Cluster analysis to identify foot motion patterns in children with flexible flatfeet using gait analysis-A statistical approach to detect decompensated pathology?

Multivariate functional principal component analysis and k-means clustering to identify kinematic foot types during gait in children with cerebral palsy

BACKGROUND

Children with neuromuscular disorders, such as cerebral palsy, frequently develop foot deformities, such as equinopronovalgus and equinosupovarus, leading to walking difficulties and discomfort. Traditional assessment methods, including clinical measures and radiographs, often fail to capture the dynamic nature of these deformities, resulting in suboptimal treatment. 3D gait analysis using multisegment foot models offers a more detailed understanding of these deformities.

RESEARCH QUESTION

To determine whether the combination of multisegment foot models, multivariate functional principal component analysis, and k-means cluster analyses could identify distinct, clinically relevant foot types in a large pediatric cohort with cerebral palsy.

METHODS

This was a retrospective analysis of 3D gait data from 197 patients with cerebral palsy collected using a multisegment foot model. Multivariate functional principal component analysis was used to reduce these data prior to using k-means clustering to identify foot posture clusters. Further analyses, including ANOVA and Fisher's Exact tests, were used to evaluate demographic, radiographic, and gait characteristics to explain the clinical relevance of each cluster.

RESULTS

Analysis of kinematic data from 371 feet revealed six clinically significant clusters, with a low misclassification rate of 2 %. One-factor ANOVAs demonstrated significant differences across clusters for all MPCs, whereas no significant differences were noted in basic anthropometric variables. Significant variations were observed in radiographic and gait function variables, and a strong association between GMFCS levels and cluster categorization was identified.

SIGNIFICANCE

The novel approach of integrating multivariate functional principal component analysis and k-means clustering identified a spectrum of foot deformities in children with CP, ranging from equinosupovarus to marked equinopronovalgus. This methodology provides an objective classification based on kinematic data and can facilitate improved diagnosis and treatment of cerebral palsy-related foot deformities.

[An update on clinical gait analysis : Current developments and applications]

The objective acquisition and assessment of joint movements and loads using instrumented gait analysis has become an established tool in clinical diagnostics. In particular, marker-based 3D gait analyses make use of an increasingly comprehensive database for the assessment of orthopaedic or neurological questions. Based on this data and medical-scientific experience, increasingly reliable approaches and evaluation strategies are emerging, which also draw on methods from artificial intelligence and musculoskeletal modelling. This article focusses on marker-based gait analyses of the lower extremity (hip, knee, foot) and how these can be used in a clinically relevant way using current methods, e.g. for determining indications or optimization of surgical planning. Finally, current developments and applications by using alternative methods from sensor technology and optical motion capture will be briefly discussed.

Dynamic Gait Analysis in Paediatric Flatfeet: Unveiling Biomechanical Insights for Diagnosis and Treatment

BACKGROUND

Flatfeet in children are common, causing concern for parents due to potential symptoms. Technological advances, like 3D foot kinematic analysis, have revolutionized assessment. This review examined 3D assessments in paediatric idiopathic flexible flat feet (FFF).

METHODS

Searches focused on paediatric idiopathic FFF in PubMed, Web of Science, and SCOPUS. Inclusion criteria required 3D kinematic and/or kinetic analysis during posture or locomotion, excluding non-idiopathic cases, adult feet, and studies solely on pedobarography or radiographs.

RESULTS

Twenty-four studies met the criteria. Kinematic and kinetic differences between FFF and typical feet during gait were outlined, with frontal plane deviations like hindfoot eversion and forefoot supination, alongside decreased second peak vertical GRF. Dynamic foot classification surpassed static assessments, revealing varied movement patterns within FFF. Associations between gait characteristics and clinical measures like pain symptoms and quality of life were explored. Interventions varied, with orthoses reducing ankle eversion and knee and hip abductor moments during gait, while arthroereisis normalized calcaneal alignment and hindfoot eversion.

CONCLUSIONS

This review synthesises research on 3D kinematics and kinetics in paediatric idiopathic FFF, offering insights for intervention strategies and further research.

Really Asymptomatic? Health-Related Quality of Life and Objective Clinical Foot Characteristics among 5-10-Year-Old Children with a Flexible FlatFoot

The potential effects of asymptomatic flexible flatfoot (FF) on children's health-related quality of life (QoL) and objective clinical foot characteristics have been poorly investigated in the literature. Therefore, this study aimed to analyse these indicators, comparing the children with asymptomatic FF and a control group.

METHODS

In total, 351 children were enrolled in this cross-sectional study-160 children with asymptomatic FF and 191 controls (children with normal feet). The children and their parents completed the Paediatric Quality of Life Inventory (PedsQL^TM 4.0). The objective foot characteristics included clinical foot posture measures, footprints, general hyperlaxity, and X-ray measurements.

