Biomechanical Fixation Analysis of Minimally Invasive Chevron Osteotomy

Category: Bunion Introduction/Purpose: The original fixation for minimally invasive Chevron-Akin ( MICA) was described with two screws: a proximal screw reaching two cortices before fixing the metatarsal head and a distal parallel screw that can reach only one cortical before fixing the head. Despite this, some authors questioned the need for two screws and were able to reproduce good results from this technique using only one screw to fix the osteotomy. Notably, no biomechanical studies evaluate this osteotomy's most stable and safe fixation. This work aims to perform a biomechanical analysis based on finite element analysis (FEM) to compare different MICA fixation configurations using screws. Our hypothesis is that the fixation of the original technique with two screws is the safest. Methods: A Three-dimensional (3D) virtual model of a foot computer tomography (CT) image was made using the Rhinoceros™ program. The element finite analysis was performed with the SimLab™ program using the Optistruct solver. From these 3D virtual models, an extracapsular chevron osteotomy with 130 degrees with 70% of lateral translation was done and fixated. Five internal fixation configurations with screws were used for fixation of MICA and assessed by FEM -: original MICA fixation with 2 screws, 2 intramedullary screws, 2 bicortical screws, 01 intramedullary screw, and 01 bicortical screw. The simulated 150 N and 300 N loads were applied to the middle foot. The FEM evaluated the total and localized displacements of the osteotomy site. For the analysis of stresses, the variables maximum principal (traction) and minimum principal (compression) were used. The equivalent von Mises stress (VMS -S) was used for the metallic implants and for the bone (VMS -O). Results: The classical fixation for MICA showed the lowest values for total and localized displacement, minimum and maximum total stress, and VMS-S and VMS-o in both conditions( 150 and 300 N). The localized displacement was statistically lower for MICA screws compared to the other fixation configurations (p < 0.05) The maximum total stress was statistically lower for MICA screws compared to the other fixation configurations (p < 0.05) Conclusion: The classical fixation for MICA yields better results in terms of total and localized displacement, minimum and maximum total stress, and VMS in both conditions. These results demonstrate that the classical fixation for MICA described in the original technique is biomechanically the most efficient and safe

Semi-Automatic 3D Assessment of Zadek Osteotomy Effects

Category: Hindfoot; Sports Introduction/Purpose: Zadek's procedure is a surgical option to treat insertional Achilles tendinopathy(IAT). This procedure consists of a closing wedge osteotomy of the calcaneus with biomechanical consequences. Great modifications in the hindfoot alignment can result in poor functional outcomes for athletes. Additionally, some authors stated that Zadek osteotomy is a good choice for patients with IAT associated with cavovarus foot. This study aims to analyze the hindfoot alignment and the parameters related to Haglund's syndrome after Zadek's osteotomy using a virtual surgical simulation by specific software. The authors hypothesize that the Zadek is an effective technique to decompress the Achilles tendon against the Haglund deformity without major modifications in the alignment. Methods: A total of 20 WBCT scans of patients with IAT were included. The WBCT images were run through the Foot & Ankle module of Disior's BonelogicTM software, creating a 3D virtual model. With this 3D model built into this software, 20 virtual Zadeck osteotomies standardized with a 10 mm resection wedge were performed using the virtual osteotomy module of Bonelogic®. The Calcaneal Inclination angle (sagittal view)7; Talocalcaneal angle (sagittal view)8; Talocalcaneal angle (axial view)8; Saltzman angle (45 degrees view)9; Saltzman angle (20 degrees view)9; Hindfoot moment arm angle;10 Hindfoot angle10; Fowler Philips angle11 and the calcaneal length7 were measured before and after the virtual osteotomy. These results were compared and statistically analyzed. Results: A virtual Zadek osteotomy was realized in 20 WBCT from patients with an insertional Achilles tendinopathy. Most of the patients were female, and the mean age was 55 years. There were significant statistical differences in the average of the calcaneal length (79 mm to 73 mm), Fowler Philips angle (57º to 43º), calcaneal pitch ( 24º to 20º ), sagittal talocalcaneal angle (55º to 47º ), and the hindfoot moment arm angle (20 º to 21,8º). The axial talocalcaneal angle, Saltzman view 45 º and 20 º, and Hindfoot moment arm showed subtle modifications. Conclusion: The virtual analysis of Zadek's osteotomy decreased the Fowler Philips angle, shortened the calcaneus, and modified the alignment in the sagittal view. It suggests that Zadek's procedure reduces the bone impingement with Achilles and the Achilles push. The effect of this osteotomy in Hindfoot Alignment was subtle, modifying only the sagittal plane

