Midtarsal Joint Research Articles

Radiographic Characterization of Midfoot and Transverse Tarsal Joint Osteoarthritis

Category:Ankle Arthritis; Midfoot/ForefootIntroduction/Purpose:Midfoot osteoarthritis affects over 16% of adults over the age of 50, interfering with activities of daily living and leisure. Non-operative management includes anti-inflammatory, carbon fiber shank/custom orthotics, and cortico-steroid injections. To improve accuracy, these injections are often done under fluoroscopic guidance. Operative intervention with midfoot fusions is sometimes performed, though non-union rates and continued pain after surgery can be challenging. Sometimes, there can be difficulty in determining exactly which midfoot joints are most arthritic/symptomatic based on radiographs. This study aims to quantify how well surgeons are able to diagnose midfoot and transverse tarsal joint arthritis on standing radiographs versus advanced imaging.Methods:We reviewed the records of 113 patients (144 feet) with midfoot arthritis, who were treated from 2015 to 2019 at an academic medical center by a single fellowship trained foot and ankle surgeon. The mean age was 63.0 years, the average BMI was 31.5, and 7 patients eventually underwent surgery. Each patient underwent both plain radiographs, according to a standardized protocol, and either a CT or MRI scan. Radiographs and advanced images were graded separately for the presence of joint space narrowing, subchondral cysts, and other signs of arthritis in the following joints: 1st tarsometatarsal (TMT), 2nd TMT, 3rd TMT, 4th TMT, 5th TMT, naviculocuneiforms (NC), talonavicular (TN), calcaneocuboid (CC), subtalar (ST), and 1st metatarsophalangeal (MTP). The sensitivity, specificity, precision, negative predictive value, and overall accuracy of radiographs compared to CT scans was calculated for each joint. Statistical significance was assessed using a paired t-test.Results:The most common joints affected by arthritis were the 2nd TMT (radiograph=75.7%, CT=79.9%) and 3rd TMT (radiograph=65.5%, CT=70.4%). Advanced imaging showed a significantly higher rate of arthritis in the 1st TMT (P<0.01), 4th TMT (P<0.01), and 5th TMT (P<0.01), as compared to radiograph. Only 16.9% of patients' radiographs had a direct correlation with the results of their CT scan. A CT scan showed one or two additional affected joints by 19.7% and 13.0 %, respectively; and rarely showed one or two less joints affected by arthritis (8.1% and 3.2%, respectively). We found radiographic sensitivity and specificity to be highly variable (1st TMT=61.3% & 92.3%, 3rd TMT=79.5% & 69.3%).Conclusion:Radiographs vary drastically in their sensitivities and specificities in diagnosing arthritic joints in the midfoot and transverse tarsal joints. When treating midfoot osteoarthritis surgically, we recommend obtaining advanced imaging preoperatively, rather than relying on plain radiographs alone to determine which joints may need to be managed surgically.

Compression of A Midfoot Osteotomy Using A Circular External Fixator: What is the Ideal Pin Configuration?

