Adult Acquired Flatfoot Deformity: Anatomy, Biomechanics, Staging, and Imaging Findings

Comparison of travel distance of center of pressure using the footscan system in individuals with and without flatfoot

BackgroundDiagnosis and treatment of flatfoot are often overlooked. Current diagnostic methods, such as lateral foot radiography and physical examination, primarily assess simple static foot conditions. The Footscan test can be employed to evaluate the static and dynamic balance of patients with flatfoot; however, the precise reference value for various Footscan test results remains undetermined.ObjectiveThis study aimed to contribute to the body of knowledge regarding flatfoot diagnosis by identifying objective differences between patients with and without flatfoot.MethodsThis study focused on individuals aged 19-50 years without ankle injuries or surgeries that could affect balance. The Footscan system was used to evaluate static balance using the total travel distance (TD) of the center of pressure in the standing position for 10 s. For dynamic balance indices, the sole was divided into forefoot, midfoot, and hindfoot zones by the system, and the contact distribution of each zone was quantified as a percentage during a 1-min walking period. Statistical analysis was performed to compare the normal and flatfoot groups, leading to the determination of cutoff values for clinically significant indices.ResultsThe study included 116 feet of 58 healthy individuals and 56 feet of 28 patients with flatfoot. Significant differences were found between the two groups for all static and dynamic balance variables. Logistic regression analysis identified TD (p = 0.001) and midfoot contact distribution (p < 0.001) as significant risk factors of flatfoot. Receiver operating characteristic analysis determined the cut-off values with the highest sum of sensitivity and specificity for diagnosis: TD ≥ 20.5 mm and midfoot contact distribution ≥ 18.95%.ConclusionsThe Footscan test indices showed significant differences in static and dynamic balance between patients with flatfoot and normal individuals. TD and midfoot contact distribution emerged as meaningful indicators of diagnostic potential.

Comparative study of subtalar arthroereisis, medializing calcaneal osteotomy and the combination of both techniques for the treatment of symptomatic adult flatfeet

BACKGROUND

Symptomatic adult flatfeet are a common problem that is treated with various therapeutic approaches. In this study, three different surgical approaches, subtalar arthroereisis (SA), medializing calcaneal osteotomy (MDCO) and a combination of both techniques (SA+MDCO) were analyzed.

METHODS

32 patients (36 feet) with pes planovalgus (mean age 49 +/- 16 years) were surgically treated with either SA (n = 8 feet), MDCO (n = 9 feet) or SA+MDCO (n = 19 feet). The American Orthopaedic Foot and Ankle Society (AOFAS) and the European Foot and Ankle Society (EFAS) questionnaires, as well as radiological parameters were compared before and after surgery within and between groups. At follow up (6 +/- 2 years) patients were additionally invited for dynamic pedobarography and static hindfoot axis examination.

RESULTS

Within all three groups AOFAS and EFAS questionnaire values and radiological parameters improved significantly after surgery. Questionnaires did not differ between all groups. Before surgery the SA+MDCO group displayed the most severe radiological flatfeet parameter in comparison to the other cohorts. After surgery, the SA and SA+MDCO groups were greatly improved, while the MDCO group displayed less correction, indicating poorer surgical results with MDCO only. Pedobarography of surgically treated feet revealed similar results in comparison to the contralateral side within all three groups and all feet displayed a normal gait line after surgery.

CONCLUSIONS

Analyzing questionnaires and radiographs, all three surgical techniques (SA, MDCO and SA+MDCO) significantly improved the severity of flatfoot deformity. Pedobarography revealed similar dynamic properties of treated feet in comparison to the contralateral side. While treatment with SA showed better results than treatment with MDCO alone, the combination of SA+MDCO was most effective. In this study, severe adult flatfeet benefited most from a surgical combination of SA+MDCO with respect to normalization of radiological parameter.

LEVEL OF EVIDENCE/CLINICAL RELEVANCE

Therapeutic Level III.

Incidence of Adult Acquired Flatfoot Deformity Referred to Specialist Care in Sweden

INTRODUCTION

Adult acquired flatfoot deformity (AAFD) is a disabling condition that may require complex surgical treatment. Little is known about the incidence of AAFD in the general population and specifically of AAFD requiring specialist care. We aimed to describe the incidence of AAFD referred to specialist care in the Swedish general population.

METHODS

We conducted a nation-wide epidemiological register study to estimate the incidence of referred AAFD in the general population. We retrieved data from the Swedish National Patient Register. All individuals aged 16 years or older, with a first-time diagnosis of AAFD (ICD-10 code M214) between 2007 and 2018 were identified. Total incidences, change over time, and gender-specific and age-specific incidences per 100,000 person-years were calculated using population size data from Statistics Sweden. Incidences were compared using the Poisson test.

RESULTS

The incidence rate of referred AAFD in the general population was 23.0 (95% CI 22.7-23.3) per 100,000 person-years. The incidence rate in women was 30.4 (95% CI 29.9-30.8) and in men was 15.4 (95% CI 15.1-15.8). The highest incidence rates were found in the age Group 61-75 years. The incidence rates varied significantly across the 21 regions in Sweden. The age-standardized and sex-standardized incidence rates ranged from 8.3 (95% CI 7.2-9.4) to 69.1 (95% CI 62.4-75.8).

CONCLUSION

AAFD requiring referral to specialist care is common in the general population. Women had nearly twice the incidence of AAFD compared to men. Large unexplained regional variations in the incidence rates exist.

Review of Ankle and Foot Tendon Transfers, Emphasizing Indications, Anatomy, and Imaging Appearances

Ankle and foot tendon transfer involves moving a tendon from its anatomic location to another location to reinforce a weakened muscle-tendon unit. An ideal donor tendon should have appropriate strength, excursion, phase, and tensioning. Imaging plays an important role in treatment selection and pre- and postoperative evaluation. Radiographs enable assessment of hardware position, bone tunnels, and foot alignment. Weight-bearing views or CT provides a more precise evaluation of alignment, potentially uncovering flexible deformities. MRI depicts the status of the donor and transfer sites and both bone and soft-tissue complications. There are three common indications for a tendon transfer. The first is reinforcement or replacement of a diseased tendon. Flexor digitorum longus to posterior tibial tendon (PTT) transfer is a popular method to address PTT dysfunction. Flexor hallucis longus to Achilles tendon (AT) transfer is used to address a tendinotic or partially torn AT. The second indication is restoration of bone alignment. Anterior transfer of the PTT or peroneus longus (PL) is a treatment option for footdrop. The choice depends on whether peroneal neuropathy is partial or complete. Options for varus deformities are anterior tibial tendon (ATT) transfer, split transfers (ATT or PTT), and PL to peroneus brevis (PB) transfer. The final indication is correction of lateral ankle or subtalar joint instability. Current techniques involve PB looping (Watson-Jones, Lee, Castaing), rerouting (Evans), or both (Chrisman-Snook). These have been abandoned in favor of other anatomic procedures, although some are still being performed and will likely still be encountered by the radiologist. ©RSNA, 2025 Supplemental material is available for this article.

Hallux valgus and pes planus: Correlation analysis using deep learning-assisted radiographic angle measurements

BACKGROUND

The relationship between hallux valgus (HV) and pes planus remains unresolved. This study aims to determine the correlation between HV and pes planus using a deep learning (DL) model to measure radiographic angle parameters.

METHODS

In total, radiographs of 212 feet detectable by the DL model were analyzed. HV was evaluated using the hallux valgus and intermetatarsal angles, while pes planus was assessed using the lateral talo-first metatarsal (Meary's) and calcaneal pitch angles. Correlation analyses were performed for each DL model-measured angle parameter. We investigated whether pes planus worsened with increasing severity of HV and vice versa.

RESULTS

All parameters were significantly correlated with each other. Pes planus worsened with increasing severity of HV, and as the severity of pes planus increased, HV also worsened.

CONCLUSION

Utilizing the DL model-assisted radiographic angle measurements, this study established a significant correlation between HV and pes planus.

LEVEL OF EVIDENCE

III.

Assessing postural stability in flatfoot using a time-in-boundary method during single-leg standing

Flatfoot, a foot deformity characterized by the collapse of the arch, significantly impacts an individual's balance and stability. This study explored postural adjustments and sway excursions in individuals with and without flatfoot using the Time-in-Boundary method. This method assessed relative stability by exploring various center of pressure radius thresholds during three trials of single-leg stance. We observed significant interactions in threshold levels (F = 4.37, p = 0.04) and normalized relative stable times (F = 7.64, p = 0.01), particularly in the initial trials. Initially, the flatfoot group showed marked decreases in stable times at 10 mm, 15 mm, and 20 mm thresholds, which expanded to 25 mm and 30 mm in subsequent trials. Despite a significant decrease in stability at the 30 mm threshold in early trials, participants exhibited improved stability control as trials progressed. This enhancement likely reflects a combination of a learning effect and an increased understanding of the task requirements, underscoring the adaptability of postural control systems to the biomechanical challenges posed by flatfoot. The Time-in-Boundary method has proven to be an effective tool for clinicians to assess postural control, playing a vital role in developing customized rehabilitation strategies for individuals with flatfoot.

Subtalar arthroereisis for simultaneous treatment of flexible pes planus during surgical correction of hallux valgus

BACKGROUND

Scarf osteotomy is a well-established procedure for hallux valgus, yet recurrence rates range from 3.6% to 10%. Pes planus, which often coexisting with hallux valgus, is a risk factor for recurrence. This study aimed to evaluate the effectiveness of simultaneous correction of hallux valgus and flexible pes planus.

