Aims. This study addressed two questions: first, does surgical correction of an idiopathic scoliosis increase the volume of the rib cage, and second, is it possible to evaluate the change in lung function after corrective surgery for adolescent idiopathic scoliosis (AIS) using biplanar radiographs of the ribcage with 3D reconstruction?. Methods. A total of 45 patients with a thoracic AIS which needed surgical correction and fusion were included in a prospective study. All patients underwent pulmonary function testing (PFT) and low-dose biplanar radiographs both preoperatively and one year after surgery. The following measurements were recorded: forced vital capacity (FVC), slow vital capacity (SVC), and total lung capacity (TLC). Rib cage volume (RCV), maximum rib hump, main thoracic curve Cobb angle (MCCA), medial-lateral and anteroposterior diameter, and T4-T12 kyphosis were calculated from 3D reconstructions of the biplanar radiographs. Results. All spinal and thoracic measurements improved significantly after surgery (p < 0.001). RCV increased from 4.9 l (SD 1) preoperatively to 5.3 l (SD 0.9) (p < 0.001) while TLC increased from 4.1 l (SD 0.9) preoperatively to 4.3 l (SD 0.8) (p < 0.001). RCV was correlated with all functional indexes before and after correction of the deformity. Improvement in RCV was weakly correlated with correction of the mean thoracic Cobb angle (p = 0.006). The difference in TLC was significantly correlated with changes in RCV (p = 0.041). It was possible to predict postoperative TLC from the postoperative RCV. Conclusion. 3D rib cage assessment from biplanar radiographs could be a minimally invasive method of estimating pulmonary function before and after spinal fusion in patients with an AIS. The 3D RCV reflects virtual chest capacity and hence pulmonary function in this group of patients. Cite this article: Bone Joint J 2022;104-B(1):112–119

Purpose of the study: Leg length discrepancy after THA is a common complication and source of recurrent complaints from patients. To date, no reliable and reproducible technique has come forward to enable accurate quantification of all radiological parameters of the lower limb. Nevertheless, preoperative planning for hip arthroplasty requires knowledge of many limb parameters, in particularly leg length discrepancy, femoral offset, or the head-neck angle. The most widely used method is to use the 2D radiographs. The EOS system uses two digitalised 2D images taken orthogonally in a weight-bearing position to enable 3D reconstruction of the lower limb. The inter- and intraoperator reproducibility has been studied and validated. The purpose of our study was to compare the inter- and intra-operator reproducibilities of the measures taken on the standard full-length x-ray and those determined on the 3D EOS reconstructions. Material and method: Twenty-five patients scheduled for THA were included in this study (50 lower limbs). Two independent operators determine the measures on the AP EOS view and on the 3D reconstructions obtained from two orthogonal EOS images. The following parameters were measured: femur length, tibia length, limb length, HKA, HKS, femoral offset, neck-shaft angle, head diameter, and length of the femoral neck. Each observer performed two series of measurements. Interobserver reproducibility was assessed with the intraclass correlation coefficient (CI: 95%). Student’s t test was used to compare the clinical parameters measured on the 2D and 3D images. Results: Inter- and intraobserver reproducibility were 0.867 and 0.903 on the 2D x-rays and 0.911 and 0.940 on the 3D reconstructions. The better reproducibility of the EOS reconstruction was confirmed for all parameters tested in this study. Comparison of the 3D and 2D measurements revealed significant differences. Discussion: Our study demonstrated that measurements made on EOS 3D reconstructions offer better inter- and intraobserver reproducibility than those made on the standard AP view. In addition, the 3D reconstruction takes into consideration of the projection of the anatomic structures in the plane of the AP radiograph. The EOS appears to be a pertinent tool giving reliable results for the pre- and postoperative work-up for arthroplasty of the lower limb

