Increase in foot arch asymmetry after full marathon completion.

Long-distance running results in lowering of the foot medial longitudinal arch, but it is unknown whether the left and right arches decrease equally. This study aimed to determine whether foot arch asymmetry increases upon completion of a full marathon and to identify factors capable of explaining the degree of asymmetry of navicular height and navicular height displacement. The three-dimensional foot posture data of 74 collegiate runners were obtained using an optical foot scanner system before (PRE) and immediately after (POST) a full marathon. The navicular height and arch height ratio (normalised navicular height by foot length) of both feet significantly decreased from PRE to POST full marathon completion (44.3 ± 6.3 mm versus 40.8 ± 6.5 mm, 17.8 ± 2.5 versus 16.6 ± 2.7, respectively; p < 0.001, both). The asymmetry of the arch height ratio was significantly greater POST than PRE marathon. Multiple linear regression analysis indicated that the POST-race Asymmetry Index (AI) of navicular height was significantly predicted by the PRE-race AI of navicular height; navicular height displacement was predicted by PRE-race navicular height and the marathon time. Full marathon running induced increasing asymmetry and lowering of the medial longitudinal arch in runners.

Combined Posteromedial and Posterolateral Approaches for 2-Part Posterior Malleolar Fracture Fixation.

BACKGROUND: This study investigated the clinical efficacy of combined posteromedial and posterolateral approaches for repair of 2-part posterior malleolar fractures associated with medial and lateral malleolar fractures. METHODS: This case series report included 27 Weber B with Haraguchi type II patients with medial and lateral malleolar fractures combined with 2-part posterior malleolar fractures. Patients were treated with open reduction and internal fixation through a combination of posteromedial and posterolateral approaches from January 2015 to January 2018. There were 11 males and 16 females, with an average age of 61.5 years (range, 53-67 years). The procedures were performed on prone patients under spinal anesthesia. The medial, lateral, and posterior malleolar fractures were exposed through posteromedial and posterolateral approaches performed at the same time. The lateral malleolar fracture was fixed using a plate, the medial malleolar fracture was fixed using screws, and the posterior malleolar fracture was fixed using a plate or cannulated screws according to the size of the fragments. We performed follow-up on 22 patients for an average of 30 months (range, 18-48 months). RESULTS: Primary healing of the incisions was achieved in all cases, and no infection was found. The mean time of bone union was 12.5 weeks (range, 10-15 weeks). The mean time from the operation to full weightbearing was 13 weeks (range, 11-16 weeks). We used the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Scale to score patient outcomes; the mean score was 85.4 (range, 80-92) at the final follow-up. No significant pain was found at the final follow-up. CONCLUSION: This study showed that satisfactory outcomes were achieved with combined posteromedial and posterolateral approaches. Therefore, we believe this approach was a good alternative strategy to repair 2-part posterior malleolar fractures associated with medial and lateral malleolar fractures. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Effect of Achilles tendon on kinematic coupling relationship between tarsal bones: a pilot finite element study.

BACKGROUND: The procedure of percutaneous Achilles tenotomy (PAT) is an important component of the Ponseti method. However, few studies reported the influence of Achilles tendon on kinematic coupling relationship between tarsal bones. The purpose of present study was to demonstrate the effect of Achilles tendon on the kinematic coupling relationship between tarsal bones, and to illustrate how kinematic coupling relationship between tarsal bones works in term of finite element analysis. METHODS: A three-dimensional finite element model of foot and ankle was constructed based on the Chinese digital human girl No.1 (CDH-G1) image database using the software of mimics, Geomagic studio, HyperMesh, and Abaqus. The last manipulation of the Ponseti method before the procedure of PAT was simulated. The talus head and the proximal tibia and fibula bone were fixed in all six degrees of freedom, and the outward pressure was added on the first metatarsal head to investigate the kinematic coupling relationship between tarsal bones. RESULTS: The least relationship of kinematic coupling between tarsal bones was found in calcaneus. Stress concentration was mainly observed at the navicular, talus and the medial malleolus. The difference in displacement of the navicular was only found with the Achilles tendon stiffness of 0 N/mm and others. No difference in the navicular displacement was found in the stiffness of Achilles tendon between 40, 80, 200, 400, and 1000 N/mm. The maximum displacement of navicular was observed at the ankle position of PF-20° (plantar flexion-20°). The difference in displacement of the navicular was greater at the ankle position of PF-20° with the Achilles tendon stiffness of 0 N/mm than that at the ankle position of PF-40° with the Achilles tendon stiffness of 40 N/mm. CONCLUSIONS: Based on the findings from this study, it was demonstrated that the Achilles tendon existence or not and ankle position had great influence, while increased stiffness of Achilles tendon had no influence on kinematic coupling relationship between tarsal bones. For the cases with severe equinus, earlier implementation of PAT procedure (with the purpose of release the Achilles tendon and reduce the degree of ankle plantar flexion) may be beneficial to the deformity correction.

