The transverse arch in the human feet: A narrative review of its evolution, anatomy, biomechanics and clinical implications.

The dominant characteristics of the human foot are its shock-absorbing capability during walking or gait cycle and its adaptation to uneven surfaces. On the stance phase of the gait, the foot has to be flexible at first for shock absorption and adapt to the terrain; whereas, during the propulsive phase, it has to be dynamically rigid to function as a lever. Foot flexibility and rigidity are mainly controlled at the subtalar and midtarsal joints by tendons and ligaments. The subtalar joint is part of the longitudinal arch, but the midtarsal joint along with the tarsometatarsal joint are components of the transverse arch. However, the existence and functional role of transverse arch in human was challenged by some authors. But recent studies have revealed that the transverse arch has a predominant role in midfoot stiffness (Venkadeshan et al., 2020, & Holowoka et al., 2017). This midfoot stiffness allows the human foot to store elastic energy at the time of heel strike, which is utilized during the push-off mechanism for propulsion, thus making bipedalism more energy-efficient. Moreover, the transverse arch allows the longitudinal arch to be flexible like a lever and, at the same time, makes the arch of the foot rigid to behave like a stiff spring lever. Understanding the role of the transverse arch is obligatory to study the biomechanics of foot injuries and Charcot or diabetic foot. Studies on diabetic foot have shown that the modulation of transverse arch biomechanics and off-loading modalities would improve outcomes in the form of wound-healing and prevention of re-ulceration.

Morphological characteristics of the plantar calcaneocuboid ligaments.

BACKGROUND: The aim of this study was to clarify the differences in morphological features between the long plantar ligament (LPL) and the short plantar ligament (SPL). METHODS: This investigation examined 50 legs from 25 Japanese cadavers. The LPL and SPL of each leg were classified into one of three types based on the shape and number of fiber bundles. Then, fiber bundle length, fiber bundle width, and fiber bundle thickness were measured. RESULTS: The LPL was rectangular in shape (Type I) in 12%, hourglass shape (Type II) in 62%, and triangular in shape (Type III) in 26%. The SPL was a single fiber bundle (Type I-a) in 26%, a surface fiber bundle and a deep fiber bundle (Type I-b) in 60%, and a surface fiber bundle (medial and lateral) and a deep fiber bundle (Type II) in 14%. Regarding the morphological characteristics, there were no significant differences among the types in the LPL, but there were differences between types and between surface and deep fiber bundles in the SPL. CONCLUSIONS: For the LPL, the hourglass shape is the most common type. However, there appeared to be no functional difference due to the difference in the shape of the LPL, since there were no significant differences among the types in the LPL. For the SPL, there were types of single, double and triple fiber bundles; there may be functional differences based on the number of fiber bundles and between superficial and deep fibers.

Micromorphology and topography of tarsal joint capsule's vascular elements in cats and dogs.

Both cats and dogs belong to animals with the same type of limb support but have different nature of movement. Despite belonging to digitigrade animals, cats and dogs have a different nature of motion. While moving, the medial joint surface in cats and lateral surface in dogs carry the larger pressure. The aim of the study was to compare the similar surfaces of the cat's and dog's tarsal joint capsule and to detect differences in its histostructure and vascularisation. For the study, we used the capsule of the tarsal joint of five cats and five dogs dissected with accordance to anatomical surfaces. Sections of the capsule joint were stained with haematoxylin-eosin. The sections were examined with a microscope at magnification ×250 and ×400. The statistical analysis of the results was done using Student's t test. During the research, a difference in histostructure and vascularisation of tarsal joint capsule in cats and dogs on respective surfaces were found. The medial surface of the tarsal joint capsule was the most saturated with hemomicrocirculatory bed structures in cats, whereas this was the lateral surface in dogs. The most active metabolic processes also take place in these areas of the joint capsule, which is important to know when prescribing therapeutic procedures and determining an optimal surgical access.

The Os Peroneum incidence - A cadaveric study.