High-Heel Wearing Does Not Change The Forefoot Alignment In Non-Frequent Users Without Hallux Valgus: 3D Weight-Bearing Scan Study

Category: Lesser Toes; Midfoot/Forefoot Introduction/Purpose: Women wearing high heels for 20 years without Hallux valgus angle alterations make it debatable that causes Hallux valgus deformation. A recent systematic review determined that 4.13 ± 0.34 cm of heel height would improve foot weight-bearing . Wearing high heels would realign the foot, causing an inversion of the foot, which locked the navicular-cuneiform and cuneo-metatarsal joints rather than primarily rotate the metatarsophalangeal joint. Nowadays, weight-bearing scans could favor understanding the alignment mechanism involved in the foot and ankle with different shoe heights. Therefore, we aimed to determine the acute foot alignment in non-frequent HH users without Hallux valgus during stand posture. Here, we hypothesize that high heels studied by weight-bearing scans shows radiology changes linked to hindfoot alignment rather than primary forefoot rotation. Methods: This comparative cross-sectional study, participants were randomly submitted to a tridimensional weight-bearing CT. Foot alignment for barefoot and wearing custom high heels of 3, 6, and 9 cm. Forty-one feet from twenty-one participants (11 males and 10 females, aged 30.8 ± 8.9 years, and Body Mass Index 25.5 ± 2.0 m kg-2) were submitted to a tridimensional weight- bearing scan in barefoot and wearing high heels of 3, 6, and 9 cm. The inclusion criteria were: Aged between 20 and 50 years, and no regular wearing of heels.Participants were instructed to bear weight in their regular standing upright posture, dispensing the body weight uniformly between the lower limbs with the feet set at shoulder width. Declination talar, forefoot arch, foot ankle offset, 1st, 2nd, and 3rd metatarsophalangeal dorsiflexion, and metatarsal rotation and sesamoid rotation angles were compared with repeated measurement analysis and multiple comparisons as well as the raters intraclass coefficient. Results: When height increases, the declination talar angle decrease (p < 0.001), the foot ankle offset decreases (p < 0.001), the 1st, 2nd, and 3rd dorsiflexion angle increases (p < 0.001), and metatarsal rotation angle (p=0.696) and sesamoid rotation angles (p=0.649) did not change. The forefoot arch for 6 cm was higher than 3 cm (p < 0.001) and then 9 cm (p=0.001), and the forefoot arch for 9 cm was higher than 3 cm (p=0.049). Conclusion: The main finding was that increased forefoot arch, lower ankle offset, no metatarsal rotation angle, and no sesamoid rotation angle strongly suggest an acute primary hindfoot alignment adaptation mechanism rather than forefoot rotation with increase of heel heigth. The most critical mechanism combines the activation of the windlass mechanism together with a stiffer alignment of Hindfoot. Our interpretation here is supported by the lower FAO, and increased forefoot arch and metatarsophalangeal joints, giving insight into pathology foot deformation like Hallux valgus. Thus, our findings suggest that it is debatable that wearing high heels can trigger forefoot deformity

Outcomes of the Bone-Block Lapidus Arthrodesis (LapiCotton) in the Treatment of the Collapsed Foot