Category:Midfoot/Forefoot; Diabetes; TraumaIntroduction/Purpose:Foot and ankle deformity correction through midfoot osteotomy can be implemented in a wide variety of clinical situations. Use of a circular ring fixator for osteotomy fixation is particularly useful for patients with poor soft tissue envelopes and/or active infection as can occur in diabetes and Charcot arthropathy. The foot pins in a ring fixator can be configured to apply compression at the osteotomy site. However, the optimal pin configuration and force has yet to be determined. The purpose of this study was to quantify compressive forces achieved across midfoot osteotomies with various wire configurations in a circular ring fixator construct.Methods:Nine through-knee amputation cadavers were stabilized with a standard circular external fixation carbon frame. A midfoot osteotomy through the transverse tarsal joint was performed using an oscillating saw. A 4mm bone wedge was removed from the osteotomy site for placement of a Tekscan pressure sensor. A two-ring frame was applied in the standard fashion and three parallel 1.8mm smooth wires were placed parallel to each other through the foot distal to the osteotomy: wire #1 proximally through the cuneiforms, wire #2 through the base of the metatarsals, wire #3 through the metatarsal shafts. After baseline pressure readings, wires were sequentially attached (wire #1 alone, wire #1-2, wire #1-3) to the ring fixator and tensioned to 90kg. Pressure readings were recorded at the osteotomy site for each sequential wire tensioning both at the hole location where the wire naturally crossed, 'neutral', and again at one hole 'proximal' (e.g., toward the osteotomy).Results:Average compressive load at neutral hole positioning for wire #1 was 382 N. The addition of wire #2 increased the compressive load to 439 N on average. The addition of wire #3 decreased compressive force to 372 N. Similar trends were seen in proximal hole positioning where average compressive force increased following tensioning of wire #2 from 580 N to 600 N but compressive force decreased on wire #3 addition to 425 N. Therefore, tensioning forefoot thin wires in the proximal hole position increases compressive forces by 50% compared to neutral position, and adding a second wire increased compressive force by up to 15% compared to a single forefoot wire.Conclusion:In a circular frame midfoot fusion model, the greatest compressive force was achieved with two wires tensioned in the proximal hole position. The addition of a third wire led to force decrease likely due to off-axis forces that may distract the osteotomy site given the difficulty of passing all wires perfectly parallel in all planes. Ideal positioning and tensioning of forefoot pins may optimize construct stability and compression and improve healing of the midfoot osteotomy.

Bevel-geared mechanical foot: a bioinspired robotic foot compensating yaw moment of bipedal walking

The human foot structure has been evaluated, especially on its contribution to stable bipedal locomotion. This paper presents a bevel-geared mechanical bioinspired robotic foot that emulates the rotational motions of the human subtalar and oblique midtarsal joints. The motions generate a yaw moment at touch-down and may contribute to suppressing yaw rotation of the whole body. We develop a musculoskeletal biped robot equipped with feet and conduct walking experiments to measure the generated yaw moment during walking. Experimental results demonstrate that the peak of the yaw moment and the amplitude change of the torso yaw rotation significantly decrease by 41.4% and 13.0% with the geared foot, respectively. This study proposes a mechanical design for reducing the yaw moment and whole-body rotation of a bipedal walking robot without complicated control.

Posterior tibial tendon dysfunction alters the midfoot mechanics and energetics during gait

A comprehensive insight into the in vivo foot kinetics of patients with posterior tibial tendon dysfunction (PTTD) is lacking to support clinical decision making. Our goal was to study how PTTD alters the kinetic and kinematic characteristics of the foot and ankle with a special focus on the midfoot joints. Multisegment foot joint kinetics and kinematics were compared based on the Rizzoli Foot Model and inversed dynamics between a control group (n = 25), patients with PTTD Stage II (n = 21) and PTTD Stage III (n = 4) over the entire stance phase. Compared to controls, a mean decrease in power generation of 1.3 W/kg was found in the Ankle joint in PTTD II patients (p < 0.001) and PTTD III patients of 1.5 W/kg (p < 0.001). In the Chopart joint, there was a mean increase in power absorption of 0.4 W/kg in the PTTD III patients (p = 0.014) and a mean decrease in power generation of 0.6 W/kg (p < 0.001) in the PTTD II patients. The distribution of total negative work showed a shift from the Ankle and first metatarsal phalangeal joint towards the Chopart joint in both PTTD compared with the control subjects. A significant reduction in range of motion was observed among both PTTD groups. The outcome of this study will enable the possibility to customize the conservative and surgical treatment of each patient with PTTD, to improve or even restore the kinetic features. This will prevent the natural deterioration of function seen in this pathology.

A new methodology to estimate flat foot in skeletal remains - the example of Mediterranean collections.

