Multisegmental foot and ankle motion analysis after hallux valgus surgery

Lower limb kinematic changes during gait after hallux valgus surgery: A prospective observational study

BACKGROUND

Patients with hallux valgus are known to alter lower limb joint kinematics during gait. However, little information is available about gait changes following hallux valgus surgery. We aimed to longitudinally investigate lower limb kinematic changes at the mid and terminal stances of gait after hallux valgus surgery.

METHODS

This prospective observational study included 11 female patients (17 feet), who underwent first metatarsal osteotomy. Gait analyses were performed preoperatively and 1- and 2-year postoperatively using a three-dimensional motion capture system. Toe-out angle, ankle, knee, and hip joint angles during gait were calculated from the recorded data. The spatiotemporal parameters and these angles at the mid and terminal stances of gait were statistically compared between preoperative and postoperative periods.

FINDINGS

All spatiotemporal parameters remained unchanged postoperatively. The toe-out angle was significantly greater at 1- and 2-year postoperatively. The ankle pronation angle, the knee abduction angle, and the hip adduction angle at the mid and terminal stances of gait were smaller postoperatively compared to the preoperative. These angular changes showed a similar trend at 1 and 2 years postoperatively. However, the postoperative changes of the sagittal joint angles were relatively small.

INTERPRETATION

Hallux valgus surgery can affect the toe-out angle and the lower limb coronal kinematics at the mid and terminal stances of gait in patients with hallux valgus. However, surgical correction of hallux valgus deformity did not directly improve the gait characteristics in patients with hallux valgus.

Biomechanical comparison of two surgical methods for Hallux Valgus deformity: Exploring the use of artificial neural networks as a decision-making tool for orthopedists

Hallux Valgus foot deformity affects gait performance. Common treatment options include distal oblique metatarsal osteotomy and chevron osteotomy. Nonetheless, the current process of selecting the appropriate osteotomy method poses potential biases and risks, due to its reliance on subjective human judgment and interpretation. The inherent variability among clinicians, the potential influence of individual clinical experiences, or inherent measurement limitations may contribute to inconsistent evaluations. To address this, incorporating objective tools like neural networks, renowned for effective classification and decision-making support, holds promise in identifying optimal surgical approaches. The objective of this cross-sectional study was twofold. Firstly, it aimed to investigate the feasibility of classifying patients based on the type of surgery. Secondly, it sought to explore the development of a decision-making tool to assist orthopedists in selecting the optimal surgical approach. To achieve this, gait parameters of twenty-three women with moderate to severe Hallux Valgus were analyzed. These patients underwent either distal oblique metatarsal osteotomy or chevron osteotomy. The parameters exhibiting differences in preoperative and postoperative values were identified through various statistical tests such as normalization, Shapiro-Wilk, non-parametric Wilcoxon, Student t, and paired difference tests. Two artificial neural networks were constructed for patient classification based on the type of surgery and to simulate an optimal surgery type considering postoperative walking speed. The results of the analysis demonstrated a strong correlation between surgery type and postoperative gait parameters, with the first neural network achieving a remarkable 100% accuracy in classification. Additionally, cases were identified where there was a mismatch with the surgeon's decision. Our findings highlight the potential of artificial neural networks as a complementary tool for surgeons in making informed decisions. Addressing the study's limitations, future research may investigate a wider range of orthopedic procedures, examine additional gait parameters and use more diverse and extensive datasets to enhance statistical robustness.

Validation of the Foot and Ankle Outcome Score (FAOS) for Osteochondral Lesions of the Ankle

BACKGROUND

The purpose of this study was to validate the Foot and Ankle Outcome Score (FAOS) for osteochondral lesions of the talus (OLTs). We hypothesize that the FAOS will meet all 4 psychometric criteria for validity in this patient population.

METHODS

From 2008 to 2014, a total of 208 patients with OLTs were included in the construct validity portion of the study. All patients completed FAOS and 12-Item Short-Form Health Survey (SF-12) scores. Twenty additional patients were prospectively recruited and were asked to complete questionnaires to determine the relevance of each of the FAOS questions as it related to their OLT. Forty-four patients completed the FAOS 1 month after the first FAOS to assess reliability via Spearman correlation coefficient. Responsiveness of the FAOS was assessed with 54 patients who had both preoperative and postoperative FAOS scores via Student paired t test with significance determined as P < .05. In total, 229 unique patients were included in this study.