RESULTS

Children with asymptomatic FF had a significantly lower QoL (overall and all four dimensions). The parents' assessment of the QoL of their children with asymptomatic FF in most cases was lower compared to their children's self-reported QoL. Moreover, almost all clinical foot measures also had significantly worse profiles among asymptomatic FF cases compared to the controls. This was observed with the Foot Posture Index-6 (FPI-6), the navicular drop (ND) test, the Chippaux-Smirak Index (CSI), Staheli's Index (SI), the Beighton scale, and radiological angles (except the talo-first metatarsal angle).

CONCLUSION

The findings suggest that asymptomatic FF not always reflects a normal foot development. This condition is related to decreased health-related quality of life, so the 5-10-year-old children's and their parents' complaints should be considered more closely in identification, treatment, and monitoring plans.

Clinical, Radiographic and Gait Parameters Associated with Medial Arch Pain in the Flexible Pediatric Flatfoot

Pain in the flexible flatfoot is a common complaint, if present it is important to find its exact location and causes Therefore, the study aimed to find differences between children with and without medial arch pain and relate them to the reduction of pain following surgical treatment. Children with idiopathic flexible flatfeet were retrospectively included in the study. All children underwent a clinical, radiographic, and gait examination. The feet were subdivided into 2 groups: asymptomatic and those with medial arch pain. Factors associated with medial arch pain were identified via t test. Significant radiological and gait parameters were correlated to the change in medial arch pain score following surgery. Included were 322 feet belonging to 177 children, with the mean age of 11.8 (SD = 2.2) years. The pain was perceived in 52% of the feet, of these, 74% in the medial arch. In the group with pain, 31 feet received a gait analysis following surgery. The radiological parameters, talus-1 and -2 metatarsal angles and the gait parameter, calcaneal lateral shift during walking showed a significant difference (p ≤ .004) between the no pain and pain groups and were associated (R² ≥0.14, p ≤ .04) with the reduction in pain following surgery. The increased talus-1 and -2 metatarsal angles and the calcaneal lateral shift may cause increased tension on the soft-tissues along the medial side of the foot and may produce pain. Therapies aiming at improving the medial arch pain should be directed to normalize the talus-1 or -2 metatarsal angles and the calcaneal lateral shift.

Results of the Italian Pediatric Orthopedics Society juvenile flexible flatfoot survey: diagnosis and treatment options

The objectives of this study were to collect and analyze current diagnosis and treatment options of symptomatic flexible flatfoot (FFF), as well as to identify treatment expectations, among the members of the Italian Pediatric Orthopedics Society (SITOP). Diagnosis and treatment preferences were recorded according to a web-based survey. The survey was divided into six main sections: (1) general clinical parameters; (2) foot aspects; (3) X-ray angles (or lines); (4) expectations; (5) standard clinical assessment; (6) treatment options. One hundred and ten out of 248 SITOP members answered to the questionnaire. Age (85.5%), pain at the level of the plantar arch or fascia (61.8%), fatigue (59.1%) were the clinical parameters of crucial importance. Heel valgus (85.4%), flexibility (61.8%) and forefoot supination (47.3%) were identified as the most important foot aspects. Ninety-two responders (83.6%) identified the 'improved ability to walk longer without symptoms or discomfort' as the principal treatment expectation. Pain evaluated through the visual analog scale (VAS) was considered crucial in 31.8% of cases. All respondents confirmed they also treat patients with FFF surgically; in particular, 97.3% of SITOP affiliates declare to perform arthroereisis followed by lateral column lengthening (29.1%) and medializing calcaneal osteotomy (9.1%). Although in this survey heterogeneous findings for diagnosis and treatment of patients with symptomatic FFF within SITOP members were found, a large preference for age, heel valgus, flexibility as clinical aspects and parameters, as well as nonoperative treatment and arthroereisis, was reported.

Identification of Patients with Similar Gait Compensating Strategies Due to Unilateral Hip Osteoarthritis and the Effect of Total Hip Replacement: A Secondary Analysis

Despite good clinical functional outcome, deficits in gait biomechanics exist 2 years after total hip replacement surgery. The aims of this research were (1) to group patients showing similar gait adaptations to hip osteoarthritis and (2) to investigate the effect of the surgical treatment on gait kinematics and external joint moments. In a secondary analysis, gait data of 51 patients with unilateral hip osteoarthritis were analyzed. A k-means cluster analysis was performed on scores derived via a principal component analysis of the gait kinematics. Preoperative and postoperative datasets were statistically tested between clusters and 46 healthy controls. The first three principal components incorporated hip flexion/extension, pelvic tilt, foot progression angle and thorax tilt. Two clusters were discriminated best by the peak hip extension during terminal stance. Both clusters deviated from healthy controls in spatio-temporal, kinematic and kinetic parameters. The cluster with less hip extension deviated significantly more. The clusters improved postoperatively but differences to healthy controls were still present one year after surgery. A poor preoperative gait pattern in patients with unilateral hip osteoarthritis is associated with worse gait kinematics after total hip replacement. Further research should focus on the identification of patients who can benefit from an adapted or individualized rehabilitation program.