METHODS

A total of 85 feet with hallux valgus associated with adult flexible pes planus were retrospectively reviewed. All patients were treated with scarf osteotomy (SO). Subtalar arthroereisis using a HyProCure implant (SOH) was performed to correct hindfoot valgus based on shared decision-making. We collected and compared pre- and at least 2 year postoperative clinical outcomes (American Orthopaedic Foot & Ankle Society (AOFAS) forefoot, hindfoot score, Visual Analog Scale (VAS) pain intensity) and radiographic outcomes (hallux valgus angle (HVA), intermetatarsal angle (IMA), Meary's angle, talonavicular coverage angle (TNCA), and calcaneal pitch (CP) angle in both groups.

RESULTS

Of the cases reviewed, 51 feet were allocated to SO group, and 34 feet were in SOH group. Recurrence frequency was 5 feet (9.8%) in the SO group, while no recurrences were reported in the SOH group. There was no significant difference in AOFAS forefoot and VAS scores between the groups, However, the SOH group demonstrated significant improvement in AOFAS hindfoot scores and CP angle, as well as a greater reduction in Meary's angle and TNCA, compared to the SO group. Changes in HVA and IMA did not differ significantly between the groups. Three feet in the SOH group experienced sinus tarsi pain, which resolved after removal of the HyProCure implant.

CONCLUSIONS

Subtalar arthroereisis with a HyProCure implant is an effective treatment option for adult flexible pes planus associated with scarf osteotomy for hallux valgus, leading to a steady improvement in the patients forefoot deformity and increased patient satisfaction at least 2 years postoperatively.

Enhanced diagnosis of pes planus and pes cavus using deep learning-based segmentation of weight-bearing lateral foot radiographs: a comparative observer study

A weight-bearing lateral radiograph (WBLR) of the foot is a gold standard for diagnosing adult-acquired flatfoot deformity. However, it is difficult to measure the major axis of bones in WBLR without using auxiliary lines. Herein, we develop semantic segmentation with a deep learning model (DLm) on the WBLR of the foot for enhanced diagnosis of pes planus and pes cavus. We used 300 consecutive WBLRs from young Korean males. The semantic segmentation model was developed based on U2-Net. An expert orthopedic surgeon manually labeled ground truths. We used 200 radiographs for training, 100 for internal validation, and two external datasets for external validation. The model was trained using a hybrid loss function, combining Dice Loss and boundary-based loss, to enhance both overall segmentation accuracy and precise delineation of boundary regions between pes planus and pes cavus. Angle measurement errors with minimum moment of inertia (MMI) and ellipsoidal fitting (EF) based on the segmentation results were evaluated. The DLm exhibited better results than human observers. For internal validation, the absolute angle errors of the DLm using MMI and EF were 0.92 ± 1.32° and 1.34 ± 2.07°, respectively. In external validation, these errors were 1.17 ± 1.60° and 1.60 ± 2.42° for AMC's dataset, and 1.23 ± 1.39° and 1.68 ± 1.98° for the LERA dataset, respectively. The DLm showed higher overall diagnostic accuracy than human observers in identifying flatfoot angles, regardless of the measurement methods. The absolute angle errors and diagnostic accuracy of the developed DLm are superior to those of the three human observers. Furthermore, when comparing the angle measurement methods within the DLm, the MMI method proves to be more accurate than EF. Finally, the proposed deep learning model, particularly with the implementation of the U2-Net demonstrates enhanced boundary segmentation and achieves sufficient external validation results, affirming its applicability in the real clinical setting.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13534-024-00439-3.

HyProCure for progressive collapsing foot deformity: is subtalar arthroereisis a good procedure?

PURPOSE

To investigate the treatment outcomes of subtalar arthroereisis (SA) in progressive collapsing foot deformity (PCFD) patients, to assess the clinical efficacy in PCFD patients after HyProCure removal, and to evaluate safety and effectiveness of SA.

METHODS

In this retrospective study, 202 cases (213 feet) of PCFD patients treated with SA from June 2015 to December 2022 were selected. General data and surgical information were recorded, and clinical efficacy was evaluated through imaging and clinical indicators. Furthermore, for 36 patients (36 feet) who underwent secondary surgery to remove HyProCure, imaging and clinical evaluation indicators at 1-year post-removal were recorded. Complications were also documented.

RESULTS

The main complications were sinus tarsi pain (91.37%), with partial relief or disappearance of symptoms in some patients after conservative treatment. The imaging indicators improved significantly after SA (P < 0.01), and AOFAS score and VAS were significantly improved (P < 0.01), with a 100% excellent rate in patients one year after SA. For patients who removed HyProCure, the imaging indicators exhibited a significant improvement at preoperation and post-SA (P < 0.01), and no statistical difference was observed between post-SA and post-removal (P > 0.05). Regarding clinical indicators, AOFAS score at post-SA was difference compared with preoperation and post-removal separately (P < 0.01). However, the difference in VAS between preoperation and post-SA was not statistically significant (P > 0.05). Notably, there was a significant improvement at post-removal compared with post-SA (P < 0.01).

CONCLUSION

PCFD patients showed significant improvement in imaging and clinical evaluations after SA, with no significant flatfoot recurrence in patients who had HyProCure removed. Therefore, the application of HyProCure in SA can be considered a safe and effective surgical treatment for PCFD patients.

Advancing Adult-Acquired Flatfoot Deformity Treatment: Enhanced Biomechanical Support Through Graphene Oxide-Integrated Bioengineered Grafts Tested In Silico

Adult-Acquired Flatfoot Deformity (AAFD) is a progressive orthopedic condition causing the collapse of the foot's medial longitudinal arch, often linked with injuries to the plantar arch's passive stabilizers, such as the spring ligament (SL) and plantar fascia. Conventional treatment typically involves replacing the SL with synthetic material grafts, which, while providing mechanical support, lack the biological compatibility of native ligaments. In response to this shortcoming, our study developed an electrospun, twisted polymeric graft made of polycaprolactone (PCL) and type B gelatin (GT), enhanced with graphene oxide (GO), a two-dimensional nanomaterial, to bolster biomechanical attributes. The addition of GO aimed to match the native ligamentous tissue's mechanical strength, with the PCL-GT-GO 2.0% blend demonstrating an optimal Young's modulus of 240.75 MPa. Furthermore, the graft showcased excellent biocompatibility, evidenced by non-hemolytic reactions, suitable wettability and favorable platelet aggregation-essential features for promoting cell adhesion and proliferation. An MTT assay revealed cell viability exceeding 80% after 48 h of exposure, highlighting the potential of the graft as a regenerative scaffold for affected ligaments. Computational modeling of the human foot across various AAFD stages assessed the graft's in situ performance, with the PCL-GT-OG 2.0% graft efficiently preventing plantar arch collapse and offering hindfoot pronator support. Our study, based on in silico simulations, suggests that this bioengineered graft holds significant promise as an alternative treatment in AAFD surgery, marking a leap forward in the integration of advanced materials science for enhanced patient care.

Midfoot and Forefoot Disorders in Adolescents and Adults with X-Linked Hypophosphatemia

Objectives: X-linked hypophosphatemia (XLH, OMIM 307800) is a rare genetic disorder that affects phosphate metabolism. While lower limb deformity represents a hallmark symptom of patients with XLH, the effect on the foot has not been investigated. This study aimed to characterise foot pathologies and assess related outcome scores in adolescents and adults with XLH. Methods: Patients aged ≥ 16 years with genetically verified XLH were included in this study. Physical examination was performed, and foot scores as well as foot X-rays were assessed. Radiographic analysis included the assessment of osteoarthritis, enthesopathies, and alignment abnormalities. Results: Twenty-six participants (51 limbs) with a mean age of 33.9 ± 15.4 years were eligible for the study. Patients with XLH presented with flatfoot deformity (reduced Meary angles > -4° in 84.3%), elevated first and fifth metatarsal angles > 30° (IM 1-5, 53.5%) and hallux valgus angles > 15° (36.0%). Moderate-to-severe joint space narrowing was observed in the talonavicular (49%) and cuneonavicular joints (41.2%). The American Orthopedic Foot and Ankle Society (AOFAS) score was associated with mildly reduced midfoot function. Conclusions: A high rate of bony deformity, joint degeneration, and decreased foot scores indicated the impact of forefoot and midfoot disorders in patients with XLH.

Contribution of the plantar fascia and long plantar ligaments to the stability of the longitudinal arch of the foot

The contribution of the Plantar Fascia (PF) and Long Plantar Ligament (LPL), two ligaments extending from the hindfoot to the forefoot, to arch stability has been studied in the past using in vivo, in vitro, and in silico methodologies. In silico studies were based on one single model obtained from one single subject and did not account for the known inter-subject morphological and biomechanical variations. In the present study, we developed computational dynamic models of nine different legs obtained from nine different individuals to evaluate the role of the LPL and PF in arch support, accounting for biological differences between subjects. These models were validated by comparing the simulation results against experimental results from the corresponding cadaver legs. After validation, we simulated body weight conditions for each model by applying a vertical load to the tibia, starting from zero and increasing linearly to 720 N. Kinematic and dynamic parameters, including the variation of the medial arch angle and of the navicular height, as well as the passive forces developed by the LPL and PF, were used to evaluate the contribution of these ligaments to arch support under body weight. The results indicate that a total collapse of the medial longitudinal arch occurred only when both the LPL and PF were absent, but a stable arch was maintained when either one of these two ligament structures were present. The results varied significantly among the specific models, highlighting the importance of using multiple models to account for inter-subject morphological differences.

Validation of patient-specific flatfoot models on finite element analysis

Adult-acquired flatfoot causes various deformities. If a patient-specific foot model can be created using the finite element method, it can be used to study the appropriate surgical technique for each patient. Nine patient-specific flatfoot models were created, and loading simulations were performed. To validate the models, the patients' weight-bearing radiographs were compared with the parameters of the models. The CCC values ranged from 0.917 to 0.993 , all exceeding the moderate threshold according to the McBride criteria. Our model reproduces the biomechanics of a patient's foot under loading conditions, which may be useful for investigating patient-specific surgical procedures.

