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Hallux rigidus is a common degenerative condition of the hallux metatarsophalangeal joint (MTPJ) characterized by pain, swelling, stiffness, and limited range of motion with characteristic corresponding clinical, physical examination, and radiographic findings. Many historical risks factors including trauma and family history and patient factors including hallux valgus interphalangeus and inflammatory arthropathies have a well-substantiated etiologic role in the disease process. The purpose of this section is to review the normal and pathologic anatomy and biomechanics of the hallux MTPJ while providing an overview of the current understanding and remain debate regarding the disease process., Competing Interests: Disclosure The authors have no pertinent financial or funding disclosures related to the content of this article., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This study aimed to delineate the detailed anatomy of the metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints in healthy horses using cone beam computed tomography (CBCT). The fetlock region of 15 cadaveric forelimbs and 14 cadaveric hindlimbs from nine adult horses without orthopaedic disease underwent CBCT scanning. Additionally, arthrography CBCT scans were conducted following intra-articular injection of a radiopaque contrast medium containing blue epoxy resin dye. Subsequently, limbs were frozen and sectioned to visualize anatomical structures in sectional planes corresponding to selected CBCT images. CBCT proved suitable for detailed visualization of the bony components of the fetlock region. Furthermore, the common digital extensor tendon, superficial and deep digital flexor tendons, suspensory ligament, and straight and oblique sesamoidean ligaments were identifiable on CBCT images. However, certain ligaments, such as the collateral sesamoidean ligaments and intersesamoidean ligaments, were not clearly identified. The hyaline cartilage of the MCP and MTP joint facets was assessable on the post-contrast sequence. In cases where a radiographic or ultrasound examination cannot provide a definitive diagnosis and determine the extent of disease, CBCT can provide additional valuable data on the equine MCP and MTP joint. The images obtained in this study can serve as a reference for CBCT examination of the equine MCP and MTP joint., (© 2024 The Author(s). Anatomia, Histologia, Embryologia published by Wiley‐VCH GmbH.)

This study was aimed to provide anatomical atlas of the ovine metacarpo/metatarsophalangeal joints using computed tomography (CT) scan and magnetic resonance imaging (MRI), as well as to investigate bone mineral density (BMD) and morphometric features of this joint. The limbs of twenty adult Sanjabi sheep were examined. Imaging was performed using a 16-slice multi-detector CT scanner and a 1.5 Tesla MRI scanner. The obtained images were correlated with corresponding anatomical sections. BMD was measured by Dual Energy X-ray Absorptiometry (DEXA) method. Also morphometric features included distance between metacarpal and metatarsal heads, width of metacarpal and metatarsal head, length, width and the height of the proximal sesamoid bones were measured. In MRI images, compact bones, ligaments and tendons showed less signal intensity (hypointense). The fatty tissue and bone marrow had more signal intensity (hyperintense), but articular cartilage and synovial fluid showed moderate signal intensity. BMD in the left hind limb was significantly higher than other three limbs (p ≤ 0.05). The length of proximal sesamoid bones in left forelimb was higher than right forelimb (p ≤ 0.05). The thickness of proximal sesamoid bones in left limbs was higher than those in their counterparts (p ≤ 0.05). The width of the medial head in the forelimbs was significantly greater than the hind limbs (p ≤ 0.05). The present results might be useful in managing the clinical techniques on this joint. Larger volume of the proximal sesamoid bones and wider medial head in the forelimbs compared to the hindlimbs impel this speculation that the centre of gravity is closer to the forelimbs., (© 2022 Wiley-VCH GmbH.)

Background: The plantar plate is a major stabilizing structure of the metatarsophalangeal (MTP) joint with instability frequently occurring after a tear or attenuation of this structure. Commonly, a McGlamry elevator is used to strip the plantar plate from the plantar surface of the metatarsal to improve exposure of the MTP joint. The anatomy of the proximal plantar plate and vascular consequence of stripping the plantar plate from the metatarsal is not yet well understood. The purpose of this study is to describe the proximal attachment of the plantar plate anatomically and quantify the relative contribution of blood supply to the proximal plantar plate from both the metatarsal and the plantar fascia., Methods: For anatomic evaluation, 6 lower extremity cadaver specimens without any gross evidence of foot and ankle deformity were utilized. For imaging analysis, 16 fresh frozen human adult cadaveric lower extremity specimens were used for this study, resulting in 35 MTP joints without deformity and 11 lesser MTP joints with cockup and/or crossover deformities. The specimens were prepared as described previously by Finney et al. 5 ., Results: From gross anatomic dissection, the plantar plate origin consists of a stout fibrous pedicle distinct from the surrounding synovial-type tissue that firmly anchors the plantar plate to the metatarsal. Based on nano-computed tomographic imaging, an average of 63.5% of the vascular supply to the proximal portion of the plantar plate entered from the metatarsal pedicle. The remaining 36.5% of the vascular supply entered from the plantar fascia., Conclusion: The proximal attachment of the plantar plate includes a stout fibrous pedicle anchoring the proximal portion of the plantar plate to the notch between the medial and lateral plantar condyles of the metatarsal head. The vascular supply of the proximal plantar plate is supplied from both the metatarsal pedicle and plantar fascia., Level of Evidence: Level III, retrospective comparative study.

Backgroud: The accessory tendon of the extensor hallucis longus (ATEHL) muscle is a common abnormal structure, and its clinical significance remains debatable. In this study, we provide the incidence of the ATEHL and characterize its morphological types in Asian cadavers and investigate its clinical applications., Methods: The tendons from 50 adult cadaveric feet, fixed in 10% formalin, were analyzed. We measured the length and width of both the ATEHL and the extensor hallucis brevis (EHB)., Results: All dissected specimens had an ATEHL. The first metatarsophalangeal joint was surrounded by an accessory tendon that inserted onto the joint capsule and the dorsal base of the proximal phalanx. We classified the ATEHL into 3 types based on their directions. Differences in ATEHL type based on sex were not statistically significant., Conclusions: We found an ATEHL in all cadaveric specimens in this study. We surmise that the ATEHL acts as an antagonist with the EHB when the toe is extending, which might help prevent the occurrence of hallux valgus deformity., Competing Interests: CONFLICT OF INTEREST: No potential conflict of interest relevant to this article was reported., (Copyright © 2021 by The Korean Orthopaedic Association.)

In the last decade, minimally invasive or percutaneous surgery has evolved rapidly through the development of novel techniques. Treatment of hallux valgus deformity is one of the indications for percutaneous surgery, both for bony and soft tissue correction. The release of the structures on the lateral part of the first metatarsophalangeal joint (lateral release) is one of the best indications for percutaneous surgery in the forefoot. In this article, a detailed description of the anatomy of the metatarsophalangeal joint is provided, along with the indications and tips to perform a safe percutaneous lateral release., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2020 Elsevier Inc. All rights reserved.)

As the main actuator of high-speed running, the ostrich feet are highly capable of cushioning and shock absorption. In this study, based on the elastic modulus scales and assembly order of the 3rd toe soft tissues and the functions of the metatarsophalangeal (MTP) joint, we designed fourteen bio-inspired feet. The impact process on loose sand was simulated on the finite element software Abaqus. Also the stress distributions and deformations of each component of the bio-inspired feet were clarified. With the peak acceleration as the index, the cushioning performances of the bio-inspired feet were compared on both loose sand and solid ground through height-variable impact tests. The 15-15-15 HA (hardness unit) bio-inspired foot showed lower peak acceleration and thereby better cushioning performance, but larger deformation, less-uniform stress distribution and thereby lower stability than the 15-35-55 HA bio-inspired foot. In fact, the silicon rubbers with different hardness degrees (which simulate the elasticity modulus scales of the digital cushions, fascia and skin) and the spring mechanism (which simulates the functions of the MTP joint) work as an "integrated system" of cushioning and shock absorption., Competing Interests: The authors have declared that no competing interests exist.