Differences in rearfoot, midfoot, and forefoot kinematics of normal foot and flatfoot during running

Flatfoot is a common foot deformity, which could contribute to running injuries such as medial tibial stress syndrome. Intrafoot kinematics of flatfoot during walking have often been documented using multisegment foot models. However, the intrafoot kinematics of flatfoot during running remains unclear, despite the possible relationship between flatfoot and running injuries. We aimed to clarify rearfoot, midfoot, and forefoot kinematics when running in participants with normal foot and flatfoot. Participants with the normal foot (n = 14) and flatfoot (n = 14) were asked to runover-ground at their preferred speed. Three-dimensional kinematics of the rearfoot, midfoot, and forefoot during running were calculated based on the Rizzoli foot model. A two-sample t-test of statistical parametric mapping was performed to determine differences between normal foot and flatfoot in time histories of intrafoot kinematics during running. No differences were found between groups in characteristics and spatiotemporal parameters. In the frontal rearfoot angle, a significantly increased eversion from 24% to 100% (p < .001) was observed in the flatfoot compared to the normal foot. At the midfoot angle, a significantly increased eversion from 0% to 4% (p < .049) and 21% to 100% (p < .001) was observed in the flatfoot compared to the normal foot. At the forefoot angle, a significantly increased inversion from 6% to 17% (p < .047) was observed in the flatfoot compared to the normal foot. These findings may be useful to explain why flatfoot could contribute to running injuries such as medial tibial stress syndrome.

Comparison of multiple flatfoot indicators in 5-8-year-old children

Background

The foot posture is age dependent. The purpose of this study was to investigate the relationship between the 6-item version of the foot posture index (FPI) and other clinical, foot anthropometric, radiological measurements for the foot position in 5–8-year-old children.

Methods

A total of 301 participants with a mean age of 6.4  ±  1.14 years were enrolled in the study. Children were examined physically, clinically, and radiologically to measure the FPI and navicular drop (ND) test, resting calcaneal stance position (RCSP) angle, Chippaux–Smirak index (CSI), Staheli index (SI), calcaneal pitch (CP) angle, talocalcaneal angle (TCA), and the first lateral metatarsal angle. Tibial torsions, internal rotation of the hip as an indirect method of femoral anteversion, and Beighton scale were analyzed for factors associated with flatfoot prevalence.

Results

The study included children with normal and flexible flatfeet. Statistical analysis showed a significant FPI score correlation with other parameters (SI, CSI, RCSP, ND, CP, TMA, and TCA showed strong and moderate correlations, p < 0.001). Overall, the strongest associates are CSI (β = 0.34) and ND (β = 0.28). Other indicators have relatively small relationships with the FPI.

Conclusion

A positive correlation was observed between FPI-6 and ND test, CSI in 5–8-year-old children. All three prominent foot posture indicators (FPI-6, ND, and CSI) might be used as a primary or preferred tool in clinical practice.

Osteoarthritis year in review 2020: mechanics

The mechanical environment of the joint during dynamic activity plays a significant role in osteoarthritis processes. Understanding how the magnitude, pattern and duration of joint-specific loading features contribute to osteoarthritis progression and response to treatment is a topic of on-going relevance. This narrative review synthesizes evidence from recent papers that have contributed to knowledge related to three identified emerging subthemes: 1) the role of the joint mechanical environment in osteoarthritis pathogenesis, 2) joint biomechanics as an outcome to arthroplasty treatment of osteoarthritis, and 3) methodological trends for advancing our knowledge of the role of biomechanics in osteoarthritis. Rather than provide an exhaustive review of a broad area of research, we have focused on evidence this year related to these subthemes. New research this year has indicated significant interest in using biomechanics investigations to understand structural vs clinical progression of osteoarthritis, the role and interaction in the three-dimensional loading environment of the joint, and the contribution of muscle activation and forces to osteoarthritis progression. There is ongoing interest in understanding how patient variability with respect to gait biomechanics influences arthroplasty surgery outcomes, and subgroup analyses have provided evidence for the potential utility in tailored treatment approaches. Finally, we are seeing a growing trend in the application of translational biomechanics tools such as wearable inertial measurement units for improved integration of biomechanics into clinical decision-making and outcomes assessment for osteoarthritis.

Flat foot and spinal degeneration: Evidence from nationwide population-based cohort study

BACKGROUND/PURPOSE

Flat foot can alter the lower limb alignment and cause knee and back pain. To explore the association between flat foot and spinal degeneration.