BACKGROUND: The Os Peroneum (OP) is a small sesamoid bone, which can be found in the Peroneus Longus Tendon (PLT) sheath, near the calcaneocuboid joint. Size and shape variability is quite common as well as a multipartite OP that can be found in some cases. Trying to explore and understand this variability, this study was carried out in order to provide us with answers about the presence and shape of OP in our specimens. METHODS: Twenty cadaveric lower extremities were obtained according to the body donation program of our institution. Dissections were performed to expose the OP (when present) starting proximally at the origin of the PLT and Peroneal Brevis Tendon (PBT) finalizing at the insertion of the PLT in the first metatarsal. RESULTS: In twenty feet, nine distinct OP were found, whilst six feet had a thickening of the tendon. On the remaining five foot, we did not identify an OP. CONCLUSIONS: In this study, 45% of the feet analyzed had an OP. The authors believe the variability of OP prevalence reported in the literature can be associated with differences in its definition.

Estimating the in vivo location of the talus from external surface landmarks.

OBJECTIVES: Finite element analysis has gained popularity in anthropological research to connect morphological form to measurable function but requires that loads are applied at appropriate anatomical locations. This is challenging for the ankle because the joint surfaces are not easily determined given their deep anatomical location. While the location of the talonavicular and subtalar joints can be directly determined via medical imaging, regression equations are a common, less invasive method to estimate joint locations from surface anatomy. We propose a regression-based method to locate the in vivo positions of the talonavicular and subtalar joints employing three-dimensional (3D) surface markers, such as those used routinely in gait studies. METHODS: Navicular height was measured on weight-bearing radiographs (WBR) and simulated weight-bearing computed tomography (SWCT) scans to ensure SWCT correctly simulated foot weight-bearing configuration. The location of external foot markers and internal locations of the talonavicular and posterior subtalar joint were measured on each SWCT. Stepwise regression analysis was used to select the external markers that best predicted the three internal locations. RESULTS: Navicular heights measured on WBR and SWCT scans were not statistically different (p = .44), indicating that SWCTs recreate the weight-bearing position of the foot. The navicular tubercle and medial and lateral malleoli were the best predictors of subtalar and talonavicular joint locations. These palpable anatomical locations explained more variation in internal joint location (r2 > .79; SEE < 3.0 mm) than other landmarks. DISCUSSION: This study demonstrates that external palpable landmarks can predict the location of the talonavicular and subtalar joints.

Comparative anatomy of the mouse and human ankle joint using Micro-CT: Utility of a mouse model to study human ankle sprains.

The use of mouse models as a tool to study ankle sprain requires a basic understanding of the similarities and differences between human and mouse ankle joint anatomy. However, few studies have been conducted that address the merits and drawbacks of these differences in the functioning of joints. Twenty hindfoot specimens were obtained from 10 male C57BL/6J mice and scanned using micro-CT. The foot and ankle skeletal structures were reconstructed in three dimensions. Morphological parameters were then measured using a plane projection method and normalized data were compared with those of human ankles. There was no significant difference in the malleolar width, maximal tibial thickness, tibial arc length, trochlea tali arc length or trochlea tali width of the mouse specimens compared with the human model. However, a groove was observed on the talar dome in the mouse specimens which was not observed in humans, the talar dome being more symmetric. The mouse ankle was to a large extent able to mimic the mechanism of a human ankle and so a mouse model could be appropriate for expanding our understanding of ankle biomechanics in general. However, the structural differences in the talar dome in the mouse and human should not be ignored. Although there are some differences in the mouse and human ankle that cannot be ignored, compared to other animals, the human ankle is more similar to that of the mouse.

Normal Anatomy and Traumatic Injury of the Midtarsal (Chopart) Joint Complex: An Imaging Primer.

The midtarsal (Chopart) joint complex consists of the talonavicular and calcaneocuboid joints and their stabilizing ligaments. Detailed assessment of this complex at MRI can be challenging owing to frequent anatomic variation and the small size of the structures involved. Nevertheless, a wide spectrum of pathologic conditions affect the joint complex, and its imaging evaluation deserves more thorough consideration. This review focuses on MRI evaluation of normal ligamentous anatomy and common variations about the Chopart joint, presenting practical imaging tips and potential diagnostic pitfalls. Imaging findings across a spectrum of traumatic Chopart joint injuries are also reviewed, from midtarsal sprains to Chopart fracture-dislocations. Midtarsal sprains-commonly associated with ankle inversion injuries-are emphasized, along with their often predictable radiographic and MRI injury patterns. Online DICOM image stacks are available for this article. ©RSNA, 2018.