The first metatarsophalangeal joint (MTPJ) is vital to the biomechanics of the foot and supports a weight up to eight times heavier than the body during athletic activities. The first MTPJ comprises osseous and cartilaginous surfaces along with a complex of supporting structures, including the dorsal extensor tendons, collateral ligaments, and a plantar plate complex. In contradistinction to the lesser MTPJ plantar plates, a single dominant fibrocartilaginous capsular thickening does not exist at the first MTPJ. Instead, the plantar plate complex comprises a fibrocartilaginous pad that invests the hallux sesamoids and is inseparable from the plantar capsule, the intersesamoid ligament, paired metatarsosesamoid and sesamoid phalangeal ligaments (SPLs), and the musculotendinous structures. Acute injury at the first MTPJ is typically secondary to forced hyperextension-turf toe-and can involve multiple structures. During hyperextension, the resulting forces primarily load the distal SPLs, making these structures more susceptible to injury. SPL injuries are best seen in the sagittal plane at MRI. Radiography can also aid in diagnosis of full-thickness SPL tears, demonstrating reduced sesamoid excursion at lateral dorsiflexed (stress) views. Hallux valgus is another common condition, resulting in progressive disabling deformity at the first MTPJ. Without appropriate treatment, first MTPJ injuries may progress to degenerative hallux rigidus. The authors detail the anatomy of the first MTPJ in cadaveric forefeet by using high-resolution 3-T and 11.7-T MRI and anatomic-pathologic correlation. Injuries to the plantar plate complex, collateral ligaments, and extensor mechanism are discussed using clinical case examples. Online supplemental material is available for this article. © RSNA, 2020.

Background: The windlass mechanism, first described by John Hicks in 1954, defines the anatomical and biomechanical relationship between the hallux and the plantar fascia. Hallux valgus (HV) and plantar fasciitis are the most common foot disorders, and, to date, no study has evaluated the relationship between these disorders. The purpose of this study was to determine the incidence of and factors associated with plantar fasciitis in patients with HV deformity., Methods: In this prospective observational study, 486 patients with HV were divided into three groups according to stage of HV deformity. Patient sex, age, and body mass index were recorded. Presence of accompanying plantar fasciitis and heel spur was investigated by physical and radiographic examination. First metatarsophalangeal joint dorsiflexion of the affected side was measured. Patients with or without plantar fasciitis were also compared to evaluate factors associated with plantar fasciitis., Results: Mean age and body mass index of the patients were significantly different among the three HV groups. The incidence of plantar fasciitis and heel spur significantly increased in correlation with the severity of HV deformity. Increased age and HV stage and decreased first metatarsophalangeal joint dorsiflexion were significantly associated with presence of plantar fasciitis in HV., Conclusions: In this study, the incidence of plantar fasciitis was significantly increased in correlation with the severity of HV deformity. Significant association was found between plantar fasciitis and HV, which are anatomically and biomechanically related to each other by the windlass mechanism., (American Podiatric Medical Association.)

Background: Hallux abducto valgus (HAV) is a frequently seen abnormality of the first metatarsophalangeal joint. Limited conservative treatment options exist, making surgery the only definitive treatment option for a mild to moderate deformity. Since initially published in 2008, treatment of HAV with botulinum toxin injection has evolved as a potentially effective modality as shown in several subsequent independent studies., Methods: Botulinum injection of two intrinsic foot muscles (extensor halluces brevis and flexor hallucis brevis) in addition to adductor hallucis under electrical stimulation is presented as an improvement to the original method., Results: The additional muscle injections of botulinum resulted in an further reduction of the HAV deformity and associated pain., Conclusions: A significant improvement to the injection paradigm developed the author may prove to be more effective in reducing the HAV deformity and its associated pain., (American Podiatric Medical Association.)

Historically, metatarsalgia was approached as a forefoot condition, most often associated with hallux valgus. Consequently, surgical treatments were limited to that anatomic zone, disregarding more proximal structures. In order to assess this entity properly, it is necessary to consider anatomic and biomechanical factors, as well as general and local conditions of the affected patients. A thorough understanding of the multiple potential causal factors is essential to ensure selection of the optimal treatment., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The choice of treatment of hallux valgus deformity is influenced by angles measured on radiographs. Angles of interest are the hallux valgus angle (HVA), 1,2-intermetatarsal angle (IMA), and distal metatarsal articular angle (DMAA), as well as the presence of first metatarsophalangeal joint (MTPJ) subluxation. Guidelines for measuring those angles have been distributed by American Orthopaedic Foot and Ankle Society (AOFAS), although the influence of weightbearing on these angles and its clinical relevance is not clear. We conducted a study to determine the influence of weightbearing and the inter- and intraobserver agreement in the measurement. A total of 104 patients were enrolled in this study. Both weightbearing and non-weightbearing radiographs were obtained. In 2 rounds, 2 orthopedic surgeons and 2 musculoskeletal radiologists measured the angles in blinded digital radiographs according to AOFAS guidelines. Agreement on measurement of HVA, IMA, and DMAA in both weightbearing and non-weightbearing radiographs, as well as the presence of MTPJ subluxation, was calculated using the linear-weighted kappa coefficient and the intraclass correlation coefficient (ICC). Examiner agreement strength was defined according to the guidelines of Landis and Koch. HVA decreases significantly with weightbearing, whereas IMA significantly increases. The change in magnitude was 1° to 2° on average. No significant influence on DMAA could be noted. Interobserver agreement was excellent in both weightbearing and non-weightbearing radiographs for HVA (ICC 0.99 and ICC 0.99, respectively), IMA (ICC 0.98 and ICC 0.86, respectively), and DMAA (ICC 0.95 and ICC 0.97, respectively). The agreement on presence of subluxation was moderate to good (Fleiss kappa 0.50 to 0.63). Weightbearing alters forefoot geometry significantly. Adhering to AOFAS guidelines yields excellent interobserver agreement on HVA, IMA, and DMAA. First MTPJ subluxation presence is not an alternative for DMAA. The magnitude of change in IMA and HVA is small and therefore not clinically important. Both weightbearing and non-weightbearing radiographs can be used for determination of the correct treatment of hallux valgus deformity., (Copyright © 2018 the American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Previous research has identified separate sagittal plane instantaneous centers of rotation for the metatarso-phalangeal and metatarso-sesamoid joints, but surprisingly, it does not appear that any have integrated the distinctive morphological characteristics of all three joints and their respective axes into a model that collectively unifies their functional motions. Since all joint motion is defined by its centers of rotation, establishing this in a complicated multi-dimensional structure such as the metatarso-phalangeal-sesamoid joint complex is fundamental to understanding its functionality and subsequent structural failures such as hallux abducto valgus and hallux rigidus., Methods: Based on a hypothesis that it is possible to develop an instantaneous center of rotation common to all four osseous structures, specific morphometrics were selected from a sequential series of 0.5-mm sagittal plane C-T sections in one representative cadaver specimen randomly selected from a cohort of nine, seven which were obtained from the Body Donation Program, Department of Anatomy, University of California, San Diego School of Medicine, and two which were in the possession of one author (MD). All mature skeletal specimens appeared grossly normal, shared similar morphological features, and displayed no evidence of prior trauma, deformity, or surgery. Specific C-T sections isolated the sagittal plane characteristics of the inter-sesamoidal ridge and each sesamoid groove, and criteria for establishing theoretical sesamoid contact points were established. From these data, a geometric model was developed which, to be accurate, had to closely mimic all physical and spatial characteristics specific to each bone, account for individual variations and pathological states, and be consistent with previously established metatarso-phalangeal joint functional motion., Results: Sequential sagittal plane C-T sections dissected the metatarsal head from medial to lateral and, at approximately midway through the metatarsal head, the circular nature of the inter-sesamoidal ridge (crista) was isolated; other C-T sections defined, respectively, the elliptical characteristics of the tibial (medial) and fibular (lateral) sesamoid grooves in each specimen. A general plane model representing the most basic form of the joint was developed, and its center of rotation was established with a series of tangential and normal lines. Simplified tibial sesamoid and fibular plane models were developed next which, when combined, permitted the development of a spherical model with three separate contact points. Based on the morphometrics of each sesamoid groove and a more distally positioned tibial sesamoid, the model was modified to accurately define the center of rotation and one distinctive sagittal plane geometric and functional characteristic of each groove., Conclusion: Consistent with our hypothesis, this theoretical geometric model illustrates how it is possible to define an instantaneous center of rotation common to all three joints while simultaneously accounting for morphometric and spatial variability. This should provide additional insight into metatarso-phalangeal-sesamoid joint complex functionality and the physical characteristics that contribute to its failure.

