Midtarsal Joint Research Articles

Foot kinematics and kinetics data for different static foot posture collected using a multi-segment foot model

This dataset presents human foot joints kinematics and kinetics data during walking, classified by static foot posture, filling a gap in existing lower limb databases that lack data on foot joints beyond the ankle or on static posture data, despite its link to foot and lower limb pathologies. Kinematics were recorded using a three-dimensional mocap system, and kinetics through a pressure platform, employing a multi-segment foot model including the ankle, midtarsal and first metatarsophalangeal joint. The dataset contains 350 recordings of right foot joint angles and moments and contact pressures from 70 healthy subjects with varying static posture (highly pronated, highly supinated and normal). Data were collected at 100 Hz, filtered and resampled to 100 frames throughout the stance phase. Descriptive data are also provided: age, weight, height, BMI and foot anthropometric data and foot posture index. Plots, tables and ANOVAs are included for validation. Presented in .xlsx and .mat formats, this database can assist professionals in corrective footwear design, insole customization, surgical planning, and evaluating interventions on foot dynamics.

Distribution Patterns of Tumors and Tumor-Like Lesions of the Forefoot and Midfoot A 12.5-Year Study at a University Hospital.

Masses in the forefoot and midfoot are common reasons for medical presentation and can be caused by various pathological conditions. The challenge in clinical practice is to distinguish the multitude of trivialities from the few malignant entities and to arrive at a reliable clinical diagnosis in a reasonable amount of time with a moderate use of diagnostic tools. In a retrospective analysis, tumors, tumor-like lesions, and pseudotumors distal to the Chopart joint presented to our multidisciplinary university tumor board between January 2010 und June 2023 were analyzed concerning entity, location, age, and sex. Of the 167 cases included, 18 were osseous and 149 were soft tissue lesions. Overall, the metatarsal region was most frequently affected, accounting for 42.5% of all cases. Osseous lesions showed a preference for the phalanges and soft-tissue lesions occurring more frequently in the metatarsal region. In total, 88.0% of all cases were benign. All 20 malignant cases derived from soft tissue, occurred in all sections of the forefoot and midfoot and comprised 13 entities. Most lesions affected middle-aged patients, but cases occurred in almost every age group. In the examined patient population of a German university hospital, most cases were benign soft tissue lesions with a substantial share of pseudotumors and tumor-like lesions. However, the malignancy rate of 12.0% highlights the importance of differential diagnostic considerations. In cases of uncertain results, it is crucial to refer individuals with unclear masses to a specialized center for musculoskeletal tumor care early on in their treatment process. III.

Postoperative Calcaneocuboid Joint Subluxation and Midtarsal Joint Changes in Pediatric Idiopathic Flexible Flatfoot Treated With Calcaneal Lengthening Osteotomy: A Midterm Follow-up Study.

Calcaneal lengthening osteotomy (CLO) is one of the main surgical options for treatment of pediatric idiopathic flexible flatfoot (FFF). Reportedly, calcaneocuboid (CC) joint subluxation occurs after CLO; however, its effect on the midfoot remains unclear. This study aimed to investigate the radiologic midterm results after CLO treatment in pediatric idiopathic FFF. We evaluated 23 pediatric patients with idiopathic FFF aged ≥8 years, who underwent CLO from 1999 to 2017 owing to moderate to severe flatfoot deformity (assessed by visual inspection). Patients aged between 8 and 14 years were included (mean follow-up: 6.3 years; range, 3.1-11.4 years). Anteroposterior and lateral weightbearing foot radiographs were assessed for radiologic parameters preoperatively and at the 3-month, 1-year, and final follow-ups postoperatively. All patients had immediate postoperative radiologic correction of the flatfoot deformity, and these improvements were maintained until the final follow-up. The mean allograft length inserted was 9 (range, 8-10) mm. There was increased CC joint subluxation after CLO, but it improved continuously until the final follow-up. A CC joint spur was newly noted in 1 case. There were 24 cases (24/39, 61.5%) of talonavicular (TN) joint spurs at the final follow-up, but 19 of these were already present on the preoperative radiographs (19/24, 79.2%). Further, the new-onset TN joint spurs were not associated with preoperative clinicoradiologic factors. In pediatric patients with idiopathic FFF receiving CLO treatment, preoperative radiologic angles improved. CC joint subluxation increased after surgery; however, it gradually reduced without evidence of CC joint arthritic changes over the time period studied in this cohort.

