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This study aimed to elucidate the relationship between joint structures of the first tarsometatarsal and articular facet degeneration. A total of 100 feet from 50 cadavers were examined. The articular facets of the first metatarsal and medial cuneiform were categorized into four types based on the superior and inferior facets' separation, and the formation of the inferior lateral facet on the lateral plantar prominence: Type I, a single facet with no separation or inferior lateral facet; Type II-a, two facets with separation but no inferior lateral facet; Type II-b, two facets, no separation, but with an inferior lateral facet; Type III, three facets with separation and an inferior lateral facet. When both bone types matched, they were defined as Type I, Type II-a, Type II-b, and Type III joints, respectively; unmatched types were classified as Unpair joints. The severity of articular cartilage degeneration on both bones was assessed using a 5-point scale. The degeneration grade was compared among joint types. Type III joints exhibited significantly milder articular cartilage degeneration in medial cuneiform compared to Type II-a, II-b, Unpair joints. The formation of inferior lateral facet and separation of the superior and inferior facets might be crucial for the joint's stability., (© 2024. The Author(s).)

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., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

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.

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., (© 2020 Wiley-VCH GmbH.)

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., (Copyright © 2019 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.)

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 (r 2  > .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., (© 2019 Wiley Periodicals, Inc.)

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.

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., (© 2018 Wiley Periodicals, Inc.)

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.

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., Competing Interests: Acknowledgement of the Hospital’s IRB was granted (protocol n° 7/17) and parents’ informed consent was obtained for all children recruited in the study.Parents’ consent to publish was granted.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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.

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., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

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., (Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2015 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.)

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.

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., (Copyright © 2016 Elsevier Inc. All rights reserved.)

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., (Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

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., (© 2014 Anatomical Society.)

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., (© The Author(s) 2014.)

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., (© The Author(s) 2014.)

Background: There is heterogeneity in the literature regarding the anatomy and number of ligamentous bands that form the deltoid ligament (DL). Anatomic knowledge of the DL and its variations are important for surgeons who repair ankle fractures., Methods: The DL was dissected in 33 ankles from 17 formalin-fixed cadavers (mean age at death, 76.6 years) to examine its morphology. The length, width, and thickness of its constituent bands were recorded with a digital caliper. Descriptive and correlational statistics were used to investigate the relationships between band size, age at death, and sex. A literature review was conducted to compare our data to those of previous studies., Results: The DL has superficial and deep layers with up to 8 different bands., Conclusion: The DL stabilizes the medial ankle and should be evaluated in flatfoot deformities and severe ankle fractures., Clinical Relevance: Anatomic knowledge of DL variations should aid the surgeon in repairing torn DLs., (© The Author(s) 2014.)

During terrestrial locomotion, chimpanzees exhibit dorsiflexion of the midfoot between midstance and toe-off of stance phase, a phenomenon that has been called the "midtarsal break." This motion is generally absent during human bipedalism, and in chimpanzees is associated with more mobile foot joints than in humans. However, the contribution of individual foot joints to overall foot mobility in chimpanzees is poorly understood, particularly on the medial side of the foot. The talonavicular (TN) and calcaneocuboid (CC) joints have both been suggested to contribute significantly to midfoot mobility and to the midtarsal break in chimpanzees. To evaluate the relative magnitude of motion that can occur at these joints, we tracked skeletal motion of the hindfoot and midfoot during passive plantarflexion and dorsiflexion manipulations using cineradiography. The sagittal plane range of motion was 38 ± 10° at the TN joint and 14 ± 8° at the CC joint. This finding indicates that the TN joint is more mobile than the CC joint during ankle plantarflexion-dorsiflexion. We suggest that the larger range of motion at the TN joint during dorsiflexion is associated with a rotation (inversion-eversion) across the transverse tarsal joint, which may occur in addition to sagittal plane motion., (© 2014 Wiley Periodicals, Inc.)