Personalized three-dimensional (3D) femoral geometry is a great aid in the surgical planning. X-ray image is still essential to diagnose and plan surgery in total hip replacement due to its lower cost and lower dose of radiation than computer tomography (CT). The purpose of the current study is to improve 3D reconstruction process using conventional X-ray images incorporating the anatomical parameters for building up the femoral model. For 3D reconstruction, the personalized femoral appearance and parameters were firstly prepared from X-ray images and the referential CT model with anatomical parameters was modified as follows: the axial scaling, shearing transformation and radial scaling. In this study, the reconstruction algorithm was applied to X-ray images obtained from the 28 years old male. The current study showed that this 3D reconstruction technique is clinically useful and feasible because this method was based on anatomical parameters and used for whole femur. This result can provide the basic model of individual femur for using finite element method of hip or knee joint, and designing the customized hip and knee implant. In addition, this result can be applied to the visualized 3D model with more effective parameters of individual femur in the surgery navigation system

Aims. The aim of this study was to establish a reliable method for producing 3D reconstruction of sonographic callus. Methods. A cohort of ten closed tibial shaft fractures managed with intramedullary nailing underwent ultrasound scanning at two, six, and 12 weeks post-surgery. Ultrasound capture was performed using infrared tracking technology to map each image to a 3D lattice. Using echo intensity, semi-automated mapping was performed to produce an anatomical 3D representation of the fracture site. Two reviewers independently performed 3D reconstructions and kappa coefficient was used to determine agreement. A further validation study was undertaken with ten reviewers to estimate the clinical application of this imaging technique using the intraclass correlation coefficient (ICC). Results. Nine of the ten patients achieved union at six months. At six weeks, seven patients had bridging callus of ≥ one cortex on the 3D reconstruction and when present all achieved union. Compared to six-week radiographs, no bridging callus was present in any patient. Of the three patients lacking sonographic bridging callus, one went onto a nonunion (77.8% sensitive and 100% specific to predict union). At 12 weeks, nine patients had bridging callus at ≥ one cortex on 3D reconstruction (100%-sensitive and 100%-specific to predict union). Presence of sonographic bridging callus on 3D reconstruction demonstrated excellent reviewer agreement on ICC at 0.87 (95% confidence interval 0.74 to 0.96). Conclusion. 3D fracture reconstruction can be created using multiple ultrasound images in order to evaluate the presence of bridging callus. This imaging modality has the potential to enhance the usability and accuracy of identification of early fracture healing. Cite this article: Bone Joint Res 2021;10(12):759–766

Detailed preoperative planning is essential for open reduction and internal fixation of acetabular fractures if a successful outcome is to be achieved. Decisions such as patient positioning, approach, reduction techniques and implant positioning are greatly influenced by fracture pattern and displacement. These fractures are frequently complex and a thorough understanding of their 3-Dimensional (3D) form is necessary for pre-operative decision making. A combination of biplanar x-rays, 2 Dimensional CT scans (Axial, Sagittal and Coronal multi-plane reformats) and, more recently, 3D CT reconstructions are provided routinely. However, the 3D reconstructions are provided to surgeons as static 2D pictures of the 3D model (up to 6 different views), rather than a true 3D representation. In this study we used dynamic 3D models to provide additional information to surgeons. The 3D models were generated on a standard desktop or laptop computer and can be used in the operating theatre (Osirix Dicom viewing software). These true 3D reconstructions allow the surgeon to manipulate the model himself in real time so that the fracture can be viewed at any angle and overlying fragments removed to expose deeper structures. 3 experienced consultant pelvic trauma surgeons reviewed plain radiographs and 2D Pelvic CT scans from 20 acetabular fractures. They were asked to make a preoperative plan with regard to fracture classification and planned surgical approach(s). At separate, time-spaced, sittings they were provided with a 3D Static and 3D Dynamic CT reconstruction in addition. They were blinded to any previous plan and the patients’ details. A comparison was then made with regard to surgical plan and the time taken to make that plan with or without access to dynamic 3D models. The additional information provided by dynamic 3D modelling was found to reduce planning time and, in some cases, change the surgical plan