Cone-beam computed tomography imaging and three-dimensional analysis of midfoot joints during non-weightbearing and weightbearing in 11 healthy feet.

Studies report that Lisfranc injury is more common than thought. Several imaging methods for assessing the stability of Lisfranc injury have been described but many are impossible to standardize and not accurate enough. To present a three-dimensional (3D) method for analyzing the changes in the joint space width of the midfoot joint and the joints of the medial part of the Lisfranc complex in healthy individuals. Non-weightbearing and weightbearing cone-beam computed tomography (CBCT) images of 11 healthy feet were acquired and analyzed with 3D software. The mean range of joint space width changes of each joint was computed from the changes in individual image pairs. 3D analysis software was used to analyze the medial part of the Lisfranc complex. In this sample of healthy feet, the changes in the joint spaces in the medial part of Lisfranc complex, calculated with 3D analysis software, was less than 0.6 mm. The distance between bones increased or decreased, depending on which part of the joint surface the measurements were taken. In this study, we present a 3D analysis method to evaluate midfoot joint space width changes. Our analysis revealed that in healthy feet there are only minimal changes in the joint space width between weightbearing and non-weightbearing indicating minimal movement of the midtarsal joints. The 3D analysis of weightbearing CBCT data provides a promising tool for analyzing the small midfoot joints in a variety of conditions.

A comparison of foot and ankle biomechanics during running drills and distance running

ABSTRACT The aim of this study was to compare the foot-ankle joint mechanics of running drills and running. Seventeen long-distance runners performed five popular running drills (A-skip, B-skip, Bounding, Heel flicks, Straight leg running) and a run at 3.88 m/s. Kinematics, kinetics and power values were calculated for the ankle, midtarsal (MT) and metatarsophalangeal (MP) joints. Electromyographic activity was recorded for the soleus, gastrocnemius medialis, lateralis and abductor hallucis muscle. The A-skip, the B-skip and the Heel flicks induced a smaller ankle (p < 0.001, ŋ2 = 0.41), MT (p < 0.001, ŋ2 = 0.43) and MP (p < 0.001, ŋ2 = 0.47) dorsiflexion peak than running. No difference was found between the running drills and running for ankle, MT and MP moment. The Bounding induces a higher positive ankle power than running (diff: 5.5 ± 7.5 J/kg, p = 0.014, d = 1.05). The A-skip (diff: 2.8 ± 2.9 J/kg, p < 0.001, d = 1.5) and the B-skip (diff: 2.7 ± 2.1 J/kg, p < 0.001, d = 1.4) induce a smaller MT positive power than running. This study offers an analysis of the mechanical behaviour of the foot-ankle complex to help track and field coaches select their running drills in an evidence-based manner.

Clinical and Radiographic Outcomes of Nitinol Compression Staples for Midfoot and Chopart Arthrodesis