The causality between rheumatoid arthritis and postural deformities: bidirectional Mendelian randomization study and mediation analysis

Background

To better understand the preventive or therapeutic clinical interventions that may be supported by the association between rheumatoid arthritis (RA) and postural deformities including hallux valgus, flat foot, and scoliosis, this study was conducted using Mendelian randomization (MR) analysis. It aimed to investigate whether RA is causally associated with postural deformities in European populations.

Methods

Summary-level data on RA and postural deformities were obtained from the IEU OpenGWAS project and Finngen database, respectively. LDSC regression analysis was conducted to assess the genetic correlation between these diseases. The inverse variance weighting (IVW) method was employed as the primary approach for two-sample MR analyses to evaluate causality. Supplementary methods included MR-Egger, maximum likelihood, weighted median, and cML-MA. To test for potential horizontal pleiotropy, we performed the MR-Egger intercept test, cML-MA, and secondary analyses after excluding confounders. Additionally, mediation analyses were conducted using two-step MR.

Results

The IVW method revealed RA to be causally associated with hallux valgus (OR 1.132, 95% CI 1.087-1.178, P < 0.001) and flat foot (OR 1.197, 95% CI 1.110-1.291, P < 0.001). Among postural deformities, hallux valgus was causally associated with flat foot (OR 1.823, 95% CI 1.569-2.119, P < 0.001) and scoliosis (OR 1.150, 95% CI 1.027-1.287, P < 0.05). No significant horizontal pleiotropy was detected. Moreover, mediation analyses indicated that hallux valgus mediates the effect of RA on flat foot (mediation effect 0.024, 95% CI 0.005-0.044, P < 0.05), with a mediation proportion of 41.31%.

Conclusion

These findings indicate a potential causal association between genetically predicted RA and both hallux valgus and flat foot. Furthermore, hallux valgus serves as a mediator in the pathway from RA to flat foot. This underscores the importance of early screening and preventive treatment of foot deformities in RA patients. Further research is necessary to determine the applicability of these findings in non-European populations.

Biomechanical effect between conventional and 3-dimensional printed customized foot orthoses on medial longitudinal arch support and rearfoot angle in adults with flexible flatfeet

BACKGROUND

Customized foot orthoses are used to treat flexible flatfoot regarding medial longitudinal arch (MLA) support, alignment correction, and pain management. Recently, 3-dimensional (3D) printing orthosis has become the focus of discussion regarding function and manufacturing. We aimed to investigate differences in biomechanical effects between flat insole (Flat), conventional foot orthosis (Cinsole), and 3D printed foot orthosis (3Dinsole) use on MLA support and rearfoot alignment during walking in adult flexible flatfeet.

METHODS

Twelve men with flexible flatfoot were recruited. Data were collected and analyzed using a Vicon motion capture system under 3 trial conditions: Flat and >1 month after using Cinsole and 3Dinsole. Repeated-measures analysis of variance with Bonferroni post hoc tests was used to compare kinematics variables, foot pain, and satisfaction.

RESULT

Dynamic navicular drop significantly reduced with the use of the Cinsole and 3Dinsole compared with Flat ( P < 0.001; ηp 2 = 0.65). The maximum rearfoot eversion angle with the use of the Cinsole and 3Dinsole significantly reduced from Flat ( P < 0.001; ηp 2 = 0.56). Foot pain score significantly decreased after using foot orthoses; satisfaction between Cinsole and 3Dinsole was not significantly different.

CONCLUSIONS

Thus, Cinsole and 3Dinsole are effective alternative treatments of MLA support and rearfoot alignment in adults with flexible flatfoot. 3D printing is a future technology with potential to replace conventional production methods. However, material characteristics, design, and manufacturing process can affect treatment outcomes; hence, our results may not represent all variations of 3D printed foot orthoses.

Two-Dimensional and 3-Dimensional MRI Assessment of Progressive Collapsing Foot Deformity-Adult Acquired Flat Foot Deformity

This article is meant to serve as a reference for radiologists, orthopedic surgeons, and other physicians to enhance their understanding of progressive collapsing foot deformity, also known as adult acquired flat foot deformity. Pathophysiology, imaging findings, especially on MRI and 3-dimensional MRI are discussed with relevant illustrations so that the readers can apply these principles in their practice for better patient managements.

Hazard of Failed Nonoperative Management for Symptomatic Accessory Navicular in Children and Adolescents: A Population-Based Case-Cohort Study

BACKGROUND

The accessory navicular (AN) is an idiopathic condition of the foot present in 4% to 21% of the population. Most ANs remain asymptomatic, but children and adolescents who develop symptoms can have remarkably reduced quality of life. Although many respond to conservative measures, surgery is occasionally needed. Our purpose was to determine factors associated with the failure of nonoperative management.

METHODS

This single-institution retrospective case-cohort study included patients up to age 19 years presenting between 2000 and 2021 with symptomatic AN and treated with standard-of-care. All 298 surgical cases, indicating failed nonoperative treatment, were included. For the subcohort, 299 patients were randomly sampled from all eligible patients, regardless of treatment. Baseline characteristics were summarized for the surgical cases and subcohort. Proportional hazards assumptions were checked and stratification implemented when necessary. Marginal structural proportional hazard modeling was used to estimate hazard ratios with 95% confidence intervals via inverse probability and LinYing weighting methods.

RESULTS

The 298 surgical cases failed nonoperative management at a median of 5.2 months (IQR, 2.0-11.6 mo). In the subcohort, 86 failures of nonoperative management and 213 nonfailures constituted a 28.8% surgery rate. In both cohorts, nearly all patients played sports. Univariate proportional hazard modeling found older age ( P =0.02) and activity limitation ( P <0.001) at presentation, female sex ( P =0.002), higher BMI ( P =0.01), AN on the right ( P <0.001), and bone marrow edema of the AN ( P <0.001) and navicular body ( P <0.001) on MRI were associated with increased hazard of nonoperative failure. Nearly all of the surgical cohort reported improvement in pain (278/296, 94%) and returned to their primary sport (236/253, 93%) after surgery. Most also experienced full resolution of symptoms (187/281, 67%).

CONCLUSIONS

Symptomatic AN predominantly affects female athletes, leading to surgery in 28.8% of our subcohort. Conservative treatment may be less successful-and therefore surgery could be more strongly considered-in older age, activity limitation at presentation, female sex, higher BMI, right-sided AN, and bone marrow edema on MRI. Surgery is effective for symptomatic and functional improvement.

LEVEL OF EVIDENCE

Case-cohort-Level III.

Comparing the efficacy of exercise therapy on adult flexible flatfoot individuals through a network meta-analysis of randomized controlled trials

The aim of this study is to compare the efficacy of different exercise interventions for adult flexible flatfoot. Nine databases (PubMed, EMBASE, Web of Science, the Cochrane Central Register of Controlled Trials (CENTRAL), SCOPUS, PRDro, Google Scholar, China National Knowledge Infrastructure(CNKI) and Wanfang data) were systematically searched from their inception until February 2024. The search resulted in 2112 records, with 11 studies included. All networks revealed low heterogeneity and non-significant inconsistency (I2 ≤ 25.0%). Three network plots were formed for navicular drop. Firstly, compared with the control group, strengthening the posterior tibial muscle + stretching the iliopsoas muscle + TCE (MD: 3.32, 95% CI: 1.78, 4.89), PNF (MD: 1.81, 95%CI: -0.05, 3.70), SFE (MD: 1.23, 95%CI: 1.02, 1.44) all showed better effects. And strengthening the posterior tibial muscle + stretching the iliopsoas muscle + TCE exercise is considered to be the most effective intervention, with SUCRA of 0.97. Secondly, compared with the control group, hip-focused neuromuscular exercise (MD: 6.22, 95% CI: -1.69, 14.12), SFE with EMG biofeedback (MD: -0.81, 95%CI: -1.59, 3.21) all showed better effects. And hip-focused neuromuscular exercise is considered to be the most effective intervention, with SUCRA of 0.92. Thirdly, the internal foot muscle training combined with gluteus muscle strengthening is significantly better than the other two groups, with SUCRA of 0.99. For the foot posture index, comprehensive reinforcement (MD: 1.95, 95% CI - 0.19, 4.03) showed better effects compared with the control group. In the probability ranking table, comprehensive reinforcement is significantly better than the other two groups, with SUCRA of 0.98. For the foot function index, orthoses wear + stretching + eccentric progressive resistive exercise of tibialis posterior is significantly better than the other two groups, with SUCRA of 0.92. In conclusion, various exercise therapies improve the arch shape and function of patients with flexible flatfoot, particularly hip muscle and lower limb overall muscle training.

Correlation of progressive collapsing foot deformity with varus knee alignment in young adults - A case control study

Background

Majority of patients with Progressive Collapsing Foot Deformity(PCFD) have symptoms pertaining to the knee. Malalignment at the foot will have effects on the alignment of the knee. In this case control study, we compare the alignment of the knees between patients with PCFD and controls.

Materials

Sixty subjects, 30 PCFD and 30 controls, underwent radiographs in which the tibiofemoral angle and radiological parameters of PCFD were assessed. Parameters of PCFD were correlated with the tibiofemoral angle.

Results

Mean tibiofemoral angle was 3.8° among the cases and 4.8° among the controls which was statistically significant(P = 0.001). Varus knee alignment was seen in 41 out of 60 limbs with PCFD which was statistically significant(P < 0.001). The tibiofemoral angle correlated significantly with the Meary angle(P = 0.03) and the talonavicular coverage angle(P = 0.003).