Objective: To evaluate the technical feasibility, efficacy and potential soft tissue damage of a joint distraction technique to facilitate arthroscopy of the tibio-tarsal joint and to test the effect of joint venting on the maximum distraction achieved., Methods: Twenty hocks were preliminarily evaluated radiographically by standard and stressed projections. Joint distraction was applied with loads from 40 N up to 200 N, in 40 N increments, and radiographic images were obtained at each load. The effect of joint venting by an intra-articular needle was evaluated at the maximum load. Standard and stressed radiographs were repeated to evaluate potential laxity changes., Results: Joint distraction caused a significant increase in the joint space at each load of distraction except for the 40 to 80 N load increase. Joint venting produced a significant increase in the joint space. No increase of joint laxity could be inferred from the postdistraction radiographic evaluation., Clinical Significance: Hock distraction can be useful to facilitate arthroscopic procedures, increasing the joint space available for intra-articular manoeuvres. Further clinical studies are required to evaluate potential neurovascular complications., (© 2014 British Small Animal Veterinary Association.)

Objective: The aim of this study was to establish normal reference values of the forelimb and hindlimb joint angles in normal Holstein calves., Methods: Thirty clinically normal Holstein calves that were free of any detectable musculoskeletal abnormalities were included in the study. A standard transparent plastic goniometer was used to measure maximum flexion, maximum extension, and range-of-motion of the shoulder, elbow, carpal, hip, stifle, and tarsal joints. The goniometric measurements were done on awake calves that were positioned in lateral recumbency. The goniometric values were measured and recorded by two independent investigators., Results: As a result of the study it was concluded that goniometric values obtained from awake calves in lateral recumbency were found to be highly consistent and accurate between investigators (p <0.05)., Clinical Significance: The data of this study acquired objective and useful information on the normal forelimb and hindlimb joint angles in normal Holstein calves. Further studies can be done to predict detailed goniometric values from different diseases and compare them.

Six cadaver pelvic limbs were obtained from clinically sound dromedary camels and examined radiographically and ultrasonographically using a 7.5 MHz convex transducer. Radiographic examination was performed in dorsoplantar, lateromedial, dorsolateral-plantaromedial oblique and plantarolateral-dorsomedial oblique projections, and the bony structures and articulations of the tarsal joint were outlined. The tarsus was ultrasonographically investigated in four planes (dorsal, medial, lateral and plantar), and each plane was scrutinized in four levels (calcaneal tuber, tibial malleoli, base of calcaneus and proximal end of metatarsus) in both transverse and longitudinal views. Limbs were examined grossly, frozen at -20°C and sectioned. Radiographic and ultrasonographic findings correlated well with the gross anatomy and frozen sections. The normal appearance of bony and soft structures of the tarsus described in this study provided basic reference data for ultrasonographic and radiographic investigations of tarsal disorders in the dromedary camel., (© 2012 Blackwell Verlag GmbH.)

The Evans lateral column lengthening procedure allows correction of abduction, improved talar head coverage, decreased forefoot and rearfoot valgus, and improvement of medial column arch height. However, identifying the structures at risk when performing this osteotomy has proved difficult in vivo. Using 10 cadaveric lower limbs, we performed the Evans calcaneal osteotomy and determined whether violation of the calcaneal facets and the sustentaculum tali occurred. Based on our findings, we recommend directing the osteotomy from posterolateral to anteromedial., (Copyright © 2013 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

The purpose of this study was to provide a detailed computed tomographic (CT) anatomic reference for the dromedary camel tarsus. Six cadaver pelvic limbs, obtained from three clinically and radiographically sound dromedary camels, were scanned in both soft tissue and bone windows starting from the calcaneal tuber towards the proximal metatarsus. Limbs were frozen at -20°C and sectioned transversely via an electric bone saw. The CT images were evaluated and correlated with their corresponding cryosections. The resulting images provided detailed anatomic features for bones, joints and soft tissue components of the tarsus and are intended to serve as a basic reference for the CT scanning of the dromedary camel tarsal pathology., (© 2012 Blackwell Verlag GmbH.)

The absence of a midtarsal break has long been regarded as a derived feature of the human foot. Humans possess a rigid midfoot that acts as an efficient lever during the propulsive phase of bipedal gait. Non-human primates, in contrast, have a more mobile midfoot that is adaptive for tree climbing. Here, we report plantar pressure and video evidence that a small percentage of modern humans (n = 32/398) possess both elevated lateral midfoot pressures and even exhibit midfoot dorsiflexion characteristic of a midtarsal break. Those humans with a midtarsal break had on average a significantly flatter foot than those without. Midtarsal breakers also had significantly more medial weight transfer (pronation) during the stance phase of gait than those without this midfoot mobility. These data are in accordance with Elftman (Clin Orthop 16 (1960) 41-45) who suggested that pronation aligns the axes of the transverse tarsal joint, permitting elevated midfoot mobility., (Copyright © 2013 Wiley Periodicals, Inc.)