Nitinol staple use in orthopedic surgery has increased in recent years. Biomechanical studies provide useful data for use in foot/ankle; however, clinical data is limited. This study's purpose is to determine the efficacy of nitinol staples to achieve stable, bony arthrodesis in midfoot and Chopart joints, and examine their clinical outcomes and pain scores. A retrospective chart review was performed on 127 midfoot/Chopart joint arthrodeses (71 patients) using nitinol staples in isolation. The primary outcome variable was radiographic evidence of healing. Radiographs were blinded, randomized, and independently reviewed by three board certified foot and ankle surgeons. Complete/partial union was seen in 89% of all joints (113/127), increasing to 93% when including only midfoot joints (98/106). Chopart joints had significantly lower healing rates (15/21; 71%) compared to all midfoot joints (p = 0.01) and isolated tarsometatarsal joints (86/91; 95%) (p = 0.006). Neuropathy and smoking did not affect arthrodesis, but diabetes did (p = 0.004). Joints requiring bone grafting had worse rates of arthrodesis (38/49; 76%) (p = 0.002). For all joints, post-operative visual analog scale scores were significantly lower than pre-operative (p < 0.001). Pre-operative midfoot and Chopart pain scores were similar (p= 0.30). Midfoot joints had significantly lower pain scores post-operatively than pre-operatively (p < 0.001). No such significance existed in Chopart joints (p = 0.07). Isolated nitinol staples are a viable option for midfoot arthrodesis, especially tarsometatarsal joints, and offer significant pain improvement. Chopart joints may require more rigid fixation than nitinol staples, given the lower healing rate. Level of Clinical EvidenceIV

Static posture weightbearing joint angle differences in patients with varus ankle osteoarthritis

BackgroundAdvanced varus ankle osteoarthritis is a debilitating disease that can present with limited physical function, severe pain, and diminished quality of life. Weightbearing computed tomography enables submillimeter 3-dimensional visualization, computational analyses, and enhanced diagnoses in reporting complex degenerative changes more accurately. Research questionThis study set to compare static posture weightbearing joint angle differences in healthy and varus ankle osteoarthritis patients (compensated and non-compensated). MethodsOur retrospective assessment included 70 individuals, 44 of whom were diagnosed with advanced varus ankle osteoarthritis, and the remaining 26 were healthy participants to serve as controls. An automatic anatomic coordinate system was applied to each patient’s 3-dimensional talus and calcaneus bone reconstructions from weightbearing computed tomography scans. Subtalar and midtarsal joint angles were calculated using Euler angles. ResultsWe report statistical differences between the healthy group and both advanced varus osteoarthritis groups for midtarsal inversion/eversion. Specifically, both osteoarthritis groups’ midtarsal joints were more inverted and plantarflexed as compared to healthy participants. Compensated and non-compensated subtalar joints were statistically different with respect to inversion/eversion. Non-compensated ankles exhibited a similar mean to healthy ankles who were both less inverted than compensated ankles. SignificanceOur study helps physicians to better understand underlying mechanisms of peritalar compensation in varus ankle osteoarthritis. Patients featuring hindfoot compensation on average had a greater subtalar joint angle indicating greater inversion than healthy and non-compensated patients.

Human in vivo midtarsal and subtalar joint kinematics during walking, running and hopping.

The interaction among joints of the midtarsal complex and subtalar joint is important for locomotor function; however, its complexity poses substantial challenges in quantifying the joints' motions. We determine the mobility of these joints across locomotion tasks and investigate the influence of individual talus morphology on their motion. Using highly accurate biplanar videoradiography, three-dimensional bone kinematics were captured during walking, running and hopping. We calculated the axis of rotation of the midtarsal complex and subtalar joint for the landing and push-off phases. A comparison was made between these rotation axes and the morphological subtalar axis. Measurement included total rotation about and the orientation of the rotation axes in the direction of the subtalar joint and its deviation via spatial angles for both phases. The rotation axes of all three bones relative to the talus closely align with the morphological subtalar axis. This suggests that the midtarsal and subtalar joints' motions might be described by one commonly oriented axis. Despite having such an axis, the location of the axes and ranges of motion differed among the bones. Our results provide a novel perspective of healthy foot function across different sagittal plane-dominant locomotion tasks underscoring the importance of quantifying midtarsal complex and subtalar motion while accounting for an individual's talus morphology.