Conclusions

PCFD is associated with varus knee malalignment. This varus deformity early in adulthood may lead to deleterious effects like medial compartment osteoarthritis in later life. Early intervention for such patients may help avoid this knee damage.

Level of evidence

Level 3-prognostic.

Morphological changes in flatfoot: a 3D analysis using weight-bearing CT scans

BACKGROUND

Flatfoot is a condition resulting from complex three-dimensional (3D) morphological changes. Most Previous studies have been constrained by using two-dimensional radiographs and non-weight-bearing conditions. The deformity in flatfoot is associated with the 3D morphology of the bone. These morphological changes affect the force line conduction of the hindfoot/midfoot/forefoot, leading to further morphological alterations. Given that a two-dimensional plane axis overlooks the 3D structural information, it is essential to measure the 3D model of the entire foot in conjunction with the definition under the standing position. This study aims to analyze the morphological changes in flatfoot using 3D measurements from weight-bearing CT (WBCT).

METHOD

In this retrospective comparative our CT database was searched between 4-2021 and 3-2022. Following inclusion criteria were used: Patients were required to exhibit clinical symptoms suggestive of flatfoot, including painful swelling of the medial plantar area or abnormal gait, corroborated by clinical examination and confirmatory radiological findings on CT or MRI. Healthy participants were required to be free of any foot diseases or conditions affecting lower limb movement. After applying the exclusion criteria (Flatfoot with other foot diseases), CT scans (mean age = 20.9375, SD = 16.1) confirmed eligible for further analysis. The distance, angle in sagittal/transverse/coronal planes, and volume of the two groups were compared on reconstructed 3D models using the t-test. Logistic regression was used to identify flatfoot risk factors, which were then analyzed using receiver operating characteristic curves and nomogram.

RESULT

The flatfoot group exhibited significantly lower values for calcaneofibular distance (p = 0.001), sagittal and transverse calcaneal inclination angle (p < 0.001), medial column height (p < 0.001), sagittal talonavicular coverage angle (p < 0.001), and sagittal (p < 0.001) and transverse (p = 0.015) Hibb angle. In contrast, the sagittal lateral talocalcaneal angle (p = 0.013), sagittal (p < 0.001) and transverse (p = 0.004) talocalcaneal angle, transverse talonavicular coverage angle (p < 0.001), coronal Hibb angle (p < 0.001), and sagittal (p < 0.001) and transverse (p = 0.001) Meary's angle were significantly higher in the flatfoot group. The sagittal Hibb angle (B =  - 0.379, OR = 0.684) and medial column height (B =  - 0.990, OR = 0.372) were identified as significant risk factors for acquiring a flatfoot.

CONCLUSION

The findings validate the 3D spatial position alterations in flatfoot. These include the abduction of the forefoot and prolapse of the first metatarsal proximal, the arch collapsed, subluxation of the talonavicular joint in the midfoot, adduction and valgus of the calcaneus, adduction and plantar ward movement of the talus in the hindfoot, along with the first metatarsal's abduction and dorsiflexion in the forefoot.

Deep learning-based automated angle measurement for flatfoot diagnosis in weight-bearing lateral radiographs

This study aimed to develop and evaluate a deep learning-based system for the automatic measurement of angles (specifically, Meary's angle and calcaneal pitch) in weight-bearing lateral radiographs of the foot for flatfoot diagnosis. We utilized 3960 lateral radiographs, either from the left or right foot, sourced from a pool of 4000 patients to construct and evaluate a deep learning-based model. These radiographs were captured between June and November 2021, and patients who had undergone total ankle replacement surgery or ankle arthrodesis surgery were excluded. Various methods, including correlation analysis, Bland-Altman plots, and paired T-tests, were employed to assess the concordance between the angles automatically measured using the system and those assessed by clinical experts. The evaluation dataset comprised 150 weight-bearing radiographs from 150 patients. In all test cases, the angles automatically computed using the deep learning-based system were in good agreement with the reference standards (Meary's angle: Pearson correlation coefficient (PCC) = 0.964, intraclass correlation coefficient (ICC) = 0.963, concordance correlation coefficient (CCC) = 0.963, p-value = 0.632, mean absolute error (MAE) = 1.59°; calcaneal pitch: PCC = 0.988, ICC = 0.987, CCC = 0.987, p-value = 0.055, MAE = 0.63°). The average time required for angle measurement using only the CPU to execute the deep learning-based system was 11 ± 1 s. The deep learning-based automatic angle measurement system, a tool for diagnosing flatfoot, demonstrated comparable accuracy and reliability with the results obtained by medical professionals for patients without internal fixation devices.

Electromyographic Analysis of Large Muscle Activity in Progressive Collapsing Foot Deformity

BACKGROUND

There are various deformities described in the spectrum of Progressive Collapsing Foot Deformity (PCFD) which not only have adverse effects on the foot but also on the entire lower limb. Early lower limb muscular fatigue and pain during exertion is the most common complaint of patients with PCFD. Surface electromyography (sEMG) provides an accurate assessment of muscle activity. In this study, we aim to compare the activities of quadriceps, hamstrings, and gastrosoleus muscle groups of adult patients with PCFD with normal lower limbs and correlate the radiological parameters and functional effects of PCFD with the activities.

METHODS

Thirty patients with bilateral PCFD and 30 controls underwent weight-bearing anteroposterior (AP), lateral, and hindfoot alignment radiographs of the foot. Radiographic parameters of PCFD were assessed. Surface electromyography was used to assess the quadriceps, hamstrings, and gastrosoleus activities, and this was compared between the 2 groups and correlated with radiological measurements of PCFD. Tegner activity questionnaire was used to assess the functional effects of collapsed arch.

RESULTS

Electrical activities of all muscle groups were significantly higher in cases than controls. Meary's angle and hindfoot moment arm had significant correlations with hamstring activity (P = .013) and gastrosoleus activity (P = .027), respectively. Tegner scores of cases were significantly lower than those of controls (P = .041).

CONCLUSIONS

The PCFD causes an increase in activity of large muscles of the affected lower limb which act on joints other than those in the foot. This finding may be due to several compensatory mechanisms that counteract the deforming forces. This may be a cause for the frequent complaint, early fatigue, and hence functional impairment. However, most radiological parameters did not correlate with muscle activities and larger study size may be required for further association.

LEVELS OF EVIDENCE

Diagnostic: Level 3.

Effect of orthopedic insoles on lower limb motion kinematics and kinetics in adults with flat foot: a systematic review

Flatfoot is characterized by the collapse of the medial longitudinal arch, eversion of the rearfoot and abduction of the loaded forefoot. Orthopedic insoles are the frequently recommended treatment to support the arch of the foot, adjust the structure of the foot, reduce pain, improve stability and new techniques have been applied to the design of orthopedic insoles in recent years. However, the effectiveness of orthopedic insoles in different motions is still debated from the perspective of biomechanics. Therefore, this study aimed to explore the impact of orthopedic insoles on the kinematics and kinetics of lower limb motion, and to verify effectiveness and propose possible future research directions. We conducted a literature search across three databases employing Boolean operations and filtered results based on eligibility criteria. A total of 671 relevant literature were searched in this review, and 19 literature meeting the requirements were finally included. The results showed that: 1) orthopedic insoles were effective when patients walk, run and jump from the perspective of biomechanics; 2) orthopedic insoles had different result on the change of ankle sagittal angle, moment and peak pressure in the metatarsal region; 3) Whether the effect of insoles, which uses new techniques such as different 3D printed technologies and adds various accessories, can be further improved remains to be further studied; 4) Follow-up studies can pay more attention to the differences between diverse populations, increase the breadth of running and jumping and other movements research and long-term intervention.

Determining the changes in morphology and loading status following medial displacement calcaneal osteotomy for flatfoot using patient-specific finite element models

Medial displacement calcaneal osteotomy (MDCO) is the standard procedure for flatfoot. We investigated the effect of MDCO on the foot using a finite element analysis. Foot models were created from computed tomography data of 8 patients with flat feet. MDCO was performed on each model with bone translation distance of 4, 8, and 12 mm. The morphological changes, plantar pressures, and stress percentage on the talocrural and subtalar joints were evaluated before and after surgery. Morphological evaluation showed improvement in the medial longitudinal arch. The stress percentage of plantar pressure in the medial area decreased, and the stress percentage of plantar pressure in the mid- and lateral forefoot area increased. At the talocrural joint, the medial and middle stress percentage increased, while the lateral and posterior stress percentage decreased. In the subtalar joint, the stress percentage in the middle subtalar joint increased and that in the posterior subtalar joint decreased. Within the posterior subtalar joint, the anterior and medial stress percentage increased, while the posterior and lateral stress percentage decreased. Preoperative simulation using the finite element analysis may be useful in understanding postoperative morphological changes and loading conditions to perform patient-specific surgery.

Effects of Preoperative Abnormality of Posterior Tibial Tendon on the Surgical Outcomes of Medial Osteochondral Lesion of the Talus

BACKGROUND

Although surgical treatment for osteochondral lesion of the talus (OLT) can obtain good clinical outcomes, the rate of return to sports is variable. It is reported that medial OLT unrelated to trauma has abnormal structures in the medial aspect, which may induce the medial OLT due to the medial instability. The posterior tibial tendon (PTT) plays an important role in the stabilization of the foot, and high mechanical stress may be added to the PTT to compensate for medial instability in medial OLT. We investigated whether abnormal PTT findings on preoperative magnetic resonance imaging (MRI) in patients with OLT affect clinical outcomes after surgery.  Methods: Eighty-one ankles in 74 patients who were treated surgically for OLT were included in this study (41 men and 33 women; mean age, 26.0 years). Abnormalities of the PTT were evaluated using preoperative MRI. The Japanese Society for Surgery of the Foot (JSSF) scale, arch height, and ankle activity score (AAS) on standing plain radiogram were compared between patients with and those without preoperative PTT abnormalities.