RESULTS

Statistically significant associations were found between all FAOS and SF-12 subscales (P < .01). The FAOS symptoms subscale demonstrated the lowest correlation with the SF-12 physical health domains. No floor or ceiling effects were identified. Weak correlations were calculated between the 5 FAOS subscales and the SF-12 mental component summary score. All FAOS domains met the threshold for acceptable content validity (score > 2.0). All FAOS subscales demonstrated acceptable test-retest reliability, with ICC values ranging from 0.81 (ADL) to 0.92 (Pain).

CONCLUSION

This study demonstrates the acceptable yet moderate construct and content validity, reliability, and responsiveness of the FAOS for patients with OLTs of the ankle joint. We endorse the use of the FAOS in evaluating ankle OLTs in both the research and clinical setting and consider it a useful patient-reported, self-administered instrument following surgical intervention.

LEVEL OF EVIDENCE

Level IV, retrospective case study.

Effects of Foot-Toe Orthoses on Moment and Range of Motion of Knee Joint in Individuals with Hallux Valgus

Although various types of hallux valgus (HV) orthoses have been used to manage hallux valgus deformity, few previous studies have determined the biomechanical effects of applying a foot-toe orthosis as a therapeutic intervention for HV deformity on the kinetics and kinematics of the knee joint. Biomechanical variables were collected from 24 patients with HV. A three-dimensional motion capture system and force platforms were used to analyze the kinetic and kinematic variables in HV orthosis conditions during gait. To determine the biomechanical effect of each orthosis for HV on knee kinetic and kinematic values, repeated-measures ANOVA was used. The knee adduction moment was significantly decreased under a hard plastic orthosis (HPO) condition compared to that under a without foot-toe orthosis (WTO) condition (p = 0.004). There was a significant decrease in maximal external rotation of the knee joint in HPO than in WTO at the stance phase during gait (p = 0.021). All of the kinetic and kinematic data showed no significant differences between WTO and soft silicone orthosis conditions (p > 0.05). This study indicates that a stronger foot-toe orthosis, such as HPO, to correct HV deformity has a positive effect on the moment and joint motion occurring in the knee joint during walking. In particular, the application of this type of HV orthosis can reduce knee adduction moments associated with the development and progression of knee OA.

Do different multi-segment foot models detect the same changes in kinematics when wearing foot orthoses?

Background

Different multi-segment foot models have been used to explore the effect of foot orthoses. Previous studies have compared the kinematic output of different multi-segment foot models, however, no study has explored if different multi-segment foot models detect similar kinematic changes when wearing a foot orthoses. The aim of this study was to compare the ability of two different multi-segment foot models to detect kinematic changes at the hindfoot and forefoot during the single and double support phases of gait when wearing a foot orthosis.

Methods

Foot kinematics were collected during walking from a sample of 32 individuals with and without a foot orthosis with a medial heel bar using an eight-camera motion capture system. The Oxford Foot Model (OFM) and a multi-segment foot model using the Calibrated Anatomical System Technique (CAST) were applied simultaneously. Vector field statistical analysis was used to explore the kinematic effects of a medial heel bar using the two models, and the ability of the models to detect any changes in kinematics was compared.

Results

For the hindfoot, both models showed very good agreement of the effect of the foot orthosis across all three anatomical planes during the single and double support phases. However, for the forefoot, the level of agreement between the models varied with both models showing good agreement of the effect in the coronal plane but poorer agreement in the transverse and sagittal planes.

Conclusions

This study showed that while consistency exists across both models for the hindfoot and forefoot in the coronal plane, the forefoot in the transverse and sagittal planes showed inconsistent responses to the foot orthoses. This should be considered when interpreting the efficacy of different interventions which aim to change foot biomechanics.