Flat feet (pes planus) are considered a postural defect caused by the collapse of the longitudinal arch, producing complete or near-complete contact of the sole of the foot with the ground. Pes planus has been well-studied in clinical literature and paleoanthropology but has not been approached extensively in bioarchaeology. The main difficulty is related to the diagnosis of this pathology based exclusively on bone remains. In this work, we propose a metric and morphological method to discriminate flat foot in dry bones. Thus, we studied 390 pairs of adult feet in a fair state of preservation from archaeological contexts from Spain, Italy, and Oman. Morphological variability, angles, and dimensions of both the normal bones and the bones displaying flat foot characteristics were analyzed. We found a correlation between the presence of flat foot and some morphological and metric features, mainly in the subtalar and Chopart joints. These results are expressed through a combination of morphological and metric variables, which are useful to discriminate between these two groups. No markedly significant differences of flat foot frequencies between the Spanish and Italian series were found across centuries. However, we noticed a notable increase of the prevalence of flat foot in the contemporary collection, possibly due to the consequences of a rise in life expectancy and modern styles of footwear.

Recognition of ankle sprain: not only lateral collateral ligament injury

Ankle sprains are a common cause of morbidity in the general and athletic population. The majority of sprains involve the lateral aspect of the ankle, affecting the anterior talofibular ligament. However, the extent and categories of injury will depend upon the mechanism of injury. The ankle injury caused by ankle sprain is not only the injury of lateral collateral ligaments, but also chondral or osteochondral lesions of the talus, anterior ankle impingement, posterior ankle impingement and so on. In addition to the involvement of ankle joint, ankle sprain often leads to the injury of subtalar joint and transverse tarsal joint, even stress fracture, special part fracture or tendon soft tissue injury; multiple injuries often coexist. In clinical work, we should pay more attention to it.

The Effect of Neuropathy and Diabetes Type on Multisegment Foot Kinematics: A Cohort Study on 70 Participants with Diabetes

While lower limb biomechanics of people with diabetes are well described, the effects of diabetes type and of peripheral neuropathy on foot joint kinematics have not been addressed in depth. A total of 70 patients with type 1 (n = 25) and type 2 (n = 45) diabetes mellitus, with and without peripheral neuropathy, underwent functional evaluation via gait analysis using an established multisegment foot kinematic model. ANCOVA was performed to assess differences in foot joints’ range of motion (ROM) between groups with diabetes and a control group by accounting for the effects of age, body mass index (BMI) and normalized walking speed. Statistical parametric mapping was used to assess differences in temporal patterns of foot joint motion across normalized gait cycle. Small but significant correlations were found between age, BMI, speed and foot joints’ ROM. Regardless of diabetes type and presence of neuropathy, all subgroups with diabetes showed limited ROM at the midtarsal and tarsometatarsal joints. Increased midtarsal joint dorsiflexion and adduction was associated with increased tarsometatarsal joint plantarflexion. After accounting for the effect of covariates, diabetes is associated with reduced ROM and to alterations of the kinematic patterns, especially at the midtarsal and tarsometatarsal joints, irrespective of type and neuropathy.

Biomechanical Effects of Graft Shape for the Evans Lateral Column Lengthening Procedure: A Patient-Specific Finite Element Investigation.