Category: Midfoot/Forefoot; Bunion Introduction/Purpose: Progressive collapsing foot deformity (PCFD), Hallux Valgus (HV), and Midfoot Arthritis (MA) are diseases that benefit from the Lapidus procedure due to its capability to provide a stable medial column while correcting the underlying deformity. However, the technique does not go without complications. First metatarsal shortening/dorsiflexion are not uncommon, which could be exacerbated by local anatomy/revision surgery settings. Restoring length and sagittal plane position (plantarflexion) of the first ray when treating these pathologies is paramount. Performing a primary distraction and plantarflexion fusion with an allograft wedge (LapiCotton) has been advocated in the literature, potentially allowing improved deformity correction, but with the risk of increased non-union rate. The objective of this study was to report medium-term follow-up results of the LapiCotton in patients with collapsed feet. Methods: This IRB-approved comparative prospective study assessed patients diagnosed with PCFD, HV, and MA undergoing a Lapidus bone-block fusion (LapiCotton) between August 2020 and November 2022. All patients were operated on by a single fellowship-trained foot and ankle surgeon after clinical evaluation and a weight-bearing computed tomography (WBCT). After adequate joint preparation and trials, a Lapidus pre-shaped wedge allograft was placed and fixed using available implants. Adjunctive procedures were carried out as needed. Patients were kept non-weight bearing for six weeks and followed clinically, performing a WBCT at three months and subsequent follow-up. Non-Union and complications were documented. Bone healing was determined by at least 50% of bone trabeculae crossing both graft interfaces at the WBCT. Forefoot arch angle (FFA), Meary’s angle, talonavicular coverage angle (TNCA), middle facet subluxation (MFS), and foot and ankle offset (FAO) were also obtained. Two fellowship-trained readers performed all assessments. P-values >0.05 were considered significant. Results: Fifty-eight patients (60 feet) were included, mean age 53.87 (range:18-77)/BMI 31.70 (SD:7.96). Twenty-four PCFD, 19 HV, and 17 MA had an average 15.47 months (4-31) follow-up. Cuneiform-Post implants were used in 62%, plates/screws in 25%, and Lapidus nails in 13%. Median allograft size was 9mm (mode:8mm,5-19mm). Minor complications were observed in 3% (two superficial dehiscences) and major in 7% (three deep infections [5%], and one EHL contracture [2%]). Healing at the 3-month WBCT occurred in 94.8% and only in 66% at the most-recent WBCT (mean:11.08 months; 6-20). The clinical non-union rate demanding reoperation was eight clinical non-unions 13%. Mean FFA (pre:6.89,SD:6.63; postop:14.21,SD:5.48; p< 0.001), Meary (pre:15.17,SD:8.12; postop:6.31,SD:5.61; p< 0.001), TNCA (pre:26.75,SD:11.77; postop:11.59,SD:7.91; p< 0.001), MFS (pre:36.3,SD:26; postop:23.49,SD:17.35; p< 0.001), and FAO (pre:6.71,SD:5.81; postop:2.2,SD:4.33; p< 0.001) improved after the interventions. Conclusion: Although the Lapidus bone-block arthrodesis (LapiCotton) restored many of the markers associated with foot collapse and alignment, non-union rated was noted in 13% what is on the top range of non-union rates reported in the literature for Lapidus arthrodesis. The use of allograft wedges in the fusion site probably explains our findings. The fact that the sample was heterogeneous and composed of considerably severe deformities should also be considered. Also, important to highlight that WBCT findings of fusion site healing was initially 94% at 3-months and only 66% at most recent follow-up). Additional studies and longer-term follow up are needed

Integrity of the First Metatarsal Head Vascularization and Soft-Tissue Envelope Following Minimally Invasive Chevron Osteotomy for Hallux Valgus (HV) Deformity: A Micro-CT and Anatomical Assessment