Morphological and biomechanical implications of cuboid facet of the navicular bone in the gait / Implicaciones morfológicas y biomecánicas de la faceta cuboídea del navicular en la marcha

The cuboid facet of the navicular bone is an irregular flat surface, present in non-human primates and some human ancestors. In modern humans, it is not always present and it is described as an "occasional finding". To date, there is not enough data about its incidence in ancient and contemporary populations, nor a biomechanical explanation about its presence or absence. The aim of the study was to evaluate the presence of the cuboid facet in ancient and recent populations, its relationship with the dimensions of the midtarsal bones and its role in the biomechanics of the gait. 354 pairs of naviculars and other tarsal bones from historical and contemporary populations from Catalonia, Spain, have been studied. We used nine measurements applied to the talus, navicular, and cuboid to check its relationship with facet presence. To analyze biomechanical parameters of the facet, X-ray cinematography was used in living patients. The results showed that about 50 % of individuals developed this surface without differences about sex or series. We also observed larger sagittal lengths of the talar facet (LSAGTAL) in navicular bones with cuboid facet. No significant differences were found in the bones contact during any of the phases of the gait. After revising its presence in hominins and non-human primates, and its implication in the bipedalism and modern gait, we suggest that cuboid facet might be related with the size of talar facet and the position of the talonavicular joint. However, other factors such as geographical conditions, genetics and stressful activities probably affect its presence too.

La faceta cuboídea del hueso navicular es una carilla plana e irregular, presente en primates no humanos y en algunos de nuestros ancestros. En humanos modernos, no siempre está presente y es descrita como "un hallazgo ocasional" por la bibliografía. Hasta la fecha, no hay suficientes datos acerca de su incidencia en poblaciones antiguas y contemporáneas, ni una explicación biomecánica sobre su presencia o ausencia. El objetivo de nuestro estudio fue evaluar la frecuencia de la faceta cuboídea en poblaciones recientes y antiguas, su relación con las dimensiones de los huesos tarsales y su rol en la biomecánica de la marcha. Fueron estudiados 354 pares de naviculares y otros huesos del tarso provenientes de colecciones osteológicas de Cataluña, España. Aplicamos nueve medidas aplicadas al talus, navicular y cuboides para corroborar su relación con la presencia de la faceta. Para analizar sus parámetros biomecánicos, se empleó X-ray cinematography en pacientes hospitalarios. Los resultados mostraron que alrededor de un 50 % de los individuos desarrollaron esta carilla, sin diferencias entre sexos o series. Además, observamos que la longitud sagital de la faceta talar (LSAGTAL) es mayor en aquellas muestras con faceta cuboídea. No hay diferencias significativas en el contacto de los huesos en ninguna de las fases de la marcha. Después de revisar su presencia en primates no humanos, su implicancia en el bipedismo y en la marcha moderna, sugerimos que la faceta cuboídea podría estar relacionada con el tamaño de la faceta talar y la posición de la articulación talo-navicular. Sin embargo, otros factores como las condiciones geográficas, genética y stress ocupacional también podrían afectar su presencia.

Effects of the Short Foot Exercise With Neuromuscular Electrical Stimulation on Navicular Height in Flexible Flatfoot in Thailand: A Randomized Controlled Trial.