Purpose: Partial epiphysiodesis of the growth plate due to physeal aggression is a common problem in paediatric patients. Surgical management requires precise imaging. We recall other imaging techniques currently employed and describe a novel method for studying the characteristic features of epiphysiodesis bridges of the growth plate: 3D-magnetic resonance imaging (3D-MRI). Material and methods: We analysed retrospectively MRI series of 27 epiphysiodesis bridges in 23 children (ten boys and thirteen girls) aged 11.3 years (range 2.5 – 15). We recorded information concerning the cause of the physeal aggression, the joint involved, the type of bony bridge (Ogden classification), the clinical deformation, and the proposed treatment. The 27 bridges were studied on coronal MRI acquired with echo-gradient and fat suppression sequences. Data were processed with a manual 3D reconstruction program in 15 minutes to precisely define the localisation, the volume, and the morphology of the bony bridge and the active physis. Results: The epiphysiodeses were caused by trauma (65%), iatrogenic aggression (17%), ischemia-infection (purpura fulminans) (9%), juxta-physeal essential cyst (4.5%), and unknown causes (4.5%). Eighty-seven percent involved a lower limb joint, 75% of which involved the tibia. The surface of the epiphysiodesis bridge covered 20% of the physis. The bridges were peripheral (46.5%), central (46.5%), and linear (7%). Discussion: It is difficult to determine the position and the 3D relations of an epiphysiodesis bridge in a healthy active physis with imaging techniques such as plain x-rays, scintigraphy, tomography and computed tomography. The 3D-MRI method described here provides a sure way to distinguish the active growth plate which gives a high intensity signal and the epiphyseal bridge which gives a low intensity signal. Morphological (size, form) and topographic characteristics of the bony bridge and the physis can be described with precision facilitating therapeutic decision making and guiding surgery. The lack of radiation risk is also an advantage of MRI. Conclusion: The quality of the images obtained, the safety of MRI and the easy interpretation of 3D reconstructions makes this imaging technique an excellent method for pre-therapeutic analysis of epiphysiodesis bridges

Open reduction and internal fixation of acetabular fractures demands detailed preoperative planning, and given their frequent complexity, a thorough understanding of their three-dimensional (3D) form is necessary. This study aims to assess if the use of dynamic 3D models will improve preoperative planning of acetabular fractures. In this study, three experienced pelvic trauma surgeons were provided with computer based dynamic 3D models in addition to preoperative radiographs, CT scans and static 3D reconstructions of 17 acetabular fractures operatively managed at the Royal Melbourne Hospital. Surgeons, blinded to any previous operative plan or patient detail, then classified fracture type and made preoperative surgical plans. Comparison was then made to classification and operative approach documented in the patient's operation notes. Comparison was then made with regard to surgical plan and planning time with or without access to dynamic 3D models. In complex cases the additional information provided by dynamic 3D modelling was found to reduce planning time and, in some cases, change the surgical plan. For complex acetabular fractures we recommend that surgeons should have access to computer-based dynamic 3D models of the injuries for pre-operative planning

Anterior shoulder instability is associated with osseous defects of the glenoid and/or humeral head (Hill-Sachs lesions). These defects can contribute to the pathology of instability by engaging together. There is a need to continue to develop methods to preoperatively identify engaging Hill-Sachs lesions for determining appropriate surgical management.

The objective was to created a working moveable 3D CT model that allows the user to move the shoulder joint into various positions to assess the relationship between the Hill-Sachs lesion and the anterior glenoid rim. This technique was applied to a cohort series of 14 patients with recurrent anterior dislocation: 4 patients had undergone osteoarticular allografting of Hill-Sachs lesions and 10 control patients had undergone CT scanning to quantify bone loss but had no treatment to address bony pathology. A biomechanical analysis was performed to rotate each 3D model using local coordinate systems through a functional range using an open-source 3D animation program, Blender (Amsterdam, Netherlands). A Hill-Sachs lesion was considered “dynamically” engaging if the angle between the lesion's long axis and anterior glenoid was parallel.