Objective: To describe the arthroscopically accessible anatomy of the tarsal collateral ligaments in the horse., Study Design: Descriptive study., Animals: Cadaveric equine hind limbs (n = 24) obtained from horses without tarsal disease., Methods: Two pairs of tarsal joints were used to obtain silicone models of the tarsocrural joint and dissect the tarsal collateral ligaments (CLs). Ten pairs of tarsocrural joints had arthroscopic exploration and the accessible parts of the tarsal CLs were marked with an arthroscopic hook knife. Subsequently, the limbs were dissected and the marked positions were allocated to the specific parts of the CLs., Results: Ipsilateral arthroscope and instrument portals were used in each pouch of the tarsocrural joint. Via the plantaromedial pouch, the superficial (2/20 limbs), middle (7), deep (6) or both middle and deep (3) short medial CL and the long medial CL (14) were reached. Access via the plantarolateral pouch allowed manipulation of the deep short lateral CL (20/20 limbs) and the long lateral CL (20). Dorsally, arthroscopy via the dorsomedial pouch gave access to the deep short medial CL (20/20 limbs), while the superficial (9) or middle (10) or both superficial and middle (1) short lateral CL could be reached via the dorsolateral joint recess., Conclusions: Limited parts of the tarsal CLs can be observed or manipulated arthroscopically in normal equine tarsocrural joints., (© Copyright 2013 by The American College of Veterinary Surgeons.)

The trephine arthrodesis technique has been shown to be an effective method for various foot and ankle fusion procedures, with acceptable rates of fusion reported. The tarsometatarsal joints are an excellent example for this procedure because of the joint shape and soft tissue stability. The success of this procedure depends on many factors, but a large consideration is adequate joint resection. A cadaveric study to examine the joint depth of the Lisfranc complex was undertaken, allowing for improved understanding of the resection needed to maintain a stable plantar cortex while removing all apposing joint surfaces. A statistical analysis was then performed to determine the significance of the joint depth to available demographic data. A total of 51 limbs were evaluated for the depth of the first, second, and third metatarsal-cuneiform joints. The average joint depth for the first through third metatarsal-cuneiform joints was 32.3, 26.9, and 23.6 mm, respectively. The plantar cortex depth was less than 2 mm for the first through third metatarsal-cuneiform joints. The correlation between the length of the foot and the joint depth was statistically significant. Subgroups stratified by shoe size were analyzed for differences in joint size and were also statistically significant. A better understanding of the tarsometatarsal joint anatomy would benefit the trephine technique for Lisfranc arthrodesis., (Copyright © 2012 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: To compare computed tomography (CT) images of equine tarsi with cross-sectional anatomic slices and evaluate the potential of CT for imaging pathological tarsal changes in horses., Sample: 6 anatomically normal equine cadaveric hind limbs and 4 tarsi with pathological changes., Procedures: Precontrast CT was performed on 3 equine tarsi; sagittal and dorsal reconstructions were made. In all limbs, postcontrast CT was performed after intra-articular contrast medium injection of the tarsocrural, centrodistal, and tarsometatarsal joints. Images were matched with corresponding anatomic slices. Four tarsi with pathological changes underwent CT examination., Results: The tibia, talus, calcaneus, and central, fused first and second, third, and fourth tarsal bones were clearly visualized as well as the long digital extensor, superficial digital flexor, lateral digital flexor (with tarsal flexor retinaculum), gastrocnemius, peroneus tertius, and tibialis cranialis tendons and the long plantar ligament. The lateral digital extensor, medial digital flexor, split peroneus tertius, and tibialis cranialis tendons and collateral ligaments could be located but not always clearly identified. Some small tarsal ligaments were identifiable, including plantar, medial, interosseus, and lateral talocalcaneal ligaments; interosseus talocentral, centrodistal, and tarsometatarsal ligaments; proximal and distal plantar ligaments; and talometatarsal ligament. Parts of the articular cartilage could be assessed on postcontrast images. Lesions were detected in the 4 tarsi with pathological changes., Conclusions and Clinical Relevance: CT of the tarsus is recommended when radiography and ultrasonography are inconclusive and during preoperative planning for treatment of complex fractures. Images from this study can serve as a CT reference, and CT of pathological changes was useful.