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Minimally invasive surgery (MIS) Chevron-osteotomy for HV treatment offers a surgical alternative to open surgery with minimal surgical dissection and a hypothetical decreased risk for soft-tissue complications. During this procedure, there is a concern regarding the injury to the blood supply of the 1st-metatarsal-head. The objective of this study was to assess the incidence of injuries: (1) to the soft-tissue envelope around the first metatarsal head complex and, (2) to the blood supply of the first metatarsal head and also by using Micro-CT, (3) looking for safe zones close to the first metatarsal head to perform MIS Chevron osteotomy. We hypothesized that the MIS Chevron-type osteotomy procedure would preserve the soft-tissue envelope of the first-metatarsal-head complex and the blood supply of the 1st-metatarsal-head. Methods: Sixteen HV deformity cadaveric specimens were used to perform MIS Chevron-type osteotomy of the first metatarsal head. Anatomical dissection of all specimens was then performed to assess macroscopic injury to the first metatarsal head complex soft-tissue structures, including Extensor Hallucis Longus (EHL) tendon, Extensor Hallucis Brevis (EHB) tendon, Flexor Hallucis Longus (FHL) tendon, Flexor Hallucis Brevis (FHB) tendon, Abductor Hallucis tendon, Adductor Hallucis tendon, Sesamoid complex, Dorsolateral and Dorsomedial digital branches of the first toe and the Dorsomedial digital branch to the second. Macroscopic injuries were classified using a calibrated digital caliper. Any chondral damage to the first metatarsal head was quantified in mm². To assess the amount of first metatarsal head blood supply, specimens were perfused with 200 ml of a low viscosity radiopaque polymer, MV 117 (Flowtech), preoperatively, followed by Micro-CT assessment. Descriptive statistics and percentages were utilized for categorical data. Results: We did not find injuries in the EHL, EHB, FHL, Abductor-Hallucis, and Adductor-Hallucis tendons. We found a 2mm injury in the FHB tendon in one specimen. No injuries were found in the Dorsomedial and Dorsolateral nerves of the first-toe, the Dorsomedial-nerve of the second-toe, and Medial branch of the dorsomedial-nerve of the first-toe. In 3 cases, we found an injury on first-metatarsal-head (1mm) due to the passage of the K-wire and, in 1 case, due to the inadvertent passage of the drill (4.41mm). Macroscopically and using Micro-CT, we did not observe injuries in the First-Dorsal-Metatarsal-Artery (FDMA), Lateral-Dorsal-Branch of FDMA, and Plantar-Metatarsal-Artery. Micro-CT helped estimate a safe distance to finish the proximal exit of Chevron-osteotomy (25mm from the most distal point of the first metatarsal head). Conclusion: In this study, the minimally invasive Chevron osteotomy for treating HV seems to be a technically safe procedure, presenting a low rate of iatrogenic injuries with a low degree of severity. In addition, using Micro-CT promoted a better visualization of the microvasculature that nourishes the first metatarsal head. We observed that a proximal distance of 25 mm from the most distal part of the first metatarsal head could be a safe place to finalize the Chevron osteotomy, minimizing the risk of injury to the blood supply of the first metatarsal head

Impact of Sesamoid Coverage on Clinical Foot Function Following Fourth-Generation Percutaneous Hallux Valgus Surgery