The forefoot functions as the base of support during late stance, rotating about the dual-axis of the metatarsophalangeal joints. Previous research has shown that joint axis definition affects estimated joint moments about the forefoot. However, little is known about how metatarsophalangeal joint center definition affects estimated joint kinetics. This study compared moments about the metatarsophalangeal joint using four different defined joint centers. There was a significant difference (p < .001) in peak moments between joint center definitions, differing by up to 0.488 N-m/kg for the slow and 0.878 N-m/kg for the fast running speeds tested. Additionally, there was a significant difference (p < .001) for when peak plantar flexor moment occurred during the slower running condition. The more posteriorly oriented joint centers resulted in higher moments and earlier onset of the plantar flexor moment. In addition to careful modeling of the metatarsophalangeal joint axis, it is recommended that joint center definition should be considered as well., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background:: Evaluation of patients undergoing hallux valgus surgery has historically emphasized radiographic angles and relationships. However, patient-reported outcomes are increasingly important as health care systems trend towards a "value-based" delivery approach., Methods:: We conducted a retrospective analysis of pre-existing data in our practice to examine whether patient-reported outcomes after bunion surgery, determined via Foot and Ankle Outcome Scores (FAOS), correlated with radiographic parameters commonly measured in hallux valgus deformity. Pearson correlation statistics and simple and multiple linear regression models were used to identify important radiographic predictors. There were 80 patients (80 feet) with mean follow-up of 59.3 ± 11.6 weeks (median 55, range 45.7-96.3 weeks) with complete data., Results:: No radiographic measurement/variable achieved anything more than a weak correlation with any of the FAOS subscale scores at final follow-up; the study's best was postoperative first-second intermetatarsal (IM) angle with sports and recreation scores ( r = -0.328, P = .005). There was no correlation found between change in hallux valgus angle, change in first-second IM angle, magnitude of preoperative hallux valgus angle or magnitude of preoperative first-second IM angle ( P > .05 for all). Furthermore, none of the study's final multivariable models achieved an R 2 > 0.24, and nearly all fell between 0.10 and 0.17., Conclusion:: We conclude that radiographic angles were not well correlated with patient-centered outcomes in hallux valgus surgery. This study calls into question the current emphasis that is placed on x-ray values both pre- and postoperatively., Level of Clinical Evidence:: Level III, comparative study.

Buffaloes represent a major source of milk production, especially in developing countries including Egypt. The buffalo foot is frequently involved in a large proportion of lameness cases. The relatively small size and complexity of its structures often render the radiographic evaluation of the foot challenging. Magnetic resonance imaging (MRI) is a noninvasive imaging technique that is regarded as both safe and accurate for assessment of the foot disorders in both man and animals. The purpose of the current investigation was to describe the MRI anatomy of buffalo foot using cadaveric hind feet. The feet were subjected to consecutive MRI scanning using a 0.3 Tesla scanner. Both T1-weighted (T1-W) and T2-weighted (T2-W) spin-echo pulse sequences were applied in dorsal, sagittal and transverse planes. The heterogeneity of signal intensities noted amongst foot components allowed for clear differentiation of bones, tendons, ligaments, adipose tissue and synovial fluid. The T1-W images provided an excellent overview of the foot. They were valuable for visualizing the bones and the alignment of tendons and ligaments. The T2-W images were particularly useful for the evaluation of synovial structures such as tendon sheaths and joint cavities. A communication between the two plantar sacs of the metatarsophalangeal (fetlock) joints was evident in T2-W images. MRI findings were further confirmed using relevant gross anatomical sections. The present study establishes a detailed MRI anatomic reference of buffalo foot that could help veterinary researchers, clinicians and surgeons for increasing the accuracy of interpretation of foot MRI scans of both healthy and diseased animals., (© 2018 Blackwell Verlag GmbH.)

The camel digits have a complex structure with tendons, joints and ligaments. The objective of the study was to determine the anatomical features of the metatarsophalangeal joint and its puncture site in dromedary camel using anatomical dissection, radiography, computed tomography (CT) bone and soft tissue window scans and 3D reconstruction render volume of CT. The study used six adult camels of both sexes (three males and three females), aged 9-15 years (Mean ± SD equal 11.80 ± 2.59 years). The camel fetlock possesses two metatarsophalangeal joints, left and right ones. The study described in detail the bony structures, ligaments and joint capsule of the metatarsophalangeal joint. The straight sesamoidean ligament was recorded in the studied one-humped camel joints. The joint capsule exhibited two recesses: dorsal and plantar recess. This is the first study to report the dorsal recess as triangular in outline with one proximal recess and two distal recesses, and the plantar recess as having two proximal recesses and one distal recess. The soft tissues examined around the fetlock were the proper extensor tendon, superficial, deep digital flexor tendon, digital scutum, collateral ligaments and sesamoidean ligaments. The plantar and dorsal pouches were the sites of joint injection. The present findings regarding joint injection indicate the plantar approach through plantar recess to fetlock to be preferable than the dorsal one as we used the proximal sesamoid bones and suspensory ligament as landmarks to inject easily., (© 2018 Blackwell Verlag GmbH.)