The transition to full-time terrestrial bipedality is a hallmark of human evolution. A key correlate of human bipedalism is the development of longitudinal and transverse arches of the foot that provide a rigid propulsive lever and critical shock absorption during striding bipedal gait. Evidence for arches in the earliest well-known Australopithecus species, A. afarensis, has long been debated. A complete fourth metatarsal of A. afarensis was recently discovered at Hadar, Ethiopia. It exhibits torsion of the head relative to the base, a direct correlate of a transverse arch in humans. The orientation of the proximal and distal ends of the bone reflects a longitudinal arch. Further, the deep, flat base and tarsal facets imply that its midfoot had no ape-like midtarsal break. These features show that the A. afarensis foot was functionally like that of modern humans and support the hypothesis that this species was a committed terrestrial biped.

Purpose: The purpose of this study was to examine the safety and access talonavicular arthroscopy provides for the purpose of arthrodesis through dorsomedial and dorsolateral portals in a cadaveric model., Methods: The talonavicular joints of 8 cadaveric specimens were arthroscopically debrided, by use of a dorsomedial instrumentation portal and a dorsolateral visualization portal. The specimens were dissected with the arthroscopic equipment left in place, the distances from the edge of the instrument to the neurovascular structures were measured, and the specimens were then examined for signs of damage. Finally, the naviculars and tali were removed, and the percentage of debrided subchondral bone was determined by use of ImageJ software (National Institutes of Health, Bethesda, MD)., Results: Examination of the talonavicular joint showed mean subchondral debridement of 98.6% of the navicular and 83.2% of the talus. The dorsomedial portal had a median distance of 4.5 mm, 10.5 mm, and 7 mm to the superficial peroneal nerve, the medial terminal branch of the deep peroneal nerve, and the dorsalis pedis, respectively. The dorsolateral portal had a median distance of 1 mm to the lateral branch of the deep peroneal nerve, with the nerve found resting on the arthroscope in 2 specimens., Conclusions: Arthroscopic debridement of the talonavicular joint is possible. Because of the risk of damage to the lateral terminal branch of the deep peroneal nerve, an alternative to the dorsolateral portal should be considered., Clinical Relevance: This study provides evidence that arthroscopic assisted talonavicular arthrodesis is possible but that further research is needed to ensure the safety of the technique., (Copyright © 2011 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

The midfoot plays a vital role in the stability of the foot as a whole. Injuries to the midfoot may be subtle and can lead to significant long-term morbidity, especially where there is a delay in diagnosis and treatment. This article describes the anatomy of the midfoot that is relevant to surgical practice. It should provide the reader with an understanding of how the anatomy of the midfoot relates to its function as well as discussing the anatomical considerations of injuries and surgery in this area. Anatomical knowledge aids clinical practice in terms of the recognition of abnormalities and the guidance of treatment.

Objective: The objective of our study was to clarify the detailed anatomy of the transverse tarsal joint ligamentous complex and evaluate the diagnostic capability of MRI in the assessment of the tarsal joint complex with detailed anatomic correlation in cadavers., Materials and Methods: Ten fresh cadaveric feet were studied with high-spatial-resolution MRI before and after intraarticular injection of a gadopentetate dimeglumine solution. MR images were evaluated by two readers, with an emphasis on the visibility of ligamentous structures and their appearance and signal intensity. Readers also measured the dimensions (length, width, and thickness) of the different components of the spring ligament complex, bifurcate ligament, and plantar calcaneocuboid ligaments. For anatomic analysis, nine cadaveric specimens were sectioned in 3-mm-thick slices in the same planes used for MRI. One additional foot specimen was used for dissection., Results: In all 10 cadaveric specimens, we were able to identify the various ligamentous elements, their different configurations, imaging characteristics, and contributions to the overall stability of the transverse tarsal joint complex., Conclusion: By clearly defining the normal ligaments that contribute to the stability of the calcaneocuboid joint, MRI allows a more precise and correct diagnosis of the etiology of the calcaneocuboid instability, perhaps permitting a more specific surgical management. MRI also allows a better understanding of the normal imaging anatomy of the different components of the ligamentous structures of the talocalcaneonavicular joint, particularly of the spring ligament complex.