OBJECTIVES: Flatfoot, or low medial longitudinal arch, contributes to back and lower extremity injuries and is caused by weak abductor hallucis (AbdH) muscles. The purpose of this study was to investigate the effects of short foot exercise (SFE) alone or with neuromuscular electrical stimulation (NMES) on navicular height, the cross-sectional area (CSA) of the AbdH muscle, and AbdH muscle activity in flexible flatfoot. METHODS: Thirty-six otherwise healthy people with flexible flatfoot were randomly assigned to a group that received SFE with placebo NMES treatment (the control group) or a group that received both SFE and NMES treatment (the experimental group). Each group received 4 weeks of treatment (SFE alone or SFE with NMES). Navicular height, the CSA of the AbdH muscle, and AbdH muscle activity were assessed before and after the intervention. RESULTS: No significant differences were found in navicular height or the CSA of the AbdH muscle between the control and experimental groups, while AbdH muscle activity showed a statistically significant difference between the groups (SFE=73.9±11.0% of maximal voluntary isometric contraction [MVIC]; SFE with NMES=81.4±8.3% of MVIC; p<0.05). Moreover, the CSA of the AbdH muscle showed a statistically significant increase after treatment in the SFE with NMES group (pre-treatment=218.6±53.2 mm2; post-treatment=256.9±70.5 mm2; p<0.05). CONCLUSIONS: SFE with NMES was more effective than SFE alone in increasing AbdH muscle activity. Therefore, SFE with NMES should be recommended to correct or prevent abnormalities in people with flexible flatfoot by a physiotherapist or medical care team.

Motion of the distal tibiofibular syndesmosis under different loading patterns: A biomechanical study.

PURPOSE: The distal tibiofibular syndesmosis is an important structure for ankle stability. The objective of this study was to evaluate the motion of the syndesmosis under different loading patterns and determine the characteristics of the syndesmotic motion. METHODS: Six fresh cadaveric lower extremity specimens with the knee reserved were tested in this study. The skin and muscles were removed with all ligaments around the syndesmosis and knee and ankle joint intact. An axial load of 600 N was applied to the specimens with the ankle joint in 10° dorsiflexion, neutral position, and 15° plantar flexion using a universal material testing machine. Then, with the ankle joint positioned neutrally, a combination of 600-N axial and 5-Nm torsional external rotation loading was applied to the specimens. The medial-lateral and anterior-posterior displacement and rotation of the distal fibula relative to the distal tibia were measured. RESULTS: Under the axial loading, the distal fibula tended to move medially and anteriorly and rotate internally with the ankle positioned from the neutral position to 15° plantar flexion. Meanwhile, when the ankle was positioned from the neutral position to 10° dorsiflexion, the distal fibula tended to move laterally and posteriorly and rotate externally. Under the combined loading, with respect to the isolated axial loading, the distal fibula tended to move medially and posteriorly, and rotate externally relative to the distal tibia. CONCLUSION: Micro motion existed in the syndesmosis. The relative motion of the syndesmosis was correlated to the ankle position and loading patterns.

Reliability of medial-longitudinal-arch measures for skin-markers based kinematic analysis.

The medial-longitudinal arch (MLA) is perhaps the most important feature characterizing foot morphology. While current skin-markers based models of the MLA angle used in stereophotogrammetry allow to estimate foot arch shape and deformation, these do not always appear consistent with foot anatomy and with standard clinical definitions. The aim of this study was to propose novel skin-markers based measures of MLA angle and investigate their reliability during common motor tasks. Markers on the calcaneus, navicular tuberosity, first metatarsal head and base, and on the two malleoli were exploited to test eight definitions of MLA angle consistent with foot anatomy, both as angles between two 3-dimensional vectors and as corresponding projections on the sagittal plane of the foot. The inter-trial, inter-session and inter-examiner reliability of each definition was assessed in multiple walking and running trials of two volunteers, tested by four examiners in three sessions. Inter-trial variability in walking was in the range 0.7-1.2 deg, the inter-session 2.8-7.5 deg, and the inter-examiner in the range 3.7-9.3 deg across all MLA definitions. The Rizzoli Foot Model definition showed the lowest inter-session and inter-examiner variability. MLA measures presented similar variability in walking and running. This study provides preliminary information on the reliability of MLA measurements based on skin-markers. According to the present study, angles between 3-dimensional vectors and minimal marker sets should be preferred over sagittal-plane projections. Further studies should be sought to investigate which definition is more accurate with respect to the real MLA deformation in different loading conditions.

