of classification systems exist for posterior malleolus fractures of the ankle. The reliability of these classification systems remains unclear. The primary aim of this study was to evaluate the reliability of three commonly utilised fracture classification systems of the posterior malleolus. 60 patients across 2 hospitals sustaining an unstable ankle fracture with a posterior malleolus fragment were identified. All patients underwent radiographs and computed tomography of their injured ankle. 9 surgeons including pre-ST3 level, ST3-8 level, and consultant level applied the Haraguchi, Rammelt, and Mason & Molloy classifications to these patients, at two timepoints, at least 4 weeks apart. The order was randomised between assessments. Inter-rater reliability was assessed using Fleiss’ kappa and 95% confidence intervals (CI). Intra-rater reliability was assessed using Cohen's Kappa and standard error (SE). Inter-rater reliability (Fleiss’ Kappa) was calculated for the Haraguchi classification as 0.522 (95% CI 0.490 – 0.553), for the Rammelt classification as 0.626 (95% CI 0.600 – 0.652), and the Mason & Molloy classification as 0.541 (95% CI 0.514 – 0.569). Intra-rater reliability (Cohen's Kappa) was 0.764 (SE 0.034) for the Haraguchi, 0.763 (SE 0.031) for the Rammelt, 0.688 (SE 0.035) for the Mason & Molloy classification. This study reports the inter-rater and intra-rater reliability for three classification systems for posterior malleolus fractures. Based on definitions by Landis & Koch (1977), inter-rater reliability was rated as ‘moderate’ for the Haraguchi and Mason & Molloy classifications; and ‘substantial’ for the Rammelt classification. Similarly, the intra-rater reliability was rated as ‘substantial’ for all three classifications

The treatment of paediatric supracondylar humeral fractures is likely one of the first procedures involving X-ray guided wire insertion that trainee orthopaedic surgeons will encounter. Pinning is a skill that requires high levels of anatomical knowledge, spatial awareness, and hand-eye coordination. We developed a simulation model using silicone soft-tissue and 3D-printed bones to allow development and practice of this skill at no additional risk to patients. For this model, we have focused on reusability and lowering raw-material costs without compromising fidelity. To achieve this, the initial bone model was extracted from open-source computed tomography scans and modified from adult to paediatric size. Muscle of appropriate robustness was then sculpted around the bones using 3D modelling software. A cutaneous layer was developed to mimic oedema using clay sculpturing on a plaster-casted paediatric forearm. These models were then used for 3D-printing and silicone casting respectively. The bone models were printed with settings to imitate cortical and cancellous densities and give high-fidelity tactile feedback upon drilling. Each humerus costs NZD $0.30 in material to print and can be used 1–3 times. Silicone casting of the soft-tissue layers imitates differing relative densities between muscle and oedematous cutaneous tissue, thereby increasing skill necessary to accurately palpate landmarks. Each soft-tissue sleeve cost NZD $70 in material costs to produce and can be used 20+ times. The resulting model is modular, reusable, and replaceable, with each component standardised and easily reproduced. It can be used to practice land-mark palpation and Kirschner wire pinning and is especially valuable in smaller centres which may not be able to afford traditional Saw Bones models. This low-cost model thereby improves equity while maintaining quality of simulation training

Virtual mechanical testing is a method for measuring bone healing using finite element models built from computed tomography (CT) scans. Previously, we validated a dual-zone material model for ovine fracture callus that differentiates between mineralized woven bone and soft tissue based on radiodensity. 1. The objective of this study was to translate the dual-zone material model from sheep to two important clinical scenarios: human tibial fractures in early-stage healing and late-stage nonunions. CT scans for N = 19 tibial shaft fractures were obtained prospectively at 12 weeks post-op. A second group of N = 33 tibial nonunions with CT scans were retrospectively identified. The modeling techniques were based on our published method. 2. The dual-zone material model was implemented for humans by performing a cutoff sweep for both the 12-week and nonunion groups. Virtual torsional rigidity (VTR) was calculated as VTR = ML/φ [N-m. 2. /°], where M is the moment reaction, L is the diaphyseal segment length, and φ is the angle of twist. As the soft tissue cutoff was increased, the rigidity of the clinical fractures decreased and soft tissue located within the fracture gaps produced higher strains that are not predicted without the dual zone approach. The structural integrity of the nonunions varied, ranging from very low rigidities in atrophic cases to very high rigidities in highly calcified hypertrophic cases, even with dual-zone material modeling. Human fracture calluses are heterogeneous, comprising of woven bone and interstitial soft tissue. Use of a dual-zone callus material model may be instrumental in identifying delayed unions during early healing when callus formation is minimal and/or predominantly fibrous with little mineralization. ACKNOWLEDGEMENTS:. This work was supported by the National Science Foundation (NSF) grant CMMI-1943287

Introduction. Pes cavovarus is a foot deformity that can be idiopathic (I-PC) or acquired secondary to other pathology. Charcot-Marie-Tooth disease (CMT) is the most common adult cause for acquired pes cavovarus deformity (CMT-PC). The foot morphology of these distinct patient groups has not been previously investigated. The aim of this study was to assess if morphological differences exist between CMT-PC, I-PC and normal feet (controls) using weightbearing computed tomography (WBCT). Methods. A retrospective analysis of WBCT scans performed between May 2013 and June 2017 was undertaken. WBCT scans from 17 CMT-PC, 17 I-PC and 17 healthy normally-aligned control feet (age-, side-, sex- and body mass index-matched) identified from a prospectively collected database, were analysed. Eight 2-dimensional (2D) and three 3-dimensional (3D) measurements were undertaken for each foot and mean values in the three groups were compared using one-way ANOVA with the Bonferroni correction. Results. Significant differences were observed between CMT-PC or I-PC and controls (p< 0.05). Two-dimensional measurements were similar in CMT-PC and I-PC, except for forefoot arch angle (p= 0.04). 3D measurements (foot and ankle offset, calcaneal offset and hindfoot alignment angle) demonstrated that CMT-PC exhibited more severe hindfoot varus malalignment than I-PC (p= 0.03, 0.04 and 0.02 respectively). Discussion. CMT-related cavovarus and idiopathic cavovarus feet are morphologically different from healthy feet, and CMT feet exhibit increased forefoot supination and hindfoot malalignment compared to idiopathic forms. The use of novel three-dimensional analysis may help highlight subtle structural differences in patients with similar foot morphology but aetiologically different pathology

Odontoid fracture of the second cervical vertebra (C2) is the most common spinal fracture type in elderly patients. However, very little is known about the biomechanical fracture mechanisms, but could play a role in fracture prevention and treatment. This study aimed to investigate the biomechanical competence and fracture characteristics of the odontoid process. A total of 42 human C2 specimens (14 female and 28 male, 71.5 ± 6.5 years) were scanned via quantitative computed tomography, divided in 6 groups (n = 7) and subjected to combined quasi-static loading at a rate of 0.1 mm/s until fracturing at inclinations of −15°, 0° and 15° in sagittal plane, and −50° and 0° in transverse plane. Bone mineral density (BMD), specimen height, fusion state of the ossification centers, stiffness, yield load, ultimate load, and fracture type according to Anderson and d'Alonzo were assessed. While the lowest values for stiffness, yield, and ultimate load were observed at load inclination of 15° in sagittal plane, no statistically significant differences could be observed among the six groups (p = 0.235, p = 0.646, and p = 0.505, respectively). Evaluating specimens with only clearly distinguishable fusion of the ossification centers (n = 26) reveled even less differences among the groups for all mechanical parameters. BMD was positively correlated with yield load (R² = 0.350, p < 0.001), and ultimate load (R² = 0.955, p < 0.001), but not with stiffness (p = 0.070). Type III was the most common fracture type (23.5%). These biomechanical outcomes indicate that load direction plays a subordinate role in traumatic fractures of the odontoid process in contrast to BMD which is a strong determinant of stiffness and strength. Thus, odontoid fractures appear to result from an interaction between load magnitude and bone quality