Morphologic variations of the dorsal tarsometatarsal ligaments of the foot.

This study investigated the anatomical features of the dorsal tarsometatarsal ligaments of the foot for the purpose of analyzing the ligamentous components and classifying their types. Fifty embalmed cadaveric feet from 27 adult cadavers were dissected in this study. The dorsal tarsometatarsal ligaments comprised nine components (first cuneiform-first metatarsal, dCn1-M1; first cuneiform-second metatarsal, dCn1-M2; second cuneiform-second metatarsal, dCn2-M2; third cuneiform-second metatarsal, dCn3-M2; third cuneiform-third metatarsal, dCn3-M3; third cuneiform-fourth metatarsal, dCn3-M4; cuboid-third metatarsal, dCb-M3; cuboid-fourth metatarsal, dCb-M4; cuboid-fifth metatarsal, dCb-M5). The dCn3-M4 and dCb-M3 had not been previously reported. The dCn1-M1, dCn1-M2, dCn3-M2, dCn3-M4, and dCb-M3 had only one band, the dCn2-M2 had two bands, and the others had one or two bands. The ligaments originating from Cb attached simultaneously to M3 and M4 (4/50), M4 and M5 (7/50), or M3 and M5 (5/50), which were Y-shaped (dCb-M3, 4 and dCb-M3, 5), or V-shaped (dCb-M4, 5). The dorsal tarsometatarsal ligaments were classified into four types according to the presence of each component. In Type I (52%), Type II (36%), Type III (10%), and Type IV (2%), all components were observed except for one, two, three, and four components, respectively. The dimensions of each component were measured, and as a result the dCn1-M1 was found to be the widest and longest of the dorsal ligaments while the dCn1-M2 was found to be the thickest. The dorsal tarsometatarsal ligaments comprised nine components and were classified into four types. Clin. Anat. 32:212-217, 2019. © 2018 Wiley Periodicals, Inc.

Effect of plano-valgus foot posture on midfoot kinematics during barefoot walking in an adolescent population.

BACKGROUND: Plano-valgus is a common alteration of the paediatric foot, characterized by valgus hindfoot, foot pronation and drop of the medial longitudinal arch. Despite their importance in the diagnosis and classification of plano-valgus foot condition, little information is available on functional alterations of the major joints spanning the medial longitudinal arch - i.e. midtarsal and tarso-metatarsal. Aim of the study was to provide objective description of the alterations in plano-valgus midfoot joints with respect to those in an age-matched normally-developed feet population. METHODS: Twenty adolescents (13.3 ± 0.8 years) with bilateral plano-valgus feet underwent clinical examination and were gait-analysed via a validated 4-segment foot model. This allowed to measure static foot posture, kinematics of the main foot joints, and medial longitudinal arch deformation during walking at comfortable speed. Range of motion and temporal profiles of joint rotations were compared to those from a control population of age-matched adolescents with normally-developed feet. RESULTS: The plano-valgus midtarsal joint was more dorsiflexed, everted and abducted than that in the control group, and showed reduced sagittal-plane RoM (plano-valgus = 15.9 degrees; control = 22.2 degrees; P <  0.01). The tarso-metarsal joint was more plantarflexed and adducted, and showed larger frontal-plane RoM. The MLA showed larger RoM and was lower throughout the stance phase of the gait cycle. CONCLUSION: Significant postural and kinematic alterations are present at the midtarsal and tarso-metarsal joints of adolescents with plano-valgus feet. Objective identification and quantification of plano-valgus foot alterations, via non-invasive gait-analysis, is relevant to improving the diagnosis of this condition and to evaluating the effect of conservative treatments and of surgical corrections by different techniques.

Imaging of Chopart (Midtarsal) Joint Complex: Normal Anatomy and Posttraumatic Findings.

OBJECTIVE: The objective of this article is to review the normal anatomy and posttraumatic findings of the Chopart joint complex. Key imaging features of the normal ligaments and patterns of ligamentous and osseous injuries are discussed. CONCLUSION: Traumatic midtarsal injuries, particularly midtarsal sprain, are often overlooked clinically and on imaging but are relatively common and typically are associated with inversion ankle injuries. Radiologists should be familiar with Chopart joint anatomy and the imaging features of midtarsal injuries because early diagnosis may help optimize clinical management.