Association of quadriceps angle with plantar pressure distribution, navicular height and calcaneo-tibial angle.

OBJECTIVE: The aim of study was to analyze the association between Quadriceps Angle (QA) and plantar pressure, navicular height (NH), and calcaneo-tibial angle (CTA). METHODS: A total of 64 volunteers (mean age: 22.25 ± 2.54 (range:19-33)) participated in this cross sectional study. EMED-m (Novel GmbH, Germany) electronic pedobarograph was employed for dynamic plantar pressure measurement using two step protocol. The angle between the vertical axis of calcaneus and the long axis of Achilles tendon for CTA. The height of navicular tubercle from the ground was measured while the subject was standing on both feet for NH. QA was measured while the subject was standing in a relaxed posture where both feet bearing equal weight. RESULTS: There were significant negative correlations between QA and maximum force (MxF) under the 4th. metatarsal head (MH4). The QA was also significantly correlated with MxF and force-time integral (FTI) under the bigtoe (BT). FTI under the 3rd. metatarsal head (MH3), MH4 and 5th. metatarsal head (MH5) were significantly negatively correlated with QA. Pressure-time integral (PTI) under the MH4 and MH5 were found to be significantly negatively correlated with QA. A significant correlation was also found between QA and NH (p < 0.0001), whilst there was no correlation between QA and CTA. Regression analysis showed that NH was appeared as the major contributor for the QA (ß = -0.49, p < 0.001) in the dynamic condition, followed by BT-FTI (ß = 0.37, p < 0.001) and MH5-MxF (ß = -0.21, p < 0.037). CONCLUSION: These findings may imply that the NH which can at least be controlled by appropriate shoe inserts may affect QA. This way, loading pattern of both plantar region and whole lower extremity may be altered. LEVEL OF EVIDENCE: Level III, Diagnostic Study.

Evaluating the Medial Longitudinal Arch of the Foot: Correlations, Reliability, and Accuracy in People With a Low Arch.

BACKGROUND: The medial longitudinal arch of the foot is a variable structure, and a decrease in its height could affect several functions and increase the risk of injuries in the lower limbs. There are many different techniques for evaluating it. OBJECTIVE: The objective of this study was to evaluate the correlations of the Navicular Drop Test, several footprint parameters, and the Foot Posture Index-6 in people with a low medial longitudinal arch. Intrarater reliability and interrater reliability were also estimated. DESIGN: This was a repeated-measures, observational descriptive study. METHODS: Seventy-one participants (53.5% women; mean age = 24.13 years; SD = 3.41) were included. All of the parameters were collected from the dominant foot. The correlation coefficients were calculated. The reliability was also calculated using the intraclass correlation coefficient, 95% CI, and kappa coefficient. RESULTS: Statistically significant correlations were obtained between the Navicular Drop Test and the footprint parameters, with r absolute values ranging from 0.722 to 0.788. The Navicular Drop Test and the Foot Posture Index-6 showed an excellent correlation (Spearman correlation coefficient = 0.8), and good correlations (Spearman correlation coefficient = |0.663-0.703|) were obtained between the footprint parameters and the Foot Posture Index-6. Excellent intrarater reliability and interrater reliability were obtained for all of the parameters. LIMITATIONS: Radiographic parameters, the gold standard for evaluating the medial longitudinal arch height, were not used. In addition, the results of this research cannot be generalized to people with normal and high medial longitudinal arches. CONCLUSIONS: In participants with a low medial longitudinal arch, the Navicular Drop Test showed significant correlations with footprint parameters; correlations were good for the arch angle and Chippaux-Smirnak Index, and excellent for the Staheli Index. The Foot Posture Index-6 showed an excellent correlation with the Navicular Drop Test and a good correlation with the footprint parameters evaluated. All of the parameters showed high reliability.