Background. Weightbearing computed tomography scans allow for better understanding of foot alignment in patients with Progressive Collapsing Foot Deformity. However, soft tissue integrity cannot be assessed via WBCT. As performing both WBCT and magnetic resonance imaging is not cost effective, we aimed to assess whether there is an association between specific WBCT and MRI findings. Methods. A cohort of 24 patients of various stages of PCFD (mean age 51±18 years) underwent WBCT scans and MRI. In addition to signs of sinus tarsi impingement, four three-dimensional measurements (talo-calcaneal overlap, talo-navicular coverage, Meary's angle axial/lateral) were obtained using a post processing software (DISIOR 2.1, Finland) on the WBCT datasets. Sinus tarsi obliteration, spring ligament complex and tibiospring ligament integrity, as well as tibialis posterior tendon degeneration were evaluated with MRI. Statistical analysis was performed for significant (P<0.05) correlation between findings. Results. None of the assessed 3D measurements correlated with spring ligament complex or tibiospring ligament tears. Age, body mass index, and TCO were associated with tibialis posterior tendon tears. 75% of patients with sinus tarsi impingement on WBCT also showed signs of sinus tarsi obliteration on MRI. Of the assessed parameters, only age and BMI were associated with sinus tarsi obliteration diagnosed on MRI, while the assessed WBCT based 3D measurements were, with the exception of MA axial, associated with sinus tarsi impingement. Conclusion. While WBCT reflects foot alignment and indicates signs of osseous impingement in PCFD patients, the association between WBCT based 3D measurements and ligament or tendon tears in MRI is limited. Partial or complete tears of the tibialis posterior tendon were only detectable in comparably older and overweight PCFD patients with an increased TCO. WBCT does not replace MRI in diagnostic value. Both imaging options add important information and may impact decision-making in the treatment of PCFD patients

Cartilage diseases have a significant impact on the patient's quality of life and are a heavy burden for the healthcare system. Better understanding, early detection and proper follow-up could improve quality of life and reduce healthcare related costs. Therefore, the aim of this study was to evaluate if difference between osteoarthritic (OA) and non-osteoarthritic (non-OA) knees can be detected quantitatively on cartilage and subchondral bone levels with advanced but clinical available imaging techniques. Two OA (mean age = 88.3 years) and three non-OA (mean age = 51.0 years) human cadaveric knees were scanned two times. A high-resolution peripheral quantitative computed tomography (HR-pQCT) scan (XtremeCT, Scanco Medical AG, Switzerland) was performed to quantify the bone microstructure. A contrast-enhanced clinical CT scan (GE Revolution Evo, GE Medical Systems AG, Switzerland) was acquired with the contrast agent Visipaque 320 (60 ml) to measure cartilage. Subregions dividing the condyle in four parts were identified semi-automatically and the images were segmented using adaptive thresholding. Microstructural parameters of subchondral bone and cartilage thickness were quantified. The overall cartilage thickness was reduced by 0.27 mm between the OA and non-OA knees and the subchondral bone quality decreased accordingly (reduction of 33.52 % in BV/TV in the layer from 3 to 8 mm below the cartilage) for the femoral medial condyle. The largest differences were observed at the medial part of the femoral medial condyle both for cartilage and for bone parameters, corresponding to clinical observations. Subchondral bone microstructural parameters and cartilage thickness were quantified using in vivo available imaging and apparent differences between the OA and non-OA knees were detected. Those results may improve OA follow-up and diagnosis and could lead to a better understanding of OA. However, further in vivo studies are needed to validate these methods in clinical practice

There is currently no commercially available and clinically successful treatment for scapholunate interosseous ligament rupture, the latter leading to the development of hand-wrist osteoarthritis. We have created a novel biodegradable implant which fixed the dissociated scaphoid and lunate bones and encourages regeneration of the ruptured native ligament. To determine if scaphoid and lunate kinematics in cadaveric specimens were maintained during robotic manipulation, when comparing the native wrist with intact ligament and when the implant was installed. Ten cadaveric experiments were performed with identical conditions, except for implant geometry that was personalised to the anatomy of each cadaveric specimen. Each cadaveric arm was mounted upright in a six degrees of freedom robot using k-wires drilled through the radius, ulna, and metacarpals. Infrared markers were attached to scaphoid, lunate, radius, and 3rd metacarpal. Cadaveric specimens were robotically manipulated through flexion-extension and ulnar-radial deviation by ±40° and ±30°, respectively. The cadaveric scaphoid and lunate kinematics were examined with 1) intact native ligament, 2) severed ligament, 3) and installed implant. Digital wrist models were generated from computed tomography scans and included implant geometry, orientation, and location. Motion data were filtered and aligned relative to neutral wrist in the digital models of each specimen using anatomical landmarks. Implant insertion points in the scaphoid and lunate over time were then calculated using digital models, marker data, and inverse kinematics. Root mean squared distance was compared between severed and implant configurations, relative to intact. Preliminary data from five cadaveric specimens indicate that the implant reduced distance between scaphoid and lunate compared to severed configuration for all but three trials. Preliminary results indicate our novel implant reduced scapho-lunate gap caused by ligament transection. Future analysis will reveal if the implant can achieve wrist kinematics similar to the native intact wrist

Applications of weightbearing computed tomography (WBCT) imaging in the foot and ankle have emerged over the past decade. However, the potential diagnostic benefits are scattered across the literature, and a concise overview is currently lacking. Therefore, we aimed to systematically review all reported diagnostic applications per anatomical region in the foot and ankle. A systematic literature search was performed in the electronic databases PubMed, EMBASE, Cochrane Library, and Web of Science. Search terms consisted of “weightbearing/standing CT and ankle, hind-, mid- or forefoot”. English language studies analyzing the diagnostic applications of WBCT were included. Studies were excluded if they simulated weightbearing CT, described normal subjects, included cadaveric samples or samples were case reports. The modified Methodological Index for Non-Randomized Studies (MINORS) was applied for quality assessment. The added value was defined as the review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and registered in the Prospero database (CRD42019106980). A total of 48 studies (prospective N=8, retrospective N=36, cohort study N=1, diagnostic N=2, prognostic comparative study N=1) were found to be eligible for review. The following diagnostic applications were identified per anatomical area in the foot: ankle (osteoarthritis N=5, ligament injury N=6); hindfoot (deformity N=9); midfoot (Lisfranc injury N=2, flatfoot deformity N=13, osteoarthritis N=1); forefoot (hallux valgus N=12). The identified studies contained diagnostic applications that could not be used on plain radiographs. The mean MINORS equaled 10.1 on a total of 16 (range: 8 to 12). Diagnostic applications of weightbearing CT imaging are most frequently studied in hindfoot deformity, but other area's areas are on the rise. Post-processing of images was identified as the main added value compared to WBRX. However, the findings should be interpreted with caution as the average quality score was moderate. Therefore, future prospective studies are warranted to consolidate the role of WBCT in diagnostic and therapeutic algorithms

The emergence of patient specific instrumentation has seen an expansion from simple radiographs to plan total knee arthroplasty (TKA) with modern systems using computed tomography (CT) or magnetic resonance imaging scans. Concerns have emerged regarding accuracy of these non-weight bearing modalities to assess true mechanical axis. The aim of our study was to compare coronal alignment on full length standing AP imaging generated by the EOS acquisition system with the CT coronal scout image. Eligible patients underwent unilateral or bilateral primary TKA for osteoarthritis under the care of investigating surgeon between 2017 and 2022, with both EOS X-Ray Imaging Acquisition System and CT scans performed preoperatively. Coronal mechanical alignment was measured on the supine coronal scout CT scan and the standing HKA EOS. Pre-operative lower limb coronal alignment was assessed on 96 knees prior to TKA on the supine coronal scout CT scan and the standing HKA EOS. There were 56 males (56%), and 44 right knees (44%). The mean age was 68 years (range 53-90). The mean coronal alignment was 4.7 degrees (SD 5.3) on CT scan and 4.6 degrees (SD 6.2) on EOS (p=0.70). There was a strong positive correlation of coronal alignment on CT scan and EOS (pearson. 0.927, p=0.001). The mean difference between EOS and CT scan was 0.9 degrees (SD 2.4). Less than 3 degrees variation between measures was observed in 87% of knees. On linear regression for every 1° varus increase in CT HKA alignment, the EOS HKA alignment increased by 0.93° in varus orientation. The model explained 86% of the variability. CT demonstrates excellent reliability for assessing coronal lower limb alignment compared to EOS in osteoarthritic knees. This supports the routine use of CT to plan TKA without further weight bearing imaging in routine cases