The ostrich (Struthio camelus) is the largest extant biped. Being flightless, it exhibits advanced cursorial abilities primarily evident in its characteristic speed and endurance. In addition to the active musculoskeletal complex, its powerful pelvic limbs incorporate passive structures wherein ligaments interact with joint surfaces, cartilage and other connective tissue in their course of motion. This arrangement may enable energy conservation by providing joint stabilisation, optimised limb segment orientation and automated positioning of ground contact elements independently of direct muscle control. The intertarsal joint is of particular interest considering its position near the mid-point of the extended limb and its exposure to high load during stance with significant inertial forces during swing phase. Functional-anatomical analysis of the dissected isolated joint describes the interaction of ligaments with intertarsal joint contours through the full motion cycle. Manual manipulation identified a passive engage-disengage mechanism (EDM) that establishes joint extension, provides bi-directional resistance prior to a transition point located at 115 degrees and contributes to rapid intertarsal flexion at toe off and full extension prior to touch down. This effect was subsequently quantified by measurement of intertarsal joint moments in prepared anatomical specimens in a neutral horizontal position and axially-loaded vertical position. Correlation with kinematic analyses of walking and running ostriches confirms the contribution of the EDM in vivo. We hypothesise that the passive EDM operates in tandem with a stringently coupled multi-jointed muscle-tendon system to conserve the metabolic cost of locomotion in the ostrich, suggesting that a complete understanding of terrestrial locomotion across extinct and extant taxa must include functional consideration of the ligamentous system.

The equine tarsus is the most commonly affected hindlimb region associated with lameness. Diagnostic imaging is routinely applied but because of its complexity, being composed of 10 multifaceted bones and different joints, multiple ligaments, tendons and bursae, imaging this region can be a challenge. This is the first part of a two-part review of the structures and disorders of the equine tarsus. It describes the principal disorders affecting the soft tissues of the tarsal region and addresses some of the technical aspects in taking radiographic, ultrasonographic and scintigraphic images of the different soft tissue lesions. Where applicable, comments on the diagnostic use of contrast radiography, arthroscopy and tenoscopy are made. In current clinical practice a combination of radiography and ultrasonography is still most frequently used to arrive at a diagnosis.

Objective: To investigate effects of age on thickness and morphologic characteristics of hyaline cartilage, calcified cartilage, total cartilage, and subchondral bone (SCB) in the equine tarsometatarsal joint., Sample Population: 23 tarsal joints from cadavers of 23 ponies (11 days to 25 years old); ponies were limited to pasture exercise and euthanatized for reasons not related to this study. Procedures-Tarsi were allocated into several age groups (11 days old [n = 3], 6 to 9 months old [4], 2 to 3 years old [3], 6 to 8 years old [4], 11 to 17 years old [6], and 20 to 25 years old [3]). Histologic examination and histomorphometric measurement of hyaline cartilage, calcified cartilage, total cartilage, and SCB were performed at medial and lateral sites., Results: A significant decrease was detected in thickness of hyaline cartilage and total cartilage with increasing age, but there was a significant increase in thickness of calcified cartilage and SCB with increasing age. Differences in chondrocyte and collagen fiber arrangement, tidemark, and osteochondral junction morphology were evident among age groups., Conclusions and Clinical Relevance: These findings suggested that the various tissues of the osteochondral unit change in different ways with age. The response of each tissue may be related to relative response of the tissues to strains induced by pasture exercise but could have an influence on how the overall properties of the osteochondral unit change with age. The findings may also be suggestive of changes that develop prior to the onset of osteoarthritis.

Background: The role of the posterior talofibular ligament (PTFL) in the clubfoot deformity remains unclear. We conducted an anatomical study to precise its topography and role in maintaining tibiotalar equinus in patients with clubfoot deformity., Methods: Ten ankles were dissected using a wide posterior exposure. The PTFL was identified at the posterior aspect of the ankle and its relations with other anatomical structures were noted., Results: After opening of the tibiotalar and subtalar joints, the superior aspect of the PTFL was clearly seen, running horizontally from the fibula to a prominent tubercle on the posterior surface of the talus. The tibiotalar and subatalar joint capsules joined together laterally on the posterior edge of the PTFL and medially on the posterior part of the talus. A fibrous structure identified as being the "tibial slip" was noted in four cases between the posterior medial aspect of the lateral malleolus and the tibiotalar posterior capsule. Two different groups of fibers were identified inside the PTFL., Conclusions: Correcting the equinus and inversion of the talus needed an extensive release of soft tissues of the posterior part of the ankle. Our description of both short anterior and long posterior fibers of the PTFL improved our comprehension of functional anatomy of this ligament. We have found that PTFL is part of a posterior joint complex between the tibiotalar and subtalar joint. The posterior joint complex is a heritage of ankle evolution from a prehensile to a weight-bearing joint pattern. The inferior tibiofibular transverse ligament, the tibial slip and the calcaneofibular ligament are interpreted as derivatives of this ancestral meniscus and stabilize the weight-bearing ankle. Because the posterior fibers of the PTFL and the tibial slip are part of the complex, they should be excised like the posterior capsules during clubfoot surgery.