In the classical vulnerable position of the shoulder (abduction=90, external rotation=0–135), none of the Hill-Sachs lesions aligned with the anterior glenoid in any of our patients (Figure 1). Therefore, we considered there to be a “low risk” of engagement in these critical positions, as the non-parallel orientation represents a lack of true articular arc mismatch and is unlikely to produce joint instability. We then expanded our search and simulated shoulder positions throughout a physiological range of motion for all groups and found that 100% of the allograft patients and 70% of the controls had positions producing alignment and were “high risk” of engagement (p = 0.18) (Table 1). We also found that the allograft group had a greater number of positions that would engage (mean 4 ± 1 positions of engagement) compared to our controls (mean 2 ± 2 positions of engagement, p = 0.06).

We developed a 3D animated paradigm to dynamically and non-invasively visualize a patient's anatomy and determine the clinical significance of a Hill-Sachs lesion using open source software and CT images. The technique demonstrated in this series of patients showed multiple shoulder positions that align the Hill-Sachs and glenoid axes that do not necessarily meet the traditional definition of engagement. Identifying all shoulder positions at risk of “engaging”, in a broader physiological range, may have critical implications towards selecting the appropriate surgical management of bony defects. We do not claim to doubt the classic conceptual definition of engagement, but we merely introduce a technique that accounts for the dynamic component of shoulder motion, and in doing so, avoid limitations of a static criteria assumed traditional definition (like size and location of lesion). Further investigations are planned and will help to further validate the clinical utility of this method.

For any figures or tables, please contact the authors directly.

Aims. The aim of this study was to analyse the effect of altered viewing perspectives on the measurement of the glenopolar angle (GPA) and the differences between these measurements made on 3D CT reconstructions and anteroposterior (AP) scapular view radiographs. . Materials and Methods. The influence of the viewing perspective on the GPA was assessed, as were the differences in the measurements of the GPA between 3D CT reconstructions and AP scapular view radiographs in 68 cadaveric scapulae. Results. The median GPA in 3D reconstructions and AP scapular views were 42.7° (95% confidence intervals (CI), 42.0° to 43.5°) and 41.3° (95% CI 40.4° to 42.0°) respectively (p < 0.001). All but five of 20 malpositions demonstrated a significant difference in GPA compared with the respective AP scapular view (p ≤ 0.005). The GPA was most susceptible to malposition in retroversion/anteversion. Inter- and intra-observer reliability for all measurements of the GPA was excellent for 3D CT reconstructions (intraclass correlation (ICC) 0.93 (95% CI 0.87 to 0.96) and 0.94 (95% CI 0.89 to 0.97), respectively) and higher than on AP scapular radiographs (p < 0.001). The intra- and inter-observer reliability was excellent in AP scapular views and malpositions in extension/flexion (ICC ≥ 0.84) but tended to decrease with increasing viewing angle in retroversion/anteversion. Conclusion. These data suggest that 3D reconstructions are more reproducible than AP scapular radiographs in the assessment of the GPA and should be used to compare data in different studies, to predict outcome, define malunion, and act as an indication for surgery in patients with a scapular fracture. Cite this article: Bone Joint J 2016;98-B:1510–16

Introduction: Articular cartilage injuries cause pain and disability and lead to early osteoarthritis. Autologous chondrocytes implantation (ACI) demonstrated long-term clinical benefit. However, clinical application of ACI is laborious requiring arthrotomy of the knee, harvest of a periosteal flap from a secondary surgery site and suturing over the cartilage lesion. Use of the periosteal flap often leads to tissue hypertrophy requiring an arthroscopic intervention. BioCart™II is a new matrix-assisted autologous chondrtocytes implant. The autologous cells, propagated with a unique growth factor variant, are delivered within a biocompatible and biodegradable scaffold made of human fibrin and hyaluronic acid. BioCart™II eliminates the need for a periosteal flap and enables implantation by a minimally invasive procedure thus significantly simplifying surgery and reducing rehabilitation time.

Methods: Chondrocytes were obtained from cartilage tissue using enzymatic digestion. The cells were then expanded in medium supplemented with a fibroblast growth factor (FGF) variant. Chondrogenic potential of the cultured chondrocytes was determined by in vitro high density pellet culture. The pellet cultures were analyzed for expression of cartilage specific markers by PCR and histology. Distribution of the cells within the fibrin-hyaluronic acid scaffold was studied by histology using H& E staining, presence of proteoglycans and collagen types I and II (Col-I, II) was determined by specific stains and immunohistochemistry (IHC).