Effects on gait kinematics, pedobarography, functional and subjective results after isolated chopart injury

BackgroundThis study analysed changes in gait and pedobarography and subjective and functional outcomes after isolated Chopart joint injury.MethodsThe results of 14 patients were reviewed. Kinematic 3D gait analysis, comparative bilateral electromyography (EMG) and pedobarography were performed.ResultsOn the injured side, the 3D gait analysis showed a significantly increased internal rotation and decreased external rotation of the hip and significantly decreased adduction and decreased range of motion (ROM) for the ankle. On the healthy side, the pedobarography revealed a significantly increased mean force in the forefoot, an increased peak maximum force and an increased maximum pressure in the metatarsal. When standing, significantly more weight was placed on the healthy side.The EMG measurements showed no significant differences between the healthy and injured legs.ConclusionsAfter isolated Chopart injuries, significant changes in gait and pedobarography can be seen over the long term.

Direct visualization and measurement of the plantar aponeurosis behavior in foot arch deformation via the windlass mechanism.

The plantar aponeurosis (PA) is an elastic longitudinal band that contributes to the generation of a propulsive force in the push-off phase during walking and running through the windlass mechanism. However, the dynamic behavior of the PA remains unclear owing to the lack of direct measurement of the strain it generates. Therefore, this study aimed to visualize and quantify the PA behavior during two distinct foot postures: (i) neutral posture and (ii) windlass posture with midtarsal joint plantarflexion and metatarsophalangeal joint dorsiflexion, using computed tomography scans. Six healthy adult males participated in the experiment, and three-dimensional reconstruction of the PA was conducted to calculate its path length, width, thickness, and cross-sectional area. This study successfully visualized and quantified the morphological changes in the PA induced by the windlass mechanism, providing a precise reference for biomechanical modeling. This study also highlighted the interindividual variability in the PA morphology and stretching patterns. Although the windlass posture was not identical to that observed in the push-off phase during walking, the observed PA behavior provides valuable insights into its mechanics and potential implications for foot disorders.

Revisiting the inferior supports of Chopart joint complex.

The Chopart joint complex is a joint between the midfoot and hindfoot. The static and dynamic support system of the joint is critical for maintaining the medial longitudinal arch of the foot. Any dysfunction leads to progressive collapsing flatfoot deformity (PCFD). Often, the tibialis posterior is the primary cause; however, contrary views have also been expressed. The present investigation intends to explore the comprehensive anatomy of the support system of the Chopart joint complex to gain insight into the cause of PCFD. The study was conducted on 40 adult embalmed cadaveric lower limbs. Chopart joint complexes were dissected, and the structures supporting the joint inferiorly were observed and noted. The articulating bones exhibit features like a cuboid shelf and navicular beak, which appear to offer inferior support to the joint. The expanse of the spring ligament complex is more medial than inferior, while the superomedial part is more extensive than the intermediate and inferoplantar parts. The spring ligament is reinforced by the tendons in the superomedial part (the main tendon of tibialis posterior), the inferomedial part (the plantar slip of tibialis posterior), and the master knot of Henry positioned just inferior to the gap between the inferomedial and inferoplantar bundles. This study highlights that the medial aspect of the talonavicular articulation has more extensive reinforcement in the form of superomedial part of spring ligament and tibialis posterior tendon. The findings are expected to prompt further research in weightbearing settings on the pathogenesis of flatfoot.

Increasing midtarsal joint stiffness reduces triceps surae metabolic costs in walking simulations but has little effect on total stance limb metabolic cost

The human foot’s arch is thought to be beneficial for efficient gait. This study addresses the extent to which arch stiffness changes alter the metabolic energy requirements of human gait. Computational musculoskeletal simulations of steady state walking using direct collocation were performed. Across a range of foot arch stiffnesses, the metabolic cost of transport decreased by less than 1% with increasing foot arch stiffness. Increasing arch stiffness increased the metabolic efficiency of the triceps surae during push-off, but these changes were almost entirely offset by other muscle groups consuming more energy with increasing foot arch stiffness.

Biomechanical effects of Evans versus Hintermann osteotomy for treating adult acquired flatfoot deformity: a patient-specific finite element investigation.