Normative size of the osseous part of calcaneal bursa and its comparison with other calcaneal articular areas.

The retro-calcaneal bursa presents a synovial and a non-synovial osseous part of variable dimensions. Studies objectively measuring the variability of the size of this osseous bursal surface cannot be found in literature. The objective of this study was to investigate (i) the dimension variability of the bony part of the bursa and (ii) the relationship of this surface to other articulating areas of the calcaneus. A digital planimeter was used to measure the bursae (n=86) and other articular surface areas of the calcaneus and statistically compared with ANOVA and correlation estimations. The osseous area measured 1.12 (±0.55) cm2, with only the superior articulating area demonstrating a weak correlation to this osseous surface. The osseous area presents a weak correlation with the axial articulating area of the calcaneus. Information on the size of the bony bursa may help safe excision of retrocalcaneal exostoses and in Achille's tendon repair around the posterior tuberosity.

Anatomic Description of the Naviculocuneiform Articulation.

The naviculocuneiform articulation is composed of the navicular proximally and the 3 cuneiforms distally. It is not uncommon to perform surgical interventions at this joint for multiple pathologic foot etiologies. To date, no detailed anatomic measurement is available for each cuneiform articulation on the navicular. The purpose of the present study was to present an anatomic description of this complex joint to aid in better surgical understanding and improve surgical outcomes. Ten fresh, frozen, and thawed below-the-knee cadaveric specimens were used for anatomic dissection of the navicular and associated cuneiforms. The height and width were recorded across the largest span of the entire navicular-cuneiform joint complex and each facet. The mean navicular height and width was 19.9 mm and 34.7 mm, respectively. The medial cuneiform facet mean height and width was 19.9 mm and 15.8 mm, respectively. The intermediate cuneiform facet mean height and width was 20.4 mm and 16.9 mm, respectively. The lateral cuneiform facet mean height and width was 17.5 mm and 14.7 mm, respectively. A detailed description of this joint complex will aid foot and ankle surgeons in screw placement and surgical decision-making when performing complex medial column fusions. Advanced 3-dimensional weightbearing computed tomography would give us a better idea of the motion that occurs within this complex joint.

Talonavicular joint arthroscopic portals: A cadaveric study of feasibility and safety.

BACKGROUND: The objectives of the study were to evaluate the safety of hypothetical arthroscopic portals from talonavicular joint and to evaluate their reproducibility and enforceability. METHODS: 19 cadaveric feet were marked and four arthroscopic portals were made (medial, dorsomedial, dorsolateral and lateral). The specimens were dissected in layers and the distances between neurovascular structures and the trocars were measured. RESULTS: Medial and dorsomedial portals were in average 8.3 and 8.7, respectively, to the saphenous vein and nerve. Dorsolateral portal was in average 8.1mm to the deep peroneal nerve and dorsalis pedis artery, and 9.1mm to the medial dorsal cutaneous branch of the superficial peroneal nerve. Lateral portal was in average 12.3mm to the intermediate dorsal cutaneous branch of the superficial peroneal nerve. CONCLUSION: Tested portals shown to have a good safety margin for the foot neurovascular deep dorsal structures and an acceptable safety margin for the superficial neurovascular structures.

Subchondral bone density distribution of the talus in clinically normal Labrador Retrievers.

BACKGROUND: Bones continually adapt their morphology to their load bearing function. At the level of the subchondral bone, the density distribution is highly correlated with the loading distribution of the joint. Therefore, subchondral bone density distribution can be used to study joint biomechanics non-invasively. In addition physiological and pathological joint loading is an important aspect of orthopaedic disease, and research focusing on joint biomechanics will benefit veterinary orthopaedics. This study was conducted to evaluate density distribution in the subchondral bone of the canine talus, as a parameter reflecting the long-term joint loading in the tarsocrural joint. RESULTS: Two main density maxima were found, one proximally on the medial trochlear ridge and one distally on the lateral trochlear ridge. All joints showed very similar density distribution patterns and no significant differences were found in the localisation of the density maxima between left and right limbs and between dogs. CONCLUSIONS: Based on the density distribution the lateral trochlear ridge is most likely subjected to highest loads within the tarsocrural joint. The joint loading distribution is very similar between dogs of the same breed. In addition, the joint loading distribution supports previous suggestions of the important role of biomechanics in the development of OC lesions in the tarsus. Important benefits of computed tomographic osteoabsorptiometry (CTOAM), i.e. the possibility of in vivo imaging and temporal evaluation, make this technique a valuable addition to the field of veterinary orthopaedic research.