Results: Cells cultured in the presence of the FGF variant exhibit a dramatic increase in proliferation rate compared with untreated cells. The chondrogenic potential of cells cultured for 4, 7, and 10 days in the presence of the growth factor were tested by pellet culture. Cells cultured for 4 days did not form a hyaline-like pellet, while cells cultured for 7 and 10 days form pellets with hyaline like structure which express proteoglycans and collagen type II. Col-II expression determined by real time PCR was significantly increased compared with Col-I in the pellets indicating the regeneration of hyaline cartilage phenotype. Pellet culture of chondrocytes cultured in the presence of the growth factor formed a much larger pellet and expressed more proteoglycans than pellet of cells cultured without the growth factor. Histological analysis of implants immediately post seeding demonstrate the chondrocytes are distributed throughout the fibrin-hyalronic acid scaffold. Expression of Col-II but not Col-I was observed within the scaffold by IHC.

Discussion: We present a new articular cartilage repair implant composed of autologous cells embedded within a fibrin and hyaluronic acid scaffold. Fibrin which is the natural scaffold for wound healing is used as the implant building material thereby mimicking the body’s natural healing process. The porous open channel structure of the scaffold allows for an immediate three-dimensional distribution of the cells within the scaffold to promote full thickness repair Use of the FGF variant allows implantation of BioCart™II within two to three weeks from the cartilage biopsy and increases the regenerative potential of the implant. BioCart™II is currently in clinical studies for the treatment of knee cartilage injuries.

Introduction

In clinical routine surgeons depend largely on 2D x-ray radiographs and their experience to plan and evaluate surgical interventions around the knee joint. Numerous studies have shown that pure 2D x-ray radiography based measurements are not accurate due to the error in determining accurate radiography magnification and the projection characteristics of 2D radiographs. Using 2D x-ray radiographs to plan 3D knee joint surgery may lead to component misalignment in Total Knee Arthroplasty (TKA) or to over- or under-correction of the mechanical axis in Lower Extremity Osteotomy (LEO).

Recently we developed a personalized X-ray reconstruction-based planning and post-operative treatment evaluation system called “iLeg” for TKA or LEO. Based on a patented X-ray image calibration cage and a unique 2D–3D reconstruction technique, iLeg can generate accurate patient-specific 3D models of a complete lower extremity from two standing X-rays for true 3D planning and evaluation of surgical interventions at the knee joint. The goal of this study is to validate the accuracy of this newly developed system using digitally reconstructed radiographs (DRRs) generated from CT data of cadavers.

Recently we developed a personalised X-ray reconstruction-based planning and post-operative treatment evaluation system called iLeg for total knee arthroplasty or lower extremity osteotomy. Based on a patented X-ray image calibration cage and a unique 2D-3D reconstruction technique, iLeg can generate accurate patient-specific 3D models of a complete lower extremity from two standing X-rays for true 3D planning and evaluation of surgical interventions at the knee joint. The goal of this study is to validate the accuracy of this newly developed system using digitally reconstructed radiographs (DRRs) generated from CT data of 12 cadavers (24 legs). Our experimental results demonstrated an overall reconstruction accuracy of 1.3±0.2mm.

Introduction: Reversed prostheses implantation requires screwing of the glenoid component with prefixed angles. This study is to determine anatomical angles of scapula that take part in reversed prostheses implantation.

Material and method: Seventy-three 3-dimensional computed tomography of the scapula and 108 scapular dry specimens were analyzed. Mean age of the CT-3D serie was of 52.59 years old (ranging from 16 to 84). There were 46 females and 27 males. The following measures were made on each patient: length of the neck of the inferior glenoid, angle between the glenoid surface and the upper posterior column of the scapula, angle between the major craneo-caudal glenoid axis and the base of the coracoid process and angle between the major craneo-caudal glenoid axis and the upper posterior column of the scapula. Measures were performed in the AP view as well as in the posterior view of the scapula.