Background: The dorsolateral calcaneocuboid ligaments have different configurations. In the literature they are only described as either the dorsal or lateral calcaneocuboid ligament. However, recent reconstructive surgical techniques may benefit from a better understanding of the anatomy. The aims of this study were to classify the morphology and attachments of the dorso-lateral calcaneocuboid ligaments and to determine their dimensions., Materials and Methods: The dorso-lateral aspects of the calcaneocuboid joint of 30 cadaver feet were dissected to expose the associated ligaments. Further, we evaluated possible bony landmarks of the calcaneus that could imply which shape or course the ligament would have in a specific individual., Results: Our findings showed a wide variety of configurations in shape, number, and attachment sites. A constant dorsal ligament and an additional narrower lateral ligament was detectable in half of the cases. The majority of the dorso-lateral calcaneocuboid ligament-complex had an upward course and fanning out from proximal to distal. No bony predictor for the ligaments' shape or course was found., Conclusion: The dorso-lateral ligament-complex of the calcaneocuboid joint revealed a wide variety of configurations., Clinical Relevance: Better understanding of the anatomy of these ligaments may aid in the anatomic reconstruction of these ligaments.

Background: This study investigated the association of arch height combined with first metatarsal joint axis vertical (V) orientation to the size of the 1-2 intermetatarsal angle (IMA) and first metatarsal adduction/abduction position simulating foot postures during gait, kinematics commonly affected by bunion., Materials and Methods: Nine cadaver specimens were mounted in a loading frame. Measures of arch height ratio and IMA were made. With the foot placed in positions seen during normal gait cycle an electromagnetic device measured displacement of the relative angle of rotations between the first metatarsal and navicular, and helical axis (HA) parameters. Canonical correlation analysis assessed the relationship among the variables., Results: A negative relationship (r = -0.73) was found between arch height and first metatarsal HA V-orientation. When considered as combined variables, arch height and metatarsal HA V-orientation accounted for 69% of the variance of IMA and change in first metatarsal adduction/abduction position., Conclusion: Orientation of the first metatarsal joint axis was highly variable between specimens but correlated with arch height. The conjoined factors of arch height and first metatarsal HA V-orientation accounted for most of the variance of IMA and change in first metatarsal adduction/abduction position during the sequence of foot position during simulated gait., Clinical Relevance: These findings suggest that orthotic arch support could reorient the metatarsal joint axis out-of-vertical and in effect, limit the first metatarsal from displacing into an adducted bunion deformity. These findings could help to explain the pathogenesis of bunions.

Background: An isolated injury to the calcaneocuboid joint is frequently unrecognized clinically. The possibility of an injured dorsal calcaneocuboid ligament (DCC) should be considered in all acutely swollen feet after trauma involving supination. Despite its significance, there is much confusion in the literature regarding nomenclature, morphology, and location., Materials and Methods: To determine morphometric dimensions, dissection was performed on the feet of 30 adult preserved cadaveric limbs., Results: The DCC was consistently present in all specimens in the form of either a solitary structure (66.6%) or 2 components (33.3%). For the solitary structures, the superior and inferior borders measured 18.6 +/- 2.8 mm and 17.3 +/- 2.5 mm, respectively. The widths of the calcaneal and cuboid sides were 13.8 +/- 2.2 mm and 12.4 +/- 2.1 mm, respectively. In the 2 component ligaments, the superior component had a superior and inferior length that averaged 16.9 +/- 2.1 mm and 16.4 +/- 2.8 mm, respectively. Its calcaneal and cuboid borders were 9.3 +/- 1.2 mm and 10.6 +/- 1.4 mm, respectively. The inferior component had superior and inferior sides that were 12.9 +/- 2.9 mm and 13.8 +/- 3.0 mm, respectively. The widths of the calcaneal and cuboid sides were 8.3 +/- 1.4 mm and 7.2 +/- 1.0 mm, respectively., Conclusion: We have demonstrated variations in the morphology of the DCC along with its morphometric dimensions., Clinical Relevance: Knowledge of the morphologic variations and dimensions of the DCC can be of aid when planning for surgical management of the ruptured ligament.