Objective: To perform an MR imaging-anatomical correlation to elucidate the anatomy of muscles, tendons, and ligaments about the hallux as seen on MR imaging., Materials and Methods: Four fresh and 4 embalmed cadaver specimens were used for this study. The embalmed specimens and one fresh specimen were dissected by three investigators. The fresh specimens were preserved deep frozen. They were thawed and imaged with a 3 T MR system. Proton density weighted images were obtained. The specimens were refrozen and sectioned with a band saw into 3 mm thick slices., Results: Musculotendinous structures were equally well seen in the fresh and embalmed specimens. The capsular ligaments could best be studied in the fresh specimens. Proximal to the sesamoids the following muscle and tendon anatomy was delineated: the abductor hallucis tendon inserted on the medial sesamoid bone together with the medial belly of the flexor digitorum brevis; the adductor hallucis (transverse and oblique heads) inserted on the lateral sesamoid together with the lateral head of the flexor hallucis brevis. At the level of the sesamoid bones and distally, the ligaments making up the plantar plate were delineated, including the presesamoid band, the flexor hallucis longus pulley, the sesamometatarsal ligaments, the sesamophalangeal ligaments, and the capsular ligaments., Conclusion: MRI allows for accurate assessment of the complex anatomy of the hallux. At the level proximal to the sesamoids the muscle and tendon insertions are well demonstrated. At the level of the sesamoids and distally, the ligaments making up 'the plantar plate' are well demonstrated., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Arthroscopy has been increasingly used to evaluate small joints in the foot and ankle. In the hallux metatarsophalangeal (MTP) joint, little data exist evaluating the efficacy of arthroscopy to visualize the articular surface. The goal of this cadaveric study was to determine how much articular surface of the MTP joint could be visualized during joint arthroscopy., Methods: Ten fresh cadaveric foot specimens were evaluated using standard arthroscopy techniques. The edges of the visualized joint surface were marked with curettes and Kirschner wires; the joints were then surgically exposed and imaged. The visualized surface area was measured using ImageJ ® software., Results: On the distal 2-dimensional projection of the joint surface, an average 57.5% (range, 49.6%-65.3%) of the metatarsal head and 100% (range, 100%-100%) of the proximal phalanx base were visualized. From a lateral view of the metatarsal head, an average 72 degrees (range, 65-80 degrees) was visualized out of an average total articular arc of 199 degrees (range, 192-206 degrees), for an average 36.5% (range, 32.2%-40.8%) of the articular arc., Conclusion: Complete visualization of the proximal phalanx base was obtained. Incomplete metatarsal head visualization was obtained, but this is limited by technique limitations that may not reflect clinical practice., Clinical Relevance: This information helps to validate the utility of arthrosocpy at the hallux metatarsophalangeal joint.

The aim of the study is to provide some characteristic parameters of the anatomy of metatarsals from computed tomography (CT) scans. These data are important for more anatomical metatarsal head resurfacing prosthesis conception. Measures were performed on 20 CT scans from 17 patients with a mean age of 44.35 ± 15.75 years old. The panel was composed of 40% male and 50% left feet. Measurements were divided in 2 distinct categories: linear measurements with length of metatarsal, head radius and head, and diaphysis and base thicknesses, and cross-sectional area measurements, including cortical and cancellous bone area at 10%, 25%, 50%, 60%, 75%, and 90% of the metatarsal's length. The results included the mean and SD found for each measured value. This study is the first step toward a better understanding of the metatarsal's anatomy, so as to design a more anatomical range of metatarsal head resurfacing implants., Levels of Evidence: Level IV.

Flexor tendons function as energy storage and shock absorption structures in the tarsometatarso-phalangeal joint (TMTPJ) of ostrich feet during high-speed and heavy-load locomotion. In this study, mechanisms underlying the energy storage and shock absorption of three flexor tendons of the third toe were studied using histology and scanning electron microscopy (SEM). Macroscopic and microscopic structures of the flexor tendons in different positions of TMTPJ were analyzed. Histological slices showed collagen fiber bundles of all flexor tendons in the middle TMTPJ were arranged in a linear-type, but in the proximal and distal TMTPJ, a wavy-type arrangement was found in the tendon of the M. flexor digitorum longus and tendon of the M. flexor perforans et perforatus digiti III, while no regular-type was found in the tendon of the M. flexor perforatus digiti III. SEM showed that the collagen fiber bundles of flexor tendons were arranged in a hierarchically staggered way (horizontally linear-type and vertically linear-type). Linear-type and wavy-type both existed in the proximal TMTPJ for the collagen fiber bundles of the tendon of the M. flexor perforatus digiti III, but only the linear-type was found in the distal TMTPJ. A number of fibrils were distributed among the collagen fiber bundles, which were likely effective in connection, force transmission and other functions. The morphology and arrangement of collagen fiber bundles were closely related to the tendon functions. We present interpretations of the biological functions in different positions and types of the tendons in the TMTPJ of the ostrich feet., (© 2017 Wiley Periodicals, Inc.)

Knowledge and command of anatomy is paramount to effectively treating disorders of the lesser metatarsophalangeal (MTP) joints. The osseous structures consist of the proximal phalanx of the toe and the metatarsal head. The soft tissues on the dorsum of the MTP joint include the joint capsule and the tendons of extensor digitorum longus and extensor digitorum brevis. The proper and accessory collateral ligaments form the medial and lateral walls and contribute to stability in the coronal and sagittal planes. The plantar plate forms the plantar border of the MTP joint and stabilizes the MTP joint against hyperextension and dorsal translation., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The aims of the present study were to describe the normal ultrasonographic, magnetic resonance imaging (MRI) and computed tomographic (CT) appearances of the bovine metacarpo/metatarsophalangeal (MCP/MTP) joints and to assess the normal cross-sectional dimensions of the superficial (SDFT) and deep (DDFT) digital flexor tendons. A systematic ultrasound examination was performed on the MCP/MTP joints of 22 healthy cattle and two bovine cadavers, and the cross-sectional dimensions of the SDFT and DDFT were recorded. The cadaveric MCP/MTP joints (n=8) were scanned using a 16-slice multi-detector CT scanner and a 1.5 Tesla MRI scanner, injected with green latex and sectioned into transverse (n=4), sagittal (n=2) and dorsal (n=2) slices. Ultrasonographic, CT and MRI images were correlated with corresponding findings in anatomical dissections for the distal aspects of the third and fourth metacarpal/metatarsal bones, proximal aspects of the proximal phalanges, proximal sesamoid bones, lateral, common and medial digital extensor tendons, SDFT, DDFT, axial and abaxial collateral ligaments, suspensory, palmar/plantar, interdigital intersesamoidean and interdigital phalangosesamoidean ligaments, and collateral, cruciate and short sesamoidean ligaments. The axial and collateral sesamoidean ligaments could not be evaluated by ultrasonography. The articular cartilage, and the short and cruciate sesamoidean ligaments, were not identified in CT images. The cross-sectional dimensions of the SDFT and DDFT differed significantly between the forelimbs and hind limbs (P<0.05); there were no significant differences between the contralateral limbs. The annotated ultrasonographic, CT and MRI images are intended as a normal reference that could be useful for interpretation of clinical disease in the bovine MCP/MTP joint., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Partite hallux sesamoids are clinically meaningful but their association with other sesamoids is not clear. The objective was to relate the prevalence of the partite hallux sesamoid bones to sesamoid bones at other metatarsophalangeal (MTP) joints. We conducted a retrospective review of plain radiographs of 7946 adult feet between November 2005 and September 2012 to identify partite hallux sesamoids and sesamoids at other MTP joints. Coexistence patterns of the partition and extra sesamoids were studied. Presence or absence of sesamoids at other MTP joints as well as sex and laterality were compared between the feet with and without partite hallux sesamoids using Pearson Chi-square test. Association between age and partition was evaluated using Spearman's correlation coefficient. Overall partite prevalence rate is 6.82%, and coexistence with extra MTP sesamoids was 0.42%. One pattern was partition in hallux sesamoid only, and 4 patterns were coexistence with extra sesamoids. The prevalence rates of partite hallux sesamoids were 7.17% (508/7081) and 3.93% (34/865) in feet without and with extra sesamoids, respectively. The relative risk of 1.889 (95% CI, 1.325-2.693) of partite hallux sesamoids was noted in feet without than with extra sesamoids (Χ 2 = 12.759, P < 0.001). A negative correlation between age and distribution of partition was identified (r = -0.061, P < 0.001). Partition of hallux sesamoid bones is a developmental variation, it can coexist with sesamoids at other MTP joints following a certain pattern; and its prevalence rate is almost twice higher in feet without than with extra MTP sesamoids. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:34-38, 2018. © 2017 Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)