METHODS

By using a claims dataset containing 1 million random samples, individuals with flat foot were identified between January 1, 2000, and December 31, 2013. The study assembled a flat foot group and a matched non-flat foot group. Definition of flat foot was according to International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. The diagnosis date was defined as the index date for follow-up initiation. The follow-up period was defined as the duration from the index date (or nested index date for controls) to the occurrence of spinal degenerative joint disease (DJD), or December 31, 2013. The primary outcome was record of spinal DJD retrieved from the same database. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), with the control group as a reference.

RESULTS

We identified 13,965 patients (most aged <30 years, 88%); 2793 patients were assigned to the flat foot group and 11,172 individuals to the non-flat foot group matched by age, sex, and index year. The mean follow-up duration was approximately 74 months. In total, 329 (11.78%) patients in the study group and 931 (8.33%) patients in the comparison group developed spinal DJD. The adjusted HR (95% CI) of spinal DJD for study group was 1.423(1.250-1.619) compared with the control. Sensitivity analyses with propensity score match and different scenario about spinal DJD enrollment showed similar results. Subgroup analysis showed that in patients aged >45 years with history of flat foot, the adjusted hazard ratios were 1.434, 3.065, 3.110, and 2.061 in association with spondylosis, intervertebral disc disorder, cervical stenosis, thoracic-lumbar-sacral stenosis, respectively.

CONCLUSION

Flat foot was found to be an independent risk factor for subsequent spinal DJD.

Is there a correlation between static radiographs and dynamic foot function in pediatric foot deformities?

BACKGROUND

Idiopathic flexible flatfeet, congenital clubfeet and pes cavovarus are the most common foot deformities in children. Accurate assessment to quantify the severity of these deformities by clinical examination alone can be challenging. Radiographs are a valuable adjunct for accurate diagnosis and effective treatment. However, static radiographs during relaxed standing may not reflect the dynamic changes in the foot skeleton during functional activities such as walking. Therefore, the aim of this study is to predict dynamic foot movements during walking from planar standing radiographs to reveal the significance of the radiographic analysis for the assessment of foot function.

METHODS

Patients 8-17 years with flexible flatfeet (FFF, n=217) recurrent clubfeet (RCF n=38) and overcorrected clubfeet (OCCF, n=71) of non-neurogenic or syndromic origin and pes cavovarus due to peripheral neuropathy (PNP, n=48) were retrospectively included. Patients underwent gait analysis with the Oxford Foot Model and radiographic examination in anterior-posterior and lateral view during standing. Multilinear predictor analysis of selected gait parameters was performed based on radiographic measures.

RESULTS

The variance that was explained by radiography was greatest for the transverse plane forefoot abduction with 33% for OCCF, 50% for RCF and 59% for PNP. Flatfeet and foot kinematics in the other planes or between rearfoot and tibia showed little or no relation.

CONCLUSIONS

The static measures of foot deformities by radiography could explain only a small amount of variance in foot kinematics during walking, in particular for FFF. An explanation may be that the forces during weight bearing bear little resemblance to those during gait in terms of neither magnitude nor direction. These findings suggest that foot function cannot be accurately assessed solely from static radiographic observations of the foot, commonly undertaken in clinical practice.

Does an overcorrected clubfoot caused by surgery or by the Ponseti method behave differently?

BACKGROUND

Overcorrection is a recognized problem following surgical treatment of congenital clubfoot. Recently this complication has also been mentioned following Ponseti treatment.

RESEARCH QUESTION

Do overcorrected clubfeet (OCCF) caused by surgery behave differently from those caused by Ponseti treatment in terms of segmental motion of the feet and show differences in the severity of deformity on X-rays?

METHODS

Children between 7 and 12 years with OCCF were included in this study. Depending on the aetiology causing them, the feet were divided into 2 groups (Ponseti and peritalar release surgery). 25 typically developing children served as controls. All subjects were subjected to clinical and radiological examination and 3-Dimensional gait analysis using the Oxford Foot Model.

RESULTS

Thirty-two children with OCCF, of these 18 feet in the surgical and 14 feet in the Ponseti group, were included in the study. No radiological differences were seen in the flatfoot parameters between OCCF groups except in the calcaneal inclination angle that was more pathological in the Ponseti group. The clinical ankle plantar flexion was significantly reduced in the surgical group. During walking the range motion of the hindfoot in the frontal plane was significantly reduced in surgically treated feet compared to the Ponseti group. The other parameters did not show any significant difference between groups.

SIGNIFICANCE

The overcorrected clubfeet following surgery and Ponseti showed similar appearance and showed no significant differences in 11/12 radiological parameters. The segmental motion of the feet showed no significant differences between groups except the in the range of motion of the subtalar eversion. A considerable subtalar joint motion was present even in the surgical group. These findings might help plan the treatment of these feet.