Gait biomechanics evaluation of the treatment effects for hallux valgus patients: A systematic review and meta-analysis

BACKGROUND

Hallux valgus (HV) is a foot deformity characterized by lateral deviation of the big toe and medial deviation of the first metatarsal.

RESEARCH QUESTION

This study aimed to shed light on the treatment effects of different interventions and surgical procedures for HV deformity to determine the effectiveness of gait biomechanics correction.

METHODS

English-language searches of the electronic databases were conducted in the Cochrane Library, Web of Science, PubMed, Scopus, and Embase. Gait biomechanics evaluation before and after conservative or operative treatments was essential for inclusion in this review. Methodological quality was assessed by the Institute of Health Economics (IHE) quality appraisal tool. All pooled analysis was based on the random-effects model.

RESULTS

Twenty-five articles (1003 participants) were identified in this review. Three studies chose conservative therapies for HV deformity, incorporating foot orthotics and minimalist running intervention, and surgeries were performed in twenty-two studies. For the pressure parameter alteration under the hallux, the effect size (ES) in the conservative treatment subgroup was - 0.95 with 95%CI [- 1.69, - 0.21]. It demonstrated a moderate ES of - 0.44% and 95%CI [- 0.81, - 0.07] in the surgery subgroup. The five operations' peak pressure alteration under the hallux demonstrated a moderate ES of - 0.45% and 95%CI [- 0.54, - 0.36].

SIGNIFICANCE

Both non-operative and operative treatments could achieve the forefoot pressure redistribution, decreasing loading beneath the hallux and first metatarsal regions，However, the treatment effects of surgeries were not very robust. The percutaneous DSTR-Akin technique is recommended as an adequate operative treatment, with a large ES and moderate heterogeneity. The negative gait return effect should be noticed while using Scarf osteotomy, despite positive clinical and radiographic outcomes.

The Syndesmosis Procedure Correction of Hallux Valgus Feet Associated With the Metatarsus Adductus Deformity

Metatarsus adductus and hallux valgus are common foot deformities. Corrective surgery of hallux valgus feet with metatarsus adductus deformity can be challenging and experience a high deformity recurrence rate. The purpose of this study was to demonstrate if the syndesmosis procedure can correct such feet satisfactorily without osteotomies and arthrodesis. 75 hallux valgus feet in 45 patients with a Sgarlato's metatarsal adductus angle ≥15° were studied after having undergone the syndesmosis procedure for an average of 20.22 months. Their average preoperative intermetatarsal angle of 12.56° was improved to 6.00° (p < .001) and metatarsophalangeal angle from 35.61° to 23.46° (p < .001) significantly. Their average American Orthopedic Foot and Ankle Society's clinical scores improved significantly from 56.41 to 90.53 points (p < .001). Fifty-five feet (73.33%) had preoperative metatarsal calluses, and all but 3 had a noticeable reduction in severity. Forty-one patients (91.11%) were able to return to their desired activities and footwear. All relevant raw data formed this study, including x-ray and photographic images, were submitted as Supplementary Material for online viewing and reference. Despite the possible intrinsic rigidity of metatarsus adductus forefoot, this study demonstrated that hallux valgus feet with metatarsus adductus deformity could be corrected anatomically and functionally with the soft tissue syndesmosis procedure and without correcting the preexisting metatarsus adductus deformity. This study also supports the notion that the MA deformity accentuates hallux valgus alignment preoperatively and postoperatively, and possibly all feet in general.

Wearable Devices for Gait Analysis in Intelligent Healthcare

In this study, we review the role of wearable devices in tracking our daily locomotion. We discuss types of wearable devices that can be used, methods for gait analyses, and multiple healthcare-related applications aided by artificial intelligence. Impaired walking and locomotion are common resulting from injuries, degenerative pathologies, musculoskeletal disorders, and various neurological damages. Daily tracking and gait analysis are convenient and efficient approaches for monitoring human walking, where concreate and rich data can be obtained for examining our posture control mechanism during body movement and providing enhanced clinical pieces of evidence for diagnoses and treatments. Many sensors in wearable devices can help to record data of walking and running; spatiotemporal and kinematic variables can be further calculated in gait analysis. We report our previous works in gait analysis, discussing applications of wearable devices for detecting foot and ankle lesions, supporting surgeons in early diagnosis, and helping physicians with rehabilitation.