RESULTS

Twenty-five ankles (30.9%) had PTT abnormalities on preoperative MRI. All patients with preoperative PTT abnormalities were medial OLT. There were no significant differences in the preoperative JSSF scale in the procedures for OLT. The postoperative JSSF scale and arch height were significantly lower in patients with preoperative PTT abnormalities than those without them. AAS in patients with preoperative abnormalities significantly decreased at the final follow-up.  Conclusion: PTT abnormalities on preoperative MRI may affect clinical outcomes even in preoperative asymptomatic patients in the medial OLT unrelated to trauma.

Knowledge and Attitudes Regarding Flatfoot in the Al-Jouf Region, Saudi Arabia

Background Flatfoot is a syndrome that includes multiple static and dynamic deformities, characterized by the flattening of the medial arch. It is a common disorder that may affect any age group, causing foot malalignment, pain, and loss of function. Community awareness about flatfoot is essential for the prevention and control of flatfoot complications, ultimately improving the quality of life. The current study aimed to assess community knowledge and attitudes about flatfoot in the Al-Jouf region, Saudi Arabia. Methods The study enrolled 315 participants from different sectors of the Saudi population in the Al-Jouf region. An online questionnaire was distributed to them. Answers were scored on a scale of five (never "1", rarely "2", sometimes "3", often "4", always "5"). The level of their knowledge was determined by calculating the scores. Results There were significant disparities in the answers, with the majority of participants denying the effect of flatfoot on walking (135, 42.9%), running (123, 39%), standing for long periods (186, 59%), or causing tripping. More than half of the participants agreed that flatfoot never affects school activities or participation in clubs or activities after school. However, most participants showed a good attitude toward individuals with flatfoot, as they were not bothered by their way of walking (199, 63.2%) or how their foot or ankle looks (255, 80.9%), and never embarrassed them because of their foot or ankle (266, 84.5%). Most participants agreed that no one has the right to be unkind to them because of their foot or ankle (276, 87.5%). These positive attitudes are likely due to the cultural norms of the community. Conclusion There is a decreased level of awareness about the effects of flatfoot on daily physical activities among the Saudi population in the Al-Jouf region. However, their attitude toward people suffering from flatfoot is highly appreciated. Health education programs are recommended.

Chronic Deltoid Insufficiency in Stage IV Adult Acquired Flatfoot Deformity: Do We Have a Good Answer?

Stage IV adult acquired flatfoot deformity (AAFD) with secondary chronic deltoid ligament insufficiency is a challenging deformity to treat, with minimal consensus in the literature concerning its surgical management. Many surgical treatment options have been described, including joint-sparing techniques, fusions, osteotomies, and even arthroplasties. However, questions remain as to what, if any, treatment is optimal. This contribution reviews studies on surgical treatments for stage IV AAFD with deltoid ligament failure and provides a critical analysis regarding the quality of outcomes reported for those different treatment options. PubMed and Google Scholar databases were searched between June 1, 2022, and August 15, 2022, for studies published between 1990 and 2022 that describe the treatment of stage IV AAFD with deltoid ligament insufficiency. Articles included in the study focused on subjects with stage IV AAFD and associated deltoid ligament insufficiency undergoing surgical correction. Exclusion criteria included stage I, II, and III AAFD, as well as deltoid ligament repair following acute injury/rupture. Nine studies covering five different treatment options for patients with stage IV AAFD and chronic deltoid insufficiency were included, with minimal overlap in outcome measures used to assess the efficacy of the procedure. Triple arthrodesis with deltoid ligament reconstruction resulted in a 62.5% (5/8) success rate with a residual tibiotalar (TT) angulation of 2° (success defined as <3°). Tibiotalar arthrodesis of four patients resulted in an average post-operative tibiotalar angulation of 4.8° with all patients showing progressive destabilization of the hindfoot complex at 12-18 year follow-ups. Deltoid arthroscopic laminoplasty (Brostrom) resulted in an increased American Orthopaedic Foot and Ankle Society (AOFAS) score from 49.7 pre-op to 91.9 post-op. There was no long-term follow-up of these patients. Deltoid ligament reconstruction using autografts of the peroneus longus resulted in a post-operative valgus of 2.1° in one study and <5° in another. Deltoid ligament reconstruction using an anterior tibial tendon autograft resulted in a gain of 126.4 + 40.2% in stiffness compared to an intact ligament. Twinfix suture anchors resulted in a post-operative hindfoot angle averaging 5.3°. Combined deltoid and spring ligament reconstruction resulted in a 5.1° valgus angulation. There is currently no standard of care or clinical consensus regarding surgical treatment for stage IV AAFD with deltoid insufficiency. Several studies imply that mild valgus malalignment around the tibiotalar joint can result in satisfactory outcomes. A few studies even deemed <5° of valgus tilt post-operatively successful. However, it has been described that any imbalance in tibiotalar tilt is a significant risk factor for progressive arthritis and future ligamentous failure. No treatment option was able to correct valgus tilt to an anatomical standard (i.e., to normal anatomy). These varied findings, along with the lack of consensus on post-surgical measures to assess efficacy, are worrisome and emphasize the need for better surgical options. Moreover, there is a critical need for additional research on the long-term outcomes following stage IV AAFD and deltoid insufficiency repair, particularly, as over five million people in the United States and 10% of the geriatric population are affected by AAFD with a risk of progressing to stage IV.

Impact of static foot disorders on the conservative treatment success in chronic venous disease patients without wounds

OBJECTIVE

Chronic venous disease (CVD) and static foot disorders (SFDs) are prevalent conditions that commonly cause lower extremity pain. These conditions share common factors such as age and weight in their etiology. This study aimed to investigate the impact of SFDs on the treatment response of patients undergoing conservative treatment for CVD without wounds.

MATERIALS AND METHODS

A retrospective evaluation was conducted on 328 patients (60 males, 268 females) with CVD. Parameters including age, gender, affected side, body mass index, Visual Analog Scale (VAS), Clinical-Etiological-Anatomical-Pathophysiological (CEAP) classification, and revised Venous Clinical Severity Score (rVCSS) were considered for evaluation. Radiological measurements of calcaneal pitch angle (CPA) were analyzed as a determinant of SFDs.

RESULTS

VAS and rVCSS of the patients were evaluated before and after conservative treatment of CVD without concomitant treatment of SFDs. The presence of SFDs was associated with decreased treatment success (P < .001). Among different types of SFDs, the pes cavus group exhibited the lowest change in VAS and rVCSS scores before and after conservative CVD treatment. In contrast, the normal group demonstrated the highest improvement. Patients with a normal foot medial arch consistently achieved the best treatment outcomes compared with patients with other SFDs.

CONCLUSIONS

In conclusion, SFDs affect outcomes of conservative treatment of CVD in CEAP 0 to 3 patients, with the efficacy of treatment dependent upon the severity of SFDs.

Patient Reported Outcomes Following Triple Arthrodesis for Adult Acquired Flat Foot Deformity: Minimum Two Year Follow Up

The aim of this study is to analyze patient-reported outcomes following this procedure as well as any demographics that may confer prognostic capability. A retrospective analysis was conducted of patients who underwent Triple Arthrodesis at our facility from 2014-2021. Patients were selected if they underwent an isolated triple arthrodesis. All cases included either a gastrocnemius recession versus a percutaneous tendo-achilles lengthening depending on the patient's Silverskiold examination. The electronic medical record was utilized to collect basic patient demographics, previous foot and ankle surgeries, hardware failures, additional procedures, and surgical complications. To evaluate outcomes, we compared patient reported outcomes measurement information system (PROMIS) survey scores with the general population and preoperative versus postoperative visual analog scale (VAS) scores. Foot function index (FFI) scores and scores were utilized as a validation tool for our results. A total of 132 patients met the criteria for our study with a total of 50 participants completing the PROMIS and FFI surveys. The average time point at which the outcomes were collected was 5.50 y postoperatively, ranging from 1.65 to 7.57 y. The average PROMIS physical function was 38.35, pain interference was 61.52, and depression was 49.82 for this population. The mean FFI scores were 58.56 for pain, 60.07 for disability, and 48.07 for activity limitation. There was a significant decrease in preoperative and postoperative VAS scores from 5.4 to 2.55 (p < .001). Three patients experienced wound complications related to decreased sensation. Our results indicated that only PROMIS depression scores were within one standard deviation of the population mean following a triple arthrodesis procedure. PROMIS physical function and pain interference were both outside of one standard deviation for the population.

Radiographic Analysis of Valgus Ankle Deformity With or Without Medial Longitudinal Arch Collapse

BACKGROUND

Establishing a surgical plan for ankle deformities necessitates a comprehensive understanding of the deforming forces involved, and the morphology of the ankle deformity plays an important role as well. Valgus tibiotalar tilt development has mostly been described in patients with a low medial longitudinal arch, as seen in progressive collapsing foot deformity (PCFD). However, some valgus ankles demonstrate no radiographic evidence of a collapsed medial arch. This study aims to investigate whether there are differences in the radiographic morphology of valgus ankle deformities between patients with and without a low medial longitudinal arch to explore if they have different etiologies.

METHODS

We retrospectively reviewed patients who underwent surgical treatment for asymmetric valgus ankle deformity at our institution between 2017 and 2021. Patients with a valgus tibiotalar tilt (TT) greater than 4 degrees and Meary angle greater than 30 degrees (mean: 38.9) were included in the PCFD group (n = 29). The non-PCFD group (n = 24) with TT greater than 4 degrees and Meary angle less than 4 degrees (mean: 0.3) was also established. In the weightbearing ankle anteroposterior view, the TT and medial distal tibial angle were measured. Additionally, to assess the mediolateral position of the talus, the talar center migration (TCM) and lateral talar dome-plafond distance (LTD-P) ratio in the coronal plane were measured. In weightbearing computed tomography (WBCT), the degree of axial plane talocalcaneal subluxation and the prevalence of sinus tarsi bony impingement were assessed. Intergroup comparison was conducted.