Residual strain development in biological tissue is believed to result from remodeling in response to repetitive loading. This study hypothesized that differences in in-vivo loading between levels of the bovine tail result in differences in intervertebral disc (IVD) annulus fibrosus (AF) microstructural remodeling. The hypothesis was tested by quantifying tail musculature using clinical computed tomography and tissue microstructure using collagen fiber crimp period, which has previously been correlated with residual strain. Three bovine tail segments (levels c1 through c6) were imaged using a clinical computed tomography (CT) scanner followed by removal of muscle and harvest of IVDs. The discs were frozen, and transverse cryosections were obtained. Additionally, tangential plane cryosections were obtained from the inner and outer zones of the AF. Transverse CT slices corresponding to each joint level thresholded for both disc and muscle tissue and analyzed in MATLAB. First, the centroid of the disc image was calculated to use as an origin. Then the disc area and moments of inertia about the flexion extension axis and lateral bending axis were calculated. Total muscle area was then calculated, along with muscle moments of inertia relative to the disc centroid. All muscle parameters were normalized by those of the corresponding disc. Cryosections were imaged using an inverted light microscope equipped with crossed polarizing filters and a digital camera. A MATLAB routine was used to perform Fourier transform analysis on user selected lines of interest in the transverse micrographs, yielding average fiber crimp period in the inner and outer AF. Micrographs from tangential sections were opened in ImageJ, and fiber orientation angles were measured manually. Muscle moments of inertia were analyzed using a two-way ANOVA with disc level and axis as dependent variables. Normalized muscle area was analyzed with a one-way ANOVA with disc level as a dependent variable. A two-way ANOVA, with disc level and zone (inner versus outer) was used to analyze collagen fiber crimp period and collagen fiber angle. Normalized muscle moment of inertia showed significant effects of both level and axis (p < 0 .001), decreasing at distal levels, and being lower about the flexion-extension axis than the lateral bending axis. Normalized muscle cross section showed a visible, but not significant (p=0.0721) decreasing trend with disc level. Fiber crimp period had significant effects of both level and zone (p < 0 .001), and was significantly longer in the outer zone than inner at all levels. Significant decrease in crimp period at distal levels were seen in the outer AF, but not the inner. While fiber angle was significantly (p < 0 .001) higher in the inner AF (36±6.6°) than outer AF (24±3.5°)), there was no significant effect of level. Fiber crimp period in the AF has previously been correlated with residual circumferential strain, with larger crimp period corresponding to increased residual tension. The present study suggests that at proximal levels of the tail, where peak compressive and bending stresses in the AF (as inferred from normalized muscle area and moments of inertia respectively) are greatest, there is more accumulation of residual strain

This is a retrospective study of patient out-come after spondylolytic repair using a Scott¦s or a Van Dam Procedure (tension band repair). We also looked at the use of plain static radiographs, and a reverse gantry computed tomography scanning in the assessment of healing of the spondylolytic defect. Tension band repair of spondylolysis has proved to be a useful procedure for refractory spondylolysis. However, there is no universally accepted method or determining fusion of the spondylolysis, and the definitive criteria for diagnosing a successful fusion remains controversial. The Oswestry Disability Index was measured in 2000 and in 2004. Plain static radiographs and computed tomography scans were performed on 14 patients one year after fixation of the spondylolysis. A radiologist and an independent orthopaedic surgeon assessed the presence of bridging trabecular bone in the scan and X rays. Results in 14 patients were rated as excellent and in 4 as good in year 2000 and results remained excellent to good in 16 of 17 patients followed up in year 2004. The fusion rate was 90%[18/20] on the plain radiographs. Fusion on the computed tomography scans was observed in 50% [7/14]. A high rate of good-excellent clinical results can be obtained following a Scott or Van Dam Procedure. Radiological fusion rate was higher than assessment with thin-section computed tomography scans. CT tomography studies clearly demonstrated the presence or absence of bridging bone, a property not easy to see in plain static radiographs. However, clinical significance of CT non-union is not clear

Stand-alone anterior lumbar interbody fusion (ALIF) provides the opportunity to avoid supplemental posterior fixation. This may reduce morbidity and complication rate, which is of special interest in patients with reduced bone mineral density (BMD). This study aims to assess immediate biomechanical stability and radiographic outcome of a stand-alone ALIF device with integrated screws in specimens of low BMD. Eight human cadaveric spines (L4-sacrum) were instrumented with SynFix-LR™ (DePuy Synthes) at L5/S1. Quantitative computed tomography was used to measure BMD of L5 in AMIRA. Threshold values proposed by the American Society of Radiology 80 and 120 mg CaHa/mL were used to differentiate between Osteoporosis, Osteopenia, and normal BMD. Segmental lordosis, anterior and posterior disc height were analysed on pre- and postoperative radiographs (Fig 1). Specimens were tested intact and following instrumentation using a flexibility protocol consisting of three loading cycles to ±7.5 Nm in flexion-extension, lateral bending, and axial rotation. The ranges of motion (ROM) of the index level were assessed using an optoelectronic system. BMD ranged 58–181mg CaHA/mL. Comparison of pre- and postoperative radiographs revealed significant increase of L5/S1 segmental lordosis (mean 14.6°, SD 5.1, p < 0.001) and anterior disc height (mean 5.8mm, SD 1.8, p < 0.001), but not posterior disc height. ROM of 6 specimens was reduced compared to the intact state. Two specimens showed destructive failure in extension. Mean decrease was most distinct in axial rotation up to 83% followed by flexion-extension. ALIF device with integrated screws at L5/S1 significantly increases segmental lordosis and anterior disc height without correlation to BMD. Primary stability in the immediate postoperative situation is mostly warranted in axial rotation. The risk of failure might be increased in extension for some patients with reduced lumbar BMD, therefore additional posterior stabilization could be considered. For any figures or tables, please contact the authors directly

Scapular notching is a common problem following reverse shoulder arthroplasty (RSA). This is due to impingement between the humeral polyethylene cup and scapular neck in adduction and external rotation. Various glenoid component strategies have been described to combat scapular notching and enhance impingement-free range of motion (ROM). There is limited data available detailing optimal glenosphere position in RSA with an onlay configuration. The purpose of this study was to determine which glenosphere configurations would maximise impingement free ROM using an onlay RSA prosthesis. A three-dimensional (3D) computed tomography (CT) scan of a shoulder with Walch A1, Favard E0 glenoid morphology was segmented using validated software. An onlay RSA prosthesis was implanted and a computer model simulated external rotation and adduction motion of the virtual RSA prosthesis. Four glenosphere parameters were tested; diameter (36mm, 41mm), lateralization (0mm, 3mm, 6mm), inferior tilt (neutral, 5 degrees, 10 degrees), and inferior eccentric positioning (0.5mm, 1.5mm. 2.5mm, 3.5mm, 4.5mm). Eighty-four combinations were simulated. For each simulation, the humeral neck-shaft angle was 147 degrees and retroversion was 30 degrees. The largest increase in impingement-free range of motion resulted from increasing inferior eccentric positioning, gaining 15.0 degrees for external rotation and 18.8 degrees for adduction. Glenosphere lateralization increased external rotation motion by 13. 6 degrees and adduction by 4.3 degrees. Implanting larger diameter glenospheres increased external rotation and adduction by 9.4 and 10.1 degrees respectively. Glenosphere tilt had a negligible effect on impingement-free ROM. Maximizing inferior glenosphere eccentricity, lateralizing the glenosphere, and implanting larger glenosphere diameters improves impingement-free range of motion, in particular external rotation, of an onlay RSA prosthesis. Surgeons’ awareness of these trends can help optimize glenoid component position to maximise impingement-free ROM for RSA. Further studies are required to validate these findings in the context of scapulothoracic motion and soft tissue constraints