The Evans calcaneal lengthening osteotomy procedure is widely used for correcting progressive collapsing foot deformity. However, it can result in overcorrection and degenerations of the calcaneocuboid joint. Different shapes of graft have been used in the Evans calcaneal osteotomy, but potential differences in their biomechanical effects is still unclear. The present study was designed to explore the biomechanical effects of graft shape and improve the Evans procedure to avoid or minimize detrimental effects. Twelve patient-specific finite element models were established and validated. A triangular or rectangular wedge of varying size was inserted at the lateral edge of calcaneus, and the degree of correction was quantified. The stress in spring ligaments and plantar fascia and the contact characteristics of the talonavicular and calcaneocuboid joints were calculated and compared accordingly. The rectangular graft provided a much higher degree of correction than triangular grafts did. However, the contact characteristics of the calcaneocuboid joint and talonavicular joint were abnormal, with clear sensitivity to increased graft size, and the modeled strain of the spring ligament increased. The finite element analysis predicts that the rectangular grafts provide a higher degree of correction, but risks overcorrection compared with triangular grafts. The triangular graft may have a lower degree of disturbance to the biomechanical behaviors of the midtarsal joint. The model shows that both the shape and size of an Evans osteotomy bone wedge can have effects on the contiguous joints and ligamentous structures. Those effects should be considered when selecting a bone wedge for an Evans calcaneal osteotomy. Level III, case-control study.

Midtarsal joint sprain: A case report

Midtarsal joint sprain: A case report

Weightbearing CT Analysis of the Transverse Tarsal Joint During Eversion and Inversion.

Understanding of the movement and function of the transverse tarsal joint (TTJt) continues to evolve. Most studies have been done in cadavers or under nonphysiologic conditions. Weightbearing computed tomographic (WBCT) scans may provide more accurate information about the position of the TTJt when the hindfoot is in valgus or varus. Five volunteers underwent bilateral weightbearing CT scans while standing on a platform that positioned both hindfeet in 20 degrees of valgus and 20 degrees of varus. Each bone of the foot was segmented, and the joint surfaces of the talus, calcaneus, cuboid, and navicular were identified. The principal axes for each joint surface were determined and used to calculate the angles and distances between the bones with the foot in valgus or varus. In the coronal plane, the angle between the talus and calcaneus rotated 17.1 degrees as the hindfoot moved from valgus to varus. The distance between the centers of the talus and calcaneus decreased 7.1 mm. The cuboid translated 3.9 mm medially relative to the calcaneus. There was no change in angle or distance between the cuboid and navicular. The navicular rotated 25.4 degrees into varus relative to the talus. The TTJt locking mechanism was previously thought to occur from the talonavicular and calcaneocuboid joint axes moving from parallel to divergent as the hindfoot inverts. The current data show a more complex interaction between the four bones that comprise the TTJt and suggests that the locking mechanism may occur because of tightening of the ligaments and joint capsules. This study uses weight bearing CT scans of healthy, asymptomatic volunteers standing on valgus and varus platforms to characterize the normal motion of the transverse tarsal joint of the foot. A better understanding of how the transverse tarsal joint functions may assist clinicians in both the conservative and surgical management of hindfoot pathology.

Current concept management of talus fracture: a literature review

Fractures of the talus are uncommon. The relative infrequency of these injuries relates to limited guidelines to treat talus fracture. Talus fracture is always associated with high energy injury critical to the normal function of the ankle, subtalar, and transverse tarsal joints. Outcomes vary widely and are related to the degree of initial fracture displacement. Nondisplaced fractures have a favorable outcome in most cases. Failure to recognize fracture displacement (even when minimal) can lead to undertreatment and poor outcomes. Current detailed diagnoses through Multidetector CT (MDCT) are preferred to avoid miss diagnosed in talar fracture. Although early treatment and delayed treatment did not significantly differ, multiple-choice to treat talus fracture should be known. Conservative and operative treatment can be done in accordance with clinical findings and fracture patterns. With a high risk of complication, appropriate therapy should be done. Many research and articles have been done to develop the treatment and reduce complications over talar fracture from an invasive procedure to a non-invasive procedure like arthroscopy. Therefore, we compile current treatment to give another perspective for surgeons to treat talar fracture patients

Region specificity of rheumatoid foot symptoms associated with ultrasound-detected synovitis and joint destruction