Women after Bilateral Surgical Correction of Hallux Valgus Do Not Show Improvement in Spatiotemporal Gait Parameters at 18 Weeks Postoperatively

Background: Hallux valgus (HV) is a gait-altering orthopedic deformity, somewhat more prevalent in women, which often affects both limbs. Although surgery is a commonly applied treatment, there is no consensus in the literature on how invasive HV correction affects spatiotemporal gait parameters, or how quickly improvement can be expected. We investigated gait parameters in female HV patients who underwent bilateral surgical correction of hallux valgus, both preoperatively and 18 weeks following surgery (a timeframe relevant from the perspective of physical therapy), and also in relation to a non-HV control group. Methods: A total of 23 women aged 40–70 years, with moderate to severe HV deformity in both feet, were assessed preoperatively and 18 weeks postoperatively, and an age-matched control group of 76 healthy women was also assessed. A total of 22 spatiotemporal parameters were collected during 30 s walks over an electronic walkway (Zebris Medical System). Results: Of the 22 parameters analyzed, significant differences between the preoperative experimental and control groups were found only in 4 parameters (Velocity, Right step time, Total double support and Stride time), but in 16 parameters between the postoperative experimental and control groups (the greatest impact being found for: Left and Right Step time, Stride time, Cadence, Right Foot rotation, Left Step length (% leg length) and Stride length (% leg length)). Conclusions: Women after bilateral HV correction did not exhibit improved (i.e., more normal) gait parameters at 18 weeks postoperatively; rather, they showed more gait abnormalities than preoperatively. These findings urge longer-term planning of postoperative rehabilitation, involving continual evaluation of gait improvement.

Inter-segmental foot kinematics during gait in elderly females according to the severity of hallux valgus

The objective of this study was to find the effect of hallux valgus (HV) deformity on the inter-segmental motion of the foot using an MFM with a 15-marker set (DuPont Foot Model, DuFM) in comparison with age and sex controlled healthy adults. Fifty-eight female symptomatic HV patients and 50 female asymptomatic older female volunteers were included in this study. According to the radiographic hallux valgus angle (HVA), the study population was divided into severe HV (SHV, HVA ≥ 40°, n = 25), moderate HV (MHV, 20° ≤ HVA < 40°, n = 47), and control (CON, n = 36). MHV group was divided into symptomatic MHV group (S-MHV, n = 33) and asymptomatic MHV group (A-MHV, n = 14) according to the symptoms associated with HV. For temporal parameters, gait speed and stride length were diminished according to the severity of HV deformity. Sagittal range of motion of hallux and hindfoot decreased significantly in SHV group. Loss of push-off during the preswing phase was observed and forefoot adduction motion during terminal stance was decreased in SHV group. In a subgroup analysis of MHV, asymptomatic HV minimally affects gait and inter-segmental motion during gait. HV deformity affects gait parameters and inter-segmental motion of the foot during gait in proportion to the severity of the deformity. However, the effect of MHV itself on foot kinematics might be limited while pain or arthritic change of the joint might cause changes in gait in patients with symptomatic HV.

Number of Segments Within Musculoskeletal Foot Models Influences Ankle Kinematics and Strains of Ligaments and Muscles

Multi-segment foot models (MFMs) are becoming a common tool in musculoskeletal research on the ankle-foot complex. The purpose of this study was to compare ankle joint kinematics as well as ligament and muscle strains that result from MFM with a different number of segments during vertical hopping. Ten participants were recruited and performed double-limb vertical hops. Marker positions and ground reaction forces were collected. Two-segment (2MFM), three-segment (3MFM), and five-segment MFM (5MFM) were used to calculate ankle kinematics and the strains of the anterior talofibular and calcaneofibular ligaments and of the soleus and gastrocnemius muscles. Ranges of motion and peak strains were analyzed with Kruskal-Wallis and post hoc tests, whereas the time-series of the ankle kinematics and ligament and muscle strains were analyzed with statistical parametric mapping. There were significant main effects for MFM in the talocrural joint range of motion and peak strains of ligaments and muscles. In addition, there were significant main effects for MFM in time-series data of the talocrural joint angle as well as for ligament and muscle strains. In all cases, the post hoc analyses showed that the 2MFM consistently overestimated the range of motion and tissue strains compared to the 3MFM and 5MFM, while 3MFM and 5MFM did not differ from each other in the most variables. This study showed that the number of segments in MFM significantly affects the biomechanical estimates of joint kinematics and tissue strains during hopping. Clinical significance: MFM that combine all foot structures beyond the talus into one segment likely overestimate ankle joint biomechanics. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2231-2240, 2019.