Evans and Hintermann lateral column lengthening (LCL) procedures are both widely used to correct adult acquired flatfoot deformity (AAFD), and have both shown good clinical results. The aim of this study was to compare these two procedures in terms of corrective ability and biomechanics influence on the Chopart and subtalar joints through finite element (FE) analysis. Twelve patient-specific FE models were established and validated. The Hintermann osteotomy was performed between the medial and posterior facets of the subtalar joint; while, the Evans osteotomy was performed on the anterior neck of the calcaneus around 10mm from the calcaneocuboid joint surface. In each procedure, a triangular wedge of varying size was inserted at the lateral edge. The two procedures were then compared based on the measured strains of superomedial calcaneonavicular ligaments and planter facia, the talus-first metatarsal angle, and the contact characteristics of talonavicular, calcaneocuboid and subtalar joints. The Hintermann procedure achieved a greater correction of the talus-first metatarsal angle than Evans when using grafts of the same size, indicating that Hintermann had stronger corrective ability. However, its distributions of von-Mises stress in the subtalar, talonavicular and calcaneocuboid joints were lesshomogeneous than those of Evans. In addition, the strains of superomedial calcaneonavicular ligaments and planter facia of Hintermann were also greater than those of Evans, but both generally within the safe range (less than 6%). This FE analysis study indicates that both Evans and Hintermann procedures have good corrective ability for AAFD. Compared to Evans, Hintermann procedure can provide a stronger corrective effect while causing greater disturbance to the biomechanics of Chopart joints, which may be an important mechanismof arthritis. Nevertheless, it yields a better protection to the subtalar joint than Evans osteotomy. Both Evans and Hintermann LCL surgeries have a considerable impact on adjacent joints and ligament tissues. Such effects alongside the overcorrection problem should be cautiously considered when choosing the specific surgical method. Level III, case-control study.

Midterm Results after Tibiotalar or Tibiotalocalcaneal Fusion Using an Ilizarov External Fixator.

Ankle fusion is considered a treatment of choice for end-stage ankle arthritis when a total ankle replacement procedure is not indicated. However, the potential risk of secondary arthritis in the adjacent joint after ankle fusion raises arguments on whether preserving the adjacent joint during an isolated tibiotalar (TT) fusion brings about any future benefits with regard to pain and gait discomfort. In this study, we intended to present midterm results following TT or tibiotalocalcaneal (TTC) fusion using an Ilizarov external fixator and to investigate whether spontaneous fusion occurred in the subtalar or midtarsal joint. This is a retrospective observational study. Medical records of patients who underwent TT or TTC fusion using an Ilizarov external fixator for substantial bone defects around the ankle joint between 1994 and 2018 were manually searched. Forty-one patients were included and the status of the joints adjacent to the fusion site was evaluated in radiographic examinations. Of the 34 patients who underwent TT fusion, 30 patients (88.3%) had a spontaneous fusion in the adjacent joints. Specifically, 11 patients (29.4%) had subtalar joint fusion and 19 patients (55.9%) had both midtarsal joint and subtalar joint fusion. In TTC fusion, the midtarsal joint was spontaneously fused in all 7 patients. In this study, we observed spontaneous adjacent joint fusion following TT or TTC fusion using an Ilizarov external fixator for substantial bone defects around the ankle joint. Although a careful approach should be made since patients treated in this study may not represent typical candidates that need primary joint-sacrificing procedures, we believe that this study may draw attention from surgeons concerned about the fate of the adjacent joint status after TT or TTC fusion.

Prospective Outcomes of a Biological Resurfacing Arthroplasty with Fascia Lata Autograft (BioJoint) for the Treatment of Osteoarthritis of the Midtarsal Joint Complex.