Magnetic resonance imaging offers unique insights into three-dimensional foot bone motion. Thereby, adequate devices enabling defined loading and positioning of the foot are needed to profit from this noninvasive procedure. Tarsal bone positions of three healthy subjects were repeatedly measured in a pronated and a supinated foot excursion under bodyweight with a newly developed MR imaging procedure. The quantification of the transferred motion from the loading and positioning device to the calcaneus and an estimation of the required degrees to distinguish between tarsal joint rotations were used to evaluate the applicability of the procedure to investigate tarsal joint motion. It was found that 45-70% (75-95%) of the externally applied 15 deg foot pronation (supination) were transferred to the calcaneus. Furthermore, the talonavicular joint showed the largest amount of rotation up to 20 deg eversion-inversion and abadduction, followed by the subtalar joint showing nearly half of that motion. Considerably less motion was found between the cuboid and calcaneus (about 2-6 deg) and the cuboid nearly did not rotate relative to the navicular (on average 1 deg). The estimated necessary differences between tarsal joint movements to identify individual kinematic behavior were in the order of 2 deg (4 deg related to the talonavicular joint). Since the results were in agreement with the literature, it is concluded that the applicability of the presented procedure to investigate tarsal bone mechanics is warranted. The possibility to evaluate 3D tarsal joint motion in combination with bone morphology (e.g., joint curvature) may provide new insights in the still uncertain relationship between foot function and foot morphology.

Magnetic resonance (MR) imaging is becoming increasingly important in the study of foot biomechanics. Specific devices have been constructed to load and position the foot while the subject is lying supine in the scanner. The present study examines the efficacy of such a newly developed device in replicating tarsal kinematics seen during the more commonly studied standing loading conditions. The results showed that although knee flexion and the externally applied load were carefully controlled, subtalar and talo-navicular joint rotations while lying during MR imaging and when standing (measured opto-electrically with markers attached to intracortical pins) did not match, nor were they systematically shifted. Thus, the proposed MR protocol cannot replicate tarsal kinematics seen during upright standing. It is concluded that specific foot loading conditions have to be considered when tarsal kinematics are evaluated. Improved replication of tarsal kinematics in different postures should comprehensively consider muscle activity, a fixed hip position, and a well-defined point of load application.

We describe an arthroscopic approach of tarsometatarsal arthrodesis for post-traumatic arthritis. Five tarsometatarsal portals (medial, P1-2, P2-3, P3-4, P4-5) are identified at the junctional points between the metatarsals by means of image intensifier. The first metatarsocuneiform joint is approached through the medial and P1-2 portal. Articular cartilage is denuded and micro-fracture of subchondral bone is performed with an arthroscopic awl. The second metatarsocuneiform joint is approached through the P1-2 and P2-3 portals and the third metatarsocuneiform joint is approached through the P2-3 and P3-4 portals. The articular surfaces are prepared for arthrodesis. The articulations are kept in desired position and transfixed with 4.0 mm cannulated screws. The fourth and fifth metatarsocuboid articulations are rarely included in the procedure. Arthroscopic arthrodesis or tendon arthroplasty of the lateral column can be performed through the P3-4 and P4-5 portals.