Multi-segment foot models and their use in clinical populations

BACKGROUND

Many multi-segment foot models based on skin-markers have been proposed for in-vivo kinematic analysis of foot joints. It remains unclear whether these models have developed far enough to be useful in clinical populations. The present paper aims at reviewing these models, by discussing major methodological issues, and analyzing relevant clinical applications.

RESEARCH QUESTION

Can multi-segment foot models be used in clinical populations?

METHODS

Pubmed and Google Scholar were used as the main search engines to perform an extensive literature search of papers reporting definition, validation or application studies of multi-segment foot models. The search keywords were the following: 'multisegment'; 'foot'; 'model'; 'kinematics', 'joints' and 'gait'.

RESULTS

More than 100 papers published between 1991 and 2018 were identified and included in the review. These studies either described a technique or reported a clinical application of one of nearly 40 models which differed according to the number of segments, bony landmarks, marker set, definition of anatomical frames, and convention for calculation of joint rotations. Only a few of these models have undergone robust validation studies. Clinical application papers divided by type of assessment revealed that the large majority of studies were a cross-sectional comparison of a pathological group to a control population.

SIGNIFICANCE

This review suggests that there is sufficient evidence that multi-segment foot models may be successfully applied in clinical populations. Analysis of the currently available models allows users to better identify the most suitable protocol for specific clinical applications. However new models require thorough validation and assessment before being used to support clinical decisions.

Repeatability of a Multi-segment Foot Model with a 15-Marker Set in Normal Children

Background

The use of three-dimensional multi-segment foot models (3D MFMs) is increasing since they have superior ability to illustrate the effect of foot and ankle pathologies on intersegmental motion of the foot compared to single-segment foot model gait analysis. However, validation of the repeatability of the 3D MFMs is important for their clinical use. Although many MFMs have been validated in normal adults, research on MFM repeatability in children is lacking. The purpose of this study is to validate the intrasession, intersession, and interrater repeatability of an MFM with a 15-marker set (DuPont foot model) in healthy children.

Methods

The study included 20 feet of 20 healthy children (10 boys and 10 girls). We divided the participants into two groups of 10 each. One group was tested by the same operator in each test (intersession analysis), while the other group was tested by a different operator in each test (interrater analysis). The multiple correlation coefficient (CMC) and intraclass correlation coefficient (ICC) were calculated to assess repeatability. The difference between the two sessions of each group was assessed at each time point of gait cycle.

Results

The intrasession CMC and ICC values of all parameters showed excellent or very good repeatability. The intersession CMC of many parameters showed good or better repeatability. Interrater CMC and ICC values were generally lower for all parameters than intrasession and intersession. The mean gaps of all parameters were generally similar to those of the previous study.

Conclusions

We demonstrated that 3D MFM using a 15-marker set had high intrasession, intersession, and interrater repeatability in the assessment of foot motion in healthy children but recommend some caution in interpreting the hindfoot parameters.

Foot posture in female patients 5 years after breast-conserving surgery: a case-control study

PURPOSE

Along with the improvement in the outcomes of breast cancer treatment being observed in the recent years, long-term studies to assess distant adverse effects of the treatment have become increasingly important. The objective of this study was to assess the foot posture in patients subjected to breast-conserving therapy. The assessment was made 5 years after the surgical procedure.