The Role of the Midfoot in Drop Landings.

PURPOSE: The midfoot is instrumental to foot function; however, quantifying its roles in human movement has been difficult. A forceful dynamic activity like landing may help elucidate the midfoot's contribution to foot energetics and function. The main purpose of this study was to measure midtarsal joint kinematics and kinetics during a barefoot single-leg landing task. A secondary aim of this study was to explore the relationship between static foot posture and dynamic midfoot function. METHODS: In a cross-sectional study design, 48 females (age = 20.4 ± 1.8 yr, body mass index = 21.6 ± 1.7 kg·m) performed drop landings from a height of 0.4 m onto split force platforms. Subjects hung from wooden rings and landed on their dominant leg. Midtarsal joint kinematic and kinetic data were recorded using a 14-camera optical motion capture system in conjunction with two in-ground force platforms and a custom kinetic three-segment foot model. Foot structure was measuring using the arch height index (AHI) and the static midtarsal joint angle from motion capture. RESULTS: Kinematic data revealed an average sagittal plane midtarsal joint range of motion of 27° through the landing phase. Kinetic data showed that between 7% and 22% of the total lower extremity joint, work during the landing was performed by the midtarsal joint. Both standing AHI and static midtarsal joint angle (static MA) were correlated with sagittal plane midtarsal joint range of motion (standing AHI: r = -0.320, P = 0.026; static MA: r = 0.483, P < 0.001) and with midtarsal joint work (standing AHI: r = 0.332, P = 0.021; static MA: r = -0.323, P = 0.025). CONCLUSION: The midfoot contributes substantially to landing mechanics during a barefoot single-leg landing task. Static foot posture measures have limited value in predicting midfoot kinematics and kinetics during sportlike landings.

Foot and ankle joint movements of dancers and non-dancers: a comparative study.

Ballerinas use their ankle joints more extremely and sustain injuries on the ankle joint more frequently than non-dancers. Therefore, the ankle movement of dancers is important and should be studied to prevent injuries. Measuring ankle joint range of motion (ROM) using radiographs could demonstrate the contribution to motion of each joint. The aim of this study was to analyse and compare ankle joint movements and the ratio of each joint's contribution during movement between dancers and non-dancers, using radiographic images. Dancers have lower dorsiflexion (26.7 ± 6.2°), higher plantarflexion (74.3 ± 7.1°) and higher total (101.1 ± 10.8°) ROMs than non-dancers (33.9 ± 7.0°, 57.2 ± 6.8° and 91.1 ± 9.3°, respectively) (p < 0.05). Although the ROMs were different between the two groups, the ratios of each joint movement were similar between these two groups, in all movements. Regarding total movement, the movement ratio of the talocrural joint was almost 70% and other joints accounted for almost 30% of the movement role in both dancers and non-dancers. Therefore, the differences in ROM between dancers and non-dancers were not a result of a specific joint movement but of all the relevant joints' collaborative movement.

Medial Longitudinal Arch: Accuracy, Reliability, and Correlation Between Navicular Drop Test and Footprint Parameters.

OBJECTIVE: The purpose of this study was to evaluate the correlation among the navicular drop test, the arch angle, the Staheli index and the Chippaux-Smirak index. The reliability and the correlation among the footprint parameters were also estimated. METHODS: A cross-sectional study (n = 86; 59.3% women; 27.8 years, standard deviation: 4.8 years) was carried out. The navicular drop test was evaluated and footprint parameters using a plantar pressure platform were recorded in the dominant foot. Pearson correlation coefficients, intraclass correlation coefficient, standard error of measurement, and minimum detectable change were calculated. RESULTS: Both intrarater and interrater reliability were excellent for all the parameters evaluated (intraclass correlation coefficients > 0.880). Statistically significant correlations existed between the navicular drop test and footprints parameters (arch angle = 0,643; Staheli index = 0.633; Chippaux-Smirak index = 0.614). The footprint parameters had excellent correlation with each other (0.838-0.881). The navicular drop test and the footprint parameters studied were reproducible and thus had excellent reliability. CONCLUSION: The correlations obtained between the navicular drop test and the footprint parameters evaluated were good. The navicular drop test appears to be a reproducible, valid, and simple test for evaluating medial longitudinal arch height, having fewer disadvantages than using footprint parameters.