The human foot is considered an organ with an assortment of tissues with different morphological characteristics and well defined limits, but effectively has a simple functionality when static that becomes extremely complex when in movement. Its complex structure, comprised of an elastic and resistant skin covering a bone framework, joints, muscles, tendons, veins and nerves, can be compared to an efficient mechanical assembly. After a long and extraordinary evolutive journey, the human foot has undergone numerous changes to perfect its function; it has lost most of its grabbing function whilst gaining new characteristics that have ultimately allowed the modern man to stand upright. The complex articular structure of the human foot consists of thirty four synovial joints, of which eighteen have curved surfaces and sixteen plane surfaces. Following the criteria set by the systematic, radiological and clinical anatomy, the Authors contribute further to the current knowledge on the ankle, tarsal (anatomic subtalar, transverse tarsal, cuneonavicular, intercuneiform and cuneocuboid), tarsometatarsal, intermetatarsal, metatarsophalangeal and interphalangeal joints and dorsal, plantar and interosseous ligaments of the human foot. The articular lines of the transverse tarsal (Chopart) and tarsometatarsal (Lisfranc) joints are particularly interesting and not only from a surgical point of view; through a straightforward identification of few reference points, it is possible to find the medial and lateral extremities of the Chopart's and Lisfranc's lines, the former pinpoints the boundary between the hindfoot and midfoot and the latter between the midfoot and forefoot.

Reasons for Performing Study: Understanding of the development of pathology and source of pain in distal tarsal osteoarthritis is poorly understood. Magnetic resonance imaging is often used in the analysis of human osteoarthritis (OA) because it is sensitive to early changes., Hypothesis: In association with distal tarsal joint (DTJ) pain, there will be an alteration in the characteristic subchondral bone (SCB) thickness pattern of horses with no history of pain when subjected to low-level exercise., Methods: Sixteen cadaver tarsal joints were collected from 9 mature horses with a history of tarsal pain and radiographic evidence of OA; 3 cadaver tarsi were collected from 2 mature horses with a history of tarsal pain and no radiographic abnormality. Magnetic resonance images were acquired using high-resolution sagittal 3D T1 weighted spoiled gradient echo sequence. Subchondral bone thickness was measured on sagittal images at dorsal and plantar locations on the proximal and distal aspects of the central (CT) and third (T3) tarsal bones and proximal aspect of the third metatarsal bone (MT3)., Results: In tarsi with radiographic evidence of OA medial and lateral SCB thicknesses were greater than midline on the proximal and distal aspects of CT and T3. Lateral SCB thickness was greater than medial on the proximal aspect of MT3. There was an increase in SCB thickness at the majority of sites compared with normal horses. There were too few joints in the group without radiographic changes to analyse statistically. In painful tarsi SCB thickness was greater medially than laterally at all sites. In horses without tarsal pain all lateral sites had greater SCB thickness, except the proximal aspect of CT., Conclusions: There is alteration of normal SCB thickness patterns in painful tarsi. Different thickness patterns could represent different types of pathological processes., Potential Clinical Relevance: Further work is required to elucidate the pathological processes leading to OA of the DTJs.

This study has been carried out to determine the effect of neutral position, hyperextension and hyperflexion of the tarsal joint on the tibial nerve, motor action potential latency and tarsal canal compartment pressure in dogs with the aid of electrophysiological and anatomical methods. Totally twenty healthy mongrel dogs were used. Latency of motor nerve action potential (MNAPL) studies of tibial nerve via surface stimulating and needle recording electrodes was performed on right hind limbs of all the dogs. The compartment pressures of the tarsal canal with the pressure transducer were determined from both limbs from ten of the dogs. In one dog, tarsal regions of both left and right limbs were demonstrated using magnetic resonance imaging (MRI). Two dogs were euthanatized and tarsal regions of the dogs were sectioned for correlative anatomy. Nerve conduction studies showed that the MNAP latency of the tibial nerve were 3.55 +/- 0.097 ms, 3.76 +/- 0.087 ms and 3.39 +/- 0.097 ms in neutral, hyperextension and hyperflexion positions, respectively. Hyperflexion of the tarsal joint caused prolongation of the MNAP latency of the tibial nerve with the highest pressure value being determined in tarsal canal. From the anatomical viewpoint, the distance between the flexor hallucis longus muscle and the superficial digital muscle was the shortest during hyperflexion and the plantar branch of saphenous artery, lateral and medial plantar nerves located more laterally in cadaver and MR imaging sections. As a result of this study, it is thought that tarsal region diseases as well as long time splint in the hyperflexion position as applied in the Ehmer sling can affect the compartment pressure and nerve tension because of occupying in the tarsal canal. Raising pressure and nerve stretching in the tarsal canal compartment could cause deficiencies in the conduction velocity of the tibial nerve. This might be a result of tarsal tunnel syndrome in the dog. Clinicians could consider this syndrome in cases of tarsal region diseases as well as application of long time splint in hyperflexion of tarsal joints in dogs.