To determine the clinical, safety, and radiological outcomes after biological resurfacing arthroplasty for the treatment of osteoarthritis (OA) of one or more joints of the midtarsal joint complex. All prospectively followed patients with OA to one of or multiple joints of the midtarsal joint complex who were operated with a biological resurfacing arthroplasty with a fascia lata autograft (BioJoint procedure) were included. A total of 7 patients were included (5 males, 2 females), with a median age of 52 (interquartile range [IQR] 44-55) years. The primary outcome was the Numeric Rating Scale (NRS) for pain during walking 2 years postoperatively. Range of motion (ROM), revision rates, and complications were assessed. A postoperative MRI scan was performed to assess progression of OA, graft position and ingrowth, and the degree of bone marrow edema. There was a 100% follow-up of the patients (median follow-up: 33 [IQR 26-33] months). The NRS during walking improved from 6 preoperatively to 2 at 2 years postoperatively (P < 0.05). There were no reoperations nor severe complications. The limitations in the ROM remained limited in the majority of the cases. MRI at 2 years of follow-up showed no progression of OA, reduced bone marrow edema, and no loosening of the grafts. Biological resurfacing arthroplasty with a fascia lata autograft (BioJoint procedure) for OA to one or more joints in the midtarsal joint complex showed clinically relevant pain reduction during walking, improvement in clinical and radiological outcomes, and proved to be safe and durable.

Clinical and Radiographic Outcomes of Nitinol Compression Staples for Midfoot and Chopart Arthrodesis

Category: Midfoot/Forefoot; Hindfoot Introduction/Purpose: Continuous compression implant (nitinol staples) use in orthopaedic surgery has increased in recent years. There are several advantages of nitinol staples, including a lower profile when compared to traditional fixation methods. They are easy to apply and take up a smaller footprint than most plating techniques, thus decreasing surgical time and dissection. Additionally, continuous compression across the fusion site is maintained during the resorptive phase of bone healing. Biomechanical studies provide useful data supporting the use of nitinol staples in the foot and ankle; however, clinical data is limited. This study’s purpose is to determine the efficacy of nitinol staples to achieve stable, bony healing in midfoot and Chopart joint arthrodesis, and examine their clinical outcomes, complications, and pain scores. Methods: A retrospective chart review was performed on 127 midfoot/Chopart joints (71 patients) that underwent arthrodesis using nitinol staples in isolation over a five-year period (January 2017 – February 2022). The primary outcome variable was radiographic evidence of healing. Radiographs were blinded, randomized, and independently reviewed by three board certified foot and ankle surgeons. Each investigator reviewed digital radiographs independently and recorded their radiographic finding responses. Fusions were deemed healed if greater than 50% of the arthrodesis site contained bridging bone. A partially healed arthrodesis was defined as some bridging bone, but less than 50% of the overall arthrodesis site, and a nonunion was defined as no healing seen radiographically or loss of reduction. There were no cases of complete inter-surgeon radiographic disagreement in this study. Pain scores and clinical outcomes were also collected. Smokers and diabetics represented 27% (n = 19) and 13% (n=9) of the patient population, respectively. Results: Complete/partial union was seen in 89% of all joints (113/127) and 93% of midfoot joints (98/106). Chopart joints had a significantly lower healing rate (15/21; 71%) compared to midfoot joints (p = 0.013) and TMT joints in isolation (86/91; 95%) (p = 0.006). Neuropathy and smoking had no effect on healing but diabetes did (p = 0.004). Joints requiring bone grafting had a worse healing rate (38/49; 76%) (p = 0.002). For all joints, post-operative VAS scores were significantly lower than pre-operative (p &lt; 0.00001). Midfoot and Chopart pre-operative pain scores did not differ (p= 0.30), but differed post-operatively (p = 0.003). Midfoot joints had significantly lower pain scores post-operatively than pre-operatively (p &lt; 0.00001). No such significance existed in Chopart joints (p = 0.070). Conclusion: Isolated nitinol staples are a viable option for midfoot arthrodesis, especially TMT joints, and offer significant pain improvement. Staples are lower profile, decreasing hardware irritation and potential secondary surgeries, and ease of use makes insertion efficient and reproducible. They offer the benefit of continuous compression of the fusion site, and are rigid enough to maintain reduction. Chopart joints, however, may require a more rigid fixation than nitinol staples can provide, given the lower healing rate. Caution should be exercised in diabetics and joints that may require bone grafting.