Evaluation of patient specific spinopelvic mobility requires the detection of bony landmarks in lateral functional radiographs. Current manual landmarking methods are inefficient, and subjective. This study proposes a deep learning model to automate landmark detection and derivation of spinopelvic measurements (SPM). A deep learning model was developed using an international multicenter imaging database of 26,109 landmarked preoperative, and postoperative, lateral functional radiographs (HREC: Bellberry: 2020-08-764-A-2). Three functional positions were analysed: 1) standing, 2) contralateral step-up and 3) flexed seated. Landmarks were manually captured and independently verified by qualified engineers during pre-operative planning with additional assistance of 3D computed tomography derived landmarks. Pelvic tilt (PT), sacral slope (SS), and lumbar lordotic angle (LLA) were derived from the predicted landmark coordinates. Interobserver variability was explored in a pilot study, consisting of 9 qualified engineers, annotating three functional images, while blinded to additional 3D information. The dataset was subdivided into 70:20:10 for training, validation, and testing. The model produced a mean absolute error (MAE), for PT, SS, and LLA of 1.7°±3.1°, 3.4°±3.8°, 4.9°±4.5°, respectively. PT MAE values were dependent on functional position: standing 1.2°±1.3°, step 1.7°±4.0°, and seated 2.4°±3.3°, p< 0.001. The mean model prediction time was 0.7 seconds per image. The interobserver 95% confidence interval (CI) for engineer measured PT, SS and LLA (1.9°, 1.9°, 3.1°, respectively) was comparable to the MAE values generated by the model. The model MAE reported comparable performance to the gold standard when blinded to additional 3D information. LLA prediction produced the lowest SPM accuracy potentially due to error propagation from the SS and L1 landmarks. Reduced PT accuracy in step and seated functional positions may be attributed to an increased occlusion of the pubic-symphysis landmark. Our model shows excellent performance when compared against the current gold standard manual annotation process

Abstract. INTRODUCTION. COVID-19 reduced availability of cross-sectional imaging, prompting the need to clinically justify pre-operative computed tomography (CT) in tibial plateau fractures (TPF). The study purpose was to establish to what extent does a CT alter the pre-operative plan in TPF compared to radiographs. There is a current paucity of evidence assessing its impact on surgical planning. METHODOLOGY. 50 consecutive TPF with preoperative CT were assessed by 4 consultant surgeons. Anonymised radiographs were assessed defining the column classification, planned setup, approach, and fixation technique. At a 1-month interval, randomised matched CT scans were assessed and the same data collected. A tibial plateau disruption score (TPDS) was derived for all 4 quadrants (no injury=0,split=1,split/depression=2 and depression=3). Radiograph and CT TPDS were assessed using an unpaired T-test. RESULTS. 26 female and 24 male patients, mean age 50.3, were included. Mean TPDS on radiographs and CT scans were 2.77 and 3.17 respectively. A significant higher net CT TPDS was observed of 0.4 (95%CI 0.10-0.71)[P=0.0093]. Both radiograph and CT TPDS ANOVA were significant (P<0.0001), showing high intraobserver variability for TPF classification. Fracture apex requiring fixation changed in 34% of cases between the radiographs and CT, whilst set-up and surgical approach changed in 27% and 28.5% of cases respectively. All surgeons agreed no CT was required in only 11 out of 50 cases. CONCLUSION. CT scanning in TPF significantly affects the classification, setup, approach and fixation technique when compared to radiographs alone and can justifiably be requested as part of pre-operative planning

Abstract. Introduction. Coronal plane alignment of the knee (CPAK) classification utilises the native arithmetic hip-knee alignment to calculate the constitutional limb alignment and joint line obliquity which is important in pre-operative planning. The objective of this study was to compare the accuracy and reproducibility of measuring the lower limb constitutional alignment with the traditional long leg radiographs versus computed tomography (CT) used for pre-operative planning in robotic-arm assisted TKA. Methods. Digital long leg radiographs and pre-operative CT scan plans of 42 patients (46 knees) with osteoarthritis undergoing robotic-arm assisted total knee replacement were analysed. The constitutional alignment was established by measuring the medial proximal tibial angle (mPTA), lateral distal femoral angle (LDFA), weight bearing hip knee alignment (WBHKA), arithmetic hip knee alignment (aHKA) and joint line obliquity (JLO). Furthermore, the Coronal Plane Alignment of the Knee (CPAK) classification was utilised to classify the patients based on their coronal knee alignment phenotype. Results. Mean age of the patients was 66 years (SD 9) and mean BMI 31.2 (SD 3.9). There were 27 left and 19 right sided surgeries. The Pearson's corelation coefficient was 0.722 (p=0.008) for WBHKA; 0.729 (p<0.001) for MPTA; 0.618 (p=0.14) for aHKA; 0.502 (p= 0.04) for LDFA and 0.305 (p=0.234) for JLO. CPAK classification was concordant for 53% study participants between the two groups. Conclusion. Three-dimensional CT-based modelling with computer software more accurately predicts constitutional limb alignment and JLO as defined by the CPAK classification compared to plain long-leg radiographs in pre-operative planning of total knee arthroplasty

Introduction: The purpose of this study was to evaluate the impact of volume rendering 3D computed tomography reconstructions on the inter- and intraobserver reliability of the OTA/AO and Neer classifications in the assessment of proximal humerus fractures. Material and Methods: Four observers with different levels of clinical training classified forty proximal humerus fractures according to the OTA/AO and Neer classifications. Three rounds of evaluation were performed and compared. First, fractures were classified on the basis of plain radiographs alone. Then, four weeks later, the combination of plain radiographs and computed tomography scans with conventional 3D SSD reconstructions was evaluated. Finally, four weeks later, the combination of plain radiographs, computed tomography scans, and 3D volume rendering reconstructions was assessed. These readings were repeated in a newly randomized order after an interval of twelve weeks to evaluate intraobserver reliability. Results: Interobserver reliability for the AO/ASIF classification showed good interobserver reliability with plain radiographs (k=0,65) and two-dimensional CT scans with conventional three-dimensional (SSD) reconstructions (k=0,71). Interobserver reliability improved to excellent when the fractures were classified on the basis of 3D volume rendering reconstructions scans (k=0,84). Intraobserver reliability of the OTA/AO classification was good with plain radiographs (k=0,70) and improved to excellent after adding three-dimensional SSD reconstructions (k=0,80) and three-dimensional VR reconstructions (k=0,88). Interobserver reliability of the Neer classification was poor with plain radiographs (k=0,39) and moderate with two-dimensional CT scans and conventional three-dimensional (SSD) reconstructions (k=0,56) and improved to good with the addition of 3D VR scans (k=0,74). Intraobserver reliability for was poor with plain radiographs (k=0,34), good with three-dimensional SSD reconstructions (k=0,61), and excellent with three-dimensional VR reconstructions (k=0,80). Conclusion: In this study, three-dimensional volume rendering computed tomography improved the inter- and intraobserver reliability of the AO/OTA and the Neer classifications in the assessment of proximal humerus fractures. In the opinion of the authors, 3D volume rendering CT-scans are a helpful tool for preoperative planning and classification of fractures of the proximal humerus

Traditional radiographic criteria might underestimate or fail to detect subtle types of acetabular dysplasia. Acetabular sector angles (ASA) can measure the degree of anterior and posterior coverage of the femoral head on computed tomography (CT). This study aims to determine ASA values at different axial levels in a cohort of (1) asymptomatic, high-functioning hips without underlying hip pathology (controls); and (2) symptomatic, dysplastic hips that underwent periacetabular osteotomy (PAO). Thereby, we aimed to define CT-based thresholds for hip dysplasia and its subtypes. This is an IRB approved cross-sectional study of 51 high functioning, asymptomatic patients (102 hips) (Oxford Hip Score >43), without signs of osteoarthritis (Tönnis grade≤1), who underwent a CT scan of the pelvis (mean age: 52.1±5.5 years; 52.9% females); and 66 patients (72 hips) with symptomatic hip dysplasia treated with peri-acetabular osteotomy (PAO) (mean age: 29.3±7.3 years; 85.9% females). Anterior and posterior acetabular sector angles (AASA & PASA) were measured by two observers at three CT axial levels to determine equatorial, intermediate, and proximal ASA. Inter- and intra-observer reliability coefficient was high (between 0.882–0.992). Cut-off values for acetabular deficiency were determined based on Receiver Operating Characteristic (ROC) curve analysis, area under the curve (AUC) was calculated. The dysplastic group had significantly smaller ASAs compared to the Control Group, AUC was the highest at the proximal and intermediate PASA. Controls had a mean proximal PASA of 162°±17°, with a cut-off value for dysplasia of 137° (AUC: 0.908). At the intermediate level, the mean PASA of controls was 117°±11°, with a cut-off value of 107° (AUC 0.904). Cut-off for anterior dysplasia was 133° for proximal AASA (AUC 0.859) and 57° for equatorial AASA (AUC 0.868). Cut-off for posterior dysplasia was 102° for intermediate PASA (AUC 0.933). Measurement of ASA on CT is a reliable tool to identify dysplastic hips with high diagnostic accuracy. Posterior ASA less than 137° at the proximal level, and 107° at the intermediate level should alert clinicians of the presence of dysplasia