Results: The length of the neck of the anterior glenoid was classified into two groups named ‘short-neck’ and ‘long-neck’ for both three-dimensional computed tomography and cadaveric scapulas with statistically significant differences between both groups (p< 0,001 for the three-dimensional computed tomography scapulas and p=0,034 for the cadaveric group). The angle between the glenoid surface and the upper posterior column of the scapula was also classified into two different types: type I (52° ranging from 48° to 57°) and type II (64° ranging from 60° to 70°) with statistically significant differences between both groups (p< 0,001 for the three-dimensional computed tomography scapulas and p< 0,001 for the cadaveric group). The angle between the major craneo-caudal glenoid axis and the center of the base of the coracoid process averaged 18,25° (ranging 13° from to 27°). The angle between the major craneo-caudal glenoid axis and the upper posterior column of the scapula averaged 8° (ranging 5° from to 18°).

Conclusions:

- scapulas can be classified into two groups regarding the angle between the glenoid surface and the upper posterior column of the scapula with significant differences between them.

Objectives

Pedicle-lengthening osteotomy is a novel surgery for lumbar spinal stenosis (LSS), which achieves substantial enlargement of the spinal canal by expansion of the bilateral pedicle osteotomy sites. Few studies have evaluated the impact of this new surgery on spinal canal volume (SCV) and neural foramen dimension (NFD) in three different types of LSS patients.

Accurate reconstruction of the knee pose from two X-Ray images will allow the study pre-operative kinematics (for custom prosthesis design) and the post-operative evaluation of the intervention.

We used a SSM of the distal femur, based on 24 MRI datasets, from which the mean model and its modes of variation were defined. On the SSM, N landmarks in predefined positions were defined. The user identifies the same landmarks on two X-ray projections. Back-projecting the X-ray from the identified landmarks pixel to the corresponding source, each landmark position in the 3D space is reconstructed and the mean model pose initialised with a corresponding points registration. The silhouette of the SSM is projected on each X-ray image, which is automatically segmented in order to define the bone contours. With a Robust Point Matching algorithm based on Thin Plate Splines the projected silhouette points are deformed to better approximate the contour. For each contour point, the associated silhouette point is computed. We back-projected the ray from each contour point to the source and find on each ray the point with minimum distance to the silhouette. The cost function is the squared sum of the distances for both images. After a first optimisation of the pose, we perform a shape optimisation to find the correct weights for the SSM.

To evaluate our algorithm, we used two Digitally Reconstructed Radiographs (DRR) created as projections at 90° from a CT dataset. The CT based model was reconstructed and the landmarks were defined on it with a rigid registration of the SSM. In order to validate the robustness of our reconstruction method, a random uniform noise distribution (0–50 mm on each direction) was added on each landmark. The reconstruction accuracy was measured as the distance between each reconstructed landmark and the ground truth defined on the CT.

Results show that the population of the errors for the noise levels from 0 to 30 is similar: only the population with 50 mm noise is significantly different from the results obtained with other noise levels.

We can conclude that with a noise level below 50 mm the algorithm is able to return the correct pose of the femur, while with higher noise the initial distribution of the landmarks in the 3D space prevents the correct outcome of the algorithm. The user should select the landmarks within a range of 50 mm on the 3D representation, that is half the dimension of the bounding box containing the model. We can assume that in the real case it will be more difficult to select the proper position of the landmarks, but our method proved to be robust even with misplaced landmarks.

Limb length disparity is a frequent complication after hip surgery inducing many surgeon-patients conflicts. To date no study has been able to precisely quantify such limb length disparity. EOS® system, currently validated to measure lower limb parameters, allows from two bi-dimensional numerical orthogonal radiographies in standing position to obtain a tri-dimensional reconstruction of lower limbs. A computerized system achieves the parameters calculation.

The aim of this study is to precisely measure the limb length disparities and the other hip parameters following total hip arthroplasty surgical procedure, by using a standard X-rays and using EOS® three-dimensional reconstructions.