The Variation Between Unilateral and Bilateral Weight Bearing in Hindfoot Alignment Evaluation: Part II: A Prospective In Vivo Kinematic and Plantar Pressure Study

Category: Hindfoot; Midfoot/Forefoot Introduction/Purpose: When AP, lateral, and hindfoot views weight bearing XR's were taken, patients were frequently asked to stand on the foot being examined with the other foot lifted off the floor. However, we have found that alignments of the hind and midfoot during unilateral standing are different from those when bearing weight on both feet. This study compared the kinematics and plantar pressures between unilateral and bilateral standing positions in a group of asymptomatic volunteers. Methods: Ten participants (20 feet) without symptoms, previous trauma and surgical history in both lower limbs were included. Each participant first stood comfortably on both feet, then lifted the non-examined foot off the floor. Each person switched between the above two positions three times. Kinematic data was collected using an eight-camera Optitrack 3D motion capture system to reflect changes in alignments of the ankle, subtalar, and midtarsal joints. Plantar pressure distribution was assessed using a pressure platform. Paired t-tests were used to compare the metrics between the two standing positions, with statistical significance level set at P &lt; 0.05. Results: From bilateral to unilateral weightbearing, 14 out of 21 kinematic angular parameters showed medium to high level of statistical significance (p=0.001-0.046) reflecting differences in the relative positions of the ankle, subtalar, and midtarsal joints in the two weightbearing positions resulting from pronation of the hindfoot and midfoot; the average plantar pressure change underneath the hallux (0.1616N), toes 2-5 (0.0907N), metatarsals 2-4 (0.2481N, 0.3204N, 0.2649N), midfoot (0.1794N), medial and lateral heel (0.259N, 0.246N) all showed statistically significant increase. There was a significantly higher plantar pressure increase on the medial than the lateral side of the feet. This corresponded to both the kinematic changes, and our findings in another study investigating the alignment change between the positions radiographically. Conclusion: The hindfoot and midfoot are more pronated in unilateral weightbearing than in bilateral weightbearing which may mask the severity of the deformity in a flexible cavovarus foot but increase that in a flexible flatfoot. Modification of the traditionally used unilateral weightbearing position in obtaining clinical radiographs should be considered. Bilateral WBCT scans may be a better alternative, taking advantage of allowing both feet to bearing weight naturally without concerning about one foot blocking the other during the radiographic imaging.

Non-operative Success of Treating Midfoot and Transverse Tarsal Joint Osteoarthritis

Category: Midfoot/Forefoot; Other Introduction/Purpose: Midfoot osteoarthritis affects over 16% of adults over the age of 50, interfering with activities of daily living and leisure. One form of non-operative management is cortico-steroid injections, which are often done under fluoroscopic guidance to improve accuracy. Operative intervention is sometimes performed, although non-union rates and continued pain after surgery can be challenging. This study aims to quantify how well midfoot and transverse tarsal joint arthritis can be treated non- operatively with fluoroscopic-guided injections. Methods: We reviewed the records of 132 patients (155 feet), who were newly diagnosed with midfoot arthritis between 2015 and 2019. Conservative management included periodic fluoroscopic-guided steroid injections at an academic medical center by a single fellowship-trained foot and ankle surgeon. These joints were identified by computed tomography prior. Mean age was 62.7 years and mean BMI was 30.9 kg/m2. Twenty-five feet (16.1%) eventually underwent surgical treatment, and one of those (4.0%) underwent reoperation. Results: On average, each foot received 3.1 (range, 1-21) injections, this did not differ between the surgical and conservative cohorts (operative=3.9, non-operative=3.0; p=.147). Of the 95 feet (61.3%) that received more than one injection, mean duration was 21.6 (range, 0.9-67.4) months. Injection duration did not differ between cohorts (operative=21.8 months, non-operative=21.6 months; p=.952). Cases treated surgically did not receive any injections postoperatively. Patients with higher pre-treatment Pain Catastrophizing Scale (PCS) scores in all subsection5-depression=2.9, p=.046) over a greater injection duration (depression=22.2 months, non-depression=11.4 months, p=.046). Conclusion: Overall, fluoroscopic-guided injections are sufficient for the non-operative treatment of midfoot and transverse tarsal joint arthritis, as only 16.1% of our cohort failed conservative treatment and required surgery. Therefore, although not always successful, non-operative treatment with fluoroscopic guidance injections is able to provide patients relief for an extended period.