Background: Second metatarsophalangeal (MTP) joint dislocation is associated with hallux valgus, and the treatment of complete dislocation can be difficult. The purpose of this study was to radiographically clarify the characteristic foot shape in the presence of second MTP joint dislocation., Methods: Weight-bearing foot radiographs of the 268 patients (358 feet) with hallux valgus were examined. They were divided into 2 groups: those with second MTP joint dislocation (study group = 179 feet) and those without dislocation (control group = 179 feet). Parameters measured included the hallux valgus angle (HVA), first-second intermetatarsal angle (IMA), second MTP joint angle, hallux interphalangeal angle (IPA), second metatarsal protrusion distance (MPD), metatarsus adductus angle (MAA), and the second metatarsal declination angle (2MDA). Furthermore, the dislocation group was divided into 3 subgroups according to second toe deviation direction: group M (medial type), group N (neutral type), and group L (lateral type)., Results: The IPA and the 2MDA were significantly greater in the study group than in the control group. By multiple comparison analysis, the IMA was greatest in group M and smallest in group L. The IPA was smaller and 2MDA greater in group N than in group L. The HVA and MAA in group L were greatest, and MPD in group L was smallest., Conclusions: The patients with second MTP joint dislocation associated with hallux valgus had greater hallux interphalangeal joint varus and a second metatarsal more inclined than with hallux valgus alone. The second toe deviated in a different direction according to the foot shape., Level of Evidence: Level III, retrospective comparative study.

We previously reported that digital tomosynthesis (DTS) is a reliable tool for evaluating bony structures of the hand. The current study aimed to identify the prevalence and distribution of sesamoid bones and accessory ossicles of the foot using DTS and to compare the results to those of conventional radiography (CR). Foot images (DTS, 213; CR, 44) of 213 patients taken at a tertiary hospital were retrospectively reviewed. Sesamoid bones were identified in the metatarsaophalangeal (MTP), distal interphalangeal (DIP) and interphalangeal (IP) joints of the great (I), second (II), third (III), fourth (IV), and fifth (V) toes. Accessory ossicles were observed in the midfoot and hindfoot. The mean number of sesamoid bones and accessory ossicles was 3.9 ± 1.3 for the left foot and 3.7 ± 1.0 for the right foot on CR; and 3.9 ± 1.4 for the left foot and 3.9 ± 1.3 for the right foot on DTS. Sesamoid bones were observed in MTP I (100%), MTP II (5%), MTP III (2%), MTP IV (2%), MTP V (14%), and IP (68%) on CR. Sesamoid bones were observed in MTP I (100%), MTP II (8%), MTP III (1%), MTP IV (2%), MTP V (25%), and IP I(65%) on DTS. Among accessory ossicles, the most common bone identified was os tibiale externum (23% on CR and 33% on DTS) andos peroneum (14% on CR and 21% on DTS), and os trigonum (32% on CR and 0.5% on DTS). DTS was useful for finding sesamoid bones and accessory ossicles, although there were some limitations in observing the hindfoot. Clin. Anat. 30:1072-1076, 2017. © 2017 Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)

The hallux valgus is a pathologic condition in the forefoot that often causes pain and functional limitations. Assessing all deformity components, such as the distal metatarsal articular angle (DMAA) is essential to hallux valgus treatment. Nevertheless, interobserver agreement of DMAA is poor on plain radiographs. The present study compared computed tomographic (CT) 3-dimensional (3D) reconstruction with plain radiographic measurements for measuring the DMAA. We included 43 consecutive patients (77 feet), diagnosed with hallux valgus at the orthopedic outpatient clinic at Hospital de Clínicas de Porto Alegre (Porto Alegre, Brazil) from April 2014 to June 2015 in our prospective study. The DMAAs were measured by 2 observers using CT 3D reconstruction. The results were compared between observers and with the plain radiographic measurements using the concordance correlation coefficient and the Bland-Altman plot to determine the agreement between the 2 methods. The interobserver agreement of the CT 3D measurements was high (concordance correlation coefficient 0.90; p < .001). Significant agreement was found between the plain radiographic and CT measurements (concordance correlation coefficient 0.667; p < .001). The Bland-Altman plot showed that the difference between the plain radiographic and CT measurements increased when greater DMAA values were associated with the presence of metatarsal rotation. The interobserver agreement of DMAA measurements was greater on CT 3D reconstruction than on plain radiography. The poor interobserver agreement of the radiographic DMAA might have resulted from metatarsal rotation., (Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

It is important to have a full appreciation of lower-extremity anatomical relationships before undertaking diabetic foot surgery. We sought to evaluate the potential for communication of the flexor hallucis longus (FHL) tendon with other pedal tendons and plantar foot compartments at the master knot of Henry and to provide cadaveric images and computed tomographic (CT) scans of such communications. Computed tomography and subsequent anatomical dissection were performed on embalmed cadaveric limbs. Initially, 5 to 10 mL (1:4 dilution) of iohexol and normal saline was injected into the FHL sheath as it coursed between the two hallux sesamoids. Subsequently, CT scans were obtained in the axial plane using a multidetector CT scanner with sagittal and coronal reformatted images. The limbs were then dissected for specific evaluation of the known variable intertendinous connections between the FHL and flexor digitorum longus (FDL) and quadratus plantae (QP) muscles. One cadaver demonstrated retrograde flow of contrast into the four individual tendons of the FDL, with observation of a large intertendinous slip between the FHL and FDL on dissection. Another cadaver demonstrated contrast filling in the QP with an associated intertendinous slip between the FHL and QP on dissection. These results indicate that the master knot of Henry (the location in the plantar aspect of the midfoot where the FHL and FDL tendons decussate, with the FDL passing superficially over the FHL) has at least the potential to serve as one source of communication in diabetic foot infections from the medial plantar compartment and FHL to the central and lateral compartments via the FDL and to the rearfoot via the QP.

Background: Extensor hallucis capsularis is an accessory extensor tendon that is sporadically observed at the medial side of the extensor hallucis longus tendon. Knowledge regarding frequency of occurrence and size of the tendon may help surgeons decide whether to use this tendon or not when tendon graft is needed during foot surgery. Conclusion: Extensor hallucis capsularis tendon was found in the vast majority of cadavers evaluated in this study. Most originated from the extensor hallucis longus tendon and inserted into the first metatarsophalangeal joint capsule. Application of this tendon as a tendon graft should be carefully considered due to variations of the length and the narrow width which may limited strength of this tendon graft., Objective: To evaluate the frequency, size, origin, and insertion of the extensor hallucis capsularis tendon in cadaveric study subjects., Material and Method: Extensor hallucis capsularis tendon was examined via dissection of 55 cadaveric feet. Thirty-six male and 19 female cadavers were included, with an age range of 33 to 90 years (mean 67.3±14.0). One foot from each study subject was dissected and evaluated (29 left feet and 26 right feet). Demographic data (gender, age, and height) and outcome data (frequency, origin, insertion, length, and width of the tendon) were recorded. Tendon measurement reliability was evaluated by intraclass correlation coefficient., Results: Extensor hallucis capsularis tendon was found in 90.9% of cadaveric subjects. Mean tendon length and width was 11.3±4.0 cm and 1.6±0.6 mm, respectively. Most tendons branched from the extensor hallucis longus tendon and attached to the first metatarsophalangeal joint capsule., Conclusion: Extensor hallucis capsularis tendon was found in the vast majority of cadavers evaluated in this study. Most originated from the extensor hallucis longus tendon and inserted into the first metatarsophalangeal joint capsule. Application of this tendon as a tendon graft should be carefully considered due to variations of the length and the narrow width which may limited strength of this tendon graft.