Joint-Sparing Corrections of Malunited Chopart Joint Injuries.

Treatment of malunion and nonunion at the Chopart joint aims at axial realignment of the midfoot to the hindfoot and restoration of the normal relationship of the lateral and medial columns of the foot. In carefully selected patients with intact cartilage, joint-preserving osteotomies are feasible at all 4 bony components of the Chopart joint to restore near-normal function. Priority should be given to the anatomic reconstruction of the talonavicular joint because it is essential for global foot function. Patients must be counseled about the risk of progressive arthritis or osteonecrosis necessitating late fusion.

Anatomic Parameters of the Lisfranc Joint Complex in a Radiographic and Cadaveric Comparison.

Subtle injuries to the Lisfranc joint complex are difficult to diagnose clinically and radiographically and can ultimately result in obvious disability if misdiagnosed. However, no previous study has shown the true mean average distance between the base of the first and second metatarsals (the Lisfranc distance). Therefore, in the present study, the anatomic and radiographic parameters of the Lisfranc joint were studied in detail to assist in the evaluation of Lisfranc injuries. The parameters of the Lisfranc joint complex in 100 normal volunteers and 10 cadavers were measured, including the medial, lateral depth of the mortise joint, width and height of the second metatarsal base, and distance between the base of the first and second metatarsals. The mean average Lisfranc distance was 0.24 ± 0.06 mm in the left foot and 0.25 ± 0.06 mm in the right foot for the radiographic group (p = .089) and 0.39 ± 0.04 mm in the left foot and 0.37 ± 0.04 mm in the right foot for the cadaver group (p = .129). The medial depth and Lisfranc distance in the radiographic group were smaller than the same measurements in the cadaver group, and these differences were statistically significant (medial depth, p < .001; Lisfranc distance, p < .001). The lateral depth and second metatarsal height in the radiographic group were larger than the same measurements in the cadaver group, and these differences were statistically significant (lateral depth, p < .001; second metatarsal height, p < .001). The second metatarsal width was the same in the 2 groups (p = .651). In conclusion, if the Lisfranc distance is >3.0 mm radiographically, a subtle injury to the Lisfranc joint should be highly suspected. No test of stability was performed between shallow and narrow versus deeper and broader Lisfranc mortise configurations. We merely speculated that a deeper and wider mortise is likely to be more stable than one that is shallow and narrow, probably owing to the presence of broader ligaments.

The peroneocuboid joint: morphogenesis and anatomical study.

The peroneocuboid joint, between the peroneus longus tendon and the cuboid bone, has not been anatomically well-defined and no embryological study has been published. Furthermore, the ossification of the os peroneum (a sesamoid inside the peroneus longus tendon) and its associated pathology has been considered to be generated by orthostatic and/or mechanical loads. A light microscopy analysis of serially sectioned human embryonic and fetal feet, the analysis of human adult feet by means of standard macroscopic dissection, X-ray and histological techniques have been carried out. The peroneus longus tendon was fully visible until its insertion in the 1st metatarsal bone already at embryonic stage 23 (56-57 days). The peroneocuboid joint cavity appeared at the transition of the embryonic to the fetal period (8-9th week of gestation) and was independent of the proximal synovial sheath. The joint cavity extended from the level of the calcaneocuboid joint all the way to the insertion of the peroneus longus tendon in the 1st metatarsal bone. The frenular ligaments, fixing the peroneus longus tendon to the 5th metatarsal bone or the long calcaneocuboid ligament, developed in the embryonic period. The peroneus longus tendon presented a thickening in the area surrounding the cuboid bone as early as the fetal period. This thickening may be considered the precursor of the os peroneum and was similar in shape and in size relation to the tendon, to the os peroneum observed in adults. To the best of our knowledge, this is the first study to show that the os peroneum, articular facets of the peroneus longus tendon and cuboid bone, the peroneocuboid joint and the frenular ligaments appear during the embryonic/fetal development period and therefore they can not be generated exclusively by orthostatic and mechanical forces or pathological processes.