RESULTS

Both groups demonstrated a similar degree of TT, with a mean of 11.6 degrees in the PCFD group and 13.7 degrees in the non-PCFD group (P = .2330). However, the PCFD group showed a significantly greater TCM and LTD-P ratio compared with those of the non-PCFD group (P < .0001), indicating that PCFD patients have a more medially translated talus in ankle anteroposterior radiographs. WBCT showed that the PCFD group on average had 18 degrees greater axial plane talocalcaneal subluxation (P < .0001) and 52% higher prevalence of sinus tarsi bony impingement (P = .0002) compared with the non-PCFD group.

CONCLUSION

This study suggests that valgus ankles may exhibit different radiographic morphologies depending on the status of the longitudinal arch. Valgus ankles in PCFD patients tend to have a more medially translated talus. This finding may suggest the presence of different deforming forces between the 2 groups and may indicate the need for different treatment strategies to address talar tilt.

LEVEL OF EVIDENCE

Level III, case-control.

Ankle and hindfoot motion of healthy adults during running revealed by dynamic biplane radiography: Side-to-side symmetry, sex-specific differences, and comparison with walking

This study aimed to characterize ankle and hindfoot kinematics of healthy men and women during overground running using biplane radiography, and to compare these data to those previously obtained in the same cohort during overground walking. Participants ran across an elevated platform at a self-selected pace while synchronized biplane radiographs of their ankle and hindfoot were acquired. Motion of the tibia, talus, and calcaneus was tracked using a validated volumetric model-based tracking process. Tibiotalar and subtalar 6DOF kinematics were obtained. Absolute side-to-side differences in ROM and kinematics waveforms were calculated. Side-to-side and sex-specific differences were evaluated at 10 % increments of stance phase with mixed model analysis. Pearson correlation coefficients were used to assess the relationship between stance-phase running and walking kinematics. 20 participants comprised the study cohort (10 men, mean age 30.8 ± 6.3 years, mean BMI 24.1 ± 3.1). Average absolute side-to-side differences in running kinematics waveforms were 5.6°/2.0 mm or less at the tibiotalar joint and 5.2°/3.2 mm or less at the subtalar joint. No differences in running kinematics waveforms between sides or between men and women were detected. Correlations were stronger at the tibiotalar joint (42/66 [64 %] of correlations were p < 0.05), than at the tibiotalar joint (38/66 [58 %] of correlations were p < 0.05). These results provide a normative reference for evaluating native ankle and hindfoot kinematics which may be informative in surgical or rehabilitation contexts. Sex-specific differences in ankle kinematics during overground running are likely not clinically or etiologically significant. Associations seen between walking and running kinematics suggest one could be used to predict the other.

Talonavicular-cuneiform arthrodesis in the management of Mueller-Weiss Syndrome: a retrospective case series

Mueller-Weiss Syndrome (MWS), characterized by spontaneous adult-onset tarsal navicular osteonecrosis, is an uncommon cause of chronic midfoot pain that can lead to functional impairment and progressive deformities. This study aimed to present clinical and radiological outcomes of talonavicular-cuneiform (TNC) arthrodesis in the treatment of patients with MWS. A retrospective study was performed on 8 consecutive patients (6 female, 2 male; mean age = 50 years; range = 33-64) who underwent TNC arthrodesis using plate fixation with autologous bone grafting for the treatment of MWS. To evaluate clinical status, the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Midfoot Score was performed immediately preoperatively and at the final follow-up. In radiographic evaluation, talus-first metatarsal angle (Meary's angle) was measured preoperatively and at the final follow-up. Solid fusion was also examined on postoperative radiographs and computerised tomography. The mean follow-up was 35 months (range = 24-52). The mean AOFAS improved from 37 (range = 24-53) preoperatively to 85 (range = 80-93) at the final follow-up (p < 0.001). No major intra- operative complications were observed in any of the patients. According to the Maceira and Rochera radiological staging system, 5 feet was stage 3, and 3 feet was stage 4. The mean union time was 10 months (range = 5-15). Radiographic solid fusion was achieved in all but one foot that developed talonavicular non-union. TNC arthrodesis using plate fixation with autologous bone grafting seems to be an effective surgical method for reconstruction of MWS.

Does the Presence of Asymptomatic Flatfoot Deformity Impact the Clinical and Radiographic Outcomes of the Minimally Invasive Chevron and Akin Bunionectomy?

BACKGROUND

Flatfoot deformity is believed to play a role in hallux valgus development and recurrence. While symptomatic flatfoot deformity can be treated with separate procedures at the time of hallux valgus correction, the question remains whether the patient undergoing correction of a symptomatic hallux valgus deformity should have their asymptomatic flatfoot concurrently addressed. We aimed to investigate whether the presence of asymptomatic flatfoot influences patient-reported and radiographic outcomes of the minimally invasive chevron and Akin bunionectomy.

METHODS

A total of 104 patients were included in this study. Forty-two asymptomatic patients met the radiographic criteria for flatfoot while 62 had a normal arch. Patient-reported outcomes were evaluated and compared between the two groups using validated PROMIS measures preoperatively and at a minimum one-year postoperatively. Radiographic outcomes including hallux valgus angle (HVA), intermetatarsal angle (IMA), Meary's angle, calcaneal pitch (CP), and talonavicular coverage angle (TNCA) were measured and compared preoperatively and minimum six-months postoperatively.

RESULTS

Both groups demonstrated similar preoperative and postoperative PROMIS scores with significant improvements in physical function, pain interference, pain intensity, and global physical health. Preoperatively, HVA was similar between both groups, however the flatfoot group showed a greater IMA, Meary's angle, TNCA, and lower CP. Postoperatively, HVA and IMA were similar between groups, although patients in the flatfoot group retained a significantly greater Meary's angle, TNCA, and lower CP. Both groups showed significant improvements in HVA, IMA, and TNCA.

CONCLUSION

Our study indicates that the minimally invasive chevron and Akin bunionectomy leads to improved clinical and radiographic hallux valgus outcomes without adversely impacting radiographic flatfoot parameters. Therefore, the MIS bunionectomy may be an effective option for hallux valgus correction in patients with mild, asymptomatic flatfoot.

LEVEL OF EVIDENCE

Level III, retrospective cohort.

Correlation Between Traditional Anteroposterior Radiographic Measurements With Lateral Radiographic Measurements Following Triplanar Correction of Hallux Valgus and With Patient-Reported Outcomes From a Prospective Multicenter Trial

Hallux valgus (HV) is a common condition in which the first ray is deformed, leading to pain and altered joint mechanics. A variety of radiographic measurements are used to evaluate HV. Little is known about measurements used in the assessment of HV on lateral radiographs compared to anteroposterior (AP) radiographs. The primary aim of this study was to correlate lateral measurements with AP measurements pre and postoperatively. The secondary aim was to correlate lateral measurements with patient-reported outcome measures (PROMs) pre and postoperatively. One hundred eighty-three patients were initially enrolled in the study. Two fellowship-trained musculoskeletal radiologists independently performed all measurements. On AP radiographs, hallux valgus angle (HVA) and intermetatarsal angle (IMA) were measured. On lateral radiographs, sagittal IMA, Meary's angle, and sagittal first ray length were measured. Measurements were recorded at baseline and 6, 12, and 24 months postoperatively. Intraclass correlation coefficients (ICCs) were used for inter-reader analysis. ICCs were moderate to very strong among readers. There were significant but weak correlations between lateral measurements and AP measurements. For at least 1 timepoint, IMA correlated with sagittal IMA, sagittal first ray length, and Meary's angle. HVA only correlated with sagittal first ray length. These correlations were all weak in magnitude. There were a few significant but weak correlations between the measurements in the study and PROMs. This study showed that sagittal IMA, sagittal first ray length, and Meary's angle are not predictive of AP measurements or patient outcomes and are not useful in preoperative assessment of HV.

The impact of sustentaculum tali fracture on clinical outcome in patients affected by isolated calcaneal fractures

INTRODUCTION

The sustentaculum tali is displaced in almost half of calcaneal fractures and during surgical fixation represents one of the main reference points upon which the other bone has to be reduced. The purpose of this study was to investigate which subtalar joint fracture pattern is more frequently associated with sustentaculum tali involvement. Furthermore, correlation between postoperative clinical outcome and sustentaculum tali integrity was performed.

MATERIAL AND METHODS

Patients with isolated calcaneal fractures were analyzed. Sanders-type fracture and involvement of both sustentaculum tali and calcaneocuboid joint were detected on computed tomography imaging; postoperative AOFAS scores were analyzed according to sustentacular involvement.

RESULTS

Fifty calcaneus fractures in 47 patients were included in the final analysis. The sustentaculum tali was fractured in 18 cases (36.0%), thus contradicting its supposed constant position. Sanders type 3 and 4 fractures were more frequently associated with fractured sustentaculum than type 2 (p = 0.012). Sanders type 4 fractures were associated with displaced sustentacular fragment significantly more than type 2 and 3 (p = 0.043). Patients with intact sustentaculum tali reported significantly higher (p < 0.001) mean AOFAS scores than the uninjured group (84.4 ± 9.1 and 74.3 ± 9.5, respectively).

CONCLUSION

Sanders type 3 and 4 fractures were more frequently associated with sustentaculum tali and/or calcaneocuboid joint involvement than simpler fractures. Injury of sustentaculum tali was related to significant worse postoperative clinical outcomes, underlying the relevance of this fragment on clinical course.