Impact of pronated foot on energetic behavior and efficiency during walking

BackgroundThe longitudinal arch of the foot acts like a spring during stance and contributes to walking efficiency. Pronated foot characterized by a collapsed medial longitudinal arch may have the impaired spring-like function and poor walking efficiency. However, the differences in the energetic behavior during walking between individuals with pronated foot and neutral foot have not been considered. Research questionHow does the energetic behavior within the foot and proximal lower limb joints in pronated foot affect walking efficiency? MethodsTwenty-one healthy young adults were classified into neutral foot and pronated foot based on the Foot Posture Index score. All subjects walked across the floor and attempted to have the rearfoot and forefoot segments contact separate force plates to analyze the forces acting on isolated regions within the foot. Kinematic and kinetic data were recorded by a three-dimensional motion capture system. The hip, knee, ankle, and mid-tarsal joint power was quantified using a 6-degree-of-freedom joint power method. To qualify total power within all structures of the foot and forefoot, we used a unified deformable segment analysis. Additionally, we calculated the center of mass power to quantify the total power of the whole body ResultsThere is no difference in the mid-tarsal joint work between the pronated foot and neutral foot. On the other hand, pronated foot exhibited greater net negative work at structures distal to the forefoot during walking. Additionally, pronated foot exhibited less net positive work at the ankle and center of mass during walking compared to neutral foot. SignificanceIndividuals with pronated foot generate the mid-tarsal joint work by increasing the work absorbed at structures distal to the forefoot, which results in reduced energy efficiency during walking. That energy inefficiency may reduce positive work at the ankle and affect the walking efficiency in individuals with pronated foot.

Mechanics of the human foot during walking on different slopes.

When humans walk on slopes, the ankle, knee, and hip joints modulate their mechanical work to accommodate the mechanical demands. Yet, it is unclear if the foot modulates its work output during uphill and downhill walking. Therefore, we quantified the mechanical work performed by the foot and its subsections of twelve adults walked on five randomized slopes (-10°, -5°, 0°, +5°, +10°). We estimated the work of distal-to-hindfoot and distal-to-forefoot structures using unified deformable segment analysis and the work of the midtarsal, ankle, knee, and hip joints using a six-degree-of-freedom model. Further, using a geometric model, we estimated the length of the plantar structures crossing the longitudinal arch while accounting for the first metatarsophalangeal wrapping length. We hypothesized that compared to level walking, downhill walking would increase negative and net-negative work magnitude, particularly at the early stance phase, and uphill walking would increase the positive work, particularly at the mid-to-late stance phase. We found that downhill walking increased the magnitude of the foot's negative and net-negative work, especially during early stance, highlighting its capacity to absorb impacts when locomotion demands excessive energy dissipation. Notably, the foot maintained its net dissipative behavior between slopes; however, the ankle, knee, and hip shifted from net energy dissipation to net energy generation when changing from downhill to uphill. Such results indicate that humans rely more on joints proximal to the foot to modulate the body's total mechanical energy. Uphill walking increased midtarsal's positive and distal-to-forefoot negative work in near-equal amounts. That coincided with the prolonged lengthening and delayed shortening of the plantar structures, resembling a spring-like function that possibly assists the energetic demands of locomotion during mid-to-late stance. These results broaden our understanding of the foot's mechanical function relative to the leg's joints and could inspire the design of wearable assistive devices that improve walking capacity.