Background: The impact of pronation and sesamoid coverage on clinical outcomes following percutaneous hallux valgus surgery are not currently known. The aim of this study was to investigate if sesamoid coverage was associated with worse clinical outcomes at 12-month follow-up following percutaneous hallux valgus surgery. Methods: Retrospective comparative observational study of clinical and radiographic outcomes based on a previously published prospective dataset. Patients were stratified into 3 cohorts based on the degree of sesamoid coverage (normal, mild, or moderate) on 12-month weightbearing radiographs following fourth-generation percutaneous hallux valgus surgery. Primary outcome was a validated patient-reported outcome measure (PROM), the Manchester-Oxford Foot Questionnaire (MOXFQ). Secondary outcomes included Euroqol-5D, VAS Pain, and radiographic deformity correction. Results: Forty-seven feet underwent primary fourth-generation HV surgery and were stratified into 3 cohorts. There were 19, 16, and 12 feet in the normal, mild, and moderate cohorts respectively. There was no significant difference in either pre- or postoperative foot function (all MOXFQ domains, P  > .05) or health-related quality of life (EQ-5D Index or VAS, P  > .05). The MOXFQ Index preoperatively was as follows: normal cohort, 56.1 ± 26.9; mild cohort, 54.1 ± 17.9; and severe cohort, 49.6 ± 23.8; and postoperatively was as follows: normal cohort, 15.6 ± 21.5; mild cohort, 11.4 ± 15.5; and severe cohort, 11.4 ± 13.6 ( P  = .737-.908). There was significantly worse hallux valgus angle (HVA) and intermetatarsal angle (IMA) between the cohorts ( P  < .01). Although HVA and IMA were corrected to normal parameters following surgery in all cohorts, there was a significantly worse postoperative HVA in the moderate sesamoid coverage (5.3 ± 3.9 vs 7.9 ± 5.3 vs 11.4 ± 3.7, P  < .01); however, IMA was not significantly different (3.4 ± 2.2 vs 4.1 ± 2.7 vs 5.2 ± 2.9, P  = .168). Conclusion: This study found that cases where the sesamoids were not reduced had a poorer correction and had worse preoperative deformity. Clinical outcomes and foot function following fourth-generation percutaneous hallux valgus surgery were not affected by sesamoid coverage at the 12-month follow-up. The long-term implications in the difference in radiographic deformity between the 3 cohorts are not known, and further work should explore the relationship of first ray pronation and sesamoid position, particularly with regard to recurrence. Level of evidence: Level III, retrospective comparative study of prospectively collected data

A global metagenomic map of urban microbiomes and antimicrobial resistance

We present a global atlas of 4,728 metagenomic samples from mass-transit systems in 60 cities over 3 years, representing the first systematic, worldwide catalog of the urban microbial ecosystem. This atlas provides an annotated, geospatial profile of microbial strains, functional characteristics, antimicrobial resistance (AMR) markers, and genetic elements, including 10,928 viruses, 1,302 bacteria, 2 archaea, and 838,532 CRISPR arrays not found in reference databases. We identified 4,246 known species of urban microorganisms and a consistent set of 31 species found in 97% of samples that were distinct from human commensal organisms. Profiles of AMR genes varied widely in type and density across cities. Cities showed distinct microbial taxonomic signatures that were driven by climate and geographic differences. These results constitute a high-resolution global metagenomic atlas that enables discovery of organisms and genes, highlights potential public health and forensic applications, and provides a culture-independent view of AMR burden in cities.Funding: the Tri-I Program in Computational Biology and Medicine (CBM) funded by NIH grant 1T32GM083937; GitHub; Philip Blood and the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant number ACI-1548562 and NSF award number ACI-1445606; NASA (NNX14AH50G, NNX17AB26G), the NIH (R01AI151059, R25EB020393, R21AI129851, R35GM138152, U01DA053941); STARR Foundation (I13- 0052); LLS (MCL7001-18, LLS 9238-16, LLS-MCL7001-18); the NSF (1840275); the Bill and Melinda Gates Foundation (OPP1151054); the Alfred P. Sloan Foundation (G-2015-13964); Swiss National Science Foundation grant number 407540_167331; NIH award number UL1TR000457; the US Department of Energy Joint Genome Institute under contract number DE-AC02-05CH11231; the National Energy Research Scientific Computing Center, supported by the Office of Science of the US Department of Energy; Stockholm Health Authority grant SLL 20160933; the Institut Pasteur Korea; an NRF Korea grant (NRF-2014K1A4A7A01074645, 2017M3A9G6068246); the CONICYT Fondecyt Iniciación grants 11140666 and 11160905; Keio University Funds for Individual Research; funds from the Yamagata prefectural government and the city of Tsuruoka; JSPS KAKENHI grant number 20K10436; the bilateral AT-UA collaboration fund (WTZ:UA 02/2019; Ministry of Education and Science of Ukraine, UA:M/84-2019, M/126-2020); Kyiv Academic Univeristy; Ministry of Education and Science of Ukraine project numbers 0118U100290 and 0120U101734; Centro de Excelencia Severo Ochoa 2013–2017; the CERCA Programme / Generalitat de Catalunya; the CRG-Novartis-Africa mobility program 2016; research funds from National Cheng Kung University and the Ministry of Science and Technology; Taiwan (MOST grant number 106-2321-B-006-016); we thank all the volunteers who made sampling NYC possible, Minciencias (project no. 639677758300), CNPq (EDN - 309973/2015-5), the Open Research Fund of Key Laboratory of Advanced Theory and Application in Statistics and Data Science – MOE, ECNU, the Research Grants Council of Hong Kong through project 11215017, National Key RD Project of China (2018YFE0201603), and Shanghai Municipal Science and Technology Major Project (2017SHZDZX01) (L.S.