Objectives We aimed to clarify the clinical implication of ultrasound (US)-detected foot joint inflammation in tightly controlled patients with rheumatoid arthritis (RA). Methods We evaluated bilateral foot joints (second to fifth metatarsophalangeal joints of forefoot; tarsometatarsal, cuneonavicular and midtarsal joints of midfoot) of 430 RA patients for synovitis using Power Doppler (PD) imaging by US. We made a cross-sectional and a 3-year longitudinal analysis about the associations of US-detected synovitis with clinical, laboratory and radiographic data as well as foot-specific outcomes using a self-administered foot evaluation questionnaire (SAFE-Q). Results The US-detected foot synovitis was seen in 28% of patients. The US-detected synovitis was closely related to 28 joint-disease activity score (DAS28) more in the forefoot than in the midfoot, while related to joint destruction in both. Multiple regression analyses showed significant associations between midfoot PD positivity and SAFE-Q in the remission group. SAFE-Q was worsened after the 3-year interval, but PD positivity at baseline did not contribute to the changes. On the other hand, destruction of the joints with US-detected synovitis significantly progressed in 3 years than with not. Conclusions US-detected synovitis on foot joints were related to systemic inflammation, clinical symptoms, and future joint destruction with region specificity.

Cartilage Matrix Changes in Hindfoot Joints in Chronic Ankle Instability Patients After Anatomic Repair Using T2-Mapping: Initial Experience With 3-Year Follow-Up.

Anatomic repair is widely accepted as the primary surgical treatment for chronic lateral ankle instability (CLAI). T2-mapping is a powerful tool for quantitative assessment of biochemical changes in cartilage matrix. To longitudinally evaluate cartilage matrix changes in the hindfoot joints of CLAI patients before and after anatomic repair by using T2-mapping with magnetic resonance imaging (MRI). Prospective. Thirty-two CLAI patients (males/females=20/12) and 21 healthy controls (males/females=13/7). 3 T; sagittal multi-echo spin-echo technique (T2-mapping), coronal, sagittal, and axial spin-echo PD-FS, and sagittal T1WI sequences. MRI examinations were performed in CLAI patients at baseline (prior to surgery) and 3 years after anatomic repair and in healthy controls. On T2-maps, the hindfoot joints were segmented into 16 cartilage subregions. The T2 value of each subregion was measured. All patients were evaluated with the American Orthopedic Foot and Ankle Society (AOFAS) scale at baseline and after surgery. Analysis of variance (ANOVA) and Student's t-test were used. The differences corresponding to P < 0.05 were considered statistically significant. At baseline, the T2 values in most cartilage subregions of talar dome and medial posterior subtalar joint (pSTJ) were higher in CLAI patients than in healthy controls. After surgery, only the T2 value of anteriomedial talar dome decreased from that at baseline (31.11 ± 3.88 msec vs. 34.27 ± 5.30 msec). The T2 values of other subregions with elevated T2 values remained higher than healthy controls. There were no significant differences in T2 values in the midtarsal joints between CLAI patients and healthy controls (P=0.262, 0.104, 0.169, 0.103). Postoperatively, the patients' AOFAS scores improved significantly from 67.81 to 89.13. CLAI patients exhibited elevated T2 values in most subregions of talar dome and medial pSTJ. After anatomic repair, although the patients exhibited good clinical outcomes, the elevated T2 values could not be fully recovered. 2 TECHNICAL EFFICACY STAGE: 4.

Common late complications of longitudinal forefoot amputations in neuropathic foot treatment.