Hallux deformities other than hallux valgus, especially those in the sagittal plane, have not yet been elucidated in the feet of patients with rheumatoid arthritis. The objectives of the present study were to classify rheumatoid arthritis hallux deformity in both the horizontal and the sagittal planes and investigate its relationship with flatfoot. Using a cross-sectional study design, we assessed patients with rheumatoid arthritis (527 feet in 274 patients) using radiographs and classified the deformity patterns of the great toes using cluster analysis. Of the 274 patients, the range of motion in the metatarsophalangeal joint was clinically investigated in 44 (16.1%) patients. The great toes could be divided into 5 clusters according to the characteristic configuration as follows: cluster I (normal type), cluster II (hallux valgus type), cluster III (boutonniere type), cluster IV (boutonniere with hallux valgus type), and cluster V (swan-neck type). Radiographic measurements revealed the characteristic deformities of each cluster, including splayed foot for cluster II; flat foot, metatarsal primus elevatus, and plantar displacement of the proximal phalanx for cluster III; and a mixture of these characteristics for cluster IV. Plantar displacement of the proximal phalanx, which was a specific characteristic of the boutonniere deformity, correlated significantly with the decreased dorsiflexion in the metatarsophalangeal joint. Our classification method revealed the relationship of hallux deformity in the sagittal plane to flatfoot and also demonstrated the usefulness of measuring basal phalanx displacement in predicting the range of motion of the metatarsophalangeal joint., (Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

OBJECTIVE To determine and compare mean standing extension and maximum flexion angles of various joints in healthy adult alpacas and llamas, and determine the reliability of goniometric data within and between 2 observers for each joint of interest. SAMPLE 6 healthy adult llamas and 6 healthy adult alpacas. PROCEDURES The shoulder joint, elbow joint, carpal, and metacarpophalangeal (MCP) joints of the forelimbs and the hip joint, stifle joint, tarsal, and metatarsophalangeal (MTP) joints of the hind limbs were investigated. Each articulation was measured with a universal goniometer by 2 observers, who each obtained 2 measurements when each joint was maintained in standing extension and in maximal passive flexion. Two sample (unpaired) t tests were performed for comparisons of mean standing extension and maximum passive flexion angles between alpacas and llamas. Intraclass correlation coefficients were calculated for each articulation to assess interobserver and intra-observer reliability of measurements. RESULTS Llamas had larger mean standing extension angles than alpacas for the tarsal and elbow joint, but there were no significant differences between species for all other joints. For all joints, flexion measurements did not differ significantly between the 2 species. For most joints, the reliability of goniometric data between observers was good to excellent (intraclass correlation coefficients, 0.6 to 0.95) CONCLUSIONS AND CLINICAL RELEVANCE Except for the elbow joint and tarsus in extension, the angle of limb articulations during flexion and extension can be considered similar for alpacas and llamas. These measurements have relevance for veterinary surgeons when assessing joint mobility and conformation and determining appropriate angles for arthrodesis.

Background: Instability of the metatarsophalangeal (MTP) joints of the lesser toes (digiti 2-5) is increasingly being treated by repair of the plantar plate (PP). This systematic review examines the anatomy of the plantar plate of the lesser toes, and the relation between the integrity of the plantar plates of the lesser toes and lesser MTP joint stability., Methods: The databases of Embase.com, Medline (Ovid), Web of Science, Scopus, Cochrane, Pubmed not medline, Cinahl (ebsco), ProQuest, Lilacs, Scielo and Google Scholar were searched in June 2015 from inception. Studies were included if they were in English, contained primary data, and had a focus on plantar plate anatomy of the lesser toes or on the relationship between integrity of the plantar plate and MTP joint (in)stability. Study characteristics were extracted into two main tables and descriptive anatomical and histological data were summarized into one schematic 3D drawing of the plantar plate., Results: Nine studies were included in this systematic review, of which five addressed plantar plate anatomy as such and four focused directly and indirectly on plantar plate integrity related to MTP joint stability., Conclusion: This is the first systematic review regarding plantar plate anatomy related to MTP joint stability of the lesser toes. This review iterates the importance of plantar plate anatomy and integrity for MTP joint stability, and it delineates the lack of primary data regarding plantar plate anatomy of the lesser toes and MTP joint stability.

During bipedal walking, modern humans dorsiflex their forefoot at the metatarsophalangeal joints (MTPJs) prior to push off, which tightens the plantar soft tissues to convert the foot into a stiff propulsive lever. Particular features of metatarsal head morphology such as "dorsal doming" are thought to facilitate this stiffening mechanism. In contrast, chimpanzees are believed to possess MTPJ morphology that precludes high dorsiflexion excursions during terrestrial locomotion. The morphological affinity of the metatarsal heads has been used to reconstruct locomotor behavior in fossil hominins, but few studies have provided detailed empirical data to validate the assumed link between morphology and function at the MTPJs. Using three-dimensional kinematic and morphometric analyses, we show that humans push off with greater peak dorsiflexion angles at all MTPJs than do chimpanzees during bipedal and quadrupedal walking, with the greatest disparity occurring at MTPJ 1. Among MTPJs 2-5, both species exhibit decreasing peak angles from medial to lateral. This kinematic pattern is mirrored in the morphometric analyses of metatarsal head shape. Analyses of Australopithecus afarensis metatarsals reveal morphology intermediate between humans and chimpanzees, suggesting that this species used different bipedal push-off kinematics than modern humans, perhaps resulting in a less efficient form of bipedalism.

Background: Diabetic forefoot joint deformities are a known risk factor for skin breakdown and amputation, but the causes of deformity are not well understood. The purposes of this study were to determine the effects of intrinsic foot muscle deterioration and limited ankle joint mobility on the severity of metatarsophalangeal joint (MTPJ) deformity, and determine the relationships between these potential contributing factors and indicators of diabetic complications (peripheral neuropathy and advanced glycation end products)., Methods: A total of 34 participants with diabetic neuropathy (average age, 59 years; range 41-73) were studied. MTPJ angle and intrinsic foot muscle deterioration were measured with computed tomography and magnetic resonance imaging, respectively. Maximum ankle dorsiflexion was measured using kinematics. Skin intrinsic fluorescence served as a proxy measure for advanced glycation end product accumulation., Results: Total forefoot lean muscle volume (r = -0.52, P < .01) and maximum ankle dorsiflexion (r = -0.42, P < .05) were correlated with severity of MTPJ deformity. Together they explained 35% of the variance of MTPJ angle. Neuropathy was correlated with forefoot muscle deterioration (ρ = 0.53, P < .01). Skin intrinsic fluorescence was correlated to severity of neuropathy (r = 0.50, P < .01) but not maximum ankle dorsiflexion, or forefoot deterioration when controlling for neuropathy., Conclusion: These results suggest that the interplay of intrinsic foot muscle deterioration and limited ankle mobility may be the primary contributor to the development of MTPJ deformity. Identifying these muscle and ankle motion impairments as risk factors for MTPJ deformity supports the need for targeted interventions early in the disease process to slow, or possibly stop the progression of deformity over time and reduce the risk of amputation., Level of Evidence: Level IV, case series., (© The Author(s) 2015.)