Cranio-caudal and medio-lateral navicular translation are representative surrogate measures of foot function in asymptomatic adults during walking.

INTRODUCTION: The translation of the navicular bone is thought to be a representative surrogate measure to assess foot pronation and hence foot function; however, it is not known how it is related to multi-segment foot kinematics. METHODS: Cranio-caudal (NCC) and medio-lateral (NML) navicular translation and multi-segment foot kinematics from the Oxford Foot Model (OFM) were simultaneously assessed during the stance phase of walking in 20 healthy adults. Relationships to forefoot to hindfoot (FFtoHF), hindfoot to tibia (HFtoTBA) and global hindfoot (HFL) motion were explored by cross-correlations at zero phase shift. RESULTS: FFtoHF sagittal, transversal and frontal plane angles showed median cross correlations of -0.95, 0.82 and 0.53 with NCC and of 0.78, -0.81 and -0.90 with NML. HFtoTBA transversal and frontal plane angles had correlations of 0.15 and 0.74 with NCC and of -0.38 and -0.83 with NML. The HFL frontal plane angle showed correlations of 0.41 and -0.44 with NCC and NML, respectively. DISCUSSION: The strongest relationships were found between FFtoHF sagittal plane angles and NCC and between FFtoHF frontal plane angles and NML. However, cranio-caudal and medio-lateral navicular translation seem to be reasonable surrogates for the triplanar motion between the fore- and hindfoot. The medial longitudinal arch dropped and bulged medially, while the forefoot dorsiflexed, abducted and everted with respect to the hindfoot and vice-versa. The lower cross-correlation coefficients between the rear foot parameters and NCC/NML indicated no distinct relationships between rearfoot frontal plane and midfoot kinematics. The validity of rearfoot parameters, like Achilles tendon or Calcaneal angle, to assess midfoot function must be therefore questioned. The study could also not confirm a systematic relationship between midfoot kinematics and the internal/external rotation between the hindfoot and the tibia. The measurement of navicular translation is suggested as an alternative to more complex multi-segment foot models to assess foot function.

The influence of gait and speed on the dynamic navicular drop - A cross sectional study on healthy subjects.

INTRODUCTION: Variations of gait speed influence kinematic variables that may have an effect on dynamic foot deformation. The influence of gait speed on the navicular drop has not yet been investigated. METHODS: The navicular drop was evaluated in static and dynamic conditions using a 3D-motion capture system. The dynamic navicular drop was evaluated on a treadmill while walking and running at three different speeds. A repeated measures ANOVA and post-hoc tests were conducted to evaluate the differences in dynamic navicular drop, corresponding unloaded navicular height at foot strike and loaded navicular height during stance. RESULTS: Higher walking speed led to a significant decrease in navicular height at foot strike and a subsequent decrease of dynamic navicular drop (p=0.006). Across increasing running speeds, minimum navicular height was significantly decreased which in consequence led to an increased dynamic navicular drop (p=0.015). For walking and running at the same speed, there was a large effect of gait style with an increase of dynamic navicular drop by 3.5mm (p<0.001) during running. DISCUSSION: The change of gait from walking to running at the same speed had a large effect on dynamic navicular drop. The values of navicular height at foot strike and minimum navicular height during stance should be taken into account for the interpretation of dynamic navicular drop measures. Static and dynamic navicular drop measures differ substantially.

Intra- and interday reliability of the dynamic navicular rise, a new measure for dynamic foot function: A descriptive, cross-sectional laboratory study.