Worldwide trends in blood pressure from 1975 to 2015:a pooled analysis of 1479 population-based measurement studies with 19.1 million participants

Abstract Background: Raised blood pressure is an important risk factor for cardiovascular diseases and chronic kidney disease. We estimated worldwide trends in mean systolic and mean diastolic blood pressure, and the prevalence of, and number of people with, raised blood pressure, defined as systolic blood pressure of 140 mm Hg or higher or diastolic blood pressure of 90 mm Hg or higher. Methods: For this analysis, we pooled national, subnational, or community population-based studies that had measured blood pressure in adults aged 18 years and older. We used a Bayesian hierarchical model to estimate trends from 1975 to 2015 in mean systolic and mean diastolic blood pressure, and the prevalence of raised blood pressure for 200 countries. We calculated the contributions of changes in prevalence versus population growth and ageing to the increase in the number of adults with raised blood pressure. Findings: We pooled 1479 studies that had measured the blood pressures of 19.1 million adults. Global age-standardised mean systolic blood pressure in 2015 was 127.0 mm Hg (95% credible interval 125.7–128.3) in men and 122.3 mm Hg (121.0–123.6) in women; age-standardised mean diastolic blood pressure was 78.7 mm Hg (77.9–79.5) for men and 76.7 mm Hg (75.9–77.6) for women. Global age-standardised prevalence of raised blood pressure was 24.1% (21.4–27.1) in men and 20.1% (17.8–22.5) in women in 2015. Mean systolic and mean diastolic blood pressure decreased substantially from 1975 to 2015 in high-income western and Asia Pacific countries, moving these countries from having some of the highest worldwide blood pressure in 1975 to the lowest in 2015. Mean blood pressure also decreased in women in central and eastern Europe, Latin America and the Caribbean, and, more recently, central Asia, Middle East, and north Africa, but the estimated trends in these super-regions had larger uncertainty than in high-income super-regions. By contrast, mean blood pressure might have increased in east and southeast Asia, south Asia, Oceania, and sub-Saharan Africa. In 2015, central and eastern Europe, sub-Saharan Africa, and south Asia had the highest blood pressure levels. Prevalence of raised blood pressure decreased in high-income and some middle-income countries; it remained unchanged elsewhere. The number of adults with raised blood pressure increased from 594 million in 1975 to 1.13 billion in 2015, with the increase largely in low-income and middle-income countries. The global increase in the number of adults with raised blood pressure is a net effect of increase due to population growth and ageing, and decrease due to declining age-specific prevalence. Interpretation: During the past four decades, the highest worldwide blood pressure levels have shifted from high-income countries to low-income countries in south Asia and sub-Saharan Africa due to opposite trends, while blood pressure has been persistently high in central and eastern Europe