Precontoured, low-profile plates with fixed dorsiflexion angles are becoming increasingly popular for first metatarsophalangeal joint fusion. We have concerns that the routine use of a precontoured plate can lead to excessive clinical dorsiflexion. The aim of our study was to investigate the relationship between the first metatarsophalangeal joint dorsiflexion intramedullary angle and the angle formed at the dorsal cortices where the plate is applied. We hypothesized that the dorsal cortical angle was significantly less dorsiflexed than the intramedullary angle. We measured both angles on lateral weightbearing radiographs of 40 consecutive individuals presenting with forefoot symptoms. The results demonstrated that the mean dorsal cortical angle was significantly smaller (mean 0.2° plantarflexion) compared with the intramedullary angle (mean 10.6° dorsiflexion; p < .001). The interobserver and intraobserver reliability of both the intramedullary and the dorsal cortical measurements was very good. In conclusion, the dorsal cortical angle is, on average, 10.8° smaller than the intramedullary angle, with a mean angle of almost 0°. This finding should be considered when selecting plates for first metatarsophalangeal joint fusion., (Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

A turf toe injury encompasses a wide spectrum of traumatic problems that occur to the first metatarsophalangeal joint. Most of these injuries are mild and respond well to nonoperative management. However, more severe injuries may require surgical management, including presence of diastasis or retraction of sesamoids, vertical instability, traumatic hallux valgus deformity, chondral injury, loose body, and failed conservative treatment., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Hallux rigidus is a painful condition of the great toe characterized by restriction of the metatarsophalangeal joint arc of motion and progressive osteophyte formation. Precise cause of hallux rigidus remains under debate. Anatomic variations and historical, clinical, and radiographic findings have been implicated in the development and progression of hallux rigidus. Radiologic findings associated with hallux rigidus include metatarsal head osteochondral defects, altered metatarsal head morphology, and an elevated hallux interphalangeus angle measure. Associated historical findings include a positive family history and history of trauma to the joint. An understanding of relevant anatomy and pathophysiology is essential during the approach to hallux rigidus treatment., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objectives: To evaluate the spectrum and frequency of MR findings of the first metatarsophalangeal joint (MTPJ) in asymptomatic volunteers., Methods: MR imaging of 30 asymptomatic forefeet was performed with a dedicated extremity 1.5-Tesla system. Participants were between 20 and 49 years of age (mean ± SD: 35.5 ± 8.4 years). Two radiologists assessed cartilage, bone, capsuloligamentous structures, and tendons of first MTPJs on MR images., Results: Cartilage defects were observed in 27 % (n = 8) of first MTPJs, most frequently located at the base of the proximal phalanx (23 %, n = 7), whereas cartilage defects of the metatarsal head (13 %, n = 4) and the metatarsosesamoid compartment were rare (0 %-3 %, n = 0-1). Bone marrow oedema-like signal changes were present in 37 % (n = 11) and subchondral cysts in 20 % (n = 6) of first MTPJs. Hyperintense areas on intermediate-weighted sequences (range: 30-43 %, n = 9-13) and on fluid-sensitive sequences with fat suppression (range: 33-60 %, n = 10-18) within the medial and lateral collateral ligament complex were common. Plantar recesses (77 %, n = 23) and distal dorsal recesses (87 %, n = 26) were frequently observed., Conclusions: Cartilage defects, bone marrow oedema-like signal changes, subchondral cysts, plantar recesses, and distal dorsal recesses were common findings on MRI of first MTPJs in asymptomatic volunteers. The collateral ligaments were often heterogeneous in structure and showed increased signal intensity., Key Points: • Cartilage defects of asymptomatic first metatarsophalangeal joints were common on MRI. • The collateral ligaments were often heterogeneous in structure and showed increased signal intensity. • Areas of increased signal intensity within the flexor and extensor tendons were rare. • These observations need to be considered in MR examinations of symptomatic cases.

Background: The anatomy of the first metatarsophalangeal (MTP) joint, particularly the metatarsosesamoid articulation, remains poorly understood. Our goal was to quantitatively define the excursion of the sesamoids., Methods: Seven cadavers were dissected to assess the articulating surfaces throughout a normal range of motion. The dissections were digitally reconstructed in various positions using a MicroScribe., Result: For first MTP joint, excursion averaged 14.7mm for the tibial sesamoid in the sagittal plane and 7.5mm for the fibular sesamoid. The sesamoids also moved medially to laterally when the joint was dorsiflexed. For the maximally dorsiflexed joint, excursion averaged 2.8mm for the tibial sesamoid and 3.5mm for the fibular sesamoid., Conclusion: Hallucal sesamoids appear to have differential tracking: the tibial sesamoid has greater longitudinal excursion; the fibular sesamoid has greater lateral excursion. The anatomical data will interest those involved with the design of an effective hallux arthroplasty., (Copyright © 2014 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.)

With mounting attention focused on decreasing postsurgical pain and dysfunction, emphasis has been placed on approaching disorders using minimally invasive techniques. Surgical procedures of the hallux, such as hallux valgus correction, have earned the reputation for high postsurgical pain and prolonged recovery. Arthroscopic hallux procedures have the advantages of minimizing pain, swelling, and disability. Certain conditions, such as synovitis, loose bodies, and early-grade hallux rigidus, are better addressed arthroscopically. With the correct indications, hallux metatarsophalangeal arthroscopy can be a valuable tool for the foot and ankle surgeon., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objective: To describe the anatomic and histologic features of the collateral ligaments (CLs) of the metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints in cadaveric limbs obtained from nonlame horses and to compare the histologic findings with the ultrasonographic appearance of the CLs., Sample: Medial and lateral CLs of the MCP and MTP joints of 28 limbs (16 forelimbs and 12 hind limbs) from 9 adult nonlame horses euthanized for reasons unrelated to the study., Procedures: 26 limbs of 8 horses were examined by ultrasonography immediately after euthanasia. Postmortem gross and histologic examinations were performed for all 28 limbs. Histologic and ultrasonographic images were graded and compared., Results: Ultrasonographically, the mean ± SD depth and width of the superficial CL were 5.1 ± 0.7 mm and 20.5 ± 1.7 mm, respectively. On histologic examination, only 125 of 319 (39%) specimens obtained from 56 medial and lateral CLs appeared normal. Histopathologic findings varied from mild changes in cellular density and collagen fiber orientation to severe fibrocartilaginous metaplasia. The degree of CL lesion severity increased distally, and the lateral CL was affected more frequently than was the medial CL. Ultrasonographically detectable abnormalities were not correlated with the histologic findings., Conclusions and Clinical Relevance: In horses, histologic abnormalities within the CLs of the MCP and MTP joints may be an adaptive response to joint hyperextension and compression and might predispose horses to desmopathy and ligament failure in the event of trauma. Ultrasonography did not detect morphologic changes of the CL matrix. For an accurate diagnosis of subclinical lesions, more sensitive imaging techniques (eg, MRI) should be considered.