Twenty-eight patients programmed for total hip arthroplasty have been included (i.e. thirty lower limbs). Two independent performers have carried out twice the measures either on standard X-rays and using three-dimensional reconstructions of the lower limb disparities prior and after the surgical procedure.

The inter and intra-observer reproducibility for the measure of the lower limb disparities have been of the EOS® measures have been respectively of 0.854 and 0.865 and for the standard X-rays of 0.717 and 0.726.

Mean length disparity observed was before Total Hip Arthroplasty of −0.328 cm (0.705; −1.266/0.530) and was of 0.088 mm (1.326; −1.635/0.632) after. We are able to decrease the lower limbs disparity in 69.1% and for the average of 0,416cm.

Using EOS® system has allowed assessing with greater precision the possibility to restore equal lower limb length.

This assessment has permitted introducing a new planning procedure including EOS® imaging associated to the fusion of the prosthetic tri-dimensional image in order to achieve adequate lower limb length.

Aims. The Wrightington classification system of fracture-dislocations of the elbow divides these injuries into six subtypes depending on the involvement of the coronoid and the radial head. The aim of this study was to assess the reliability and reproducibility of this classification system. Methods. This was a blinded study using radiographs and CT scans of 48 consecutive patients managed according to the Wrightington classification system between 2010 and 2018. Four trauma and orthopaedic consultants, two post CCT fellows, and one speciality registrar based in the UK classified the injuries. The seven observers reviewed preoperative radiographs and CT scans twice, with a minimum four-week interval. Radiographs and CT scans were reviewed separately. Inter- and intraobserver reliability were calculated using Fleiss and Cohen kappa coefficients. The Landis and Koch criteria were used to interpret the strength of the kappa values. Validity was assessed by calculating the percentage agreement against intraoperative findings. Results. Of the 48 patients, three (6%) had type A injury, 11 (23%) type B, 16 (33%) type B+, 16 (33%) Type C, two (4%) type D+, and none had a type D injury. All 48 patients had anteroposterior (AP) and lateral radiographs, 44 had 2D CT scans, and 39 had 3D reconstructions. The interobserver reliability kappa value was 0.52 for radiographs, 0.71 for 2D CT scans, and 0.73 for a combination of 2D and 3D reconstruction CT scans. The median intraobserver reliability was 0.75 (interquartile range (IQR) 0.62 to 0.79) for radiographs, 0.77 (IQR 0.73 to 0.94) for 2D CT scans, and 0.89 (IQR 0.77 to 0.93) for the combination of 2D and 3D reconstruction. Validity analysis showed that accuracy significantly improved when using CT scans (p = 0.018 and p = 0.028 respectively). Conclusion. The Wrightington classification system is a reliable and valid method of classifying fracture-dislocations of the elbow. CT scans are significantly more accurate than radiographs when identifying the pattern of injury, with good intra- and interobserver reproducibility. Cite this article: Bone Joint J 2020;102-B(8):1041–1047

Aims. Successful cell therapy in hip osteonecrosis (ON) may help to avoid ON progression or total hip arthroplasty (THA), but the achieved bone regeneration is unclear. The aim of this study was to evaluate amount and location of bone regeneration obtained after surgical injection of expanded autologous mesenchymal stromal cells from the bone marrow (BM-hMSCs). Methods. A total of 20 patients with small and medium-size symptomatic stage II femoral head ON treated with 140 million BM-hMSCs through percutaneous forage in the EudraCT 2012-002010-39 clinical trial were retrospectively evaluated through preoperative and postoperative (three and 12 months) MRI. Then, 3D reconstruction of the original lesion and the observed postoperative residual damage after bone regeneration were analyzed and compared per group based on treatment efficacy. Results. The mean preoperative lesion volume was 18.7% (SD 10.2%) of the femoral head. This reduced to 11.6% (SD 7.5%) after three months (p = 0.015) and 3.7% (SD 3%) after one year (p < 0.001). Bone regeneration in healed cases represented a mean 81.2% (SD 13.8%) of the initial lesion volume at one year. Non-healed cases (n = 1 stage progression; n = 3 THAs) still showed bone regeneration but this did not effectively decrease the ON volume. A lesion size under mean 10% (SD 6%) of the femoral head at three months predicted no ON stage progression at one year. Regeneration in the lateral femoral head (C2 under Japanese Investigation Committee (JCI) classification) and in the central and posterior regions of the head was predominant in cases without ON progression. Conclusion. Bone regeneration was observed in osteonecrotic femoral heads three months after expanded autologous BM-hMSC injection, and the volume and location of regeneration indicated the success of the therapy. Cite this article: Bone Joint Res 2022;11(12):881–889

Aims. Several radiological methods of measuring anteversion of the acetabular component after total hip arthroplasty (THA) have been described. These are limited by low reproducibility, are less accurate than CT 3D reconstruction, and are cumbersome to use. These methods also partly rely on the identification of obscured radiological borders of the component. We propose two novel methods, the Area and Orthogonal methods, which have been designed to maximize use of readily identifiable points while maintaining the same trigonometric principles. Patients and Methods. A retrospective study of plain radiographs was conducted on 160 hips of 141 patients who had undergone primary THA. We compared the reliability and accuracy of the Area and Orthogonal methods with two of the current leading methods: those of Widmer and Lewinnek, respectively. Results. The 160 anteroposterior pelvis films revealed that the proposed Area method was statistically different from those described by Widmer and Lewinnek (p < 0.001 and p = 0.004, respectively). They gave the highest inter- and intraobserver reliability (0.992 and 0.998, respectively), and took less time (27.50 seconds (. sd. 3.19); p < 0.001) to complete. In addition, 21 available CT 3D reconstructions revealed the Area method achieved the highest Pearson’s correlation coefficient (r = 0.956; p < 0.001) and least statistical difference (p = 0.704) from CT with a mean within 1° of CT-3D reconstruction between ranges of 1° to 30° of measured radiological anteversion. Conclusion. Our results support the proposed Area method to be the most reliable, accurate, and speedy. They did not support any statistical superiority of the proposed Orthogonal method to that of the Widmer or Lewinnek method. Cite this article: Bone Joint J 2019;101-B:1042–1049

Aims. The morphology of medial malleolar fracture is highly variable and difficult to characterize without 3D reconstruction. There is also no universally accepeted classification system. Thus, we aimed to characterize fracture patterns of the medial malleolus and propose a classification scheme based on 3D CT reconstruction. Methods. We retrospectively reviewed 537 consecutive cases of ankle fractures involving the medial malleolus treated in our institution. 3D fracture maps were produced by superimposing all the fracture lines onto a standard template. We sliced fracture fragments and the standard template based on selected sagittal and coronal planes to create 2D fracture maps, where angles α and β were measured. Angles α and β were defined as the acute angles formed by the fracture line and the horizontal line on the selected planes. Results. A total of 121 ankle fractures were included. We revealed several important fracture features, such as a high correlation between posterior collicular fractures and posteromedial fragments. Moreover, we generalized the fracture geometry into three recurrent patterns on the coronal view of 3D maps (transverse, vertical, and irregular) and five recurrent patterns on the lateral view (transverse, oblique, vertical, Y-shaped, and irregular). According to the fracture geometry on the coronal and lateral view of 3D maps, we subsequently categorized medial malleolar fractures into six types based on the recurrent patterns: anterior collicular fracture (27 type I, 22.3%), posterior collicular fracture (12 type II, 9.9%), concurrent fracture of anterior and posterior colliculus (16 type III, 13.2%), and supra-intercollicular groove fracture (66 type IV, 54.5%). Therewere three variants of type IV fractures: transverse (type IVa), vertical (type IVb), and comminuted fracture (type IVc). The angles α and β varied accordingly. Conclusion. Our findings yield insight into the characteristics and recurrent patterns of medial malleolar fractures. The proposed classification system is helpful in understanding injury mechanisms and guiding diagnosis, as well as surgical strategies. Cite this article: Bone Joint J 2021;103-B(5):931–938