Radiographic Evidence of Sufficient Transverse Plane Alignment after Weil Osteotomy without Screw Fixation

Weil osteotomy is a proven procedure to restore the harmonic distal parabola of the forefoot. In addition to the proximal displacement of the head in the sagittal plane, a displacement in the transverse plane may be necessary, with the refixation of the displaced metatarsal head historically performed by screw fixation. We aimed to determine the radiological differences among 136 feet of 127 patients with 256 Weil osteotomies retrospectively enrolled and divided into groups with (n = 182) and without (n = 74) screw fixation. Demographic data, radiographic union, pre- and postoperative metatarsal angles, and differences in the dorsoplantar view were evaluated. The mean follow-up period was 3.6 months. The mean preoperative metatarsophalangeal angle was 9.24°, and the mean postoperative angle was 12.99°. The restoration of the transversal alignment plane was equally successful in both groups, with a mean extent of angle correction of 10.58°. No nonunions of the osteotomized metatarsals were observed. The radiographic comparisons revealed no significant difference between the groups (p > 0.05). However, visibility of the joint space of the metatarsophalangeal joint was achieved significantly more often in the group without screw fixation (p < 0.05). In the absence of bony malunion and the satisfactory restoration of a harmonious parabola of the forefoot, apparently there does not appear to be a necessity for regular screw fixation after Weil osteotomy based on the available data from the present study.

The Reliability of Common Radiographic Measurements Used to Describe Foot Deformities

Radiographic measurements are frequently used to classify deformity and determine treatment options. Correlation coefficients can be used to determine inter- and intrarater reliability. Reliability is a required feature of any measurement if the measurement is to provide valid information. We calculated correlation coefficients for standard radiographic measurements used to categorize foot deformities: this was done for 52 sets of radiographs assessed by 5 raters. We aimed for generalizability, and kept rater instructions to match what was originally published for each measurement of interest with schematic illustration. Overall, our results mostly showed a lack of inter-rater reliability (correlation coefficients <0.4), and strong intrarater reliability (correlation coefficients >0.6), for 12 forefoot and 12 rearfoot radiographic measurements that are commonly used. The results of this investigation bring into question the routine use of radiographic measurements to categorize deformity, select treatments, and measure surgical outcomes, between surgeons, because the validity of these measurements appears to be threatened by weak inter-rater reliability. In order for these measurements to be considered useful, it may be necessary for surgeons to more rigorously define and practice making standard radiographic measurements.

Imaging modalities for non-acute pathologies of the foot and ankle

Chronic foot and ankle pain, in contrast to acute traumatic injuries, presents a diagnostic challenge due to its diverse underlying causes. Accurate diagnosis often necessitates the utilization of various imaging modalities, emphasizing the importance of selecting the most appropriate one. The intricate structure of the foot, composed of multiple bones and supported by soft tissues like ligaments and plantar fascia, gives rise to a spectrum of mechanical disorders, including stress fractures, plantar fasciitis, Morton's neuroma, and more. In addition to mechanical issues, non-acute abnormalities encompass inflammatory diseases affecting tendons and joints, benign tumors, tumor-like lesions, vascular abnormalities, and others. This article reviews the indispensable role of imaging in the assessment of these conditions, with a focus on plain radiography, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine studies, tailored to the specific clinical presentation. By providing insights into the selection and interpretation of imaging modalities, this article aims to assist clinicians in achieving accurate diagnoses and optimizing patient care for nonacute foot and ankle pathologies.

Comparison of Foot Kinematics Between Normal Arch and Flexible Flatfoot Using the Oxford Foot Model: A Matched Case-Control Study

Background

Symptomatic flexible flatfoot causes alterations in gait, but exactly how this condition affects the intersegmental motion of the foot during the gait cycle remains unclear. Previous studies have examined the kinematics, yielding inconsistent findings. Therefore, the objective of this study was to investigate how flexible flatfoot deformity, defined as Johnson and Strom classification staging II, affects the intersegmental motion of the foot during fast walking based on a comparison with the matched control group.

Methods

Eleven participants with symptomatic flexible flatfoot and 11 healthy matched control participants were recruited using a foot screening protocol incorporated through a foot physical examinations and radiographic measurements. All demographic characteristics exhibited comparable profiles between the groups. During controlled walking, kinematic outcomes pertaining to the hallux, hindfoot, forefoot, and tibia were collected using the multisegmental Oxford Foot Model.

Results

All spatiotemporal parameters were comparable between the groups. In comparison to the control group, individuals with symptomatic flexible flatfoot demonstrated increased hallux valgus and plantarflexion, increased forefoot abduction, heightened hindfoot eversion, and internal rotation. Notably, no significant major differences were observed in the tibia motion segment. Further, significant correlations were identified between static foot measurements and the extent of the maximum deviation observed during dynamic kinematic assessments.

Conclusion

Compared with age- and gender-matched controls, participants with symptomatic flexible flatfoot exhibited significant gait pattern deviations. A significant correlation also exists between static foot deformity measurements and dynamic kinematic deviations. Collectively, these findings have implications for developing targeted therapeutic interventions to address flexible flatfoot.

Level of evidence

Level III, diagnostic study.

Comparative study of the effects of custom-made insole and ordinary insole in adults with flexible flatfoot on different slopes

BACKGROUND

Flatfoot (pes planus) is a common foot deformity, and its causes are mainly related to age, gender, weight, and genetics. Previous studies have shown that custom-made insoles could have a positive effect in improving plantar pressure and symptoms in individuals with flexible flatfeet, but it remains to be explored whether they can still show benefits in daily walking on different slopes.

OBJECTIVE

This study aims to investigate a custom-made insole based on plantar pressure redistribution and to verify its effectiveness by gait analysis on different slopes.

METHODS

We recruited 10 subjects and compared the peak pressure and impulse in each area between custom-made insole (CI) and ordinary insole (OI) groups.

RESULTS

The results illustrate that CI raises the pressure in T area, improves the ability of the subjects to move forward in the slope walking, which was beneficial to gait stability.

CONCLUSION

The redistribution of pressure in MF and MH area is promoted to provide active protection for subjects. Meanwhile, CI could decrease the impulse in MF area during uphill and level walking, which effectively reduces the accumulation of fatigue during gait. Moreover, avoiding downhill walking could be able to protect foot from injury in daily life.

Biomechanical evaluation of the spring ligament and the posterior tibial tendon by shear-waves elastography: validation of a reliable and reproducible measurement protocol

PURPOSE

The anatomy of the spring ligament complex, as well as its pathology, is not well known in daily clinical practice. The purpose of this study was to evaluate the shear-wave elastography properties of the spring ligament and the posterior tibial tendon in healthy adults, and to assess the reliability and reproducibility of these measurements.

METHODS

Shear-wave elastography was used to evaluate both ankles in 20 healthy patients (10 females/10 males) resting on a hinge support with their ankles in neutral, valgus 20° and varus 30° positions. The stiffness of the spring ligament and posterior tibial tendon was assessed by measuring the speed of shear wave propagation through each structure.

RESULTS

Posterior tibial tendon and spring ligament reach a maximum estimated stiffness in valgus 20° position (7.43 m/s vs 5.73 m/s, respectively). Flat feet were associated with greater spring ligament stiffness in the 20° valgus position (p = 0.01), but not for the posterior tibial tendon (p = 0.71). The physiologic weightbearing hindfoot attitude had no impact on the stiffness of the posterior tibial tendon or the spring ligament, regardless of the analysis position. Intra- and inter-observer agreements were all excellent for spring ligament stiffness, regardless of ankle position, and were good or excellent for posterior tibial tendon.

CONCLUSIONS

This study describes a protocol to assess the stiffness of tibialis posterior and the spring ligament by shear-wave elastography, which is reliable, reproducible, and defines a corridor of normality. Further studies should be conducted to define the role of elastography for diagnosis/ evaluation of pathology, follow-up, or surgical strategies.

Imaging of osteoarthritis from the ankle through the midfoot

Ankle, hindfoot, and midfoot osteoarthritis (OA) is most commonly posttraumatic and tends to become symptomatic in younger patients. It often results from instability due to insufficiency of supportive soft tissue structures, such as ligaments and tendons. Diagnostic imaging can be helpful to detect and characterize the distribution of OA, and to assess the integrity of these supportive structures, which helps determine prognosis and guide treatment. However, the imaging findings associated with OA and instability may be subtle and unrecognized until the process is advanced, which may ultimately limit therapeutic options to salvage procedures. It is important to understand the abilities and limitations of various imaging modalities used to assess ankle, hindfoot, and midfoot OA, and to be familiar with the imaging findings of OA and instability patterns.

A foot structure study of new arch flexibility grading system based on three-dimensional arch volume

PURPOSE

Different arch structures may cause different foot function injuries. In the past, the arch structure and flexibility of the foot were often defined by the height of the arch, and there was no three-dimensional (3D) structure classification method. In order to form a more complete 3D description, we propose a new classification system of arch volume flexibility (AVF), and then use this new classification system to investigate the relationship between the AVF and arch index (AI), and the arch height flexibility (AHF) and AI, respectively.

METHODS

It is proposed to recruit 180 young male adults for the test. We obtained arch volume and AI through 3D scanning and obtained the navicular height through manual measurement. Based on these data, we calculated the AHF and the AVF. Using the quintile method, these arches are divided into very stiff, stiff, neutral, flexible, and very flexible. According to AI value, all arches were divided into cavus, rectus, and planus. The distribution of AVF was compared using χ2 goodness of fit test. The spearman correlation test was used to compare the AHF and AVF. A p < 0.05 indicates that the difference is statistically significant.

RESULTS

All participants' plantar data was obtained through 3D scanning, but only 159 of them were complete, so only 318 feet had valid data. The left AHF is (21.23 ± 12.91) mm/kN, and the right AHF is (21.71 ± 12.69) mm/kN. The AVF of the left foot arch is (207.35 ± 118.28) mm3/kg, while the right one is (203.00 ± 117.92) mm3/kg, and the total AVF of the arch was (205.17 ± 117.94) mm3/kg. There was no statistical difference in the AVF between the left and right feet for the same participant (n = 159, p = 0.654). In cavus, the percentage of arch with AVF is 21.4% (very stiff), 21.4% (stiff), 14.3% (neutral), 7.1% (flexible), and 35.7% (very flexible). In rectus, the percentage of arch with AVF is 23.9% (very stiff), 19.6% (stiff), 14.7% (neutral), 24.5% (flexible), and 17.2% (very flexible). In planus, the percentage of arch with AVF is 14.9% (very stiff), 20.6% (stiff), 27.0% (neutral), 16.3% (flexible), and 21.3% (very flexible). Moreover, the correlation between AHF and AVF is not significant (p = 0.060).

CONCLUSION

In cavus, rectus, and planus, different AVF accounts different percentage, but the difference is not statistically significant. AVF is evenly distributed in the arches of the feet at different heights. We further found the relationship between AHF and AVF is not significant. As a 3D index, AVF may be able to describe the flexibility of the arch more comprehensively than AHF.

Ankle and subtalar joint axes of rotation and center of rotation during walking and running in healthy individuals measured using dynamic biplane radiography

The goal of this study was to determine how foot type and activity level affect ankle and hindfoot motion. Dynamic biplane radiography and a validated volumetric registration process was used to measure ankle and hindfoot motion of 20 healthy adults during walking and running. The helical axes of motion (HAM) during stance were calculated at the tibiotalar and subtalar joints. The intersection of each HAM and the rotation plane of interest defined the tibiotalar and subtalar centers of rotation (COR). Correlations between foot type and hindfoot kinematics were calculated using Pearson's correlations. The effect of activity, phase of gait, and dominant vs. non-dominant limb on HAM and COR were evaluated using linear mixed effects models. Activity and phase of gait influenced the superior location of the tibiotalar (p < 0.041) and subtalar (p < 0.044) CORs. Activity and gait phase affected tibiotalar (p < 0.049) and subtalar (p < 0.044) HAM direction during gait. Both HAM orientation and COR location changed with activity and phase of gait. These ankle and hindfoot kinematics have implications for total ankle replacement design and musculoskeletal models that estimate force and moment generating capabilities of muscles.

Flatfeet Severity-Level Detection Based on Alignment Measuring

Flat foot is a postural deformity in which the plantar part of the foot is either completely or partially contacted with the ground. In recent clinical practices, X-ray radiographs have been introduced to detect flat feet because they are more affordable to many clinics than using specialized devices. This research aims to develop an automated model that detects flat foot cases and their severity levels from lateral foot X-ray images by measuring three different foot angles: the Arch Angle, Meary's Angle, and the Calcaneal Inclination Angle. Since these angles are formed by connecting a set of points on the image, Template Matching is used to allocate a set of potential points for each angle, and then a classifier is used to select the points with the highest predicted likelihood to be the correct point. Inspired by literature, this research constructed and compared two models: a Convolutional Neural Network-based model and a Random Forest-based model. These models were trained on 8000 images and tested on 240 unseen cases. As a result, the highest overall accuracy rate was 93.13% achieved by the Random Forest model, with mean values for all foot types (normal foot, mild flat foot, and moderate flat foot) being: 93.38 precision, 92.56 recall, 96.46 specificity, 95.42 accuracy, and 92.90 F-Score. The main conclusions that were deduced from this research are: (1) Using transfer learning (VGG-16) as a feature-extractor-only, in addition to image augmentation, has greatly increased the overall accuracy rate. (2) Relying on three different foot angles shows more accurate estimations than measuring a single foot angle.

A deep learning method for foot-type classification using plantar pressure images

Background: Flat foot deformity is a prevalent and challenging condition often leading to various clinical complications. Accurate identification of abnormal foot types is essential for appropriate interventions. Method: A dataset consisting of 1573 plantar pressure images from 125 individuals was collected. The performance of the You Only Look Once v5 (YOLO-v5) model, improved YOLO-v5 model, and multi-label classification model was evaluated for foot type identification using the collected images. A new dataset was also collected to verify and compare the models. Results: The multi-label classification algorithm based on ResNet-50 outperformed other algorithms. The improved YOLO-v5 model with Squeeze-and-Excitation (SE), the improved YOLO-v5 model with Convolutional Block Attention Module (CBAM), and the multilabel classification model based on ResNet-50 achieved an accuracy of 0.652, 0.717, and 0.826, respectively, which is significantly higher than those obtained using the ordinary plantar-pressure system and the standard YOLO-v5 model. Conclusion: These results indicate that the proposed DL-based multilabel classification model based on ResNet-50 is superior in flat foot type detection and can be used to evaluate the clinical rehabilitation status of patients with abnormal foot types and various foot pathologies when more data on patients with various diseases are available for training.

Unique shape variations of hind and midfoot bones in flatfoot subjects-A statistical shape modeling approach

Flatfoot deformity is a prevalent hind- and midfoot disorder. Given its complexity, single-plane radiological measurements omit case-specific joint interaction and bone shape variations. Three-dimensional medical imaging assessment using statistical shape models provides a complete approach in characterizing bone shape variations unique to flatfoot condition. This study used statistical shape models to define specific bone shape variations of the subtalar, talonavicular, and calcaneocuboid joints that characterize flatfoot deformity, that differentiate them from healthy controls. Bones of the aforementioned joints were segmented from computed tomography scans of 40 feet. The three-dimensional hindfoot alignment angle categorized the population into 18 flatfoot subjects (≥7° valgus) and 22 controls. Statistical shape models for each joint were defined using the entire study cohort. For each joint, an average weighted shape parameter was calculated for each mode of variation, and then compared between flatfoot and controls. Significance was set at p < 0.05, with values between 0.05 ≤ p < 0.1 considered trending towards significance. The flatfoot population showed a more adducted talar head, inferiorly inclined talar neck, and posteriorly orientated medial subtalar articulation compare to controls, coupled with more navicular eversion, shallower navicular cup, and more prominent navicular tuberosity. The calcaneocuboid joint presented trends of a more adducted calcaneus, more abducted cuboid, narrower calcaneal roof, and less prominent cuboid beak compared to controls. Statistical shape model analysis identified unique shape variations which may enhance understanding and computer-aided models of the intricacies of flatfoot, leading to better diagnosis and, ultimately, surgical treatment.

Differential contribution of lateral plantar foot ligaments to lateral column stability - A cadaver based sectioning analysis

Lateral column (LC) instability occurs in adult acquired flatfoot deformity (AAFD). Differential ligament contribution to LC stability is unknown. The primary aim was to quantify this by using cadaver sectioning of lateral plantar ligaments. We also determined the relative contribution of each ligament to dorsal translation of the metatarsal head in the sagittal plane. 17 below-knee cadaveric specimens, preserved by vascular embalming method, were dissected to expose plantar fascia, long/short plantar ligaments (L/SPL), calcaneocuboid (CC) capsule and inferior 4th/5th tarsometatarsal (TMT) capsule. Dorsal forces of 0 N, 20 N and 40 N were applied to the plantar 5th metatarsal head after sequential ligament sectioning in different orders. Pins provided linear axes on each bone, allowing relative angular bone displacements to be calculated. Photography and ImageJ processing software were then used for analysis. The LPL (and CC capsule) had the greatest contribution to metatarsal head motion (107 mm) after isolated sectioning. In the absence of other ligaments, sectioning these resulted in significantly increased hindfoot-forefoot angulation (p ≤ 0.0003). Isolated TMT capsule sectioning demonstrated significant angular displacement even when other ligaments remained intact (with intact L/SPL, p = 0.0005). CC joint instability required both LPL and capsular sectioning for significant angulation to occur, whilst TMT joint stability was largely dependent on its capsule. The relative contribution of static restraints to the lateral arch has not yet been quantified. This study provides useful information on relative ligament contribution to both CC and TMT joint stability, which may in turn improve understanding of surgical interventions used to restore arch stability.

Two-Dimensional and 3-Dimensional MRI Assessment of Progressive Collapsing Foot Deformity-Adult Acquired Flat Foot Deformity

This article is meant to serve as a reference for radiologists, orthopedic surgeons, and other physicians to enhance their understanding of progressive collapsing foot deformity, also known as adult acquired flat foot deformity. Pathophysiology, imaging findings, especially on MRI and 3-dimensional MRI are discussed with relevant illustrations so that the readers can apply these principles in their practice for better patient managements.

Variability of the lower limb symmetry index associated with the gait parameters in the overweight adult population with flatfoot: a case-control study

Background: Adult acquired flatfoot is characterized by a medial arch collapse during monopodal support in the stance phase, developing eversion of the calcaneus and abduction of the forefoot linked to the hindfoot. The purpose of our research was to analyze the dynamic symmetry index in the lower limbs comparing patients with flatfoot and normal foot. Methods: A case-control study was carried out with a sample of 62 participants divided into two groups consisting of 31 participants were overweight with bilateral flatfoot and 31 participants with healthy feet. A portable plantar pressure platform with piezoresistive sensors was used to measure the load symmetry index in the lower limbs in the foot areas and gait phases. Results: Gait pattern analysis showed statistically significant differences in the symmetry index for lateral load (p = 0.004), the initial contact phase (p = 0.025) and the forefoot phase (p < 0.001). Conclusion: The adults were overweight with bilateral flatfoot evidenced alterations in the symmetry index in the lateral load and in the initial contact and flatfoot contact phases, showing greater instability in overweight adult flatfoot compared to the people with normal feet.