Objective: To investigate the morphological features of the perforator from the first plantar metatarsal artery, so as to provide anatomic basis for the reconstruction of soft-tissue defects of the forefoot., Methods: The first metatarsophalangeal joint was chosen as the landmark on 30 human cadaveric feet prefused with red latex. The following contents were observed under surgical magnifier: (1)The origin, courses,branches,distribution of the perforator of the first plantar metatarsal artery; (2)The anastomoses among the perforator of the first plantar metatarsal artery and other arteries on the medial aspect of the foot. Simulated operation was performed on one fresh specimen., Results: The perforator of the first plantar metatarsal artery passed through the space between the tendon, the abductor hallucis and the first metatarsal bone, and its entry point into the deep fascia was located (2. 3 ± 0.7 ) cm proximal to the first metatarsophalangeal joint. The perforator anastomosed with either the medial tarsal artery, the medial anterior malleolus artery or the branch of the medial plantar artery on the superior margin of the abductor hallucis, forming a longitudinal arterial chain,through which small branches were given off to the skin of the medial aspect of the foot. The perforator was( 1. 1 ± 0.2) mm in diameter and(3.2 ± 0.2) cm in length., Conclusion: The flap based on the perforator of the first plantar metatarsal artery can be harvested as an axial flap to repair the defects of soft tissue on the forefoot.

Purpose: The aim of this article is to describe the normal arthroscopic anatomy of the lesser metatarsophalangeal (MTP) joints and compare it with that seen in open dissection in cadaveric models., Methods: We performed arthroscopic examination of 18 MTP joints of 6 normal fresh frozen feet. The second, third, and fourth MTP joints were studied because of the higher incidence of pathologic conditions found in these joints. During arthroscopy, each anatomic structure identified was named and marked with different colored sutures using straight suture needles. After the arthroscopic procedure of identification and marking, each MTP joint was dissected, and all the anatomic structures were grossly identified. With these data, the correlation between the arthroscopic and the direct visualization of a normal MTP joint was established., Results: Considering the joint regions, we found that the examination accuracy of the medial gutter was 91%, whereas the central joint accuracy reached 100% and the accuracy of the lateral gutter was 98%. The overall arthroscopic accuracy for the lesser MTP joints was 96%., Conclusions: There is a high level of anatomic accuracy at the lesser MTP joint with arthroscopy., Clinical Relevance: The high overall level of anatomic accuracy of lesser MTP joint arthroscopy (96%) allows us to consider this resource as a valuable tool in the diagnosis and treatment of these joints, expanding the spectrum of indications using this method., (Copyright © 2014 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

The plantar plate of the first metatarsophalangeal (MP) joint is a critical structure of the forefoot that has been identified as a major stabilizer within the capsuloligamentous complex. Many studies have clarified and documented the anatomy of the lesser toe MP plantar plates, but few have looked closely at the anatomy of the first MP joint. Ten cadaveric specimens were examined to identify and document the objective anatomic relationship of the plantar plate, tibial sesamoid, and surrounding osseus structures. The average distance of the plantar plate distal insertion from the joint line into the proximal phalanx was 0.33 mm. The plantar plate was inserted into the metatarsal head on average 17.29 mm proximal from the joint line. The proximal aspect of the sesamoid was 18.55 mm proximal to the distal attachment of the plantar plate to the phalanx. The distal aspect of the sesamoid averaged 4.69 mm away from the distal attachment into the proximal phalanx. The footprint of the distal plate insertion was on average 6.33 mm in length in the sagittal plane. The authors hope that these objective data measures can aid in the understanding and subsequent surgical repair of this important forefoot structure.

There is not any method to measure metatarsal protrusion in the whole metatarsal. The aim of this research is to know the normal metatarsal parabola in male and female feet. The system of measurement devised by Hardy and Clapham to evaluate the protrusion between metatarsals I and II was adapted to study the whole metatarsal parabola and applied to the five metatarsals of 169 normal feet, 72 female feet and 97 male feet. Authors measured all metatarsal protrusion relative to metatarsal II. The results obtained show a female metatarsal protrusion relative to metatarsal II of +1.27% for metatarsal I, -3.36% for metatarsal III, -8.34% for metatarsal IV, and -15.54% for metatarsal V. Data obtained for male metatarsal parabola were +0.5% for metatarsal I, -3.77 for metatarsal III, -9.57 for metatarsal IV, and -17.05 for metatarsal V. Differences between both metatarsal parabola were significant.

Objectives: To explore the anatomy of the plantar aponeurosis (PA) and its biomechanical effects on the first metatarsophalangeal (MTP) joint and foot arch., Methods: Anatomic parameters (length, width and thickness of each central PA bundle and the main body of the central part) were measured in 8 cadaveric specimens. The ratios of the length and width of each bundle to the length and width of the central part were used to describe these bundles. Six cadaveric specimens were used to measure the range of motion of the first MTP joint before and after releasing the first bundle of the PA. Another 6 specimens were used to evaluate simulated static weight-bearing. Changes in foot arch height and plantar pressure were measured before and after dividing the first bundle., Results: The average width and thickness of the origin of the central part at the calcaneal tubercle were 15.45 mm and 2.79 mm respectively. The ratio of the length of each bundle to the length of the central part was (from medial to lateral) 0.29, 0.30, 0.28, 0.25, and 0.27, respectively. Similarly, the ratio of the widths was 0.26, 0.25, 0.23, 0.19 and 0.17. The thickness of each bundle at the bifurcation of the PA into bundles was (from medial to lateral) 1.26 mm, 1.04 mm, 0.91 mm, 0.84 mm and 0.72 mm. The average dorsiflexion of the first MTP joint increased 10.16° after the first bundle was divided. Marked acute changes in the foot arch height and the plantar pressure were not observed after division., Conclusions: The first PA bundle was not the longest, widest, or the thickest bundle. Releasing the first bundle increased the range of motion of the first MTP joint, but did not acutely change foot arch height or plantar pressure during static load testing.

Flexion of the toes may be active from muscle contraction or passive from the reversed windlass function of the plantar aponeurosis. The aim of this study was to estimate the flexion moments the muscles of the foot and long digital flexors may be capable of generating and compare these calculations with published data. Magnetic resonance images were used to measure the maximal cross-sectional area of the foot muscles and long digital flexors, along with the radius of curvature of the metatarsal heads. Using known physiological data the maximal flexion moments the muscles may be able to generate at the metatarsophalangeal (MTP) joints were calculated. The methodology overestimates muscle strength and flexion moments at the metatarsophalangeal joints. The calculated maximal flexion moment at the 1st MTP joint is 4.27-6.84 Nm, for the 2nd, 3rd and 4th MTP joints 3.06-4.91 Nm, and the 5th MTP joint 0.47-0.75 Nm. The flexion moments the muscles may generate at the MTP joints do not account for the flexion forces seen in normal walking. Given that maximal strength is not used in normal walking, we conclude that the reversed windlass mechanism of the plantar aponeurosis must be important in normal function of the toes., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Footprints give an estimate of the height of an individual using gender-dependent models derived for different population and ethnic groups. However, estimation of ethnicity, age and gender from a footprint may not always be possible in forensic case work., Objectives: The present study is done to develop models for stature (height) estimation from the width of footprints in the Indian population that are independent of the age and gender of individuals., Methods: The present research was conducted on 100 young adults from different regions of India. Footprints were obtained from both feet using standard techniques. Stature, and metatarsophalangeal joint (MPJ) Width (distance across the widest part of the forefoot) and calcaneal (Calc) Width (distance across the widest section of the heel) were measured on 200 footprints. Regression models were derived for estimation of stature., Results: A positive correlation is observed between footprint measurements and stature. Regression models derived from the forefoot region give a more accurate estimate of stature than the heel region of the footprint. Multiple linear regression models gave more accurate estimates of stature than the single linear regression models., Conclusions: Regression models derived in the study for Indian population may be valuable in establishing the stature of a footprint in practical scenario when the age and gender are unknown., (Copyright © 2013 Elsevier Ltd. All rights reserved.)