Introduction. Recurrence after surgical correction of hallux valgus may be related to coronal rotation of the first metatarsal. The scarf osteotomy is a commonly used procedure for correcting hallux valgus but has limited ability to correct rotation. Using weightbearing computed tomography (WBCT), we aimed to measure the coronal rotation of the first metatarsal before and after a scarf osteotomy, and correlate these to clinical outcome scores. Methods. We retrospectively analyzed 16 feet (15 patients) who had a WBCT before and after scarf osteotomy for hallux valgus correction. On both scans, hallux valgus angle (HVA), intermetatarsal angle, and anteroposterior/lateral talus-first metatarsal angle were measured using digitally reconstructed radiographs. Metatarsal pronation (MPA), alpha angle, sesamoid rotation angle and sesamoid position was measured on standardized coronal CT slices. Preoperative and postoperative(12 months) clinical outcome scores(MOxFQ and VAS) were captured. Results. Mean HVA was 28.6±10.1 degrees preoperatively and 12.1±7.7 degrees postoperatively. Mean IMA was 13.7±3.8 degrees preoperatively and 7.5±3.0 degrees postoperatively. Before and after surgery, there were no significant differences in MPA (11.4±7.7 and 11.4±9.9 degrees, respectively; p = 0.75) or alpha angle (10.9±8.0 and 10.7±13.1 degrees, respectively; p = 0.83). There were significant improvements in SRA (26.4±10.2 and 15.7±10.2 degrees, respectively; p = 0.03) and sesamoid position (1.4±1.0 and 0.6±0.6, respectively; p = 0.04) after a scarf osteotomy. There were significant improvements in all outcome scores after surgery. Poorer outcome scores correlated with greater postoperative MPA and alpha angles (r= 0.76 (p = 0.02) and 0.67 (p = 0.03), respectively). Conclusion. A scarf osteotomy does not correct first metatarsal coronal rotation, and worse outcomes are linked to greater metatarsal rotation. Rotation of the metatarsal needs to be measured and considered when planning hallux valgus surgery. Further work is needed to compare postoperative outcomes with rotational osteotomies and modified Lapidus procedures when addressing rotation

Background: Complex fractures of the tibial plateau can be difficult to characterize on plain radiographs and two-dimensional computed tomography scans. We tested the hypothesis that three-dimensional computed tomography reconstructions improve the reliability of tibial plateau fracture characterization and classification. Methods: Forty-five consecutive intra-articular fractures of the tibial plateau were evaluated by six independent observers for the presence of six fracture characteristics that are not specifically included in currently used classification schemes:. posteromedial shear fracture;. coronal plane fracture;. lateral condylar impaction;. medial condylar impaction;. tibial spine involvement;. separation of tibial tubercle necessitating anteroposterior lag screw fixation. In addition, fractures were classified according to the AO/OTA Comprehensive Classification of Fractures, the Schatzker classification system and the Hohl and Moore system. Two rounds of evaluation were performed and then compared. First, a combination of plain radiographs and two-dimensional computed tomography scans (2D) were evaluated, and then, four weeks later, a combination of radiographs, two-dimensional computed tomography scans, and three-dimensional reconstructions of computed tomography scans (3D) were assessed. Results: Interobserver agreement improved for all classification systems after the addition of three-dimensional reconstructions (AO/OTA κ2D = 0.536 versus κ3D = 0.545; Schatzker κ2D = 0.545 versus κ3D = 0.596; Hohl and Moore κ2D = 0.668 versus κ3D = 0.746). Three-dimensional computed tomography reconstructions also improved the average intraobserver reliability for all fracture characteristics, from κ2D = 0.624 (substantial agreement) to κ3D = 0.687 (substantial agreement). The addition of three-dimensional images had limited infiuence on the average interobserver reliability for the recognition of specific fracture characteristics (κ2D = 0.488 versus κ3D = 0.485, both moderate agreement). Three-dimensional computed tomography images improved interobserver reliability for the recognition of coronal plane fractures from fair (κ2D = 0.398) to moderate (κ3D = 0.418) but this difference was not statistically significant. Conclusions: Three-dimensional computed tomography is helpful for;. individual orthopaedic surgeons for preoperative planning (improves intraobserver reliability for the recognition of fracture characteristics), and for. comparison of clinical outcomes in the orthopaedic literature (improves interobserver reliability of classification systems)

Aim. To make an inoculum for induction of Implant-Associated Osteomyelitis (IAO) in pigs based on bacterial aggregates resembling those found on the human skin, i.e. aggregates of 5–15 µm with low metabolic activity. The aggregates were evaluated and compared to a standard planktonic bacterial inoculum. Method. The porcine Staphylococcus aureus strain S54F9 was cultured in Tryptone Soya Broth for seven days. Subsequently, the culture was filtered through cell strainers with pore sizes of 15 µm and 5 µm, respectively. The fraction of 5–15 µm aggregates in the top of the 5 µm filter was collected as the aggregate-inoculum. The separation of aggregates into different size fractions was evaluated by light microscopy. The metabolism of the aggregate-inoculum and a standard overnight planktonic inoculum was evaluated with isothermal microcalorimetry. In total, six female minipigs were allocated into three groups (n=2), receiving different inoculums. Group A: overnight planktonic inoculum; 10. 4. CFU S. aureus (S54F9), Group B: seven days old 5–15 µm aggregate-inoculum; 10. 4. CFU S. aureus (S54F9), Group C: saline. All inoculums were placed in a pre-drilled implant cavity in the right tibia of the pig and a sterile stainless-steel implant was inserted. The pigs were euthanized seven days after surgery. Postmortem macroscopic pathology, microbiology, computed tomography and histopathology were performed. Results. The separation of aggregates into different size fractions was done successfully by the filtering method. Isothermal microcalorimetry showed, a delayed Time-to-peak metabolic activity of the aggregate-inoculum compared to the planktonic inoculum. S. aureus was isolated from subcutis, bone and implants from all animals in groups A and B. Both group A animals showed osteomyelitis at gross inspection with suppuration and sequestration, while groups B and C animals had no macroscopic lesions. From CT scans, both group A animals also showed positive signs of osteomyelitis, i.e., osteolysis, while only one animal in group B did, and none in group C. Histopathological examination of the bones showed more extensive inflammation in group A animals compared to those in group B, which showed more osteoid formation. Conclusions. Formation and separation of low metabolism bacterial aggregates into different size fractions was possible. The aggregates can be used as inoculum in the porcine IAO model, with microbiological re-isolation from both implants and tissue. Furthermore, the aggregates caused a less aggressive IAO, than the planktonic counterparts. Using aggregated bacteria as inoculum appears to be more relevant to the clinical situation of infecting bacteria

Background. The development of T-smart tomosynthesis has greatly improved the imaging quality of THA by reducing the peri-implant artifacts. In order to find out whether these improvements could lead to diagnostic advantages on stability of cementless THA arthroplasty components, we conducted a diagnostic research by comparing T-smart tomosynthesis, X-ray, and computed tomography. Methods. We retrospectively included 48 patients who undergone THA revisions in our center between Aug, 2013 and Mar, 2014. For patients with hybrid fixation as their primary prosthesis, the femoral or acetabular components with cement fixation were excluded. There were 41 cementless femoral stems and 35 cementless acetabular cups remained for evaluation. All patients took anterior-posterior and lateral view x-ray examination, anterior-posterior T-smart tomosynthesis scan, and computed tomography before revision surgery. As the gold standard, intraoperative pull-out tests and twisting tests were done for every patient to examine the stability of all implants. 7 orthopedic surgeons evaluated the preoperative images independently, who were divided into the senior group (3 doctors with 6∼13 years’ clinical experience) and the junior group (4 doctors with 2∼4 years’ clinical experience). The x-rays were evaluated first, followed by computed tomography 4 weeks later, and after another 4 weeks’ interval the T-smart tomosynthesis were assessed. All doctors used the same criteria for diagnosis. Diagnostic accuracy for each imaging examination was calculated by comparing with the results of intraoperative tests. The diagnostic accuracy, kappa values between 3 imaging techniques were calculated, and chi-square tests were conducted to examine the difference between the senior and junior groups for each technique. Results. The accuracy of T-smart tomosynthesis on stability diagnosis (loosening or stable) is 82.6% for femoral stem and 84.5% for acetabular cup. The accuracy of X-ray is 44.3% for stem and 67.3% for cup, and the accuracy of CT is 39.6% for stem and 74.6% for cup. The kappa values between the 3 techniques range from −0.053 to 0.22. For plain X-ray, The diagnostic accuracy of the senior group is significantly higher than that of the junior group (p<0.05), but no significance was found between the 2 groups for tomosynthesis and CT. Discussion. Our research indicates that, compared with x-ray and CT, the T-smart tomosynthesis technique can greatly improve the diagnostic accuracy on stability of cementless THA components, and significantly shorten the learning curve of inexperienced surgeons. With T-smart tomosynthesis, the peri-implant trabecular bone can be clearly imaged with least metal artifacts ever. T-smart tomosynthesis is an effective and promising imaging technique for diagnosing the stability of THA components