BACKGROUND: The lack of reliable parameters to evaluate dynamic foot function, emphasizes the need for a deeper insight in foot biomechanics. The aims were to investigate the reliability of a new parameter (dynamic navicular rise dNR), and its relationship with the dynamic navicular drop (dND). METHODS: Twenty healthy participants (mean age 30.2±8.1years) had to walk on even ground and downstairs. Data of ten trials per task on two measurement days were recorded. The dNR was defined as the difference in millimetres (mm) between the minimum navicular height (NH) during stance and the NH at toe off. To test intra- and interday reliability, Intraclass Correlation Coefficients (ICC2.1) and repeatability were calculated. To obtain the absolute repeatability (RP) in mm, the equation RP=1.96×SDdifferences was used. Furthermore, the relationship between the dNR and the dND was examined by calculating Pearson (r) or Spearman (rs) correlation coefficients. RESULTS: Included participants showed a mean dNR of (12.2±3.7) mm for level walking and (14.8±3.4) mm for stair descent. The ICC2.1 for the dNR were 0.98 (intraday), 0.91 (interday) for level walking and 0.97 (intraday), 0.94 (interday) for stair descent. The interday repeatability was 3.2mm (level walking), 2.7mm (stair descent) respectively. For level walking, r was 0.31 (p=0.049), and rs=0.88 (p<0.001) for stair descent. CONCLUSIONS: The dNR seems to be highly reliable (ICCs), however, repeatability is unacceptable. For level walking, the dNR might be an independent measure, but not for stair climbing.

A minimal markerset for three-dimensional foot function assessment: measuring navicular drop and drift under dynamic conditions.

BACKGROUND: The validity of predicting foot pronation occurring mainly at the midfoot by surrogate measures from the rearfoot, like eversion excursion, is limited. The dynamic navicular mobility in terms of vertical navicular drop (dNDrop) and medial navicular drift (dNDrift) may be regarded as meaningful clinical indicators to represent overall foot function. This study aimed to develop a minimal approach to measure the two parameters and to examine their intra- and interday reliability during walking. METHODS: The minimal markerset uses markers at the lateral and medial caput of the 1st and 5th metatarsals, respectively, at the dorsal calcaneus and at the tuberosity of the navicular bone. Dynamic navicular drop and drift were assessed with three-dimensional motion capture in 21 healthy individuals using a single-examiner test-retest study design. RESULTS: Intra- and interday repeatability were 1.1 mm (ICC21 0.97) and 2.3 mm (ICC21 0.87) for dynamic navicular drop and 1.5 mm (ICC21 0.96) and 5.3 mm (ICC21 0.46) for dynamic navicular drift. The contribution of instrumental errors was estimated to 0.25 mm for dynamic navicular drop and 0.86 mm for dynamic navicular drift. CONCLUSIONS: Interday reliability was generally worse than intraday reliability primary due to day-to-day variations in movement patterns and the contribution of instrumental errors was below 23% for dynamic navicular drop but reached 57% for dynamic navicular drift. The minimal markerset allows to simply transfer the known concepts of navicular drop and drift from quasi-static clinical test conditions to functional tasks, which is recommended to more closely relate assessments to the functional behavior of the foot.

Gestation length and racing performance in 115 Thoroughbred foals with incomplete tarsal ossification.

BACKGROUND: Incomplete ossification of the cuboidal bones of the carpus and tarsus in foals has the potential for significant consequences including chronic lameness and decreased athletic ability. OBJECTIVES: To determine if the degree of ossification of the cuboidal bones is associated with gestational length and if the diagnosis of incomplete ossification is a predictor of performance in Thoroughbred racehorses. STUDY DESIGN: Retrospective cohort study. METHODS: The medical records of Thoroughbred foals less than 90 days of age from 1994 to 2011 were examined and records containing tarsal radiographs identified. Radiographs of the tarsus were examined for signs of incomplete ossification and those that were incompletely ossified graded on a scale of 1-4 using a modification of a previously reported index, with Grade 1 being the least ossified and Grade 4 being the most. Gestational length was determined by examining breeding records and foaling dates reported to the Jockey Club. Race records for 2- and 3-year-old affected foals and their maternal siblings were obtained and compared. RESULTS: Foals with Grades 1 and 2 ossification were usually premature (gestation length <325 days), but Grades 3 and 4 were not. Foals with Grades 2 and 3 ossification were significantly less likely to race than their maternal siblings and Grades 1, 2, 3 and 4 foals earned less money. MAIN LIMITATIONS: A larger sample size of foals with Grade 1 ossification would increase the power of the study. Foals radiographed at an older age may have had lower ossification scores if radiographed earlier. CONCLUSIONS: Incomplete ossification, especially Grades 1 and 2, is associated with a short gestation length. Foals with Grades 2 and 3 incomplete ossification were less likely to race and Grades 1, 2 and 3 earned around $30,000 less than their maternal siblings.