METHODS

116 female patients (mean age of 58.75 years) were qualified into a case-control study. Foot posture on the operated breast side (F1) as well as on the contralateral side (F2) was evaluated using a computer-based foot analysis tool as an extension of projection moiré-based podoscopic examination. Comparisons were made for the following parameters: limb load, L-foot length, W-foot width, L/W-Wejsflog index, ALPHA-hallux valgus angle, BETA-little toe varus angle, GAMMA-heel angle, KY-Sztriter-Godunov index, CL-Clarke's angle, HW-heel width.

RESULTS

Five years after BCT, patients placed higher load on the foot on the side of the healthy breast (p = 0.0011). No statistically significant differences were observed between F1 and F2 with respect to other foot posture parameters (p > 0.05). No statistically significant differences were observed in foot posture parameters in patients having undergone BCT + ALND (axillary lymph node dissection) procedure as compared to patients subjected to BCT + SLNB (sentinel lymph node biopsy) procedure (p > 0.05).

CONCLUSIONS

No changes in foot posture were observed in patients 5 years after the BCT procedure. The type of the surgical procedure related to the lymph nodes within the axillary fossa has no effect on changes in foot posture.

Inter-segmental motions of the foot: differences between younger and older healthy adult females

BACKGROUND

Although accumulative evidence exists that support the applicability of multi-segmental foot models (MFMs) in evaluating foot motion in various pathologic conditions, little is known of the effect of aging on inter-segmental foot motion. The objective of this study was to evaluate differences in inter-segmental motion of the foot between older and younger adult healthy females during gait using a MFM with 15-marker set.

METHODS

One hundred symptom-free females, who had no radiographic evidence of osteoarthritis, were evaluated using MFM with 15-marker set. They were divided into young (n = 50, 20-35 years old) and old (n = 50, 60-69 years old) groups. Coefficients of multiple correlations were evaluated to assess the similarity of kinematic curve. Inter-segmental angles (hindfoot, forefoot, and hallux) were calculated at each gait phase. To evaluate the effect of gait speed on intersegmental foot motion, subgroup analysis was performed according to the similar speed of walking.

RESULTS

Kinematic curves showed good or excellent similarity in most parameters. Range of motion in the sagittal (p < 0.001) and transverse (p = 0.001) plane of the hallux, and sagittal (p = 0.023) plane of the forefoot was lower in older females. The dorsiflexion (p = 0.001) of the hallux at terminal stance and pre-swing phases was significantly lower in older females. When we compared young and older females with similar speed, these differences remained.

CONCLUSIONS

Although the overall kinematic pattern was similar between young and older females, reduced range of inter-segmental motion was observed in the older group. Our results suggest that age-related changes need to be considered in studies evaluating inter-segmental motion of the foot.

Dynamic Flexion Stiffness of Foot Joints During Walking

BACKGROUND

Dynamic stiffness can be used for studying foot pathologic abnormalities and for developing prostheses and orthoses. Although previous works have studied the role of ankle joint stiffness during gait, other foot joints have not yet been analyzed. We sought to characterize the dynamic stiffness of the ankle, midtarsal, and metatarsophalangeal joints during normal walking.

METHODS

Kinematics and contact data from four healthy individuals during walking were registered with a three-dimensional motion analysis system and a pressure platform. Stance phases with flexion moment-angle linear relationships were identified, and dynamic stiffnesses were calculated from the slope of their linear regressions. Intraparticipant repeatability was analyzed using analyses of variance, and interparticipant variability was checked through the SD of averaged participant stiffnesses.

RESULTS

Flexion moment-angle linear relationships were identified (R(2) > 0.98) during the early and late midstance phases and the propulsion phase at the ankle (2.76, 5.23, and 3.42 N·m/kg/rad, respectively) and midtarsal (15.88, 3.90, and 4.64 N·m/kg/rad, respectively) joints. At the metatarsophalangeal joint, a linear relationship (R(2) > 0.96) occurred only during the propulsion phase (0.11 N·m/kg/rad). High dynamic stiffness variability was observed during the late and early midstance phases at the ankle and midtarsal joints, respectively.

CONCLUSIONS

These results may serve as a basis for future studies aimed at investigating the role of dynamic stiffness identified herein in different foot disorders. The importance of properly controlling the samples in such studies is highlighted. Study of the dynamic stiffnesses identified might be used in the design of prostheses, orthoses, and other assistive devices.