Bone metastases radiographically appear as regions with high (i.e. blastic metastases) or low (i.e. lytic metastases) bone mineral density. The clinical assessment of metastatic features is based on computed tomography (CT) but it is still unclear if the actual size of the metastases can be accurately detected from the CT images and if the microstructure in regions surrounding the metastases is altered (Nägele et al., 2004, Calc Tiss Int). This study aims to evaluate (i) the capability of the CT in evaluating the metastases size and (ii) if metastases affect the bone microstructure around them. Ten spine segments consisted of a vertebra with lytic or mixed metastases and an adjacent control (radiologically healthy) were obtained through an ethically approved donation program. The specimens were scanned with a clinical CT (AquilionOne, Toshiba: slice thickness:1mm, in-plane resolution:0.45mm) to assess clinical metastatic features and a micro-CT (VivaCT80, Scanco, isotropic voxel size:0.039mm) to evaluate the detailed microstructure. The volume of the metastases was measured from both CT and micro-CT images (Palanca et al., 2021, Bone) and compared with a linear regression. The microstructural alteration around the metastases was evaluated in the volume of interest (VOI) defined in the micro-CT images as the volume of the vertebral body excluding the metastases. Three 3D microstructural parameters were calculated in the VOI (CTAn, Bruker SkyScan): Bone Volume Fraction (BV/TV), Trabecular Thickness (Tb.Th.), Trabecular Spacing (Tb.Sp.). Medians of each parameter were compared (Kruskal-Wallis, p=0.05). One specimen was excluded as it was not possible to define the size of the metastases in the CT scans. A strong correlation between the volume obtained from the CT and micro-CT images was found (R2=0.91, Slope=0.97, Intercept=2.55, RMSE=5.7%, MaxError=13.12%). The differences in BV/TV, Tb.Th. and Tb.Sp. among vertebrae with lytic and mixed metastases and control vertebrae were not statistically significant (p-value>0.6). Similar median values of BV/TV were found in vertebrae with lytic (13.2±2.4%) and mixed (12.8±9.8%) metastases, and in controls (13.0±10.1%). The median Tb.Th. was 176±18 ∓m, 179±43 ∓m and 167±91 ∓m in vertebrae with lytic and mixed metastases and control vertebrae, respectively. The median Tb. Sp. was 846±26 ∓m, 849±286 ∓m and 880±116 ∓m in vertebrae with lytic and mixed metastases and control vertebrae, respectively. In conclusion, the size of vertebral metastases can be accurately assess using CT images. The 3D microstructural parameters measured were comparable with those reported in the literature for healthy vertebrae (Nägele et al., 2004, Calc Tiss Int, Sone et al., 2004, Bone) and showed how the microstructure of the bone tissue surrounding the lesion is not altered by the metastases

Pain and disability following wrist trauma are highly prevalent, however the mechanisms underlying painare highly unknown. Recent studies in the knee have demonstrated that altered joint contact may induce changes to the subchondral bone density and associated pain following trauma, due to the vascularity of the subchondral bone. In order to examine these changes, a depth-specific imaging technique using quantitative computed tomography (QCT) has been used. We've demonstrated the utility of QCT in measuring vBMD according to static jointcontact and found differences invBMD between healthy and previously injured wrists. However, analyzing a static joint in a neutral position is not necessarily indicative of higher or lower vBMD. Therefore, the purposeof this study is to explore the relationship between subchondral vBMDand kinematic joint contact using the same imaging technique. To demonstrate the relationship between kinematic joint contact and subchondral vBMDusing QCT, we analyzed the wrists of n = 10 participants (n = 5 healthy and n = 5 with previous wrist trauma). Participantsunderwent 4DCT scans while performing flexion to extension to estimate radiocarpal (specifically the radiolunate (RL) and radioscaphoid (RS)) joint contact area (JCa) between the articulating surfaces. The participantsalso underwent a static CT scan accompanied by a calibration phantom with known material densities that was used to estimate subchondral vBMDof the distal radius. Joint contact is measured by calculatinginter-bone distances (mm2) using a previously validated algorithm. Subchondral vBMD is presented using mean vBMD (mg/K2HPO4) at three normalized depths from the subchondral surface (0 to 2.5, 2.5 to 5 and 5 to 7.5 mm) of the distal radius. The participants in the healthy cohort demonstrated a larger JCa in the RS joint during both extension and flexion, while the trauma cohort demonstrated a larger JCa in the RL during extension and flexion. With regards to vBMD, the healthy cohort demonstrated a higher vBMD for all three normalized depths from the subchondral surface when compared to the trauma cohort. Results from our preliminary analysis demonstrate that in the RL joint specifically, a larger JCa throughout flexion and extension was associated with an overall lower vBMD across all three normalized layers. Potential reasoning behind this association could be that following wrist trauma, altered joint contact mechanics due to pathological changes (for example, musculoskeletal trauma), has led to overloading in the RL region. The overloading on this specific region may have led to a decrease in the underlying vBMD when compared to a healthy wrist. However, we are unable to conclude if this is a momentary decrease in vBMD that could be associated with the acute healing phase following trauma given that our analysis is cross-sectional. Therefore, future work should aim to analyze kinematic JCa and vBMD longitudinally to better understand how changes in kinematic JCa over time, and how the healing process following wrist trauma, impacts the underlying subchondral bone in the acute and longitudinal phases of recovery

Despite the current trend favoring surgical treatment of displaced intra-articular calcaneal fractures (DIACFs), studies have not been able to demonstrate superior functional outcomes when compared to non-operative treatment. These fractures are notoriously difficult to reduce. Studies investigating surgical fixation often lack information about the quality of reduction even though it may play an important role in the success of this procedure. We wanted to establish if, amongst surgically treated DIACF, an anatomic reduction led to improved functional outcomes at 12 months. From July 2011 to December 2020, at a level I trauma center, 84 patients with an isolated DIACF scheduled for surgical fixation with plate and screws using a lateral extensile approach were enrolled in this prospective cohort study and followed over a 12-month period. Post-operative computed tomography (CT) imaging of bilateral feet was obtained to assess surgical reduction using a combination of pre-determined parameters: Böhler's angle, calcaneal height, congruence and articular step-off of the posterior facet and calcaneocuboid (CC) joint. Reduction was judged anatomic when Böhler's angle and calcaneal height were within 20% of the contralateral foot while the posterior facet and CC joint had to be congruent with a step-off less than 2 mm. Several functional scores related to foot and ankle pathology were used to evaluate functional outcomes (American Orthopedic Foot and Ankle Score - AOFAS, Lower Extremity Functional Score - LEFS, Olerud and Molander Ankle Score - OMAS, Calcaneal Functional Scoring System - CFSS, Visual Analog Scale for pain - VAS) and were compared between anatomic and nonanatomic DIAFCs using Student's t-test. Demographic data and information about injury severity were collected for each patient. Among the 84 enrolled patients, 6 were excluded while 11 were lost to follow-up. Thirty-nine patients had a nonanatomic reduction while 35 patients had an anatomic reduction (47%). Baseline characteristics were similar in both groups. When we compared the injury severity as defined by the Sanders’ Classification, we did not find a significant difference. In other words, the nonanatomic group did not have a greater proportion of complex fractures. Anatomically reduced DIACFs showed significantly superior results at 12 months for all but one scoring system (mean difference at 12 months: AOFAS 3.97, p = 0.12; LEFS 7.46, p = 0.003; OMAS 13.6, p = 0.002, CFSS 7.5, p = 0.037; VAS −1.53, p = 0.005). Univariate analyses did not show that smoking status, worker's compensation or body mass index were associated with functional outcomes. Moreover, fracture severity could not predict functional outcomes at 12 months. This study showed superior functional outcomes in patients with a DIACF when an anatomic reduction is achieved regardless of the injury severity