To describe and quantify the complications arising in consecutive neuropathic patients undergoing partial longitudinal amputations of the foot. A retrospective study was conducted with data collected from the medical records of patients monitored at the Insensitive Foot Clinic of the Foot and Ankle Group of our institution who underwent partial amputation of foot rays from 2000 to 2016. A total of 28 patients met the inclusion criteria, with a total of 31 amputated/partially amputated feet. Of these, 18 (58.1%) feet were amputated/partially amputated due to diabetes, seven (22.6%) due to leprosy, two (6.5%) due to alcoholic neuropathy, two (6.5%) secondary to traumatic peripheral nerve injury, and two (6.5%) due to other causes. Fifth ray amputation was the most frequent type (n=12). The cause of amputation was the presence of an infected ulcer in 93.6% of the samples. At a mean follow-up time of 60 months, 13 (41.9%) feet required new amputations-five (38.5%) transtibial, five (38.5%) transmetatarsal, two (15.4%) of the toes, and one (7.7%) at Chopart's joint. Patients with diabetes had a 50.0% reamputation rate. Patients who initially underwent amputation of the fifth ray had a 58.3% reamputation rate. Partial longitudinal amputation of the foot in neuropathic patients exhibited a high reoperation rate, especially in patients with diabetes or in patients with initial amputation of the peripheral rays. Declaration of interest: The authors have no conflicts of interest.

Free moment induced by oblique transverse tarsal joint: investigation by constructive approach.

The human foot provides numerous functions that let humans deal with various environments. Recently, study of the structure of the human foot and adjustment of an appropriate reaction force and vertical free moment during bipedal locomotion has gained attention. However, little is known about the mechanical (morphological) contribution of the foot structure to the reaction force and free moment. It is difficult to conduct a comparative experiment to investigate the contribution systematically by using conventional methods with human and cadaver foot experiments. This study focuses on the oblique transverse tarsal joint (TTJ) of the human foot, whose mechanical structure can generate appropriate free moments. We conduct comparative experiments with a rigid foot, a non-oblique joint foot (i.e. mimicking only the flexion/extension of the midfoot), and an oblique joint foot. Axial loading and walking experiments were conducted with these feet. The axial loading experiment demonstrated that the oblique foot generated free moment in the direction of internal rotation, as observed in the human foot. The walking experiment showed that the magnitude of the free moment generated with the oblique foot is significantly lower than that with the rigid foot during the stance phase. Using this constructive approach, the present study demonstrated that the oblique axis of the TTJ can mechanically generate free moments. This capacity might affect the transverse motion of bipedal walking.

Simultaneous dislocation of the Lisfranc and Chopart joints: A case report, surgical technique, and literature review

Simultaneous dislocation of the Lisfranc and Chopart joints: A case report, surgical technique, and literature review

Biomechanical maturation of foot joints in typically developing boys: Novel insight in mechanics and energetics from a cross-sectional study

BackgroundA growing body of quantitative evidence has been provided regarding age-related differences in plantar foot loading, multi-segment foot kinematics and muscle activity. Fundamental insight into the joint mechanics and energetics of the maturing foot has yet to be provided. Research question/HypothesisIt was hypothesized that so-called ‘biomechancial maturation’ joint kinetics would be observed in children underneath the age of eight and that older age-groups would not differ from each other in these parameters. MethodsFourty-three typically developing boys were recruited and allocated to three different age groups: 1) an early childhood group, 2) a middle childhood group, and 3) an early and late adolescence group. Multi-segment joint kinematics and kinetics of the Ankle-, Chopart-, Lisfranc- and Hallux joint were collected during barefoot walking. One-way Analysis of Covariance was conducted to examine differences among the outcome measures with group as a fixed factor and walking cadence as covariate. ResultsThe youngest group differed significantly from the other two age groups with respect to their ankle and chopart joint peak plantarflexion moment (p < 0.05). Ankle and chopart joint peak power generation as well as the lisfranc peak plantarflexion moment was found to be significantly lower in the youngest age group compared to the oldest group (p < 0.05). At the lisfranc joint, the youngest age group demonstrated a significantly higher peak plantarflexion velocity compared to the two older age groups (p < 0.05). SignificanceThis study provides novel insight into the biomechanical maturation of the developing foot which may guide clinical interventions in paediatric cohorts.