Lisfranc injuries.

Lisfranc injuries are commonly asked about in FRCS Orthopaedic trauma vivas. The term "Lisfranc injury" strictly refers to an injury where one or more of the metatarsals are displaced from the tarsus. The term is more commonly used to describe an injury to the midfoot centred on the 2nd tarsometatarsal joint. The injury is named after Jacques Lisfranc de St. Martin (1790-1847), a French surgeon and gynaecologist who first described the injury in 1815. 'Lisfranc injury' encompasses a broad spectrum of injuries, which can be purely ligamentous or involve the osseous and articular structures. They are often difficult to diagnose and treat, but if not detected and appropriately managed they can cause long-term disability. This review outlines the anatomy, epidemiology, classification, investigation and current evidence on management of this injury.

An anatomical study comparing two surgical approaches for isolated talonavicular arthrodesis.

BACKGROUND: Two operative approaches are commonly used for isolated talonavicular arthrodesis: the medial and the dorsal approach. It is recognized that access to the lateral aspect of the talonavicular joint can be limited when using the medial approach, and it is our experience that using the dorsal approach addresses this issue. We performed an anatomical study using cadaver specimens, to compare the amount of articular surface that can be accessed by each operative approach. METHODS: Medial and dorsal approaches to the talonavicular joint were performed on each of 11 cadaveric specimens (10 fresh frozen, 1 embalmed). Distraction of the joint was performed as used intraoperatively and the accessible area of articular surfaces was marked for each of the 2 approaches using a previously reported technique. Disarticulation was performed and the marked surface area was quantified using an immersion digital microscribe, allowing a 3-dimensional virtual model of the articular surfaces to be assessed. RESULTS: The median percentage of total accessible talonavicular articular surface area for the medial and dorsal approaches was 71% and 92%, respectively (Wilcoxon signed-rank test, P < .001). CONCLUSION: This study provides quantifiable measurements of the articular surface accessible by the medial and dorsal approaches to the talonavicular joint. CLINICAL RELEVANCE: These data support for the use of the dorsal approach for talonavicular arthrodesis, particularly in cases where access to the lateral half of the joint is necessary.

Talonavicular arthroscopy for osteochondral lesions: technique and case series.

BACKGROUND: Traditional treatment of talonavicular osteochondral lesions (OCLs) requires an open procedure. Arthroscopic microfracture of talonavicular OCLs may provide a viable, minimally invasive approach. The purpose of this study was to describe an arthroscopic approach for treatment of talonavicular OCLs, describe the proximity of arthroscopic portals to important structures in cadaver specimens, and report magnetic resonance imaging (MRI) findings and clinical outcomes of this technique. METHODS: Five cadaver specimens were dissected so proximity of portals to adjacent tendons and neurovascular structures could be assessed. Subsequently, 3 athletic patients with OCLs of the talonavicular joint were treated with arthroscopic debridement and microfracture. Patient records and imaging studies were retrospectively reviewed. RESULTS: In the cadaver specimens, the mean distance between the neurovascular bundle and the medial border of the extensor hallucis longus (EHL) was 9.0 (range, 8 to 10) mm. The saphenous nerve was located a mean of 6.8 (range, 6 to 7) mm from the medial border of the tibialis anterior tendon. Therefore, portals were placed just medial to the EHL and tibialis anterior tendon to avoid the neurovascular bundle and saphenous nerve, respectively. In all patients, access, identification of the OCL, debridement, and microfracture were successfully performed. All patients demonstrated improvements in Foot and Ankle Outcome Scores and Short Form-12 scores and began gradual return to activity within 12 weeks following the operation. No significant complications occurred. MRI indicated signal consistent with reparative fibrocartilage in all patients. CONCLUSION: Talonavicular arthroscopy allowed visualization, curettage, synovectomy, loose body removal, and microfracture of OCLs that would have otherwise required an open approach. At early follow-up, all patients had returned to their previous activity levels. Arthroscopy of the talonavicular joint was a viable approach for microfracture of OCLs. LEVEL OF EVIDENCE: Level IV, case series.