Osteoarthritis (OA) is a degenerative disease that lacks regenerative treatment options. Current research focuses on mesenchymal stem cells (MSCs) and Platelet-Rich Plasma (PRP) as regenerative therapies, but extracellular vesicles (EVs) have shown to be more advantageous. This study compares the regenerative potential of human umbilical cord MSC-derived EVs (cEVs) and platelet-derived EVs (pEVs) in ex vivo and in vivo OA models. In the ex vivo study, OA conditions were induced in human cartilage explants, which were then treated either with pEVs or cEVs. Results showed a higher content of DNA and collagen in the pEVs group compared to control and cEVs groups, suggesting that pEVs could be a potential alternative to cEVs. In the in vivo study, an OA model was established in the knee joints of rats through MIA (monoiodoacetate) injection and then treated either with pEVs or cEVs. Results showed that pEVs-treated knee joints had better subchondral bone integrity and greater OA reversion, particularly in female rats, indicating that pEVs are a viable regeneration treatment for OA and outperform cEVs in terms of efficacy. Overall, the study demonstrates the potential of EVs as a regenerative treatment for OA, with pEVs showing promising results in both ex vivo and in vivo models. The use of pEVs in clinical practice could provide a faster path to translation due to the established use of platelet concentrates in therapeutics. However, further studies are needed to fully evaluate the potential of pEVs for OA treatment and to elucidate the mechanisms behind their regenerative effects. Acknowledgments: The authors thank Dr Fernando Hierro (UIB) for their technical contribution with TEM, Mª Trinidad García (UIB) for the access to radioactivity facilities, Aina Arbós (IUNICS) for her contribution in the histology staining, María Tortosa (IdISBa) for her assistance with the animal care and ADEMA School of Dentistry for the access to the cone beam computed tomography (CBCT). Funding: This research was funded by Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, co-funded by the ESF European Social Fund and the ERDF European Regional Development Fund (MS16/00124; CP16/00124), PROGRAMA JUNIOR del proyecto TALENT PLUS, construyendo SALUD, generando VALOR (JUNIOR01/18), financed by the sustainable tourism tax of the Balearic Islands; the Direcció General d'Investigació and Conselleria d'Investigació, Govern Balear (FPI/2046/2017); the Mecanisme de Recuperació i Resiliència, intended to execute research projects of «Noves polítiques públiques per a un mercat de treball dinàmic, resilient i inclusiu», collected in Pla de Recuperació, Transformació i Resiliència, financed by European Union-Next Generation EU and driven by SOIB and Conselleria de Fons Europeus, Universitat i Cultura i la Conselleria de Model Econòmic, Turisme i Treball (NG0421) and the grant SYN20/03 from IdISBa

Despite the current trend favoring surgical treatment of displaced intra-articular calcaneal fractures (DIACFs), studies have not been able to demonstrate superior functional outcomes when compared to non-operative treatment. These fractures are notoriously difficult to reduce. Studies investigating surgical fixation often lack information about the quality of reduction even though it may play an important role in the success of this procedure. We wanted to establish if, amongst surgically treated DIACF, an anatomic reduction led to improved functional outcomes at 12 months. From July 2011 to December 2020, at a level I trauma center, 84 patients with an isolated DIACF scheduled for surgical fixation with plate and screws using a lateral extensile approach were enrolled in this prospective cohort study and followed over a 12-month period. Post-operative computed tomography (CT) imaging of bilateral feet was obtained to assess surgical reduction using a combination of pre-determined parameters: Böhler's angle, calcaneal height, congruence and articular step-off of the posterior facet and calcaneocuboid (CC) joint. Reduction was judged anatomic when Böhler's angle and calcaneal height were within 20% of the contralateral foot while the posterior facet and CC joint had to be congruent with a step-off less than 2 mm. Several functional scores related to foot and ankle pathology were used to evaluate functional outcomes (American Orthopedic Foot and Ankle Score - AOFAS, Lower Extremity Functional Score - LEFS, Olerud and Molander Ankle Score - OMAS, Calcaneal Functional Scoring System - CFSS, Visual Analog Scale for pain – VAS) and were compared between anatomic and nonanatomic DIAFCs using Student's t-test. Demographic data and information about injury severity were collected for each patient. Among the 84 enrolled patients, 6 were excluded while 11 were lost to follow-up. Thirty-nine patients had a nonanatomic reduction while 35 patients had an anatomic reduction (47%). Baseline characteristics were similar in both groups. When we compared the injury severity as defined by the Sanders’ Classification, we did not find a significant difference. In other words, the nonanatomic group did not have a greater proportion of complex fractures. Anatomically reduced DIACFs showed significantly superior results at 12 months for all but one scoring system (mean difference at 12 months: AOFAS 3.97, p = 0.12; LEFS 7.46, p = 0.003; OMAS 13.6, p = 0.002, CFSS 7.5, p = 0.037; VAS −1.53, p = 0.005). Univariate analyses did not show that smoking status, worker's compensation or body mass index were associated with functional outcomes. Moreover, fracture severity could not predict functional outcomes at 12 months. This study showed superior functional outcomes in patients with a DIACF when an anatomic reduction is achieved regardless of the injury severity

Originally introduced in 1997, porous tantalum is an attractive alternative metal for orthopaedic implants because of its unique mechanical properties. Porous tantalum has been used in numerous types of orthopaedic implants, including acetabular cups in total hip arthroplasty. The early clinical results from porous tantalum acetabular cups have been promising. The purpose of this study was to evaluate the presence of bone ingrowth and the incidence of osteolytic lesions in the acetabular cup -at 10 year follow up – in patients who had a total hip arthroplasty with a monoblock porous tantalum acetabular cup. 50 consecutive patients underwent a total hip arthroplasty with a monoblock porous tantalum acetabular component. All patients had computed tomography at an average of 10 years of follow-up. The computed tomography scan used a standard, validated protocol to evaluate bony ingrowth in the cup and for the presence of osteolysis. The computed tomographic scans showed evidence of extensive bony ingrowth, and no evidence of osteolysis. This study reports the 10-year results of a monoblock porous tantalum acetabular cup. This is the first study to evaluate a porous tantalum acetabular cup with the use of computed tomography. These results show that a porous tantalum monoblock cup has excellent bony ingrowth and no evidence osteolysis at 10 year follow-up. These results suggest that porous tantalum is an attractive material for implantation in young, active patients

Abstract. Objectives. This abstract provides an update on the Open Ankle Models being developed at the University of Bath. The goal of this project is to create three fully open-source finite element (FE) ankle models, including bones, ligaments, and cartilages, appropriate musculoskeletal loading and boundary conditions, and heterogeneous material property distribution for a standardised representation of ankle biomechanics and pre-clinical ankle joint analysis. Methods. A computed tomography (CT) scan data (pixel size of 0.815 mm, and slice thickness of 1 mm) was used to develop the 3D geometry of the bones (tibia, talus, calcaneus, fibula, and navicular). Each bone was given the properties of a heterogeneous elastic material based on the CT greyscale. The density values for each bone element were calculated using a linear empirical relation, ρ= 0.0405 + (0.000918) HU and then power law equations were utilised to get the Young's Modulus value for each bone element [1]. At the bone junction, a thickness of cartilage ranging from 0.5–1 mm, and was modelled as a linear material (E=10 MPa, ν=0.4 [2]). All ligament insertions and positions were represented by four parallel spring elements, and the ligament stiffness and material attributes were applied in accordance with the published literature [2]. The ankle model was subjected to static loading (balance standing position). Four noded tetrahedral elements were used for the discretization of bones and cartilages. All degrees of freedom were restricted at the proximal ends of the tibia and fibula. The ground reaction forces were applied at the underneath of the calcaneus bone. The interaction between the cartilages and bones was modelled using an augmented contact algorithm with a sliding elastic contact between each cartilage. A tied elastic contact was used between the cartilages and the bone. FEbio 2.1.0 (University of Utah, USA) was used to construct the open-source ankle model. Results. When the double-legged stance phase loading condition was taken into consideration, stress at the antero-medial tibial wall (ranged from 1 to 7 MPa) was found to be similar to the prior work [2], indicating bulk of the load transfer was through this region. The maximum principal strain was predicted at the different regions on bones around the ankle joint. The proximal surface of the talus, and tibial distal surface were shown to have the highest maximum principal strains followed by antero-medial walls of the tibia bone, at the proximal location. Conclusions. The present open 3D FE model of the ankle will assist researchers in better understanding ankle biomechanics, precisely predicting load transfer, and examining the ankle to address unmet clinical needs for this joint. The results of the current investigation are realistic in terms of load transfer and stress-strain distribution across the ankle joint and well comparable to those reported in the literature [2]. However, sensitivity and ankle instability simulations will be performed in future work to investigate the model's reliability and robustness. 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