Distance Between the Anterior Distal Tibial Edge and the Anterior Tibial Artery in Distraction and Nondistraction During Anterior Ankle Arthroscopy: A Cadaveric Study.

BACKGROUND: Anterior ankle arthroscopy is widely applied for various osteoarthropathies. However, distraction of the ankle may put the anterior tibial artery (ATA) at risk of injury during the procedure. The purpose of this study was to assess the difference in the distance between the anterior distal tibial edge and the ATA in distraction and nondistraction of the ankle with joint space expansion by saline injection into the joint. METHODS: Eight whole fresh-frozen cadaveric feet (mean age 78.9 years) were used. Barium sulfate suspension was injected into the popliteal artery of each specimen, and the distance from 3 aspects of the anterior distal tibial edge to the ATA was measured to evaluate the possibility of damage to the ATA based on computed tomography (CT) scans, in ankle distraction and nondistraction, using a traction device developed for reproducible ankle positioning inside the CT scanner. RESULTS: The distance between the ATA and the most proximal, middle, and distal parts of the anterior distal tibial edge was 0.5 mm, 3.9 mm, and 7.4 mm, respectively, without saline injection, and 3.7 mm, 7.2 mm, and 11.6 mm, respectively, with saline injection, in nondistraction. The distance was 2.2 mm, 5.9 mm, and 9.8 mm, respectively, with 5-kg distraction, and 1.7 mm, 5.1 mm, and 8.8 mm, respectively, with 10-kg distraction, both with saline injection, respectively. CONCLUSION: The distance between the anterior distal tibial edge and the ATA with joint space expansion by saline injection into the joint increased, and that distance in distraction of the ankle decreased during anterior arthroscopic surgery. CLINICAL RELEVANCE: The anatomic relationship of the ATA to its surrounding structures may be at more risk without saline injection or with distraction during anterior ankle arthroscopy.

Optimal Starting Point for Fifth Metatarsal Zone II Fractures: A Cadaveric Study.

BACKGROUND: Identifying the optimal starting point for intramedullary fixation of tibia and femur fractures is well described in the literature using a retrograde or anterograde technique. This technique has not been applied to the fifth metatarsal, where screw trajectory can cause iatrogenic malreduction. The generally accepted starting point for the fifth metatarsal is "high and inside" to accommodate the fifth metatarsal's dorsal apex and medial curvature. We used a retrograde technique to identify the optimal starting position for intramedullary fixation of fifth metatarsal fractures. METHODS: Five matched cadaveric lower extremity pairs were dissected to the fifth metatarsal neck. An osteotomy was made to access the intramedullary canal. A retrograde reamer was passed to the base of the fifth metatarsal to ascertain the ideal entry point. Distances from each major structure on the lateral aspect of the foot were measured. Computed tomography scans helped assess base edge measurements. RESULTS: In 6 of 10 specimens, the retrograde reamer hit the cuboid with a cuboid invasion averaging 0.7 mm. The peroneus brevis and longus were closest to the starting position with an average distance of 5.1 mm and 5.7 mm, respectively. Distances from the entry point to the dorsal, plantar, medial, and lateral edges of the metatarsal base were 8.3 mm, 6.9 mm, 9.7 mm, and 9.7 mm, respectively. CONCLUSION: Optimal starting position was found to be essentially at the center of the base of the fifth metatarsal at the lateral margin of the cartilage. Osteoplasty of the cuboid or forefoot adduction may be required to gain access to this site. CLINICAL RELEVANCE: This study evaluated the ideal starting position for screw placement of zone II base of the fifth metatarsal fractures, which should be considered when performing internal fixation for these fractures.