Anomalous plantar intrinsic foot muscle attaching to the medial longitudinal arch: possible mechanism for medial nerve entrapment: a case report

BackgroundMuscular variations are potentially symptomatic and may complicate imaging interpretation. Intrinsic foot musculature and extrinsic tendon insertion variations are common. Distinct supernumerary muscles are rare. We report a novel anomalous intrinsic foot muscle on the medial longitudinal arch.Case presentationAn accessory muscle was encountered on the medial arch of the right foot of a 78-year-old white male cadaver, between layers two and three of the foot intrinsics. It did not appear to be a slip or variant of a known foot muscle. This muscle consisted of two slips that ran transversely on the plantar aspect of the medial arch, crossing the medial transverse tarsal joint and attaching to the tuberosity of the navicular, the short and long plantar ligaments, and spring ligament.ConclusionsThe medial plantar vessels and nerve passed from deep to superficial between the two slips, and this suggests a possible location for medial nerve entrapment.

Surgical Treatment of Severe Idiopathic Flexible Flatfoot by Evans-Mosca Technique in Adolescent Patients: A Long-Term Follow-Up Study.

Flexible idiopathic flatfoot is very common in growing age and rarely causes pain or disability. Surgery is indicated only in severe symptomatic cases that are resistant to conservative treatment, and numerous surgical procedures have been proposed. Lateral column calcaneal lengthening as described by Evans and modified by Mosca is a widely used surgical technique for the correction of severe symptomatic flexible flatfoot. In the present study, we report the long-term clinical and radiographic results in 14 adolescent patients (mean age: 12.8 years) affected by severe symptomatic flexible flatfoot, surgically treated by Evans–Mosca procedure, for a total of 26 treated feet (12 cases bilateral and 2 unilateral). In all cases, surgery was indicated for the presence of significant symptoms resistant to nonsurgical management. Clinical evaluation was made according to the American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale, the Foot and Ankle Disability Index (FADI) Score, and Yoo et al.'s criteria. Radiographic evaluation was made using anteroposterior and lateral weight-bearing radiographs of the feet to evaluate Meary's angle and Costa–Bertani's angle and to evaluate possible osteoarthritic changes in the midtarsal joints. At follow-up (mean: 7 years and 7 months), we observed a satisfactory result in all patients. The mean average score of the AOFAS Ankle-Hindfoot Scale improved from 60.03 points to 95.26; the mean FADI score improved from 71.41 to 97.44; and according to Yoo et al.'s criteria, the average clinical outcome score was 10.96. At radiographic examination, nonunion of the calcaneal osteotomy was never observed. Meary's angle improved from an average preoperative value of 25° to 1.38° at follow-up; Costa–Bertani's angle improved from an average preoperative value of 154.2° to 130.9° at follow-up. In no case, significant radiographic signs of midtarsal joint arthritis were observed. According to our results, we believe that Evans–Mosca technique is a valid option of surgical treatment for severe idiopathic flexible flatfoot and allows a satisfactory correction of the deformity with a low rate of complications.

Real-Time Analysis of the Dynamic Foot Function: A Machine Learning and Finite Element Approach.

Finite element analysis (FEA) has been widely used to study foot biomechanics and pathological functions or effects of therapeutic solutions. However, development and analysis of such foot modeling is complex and time-consuming. The purpose of this study was therefore to propose a method coupling a FE foot model with a model order reduction (MOR) technique to provide real-time analysis of the dynamic foot function. A generic and parametric FE foot model was developed and dynamically validated during stance phase of gait. Based on a design of experiment of 30 FE simulations including four parameters related to foot function, the MOR method was employed to create a prediction model of the center of pressure (COP) path that was validated with four more random simulations. The four predicted COP paths were obtained with a 3% root-mean-square-error (RMSE) in less than 1 s. The time-dependent analysis demonstrated that the subtalar joint position and the midtarsal joint laxity are the most influential factors on the foot functions. These results provide additionally insight into the use of MOR technique to significantly improve speed and power of the FE analysis of the foot function and may support the development of real-time decision support tools based on this method.