To determine the gross structural alterations of the nailed bone (femur or tibia) after the removal of an intramedullary nail (IMN). Eighteen patients (14 femoral and 4 tibia nail) underwent an IMN removal from their femur or tibia. Every patient had a spiral computed tomography scan and a plain X-ray study, immediately after the nail removal and also at their latest follow-up (24–30 months). The 4 patients with a tibia nail were additionally examined using a peripheral quantitative computed tomography study at their latest follow-up. All patients were asymptomatic. An intramedullary shell of compact bone was demonstrated around the nail track. This new bone was apparent on plain radiographs in all of the patients. Peripheral quantitative computed tomography study revealed that the density of the bony ring was similar to that of subcortical bone. The histologic examination of the intra-medullary shell of one of our patients suggested that the bony ring was made of cortical bone. Intramedullary nailing may enhance new cortical bone formation within the bone marrow cavity. This “cortical bone” still exists more than 2 years after implant removal. Nail insertion also causes thickening of the normal cortex at the sites of nail–cortex contact where loads are transferred from the nail to the cortex. This new finding could probably lead the research of intramedullary nailing biomechanics toward new directions as to understand the body’s reaction to IMNs

Introduction and Objective. The geometry of the proximal tibia and distal femur is intimately linked with the biomechanics of the knee and it is to be considered in total knee arthroplasty (TKA) component positioning. The aim of the present study was to evaluate the proximal tibial torsion in relation to the flexion-extension axis of the knee in healthy and pathological cohort affected by knee osteoarthritis (OA). Materials and Methods. We retrospectively analyzed computed tomography scans of OA knee of 59 patients prior to TKA and non-arthritic knee of 39 patients as control. Posterior condylar angle (PCA), femoral tibial torsion (TEAs-PTC and TEAs-PTT), proximal tibial torsion (PTC-PTT and PCAx-PTC) and distance between tibial tuberosity and the trochlear groove (TT-TG) were measured. Results. No differences were found for gender, age, TG-TT and PCAn angles. Statistically significant differences were found for all the other angles considered. Significant relation was found between Tibial Torsion and TEA-PTT angles, between PCAx-PTC and TEA-PTC, between TEA-PTT and TEA-PTC and between PCAx-PTC and TEA-PTT. All measures, except TG-TT and PCAn angles, showed high validity (AUC > 75%) in detecting OA, with TEA-PTT displaying the highest validity with an AUC of 94.38%. Conclusions. This is the first study to find significant differences in terms of proximal tibia geometry and anatomy between non arthritic and OA knees. It is conceivable that such anatomy could be implicated in the development of OA. Based on our data, the TEAs is a valid reference for correct positioning of tibial component in TKA. Indeed, setting the tibial component parallel to TEAs makes the prosthetic knee more similar to the native non-arthritic knee

Imageless computer navigation systems in total hip arthroplasty (THA) improve acetabular cup position, thereby reducing the risk of revision surgery for all causes as well as dislocation. We aimed to evaluate the registration accuracy of 3 alternate registration planes. A prospective, observational study was conducted with 45 THA in the supine position using two imageless navigation systems and 3 registration planes. Patient position was registered sequentially using an optical system (Stryker OrthoMap) and an inertial sensor-based system (Navbit Sprint) with 3 planes of reference: (Plane 1) an anatomical plane using the anterior superior iliac spines (ASISs) and the pubic symphysis; (Plane 2) a functional plane parallel to the line between the ASISs and the table plane; and, (Plane 3) a functional plane that was perpendicular to the gravity vector and aligned with the longitudinal axis of the patient. The 3 measurements of acetabular cup inclination and anteversion were compared with the measurements from postoperative computed tomography (CT) scans. For inclination, the mean absolute error was significantly lower for Plane 3 (1.80°) than for Plane 2 (2.74°), p = .038 and was lower for both functional planes than for the anatomical plane (3.75°), p < .001. For anteversion, the mean absolute error was significantly lower for Plane 3 (2.00°) than for Plane 2 (3.69°), p = .004 and was lower for both functional planes than for the anatomical plane (8.58°), p < .001. Patient registration using functional planes more accurately measured the acetabular cup position than registration using anatomic planes

Aim. Low-grade infections are difficult to diagnose. As the presence of a chronic infection requires extensive surgical debridement and antibiotic treatment, it is important to diagnose a SII prior to surgery, especially when the hardware is revised. We investigated whether serum inflammatory markers or nuclear imaging can accurately diagnose a chronic spinal instrumentation infection (SII) prior to surgery. Method. All patients who underwent revision spinal surgery after a scoliosis correction between 2017 and 2019 were retrospectively evaluated. The diagnostic accuracy of serum C-reactive protein (CRP) and Erythrocyte Sedimentation Rate (ESR), . 18. F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) and Technetium-99m-methylene diphosphonate (99mTc-MDP) 3-phase bone scintigraphy (TPBS) to diagnose infection were studied. Patients with an acute infection or inadequate culture sampling were excluded. SII was diagnosed if ≥ 2 of the same microorganism(s) were isolated from intra-operative tissue cultures. Results. 31 patients were included. The indication for hardware extraction was pseudoarthrosis in the majority of patients (n = 15). 22 patients (71%) were diagnosed with SII. In all infected cases, Cutibacterium acnes was isolated, including 5 cases with a polymicrobial infection. Sensitivity, specificity, PPV and NPV was: 4.5%, 100%, 100% and 30.0% for CRP >10.0 mg/L, 5.5%, 100%, 100% and 29% for ESR > 30 mm/h; 56%, 80%, 83% and 50% for FDG-PET/CT and 50%, 100%, 100% and 20% for TPBS, respectively. Conclusions. The prevalence of SII in patients undergoing revision spinal surgery is high, with Cutibacterium acnes as the main pathogen. No diagnostic tests could be identified that could accurately diagnose or exclude SII prior to surgery. Future studies should aim to find more sensitive diagnostic modalities to detect low-grade inflammation

Abstract. Objectives. High tibial osteotomy for knee realignment is effective at relieving symptoms of knee osteoarthritis but the operation is surgically challenging. A new personalised treatment with simpler surgery using pre-operatively planned measurements from computed tomography (CT) imaging and 3D-printed implants and instrumentation has been designed and is undergoing clinical trial. The aim of this study was to evaluate the early clinical results of a preliminary pilot study evaluating the safety of this new personalised treatment. Methods. The single-centre prospective clinical trial is ongoing (IRCCS Istituto Ortopedico Rizzoli; IRB-0013355; ClinicalTrials.gov NCT04574570), with recruitment completed and all patients having received the novel custom surgical treatment. To preserve the completeness of the trial reporting, only surgical aspects were evaluated in the present study. Specifically, the length of the implanted osteosynthesis screws was considered, being determined pre-operatively eliminating intraoperative measurements, and examined post-operatively (n=7) using CT image processing (ScanIP, Synopsys) and surface distance mapping. The surgical time, patient discharge date and ease of wound closure were recorded for all patients (n=25). Results. Over the study period the average surgical time (skin incision to suture) reduced from 54 to 31 minutes (range: 17–62, n=25). It was noted that wound closure was easier than the conventional surgery due to the lower profile of the implant. Over seventy percent of patients were discharged day 2 post-op. The position, orientation and length of all screws matched the pre-operative configuration to within approximately 1mm. Conclusions. The early trial results are promising from a clinical perspective. It was evident that surgical time was saved because no intraoperative screw length measurements were required, and the use of custom instrumentation significantly reduced the surgical inventory. The reduced invasiveness and ease of surgery may contribute to faster patient recovery compared to conventional techniques. The full trial results will be reported later this year. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest