Introduction. Research studies have established mathematical correlations between the lengths of bone segments and the possible biomechanical implications of these correlations. The Lucas sequence comprises a series of integers that adhere to the same recurrence relation as the Fibonacci sequence; it differs in that it can start with any two initial integers. The purpose of this study is to determine whether segmental lengths of the foot height, tibia, femur, and upper body follow a Lucas sequence pattern. Method. This was a retrospective radiographic review of patients who underwent full-body EOS scans. The AP scan was used to measure standing foot height (Ft), tibial length (T), femoral length (Fe), upper body length (UB), and full body length. A linear regression test was performed to determine whether a Lucas sequence-based relationship exists between Ft + T and Fe, and between T + Fe and UB. Result. The regression for the relationship between Ft + T and Fe for the entire cohort (R= 0.82, R2= 0.70), the female subset (R= 0.94, R2= 0.88) and the male subset (R= 0.75, R2= 0.57), all demonstrated a strong positive correlation between Ft + T and Fe and showed that Ft + T is a likely predictor of Fe. The regression test for the entire cohort demonstrated a moderately positive correlation between T + Fe and UB (R= 0.41, R2= 0.17, F(1, 145) = 29.42, p= 2.4E-07). A stronger correlation was found for the relationship between T + Fe and UB (R= 0.57, R2= 0.32, F(1, 35) = 16.64, p= 2.5E-05) for the female subset relative to the male subset (R= 0.20, R2= 0.038, F(1, 35) = 4.37, p= 0.04). Conclusion. This study demonstrates that total height is made up of sequential segments whose lengths approximate a Lucas series. The Fibonacci sequence is therefore once again implicated in human body proportions

Aims

This study aimed to analyze kinematics and kinetics of the tibiofemoral joint in healthy subjects with valgus, neutral, and varus limb alignment throughout multiple gait activities using dynamic videofluoroscopy.

The results of total hip arthroplasty (THA) revisions to correct leg length discrepancy (LLD) are not clear, with only two former limited series (< 25 patients). Therefore, we conducted a retrospective study of THA revisions for LLD to determine: 1) the change in LLD, 2) the function outcomes and whether obtaining equal leg lengths influenced function, 3) the complication and survival rates. This multicenter study included 57 patients: 42 THA revisions for limb shortening and 15 revisions for limb lengthening. LLD was measured on conventional radiographs and EOS. The Oxford-12 and FJS outcome scores were collected and the number of patients achieving the Oxford-12 MCID. The revisions were carried out a mean of 2.8 years after the index THA. The median LLD decreased from 7.5 mm (IQR: [5;12]) to 1 mm (IQR: [0.5;2.5]) at follow-up (p=0.0002). Overall, 55 of 57 patients (96%) had < 5 mm LLD at follow-up and 12 patients (21%) had equal leg lengths. The complication rate was 25%: 12 mechanical complications (8 periprosthetic femoral fractures, 2 stem loosening and 1 cup loosening, 1 dislocation) and 1 periprosthetic infection. The patient satisfaction was high with a median FJS of 79.2/100 and 77% of patients reached the Oxford-12 MCID. Lengthening procedures had significantly worst function than shortening (38% vs 91% of patients achieving the Oxford-12 MCID (p=0.0004)). Survivorship was 85% (95% CI: 77.9 – 92.5) at 2 years and 77% (95% CI: 66.3 – 87.1) at 4.6 years when using re-revision for any reason as the endpoint. When LLD after THA does not respond to conservative management, revision THA should be considered. Although revision THA for LLD improved medium-term functional outcomes with a high patient satisfaction rate, especially for shortening procedures, the complication rate was high, particularly related to periprosthetic femoral fracture

Aims. The aim of this study was to compare outcomes after growth-friendly treatment for early-onset scoliosis (EOS) between patients with skeletal dysplasias versus those with other syndromes. Methods. We retrospectively identified 20 patients with skeletal dysplasias and 292 with other syndromes (control group) who had completed surgical growth-friendly EOS treatment between 1 January 2000 and 31 December 2018. We compared radiological parameters, complications, and health-related quality of life (HRQoL) at mean follow-up of 8.6 years (SD 3.3) in the dysplasia group and 6.6 years (SD 2.6) in the control group. Results. Mean major curve correction per patient did not differ significantly between the dysplasia group (43%) and the control group (28%; p = 0.087). Mean annual spinal height increase was less in the dysplasia group (9.3 mm (SD 5.1) than in the control group (16 mm (SD 9.2); p < 0.001). Mean annual spinal growth adjusted to patient preoperative standing height during the distraction period was 11% in the dysplasia group and 14% in the control group (p = 0.070). The complication rate was 1.6 times higher (95% confidence interval (CI) 1.3 to 2.0) in the dysplasia group. The following complications were more frequent in the dysplasia group: neurological injury (rate ratio (RR) 5.1 (95% CI 2.3 to 11)), deep surgical site infection (RR 2.2 (95% CI 1.2 to 4.1)), implant-related complications (RR 2.0 (95% CI 1.5 to 2.7)), and unplanned revision (RR 1.8 (95% CI 1.3 to 2.5)). Final fusion did not provide additional spinal height compared with watchful waiting (p = 0.054). There were no significant differences in HRQoL scores between the groups. Conclusion. After growth-friendly EOS treatment, patients with skeletal dysplasias experienced a higher incidence of complications compared to those with other syndromes. Surgical growth-friendly treatment for skeletal dysplasia-associated EOS should be reserved for patients with severe, progressive deformities that are refractory to nonoperative treatment. Cite this article: Bone Joint J 2024;106-B(6):596–602

Adult Spine Deformity (ASD) is a degenerative condition of the adult spine leading to altered spine curvatures and mechanical balance. Computational approaches, like Finite Element (FE) Models have been proposed to explore the etiology or the treatment of ASD, through biomechanical simulations. However, while the personalization of the models is a cornerstone, personalized FE models are cumbersome to generate. To cover this need, we share a virtual cohort of 16807 thoracolumbar spine FE models with different spine morphologies, presented in an online user-interface platform (SpineView). To generate these models, EOS images are used, and 3D surface spine models are reconstructed. Then, a Statistical Shape Model (SSM), is built, to further adapt a FE structured mesh template for both the bone and the soft tissues of the spine, through mesh morphing. Eventually, the SSM deformation fields allow the personalization of the mean structured FE model, leading to generate FE meshes of thoracolumbar spines with different morphologies. Models can be selectively viewed and downloaded through SpineView, according to personalized user requests of specific morphologies characterized by the geometrical parameters: Pelvic Incidence; Pelvic Tilt; Sacral Slope; Lumbar Lordosis; Global Tilt; Cobb Angle; and GAP score. Data quality is assessed using visual aids, correlation analyses, heatmaps, network graphs, Anova and t-tests, and kernel density plots to compare spinopelvic parameter distributions and identify similarities and differences. Mesh quality and ranges of motion have been assessed to evaluate the quality of the FE models. This functional repository is unique to generate virtual patient cohorts in ASD. Acknowledgements: European Commission (MSCA-TN-ETN-2020-Disc4All-955735, ERC-2021-CoG-O-Health-101044828)

Decreasing the bulk weight without losing the biomechanical properties of commercial pure titanium (Cp-Ti) medical implants is now possible by using Laser Powder Bed Fusion (L-PBF) technology. Gyroid lattice structures that have precious mechanical and biological advantages because of similarity to trabecular bone. The aim of the study was to design and develop L-PBF process parameter optimization for manufacturing gyroid lattice Cp-Ti structures. The cleaning process was then optimized to remove the non-melted powder from the gyroid surface without mechanical loss. Gyroid cubic designs were created with various relative densities by nTopology. L-PBF process parameter optimization was progressed using with Cp-Ti (EOS TiCP Grade2) powder in the EOS M290 machine to achieve parts that have almost full dense and dimensional accuracy. The metallography method was made for density. Dimensional accuracy at gyroid wall thicknesses was investigated between designed and manufactured via stereomicroscope, also mechanical tests were applied with real time experiment and numerical analysis (ANSYS). Mass loss and strut thickness loss were investigated for chemical etching cleaning process. Gyroid parts had 99,5% density. High dimensional accuracy was achieved during L-PBF process parameters optimization. Final L-PBF parameters gave the highest 19% elongation and 427 MPa yield strength values at tensile test. Mechanical properties of gyroid were controlled with changing relative density. A minute chemical etching provided to remove non-melted powders. Compression test results of gyroids at numerical and real-time analysis gave unrelated while deformation behaviors were compatible with each other. Gyroid Cp-Ti osteosynthesis mini plates will be produced with final L-PBF process parameters. MTT cytotoxicity test will be characterized for cell viability. Acknowledgements This project is granted by TUBITAK (120N943). Feza Korkusuz MD is a member of the Turkish Academy of Sciences (TÜBA)

Aims

The aim of this study was to evaluate the reliability and validity of a patient-specific algorithm which we developed for predicting changes in sagittal pelvic tilt after total hip arthroplasty (THA).

The April 2023 Children’s orthopaedics Roundup³⁶⁰ looks at: Can you treat type IIA supracondylar humerus fractures conservatively?; Bone bruising and anterior cruciate ligament injury in paediatrics; Participation and motor abilities after treatment with the Ponseti method; Does fellowship training help with paediatric supracondylar fractures?; Supracondylar elbow fracture management (Supra Man): a national trainee collaborative evaluation of practice; Magnetically controlled growing rods in early-onset scoliosis; Weightbearing restrictions and weight gain in children with Perthes’ disease?; Injuries and child abuse increase during the pandemic over 12,942 emergency admissions.

Aims

This study aimed to evaluate rasterstereography of the spine as a diagnostic test for adolescent idiopathic soliosis (AIS), and to compare its results with those obtained using a scoliometer.

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

We present a large single surgeon case series evaluation of a new growth guidance technique for the treatment of progressive early onset scoliosis (EOS). A traditional Luque trolley construct uses wires to hold growth guidance rods together. We describe a new technique that uses domino end to side connectors in place of the wires with the aim of providing a stronger construct to better limit curve progression, while allowing longitudinal growth. We did a thorough retrospective review of patient records and radiological imaging. Sequential measurements of Cobb angle and length of rods were recorded, as well as any further surgical procedures and associated complications. This enabled us to quantify the ability of a technique to limit curve progression and simultaneously allow growth of the construct. In total, 28 patients with EOS (20 idiopathic, four syndromic, and four neuromuscular) have been treated with this technique, 25 of whom have a minimum follow-up of 2 years and 13 have a minimum follow-up of 5 years. The average correction of the preoperative Cobb angle was 48.9%. At the 2-year follow up, the average loss of this initial correction was 15 degrees, rising to only 20 degrees at a minimum of 5 years (including four patients with a follow-up of 8 years or more). The growth of the constructs was limited. The average growth at 2 years was 3.7 mm, rising to 19 mm at the 5-year follow-up. Patients who underwent surgery with this technique before the age of 8 years seemed to do better. This group had a revision rate of only 18% at an average time of 7 years after the index procedure, and the average growth was 22 mm. However, the group that had index surgery after the age of 8 years had a 64% revision rate at an average of 3.2 years after surgery and an average growth of only 11.6 mm. Overall, in the cases series, there were four hardware failures (14%) and one deep infection (3.5%), and only ten patients (36%) had one extra surgery after the index procedure. Only two of the 13 patients who are at a follow-up of 5 years or more have had revision. This modified Luque trolley technique has a good capacity for initial curve correction and for limiting further curve progression, with limited longitudinal growth before 2 years and improved growth thereafter. This technique might not be so useful after the age of 8 years because of poor growth and a higher early revision rate. We have also demonstrated a low cost technique with a low hardware failure rate that saves many future surgeries for the patient compared with other techniques used in the treatment of EOS

Aims. Leg length discrepancy (LLD) is a common pre- and postoperative issue in total hip arthroplasty (THA) patients. The conventional technique for measuring LLD has historically been on a non-weightbearing anteroposterior pelvic radiograph; however, this does not capture many potential sources of LLD. The aim of this study was to determine if long-limb EOS radiology can provide a more reproducible and holistic measurement of LLD. Methods. In all, 93 patients who underwent a THA received a standardized preoperative EOS scan, anteroposterior (AP) radiograph, and clinical LLD assessment. Overall, 13 measurements were taken along both anatomical and functional axes and measured twice by an orthopaedic fellow and surgical planning engineer to calculate intraoperator reproducibility and correlations between measurements. Results. Strong correlations were observed for all EOS measurements (r. s. > 0.9). The strongest correlation with AP radiograph (inter-teardrop line) was observed for functional-ASIS-to-floor (functional) (r. s. = 0.57), much weaker than the correlations between EOS measurements. ASIS-to-ankle measurements exhibited a high correlation to other linear measurements and the highest ICC (r. s. = 0.97). Using anterior superior iliac spine (ASIS)-to-ankle, 33% of patients had an absolute LLD of greater than 10 mm, which was statistically different from the inter-teardrop LLD measurement (p < 0.005). Discussion. We found that the conventional measurement of LLD on AP pelvic radiograph does not correlate well with long leg measurements and may not provide a true appreciation of LLD. ASIS-to-ankle demonstrated improved detection of potential LLD than other EOS and radiograph measurements. Full length, functional imaging methods may become the new gold standard to measure LLD. Cite this article: Bone Jt Open 2022;3(12):960–968

Clinically significant proximal junctional kyphosis (PJK) occurs in 20% of children treated with posterior distraction-based growth friendly surgery. In an effort to identify modifiable risk factors, it has been theorized biomechanically that low radius of curvature (ROC) implants (i.e., more curved rods) may increase post-operative thoracic kyphosis, and thus may pose a higher risk of developing PJK. We sought to test the hypothesis that EOS patients treated with low ROC (more curved rods) distraction-based treatment will have a greater risk of developing PJK as compared to those treated with high ROC (straighter) implants. This is a retrospective review of prospectively collected data obtained from a multi-centre EOS database on children treated with rib-based distraction with minimum 2-year follow-up. Variables of interest included: implant ROC at index (220 mm or 500 mm), patient age, pre-operative scoliosis, pre-operative kyphosis, and scoliosis etiology. In the literature, PJK has been defined as clinically significant if revision surgery with superior extension of the upper instrumented vertebrae was performed. In 148 scoliosis patients, there was a higher risk of clinically significant PJK with low ROC (more curved) rods (OR: 2.6 (95%CI 1.09-5.99), χ2 (1, n=148) = 4.8, p = 0.03). Patients had a mean pre-operative age of 5.3 years (4.6y 220 mm vs 6.2y 500 mm, p = 0.002). A logistic regression model was created with age as a confounding variable, but it was determined to be not significant (p = 0.6). Scoliosis etiologies included 52 neuromuscular, 52 congenital, 27 idiopathic, 17 syndromic with no significant differences in PJK risk between etiologies (p = 0.07). Overall, patients had pre-op scoliosis of 69° (67° 220mm vs 72° 500mm, p = 0.2), and kyphosis of 48° (45° 220mm vs 51° 500mm, p = 0.1). The change in thoracic kyphosis pre-operatively to final follow up (mean 4.0 ± 0.2 years) was higher in patients treated with 220 mm implants compared to 500 mm implants (220 mm: 7.5 ± 2.6° vs 500 mm: −4.0 ± 3.0°, p = 0.004). Use of low ROC (more curved) posterior distraction implants is associated with a significantly greater increase in thoracic kyphosis which likely led to a higher risk of developing clinically-significant PJK in EOS patients

Aims. Although CT is considered the benchmark to measure femoral version, 3D biplanar radiography (hipEOS) has recently emerged as a possible alternative with reduced exposure to ionizing radiation and shorter examination time. The aim of our study was to evaluate femoral stem version in postoperative total hip arthroplasty (THA) patients and compare the accuracy of hipEOS to CT. We hypothesize that there will be no significant difference in calculated femoral stem version measurements between the two imaging methods. Methods. In this study, 45 patients who underwent THA between February 2016 and February 2020 and had both a postoperative CT and EOS scan were included for evaluation. A fellowship-trained musculoskeletal radiologist and radiological technician measured femoral version for CT and 3D EOS, respectively. Comparison of values for each imaging modality were assessed for statistical significance. Results. Comparison of the mean postoperative femoral stem version measurements between CT and 3D hipEOS showed no significant difference (p = 0.862). In addition, the two version measurements were strongly correlated (r = 0.95; p < 0.001), and the mean paired difference in postoperative femoral version for CT scan and 3D biplanar radiography was -0.09° (95% confidence interval -1.09 to 0.91). Only three stem measurements (6.7%) were considered outliers with a > 5° difference. Conclusion. Our study supports the use of low-dose biplanar radiography for the postoperative assessment of femoral stem version after THA, demonstrating high correlation with CT. We found no significant difference for postoperative femoral version when comparing CT to 3D EOS. We believe 3D EOS is a reliable option to measure postoperative femoral version given its advantages of lower radiation dosage and shorter examination time. Cite this article: Bone Joint J 2022;104-B(11):1196–1201

Aims

Navigation devices are designed to improve a surgeon’s accuracy in positioning the acetabular and femoral components in total hip arthroplasty (THA). The purpose of this study was to both evaluate the accuracy of an optical computer-assisted surgery (CAS) navigation system and determine whether preoperative spinopelvic mobility (categorized as hypermobile, normal, or stiff) increased the risk of acetabular component placement error.

Aims

To develop an early implant instability murine model and explore the use of intermittent parathyroid hormone (iPTH) treatment for initially unstable implants.

Aims

One of the main causes of tibial revision surgery for total knee arthroplasty is aseptic loosening. Therefore, stable fixation between the tibial component and the cement, and between the tibial component and the bone, is essential. A factor that could influence the implant stability is the implant design, with its different variations. In an existing implant system, the tibial component was modified by adding cement pockets. The aim of this experimental in vitro study was to investigate whether additional cement pockets on the underside of the tibial component could improve implant stability. The relative motion between implant and bone, the maximum pull-out force, the tibial cement mantle, and a possible path from the bone marrow to the metal-cement interface were determined.

Abstract

MAGnetic Expansion Control (MAGEC) rods are used in the surgical treatment of children with early onset scoliosis. The magnetically controlled lengthening mechanism enables rod distractions without the need for repeated invasive surgery. The CE certification of these devices was suspended in March 2021 due, primarily, to performance evidence gaps in the documents provided by the manufacturer to regulators and notified bodies. MAGEC rods are therefore not permitted for use in countries requiring CE marking. This was a survey of 18 MAGEC rod surgeons in the UK about their perception of the impact of the CE suspension on the clinical management of their patients. Unsurprisingly, virtually all perceived a negative impact, reflecting the complexity of this patient group. Reassuringly, these surgeons are highly experienced in alternative treatment methods.

Cite this article: Bone Jt Open 2022;3(2):155–157.

Aims. The aim of this study was to compare the clinical and radiological outcomes of patients with early-onset scoliosis (EOS), who had undergone spinal fusion after distraction-based spinal growth modulation using either traditional growing rods (TGRs) or magnetically controlled growing rods (MCGRs). Methods. We undertook a retrospective review of skeletally mature patients who had undergone fusion for an EOS, which had been previously treated using either TGRs or MCGRs. Measured outcomes included sequential coronal T1 to S1 height and major curve (Cobb) angle on plain radiographs and any complications requiring unplanned surgery before final fusion. Results. We reviewed 43 patients (63% female) with a mean age of 6.4 years (SD 2.6) at the index procedure, and 12.2 years (SD 2.2) at final fusion. Their mean follow-up was 8.1 years (SD 3.4). A total of 16 patients were treated with MCGRs and 27 with TGRs. The mean number of distractions was 7.5 in the MCGR group and ten in the TGR group (p = 0.471). The mean interval between distractions was 3.4 months in the MCGR group and 8.6 months in the TGR group (p < 0.001). The mean Cobb angle had improved by 25.1° in the MCGR group and 23.2° in TGR group (p = 0.664) at final follow-up. The mean coronal T1 to S1 height had increased by 16% in the MCGR group and 32.9% in TGR group (p = 0.001), although the mean T1 to S1 height achieved at final follow-up was similar in both. Unplanned operations were needed in 43.8% of the MCGR group and 51.2% of TGR group (p = 0.422). Conclusion. In this retrospective, single-centre review, there were no significant differences in major curve correction or gain in spinal height at fusion. Although the number of planned procedures were fewer in patients with MCGRs, the rates of implant-related complications needing unplanned revision surgery were similar in the two groups. Cite this article: Bone Joint J 2022;104-B(2):257–264