Hallux valgus surgery affects kinematic parameters during gait

BACKGROUND

The aim of our study was to compare spatiotemporal parameters and lower limb and pelvis kinematics during the walking in patients with hallux valgus before and after surgery and in relation to a control group.

METHODS

Seventeen females with hallux valgus, who underwent first metatarsal osteotomy, constituted our experimental group. The control group consisted of thirteen females. Kinematic data during walking were obtained using the Vicon MX system.

FINDINGS

Our results showed that hallux valgus before surgery affects spatiotemporal parameters and lower limb and pelvis kinematics during walking. Hallux valgus surgery further increased the differences that were present before surgery. Specifically after hallux valgus surgery, the walking speed decreased even more (p=0.09, η²=0.19) while step time increased (p=0.002, η²=0.44) on both legs. The maximum ankle plantar flexion of the operated leg during toe-off decreased to a greater extend (p=0.03, η²=0.26). The asymmetry in the hip and the pelvis movements in the frontal plane (present preoperatively) persisted after surgery.

INTERPRETATION

Hallux valgus is not an isolated problem of the first ray, which could be just surgically addressed by correcting the foot's alignment. It is a long-term progressive malfunction of the foot affecting the entire kinematic chain of the lower extremity.

Validation of the Foot and Ankle Outcome Score for Hallux Rigidus

BACKGROUND

There is a clear call for improved patient-centered outcomes. The Foot and Ankle Outcome Score (FAOS) is a region-specific patient-reported measure that has been validated for a number of foot and ankle diagnoses, but not hallux rigidus.

QUESTIONS/PURPOSES

The aim of this study was to validate the FAOS in patients with hallux rigidus.

METHODS

From 2007 to 2013, 211 patients with hallux rigidus (HR) were included in the study. For the construct validity portion of the study, 125 patients completed a Short-Form 12 (SF-12) and FAOS survey. Forty additional HR patients were prospectively given questionnaires to assess the relevance of each FAOS question as it pertained to their HR. Reliability was assessed in 36 HR patients via administration of a second FAOS an average 1 month following the first. In 55 patients, preoperative and postoperative FAOS scores were compared to determine responsiveness.

RESULTS

All FAOS subscales demonstrated moderate correlation coefficients with the physical functioning, role physical, bodily pain, and physical health component scores of the SF-12, with all subscales demonstrating poor correlation with the SF-12 mental health-related domains. Content validity was high for all FAOS scores, with the exception of the daily activities subscale. All subscales achieved acceptable test-retest reliability with correlation coefficients of ≥0.72. Furthermore, all subscales were rated as responsive to change in postoperative patients (p < 0.001).

CONCLUSION

This study demonstrates the acceptable construct and content validity, reliability, and responsiveness of the FAOS for hallux rigidus. Due to its broad applicability and proven validation across multiple foot and ankle pathologies, the FAOS represents a patient-centered outcome measure that can be reliably used for the assessment of patients with hallux rigidus.

Repeatability of a multi-segment foot model with a 15-marker set in healthy adults

Background

Several 3D multi-segment foot models (MFMs) have been introduced for the in vivo analysis of dynamic foot kinematics. However, reproducibility of a model should be checked and ascertained before clinical utilization of a MFM. The purpose of this study was to determine the reliability of recently introduced MFM with a 15-marker set by assessing the participant’s stride-to-stride (intra-session) and visit-to-revisit (inter-session) repeatability.

Methods

Twenty healthy adults with a mean age of 28.9 years (10 males and 10 females) were tested. Three representative strides from five separate trials were used for analysis from each session. Kinematic data of foot segmental motion was collected and tracked using the Foot3D Multi-Segment Software (Motion Analysis Co., Santa Rosa. CA). A retest was performed in the same manner at an interval of 4 weeks. Coefficients of multiple correlation (CMC) and intra-class correlation coefficient (ICC) were calculated in order to assess the intra-session and inter-session repeatability.

Results

Inter-segment foot angles from healthy adults from a MFM with 15-marker set showed a narrow range of variability during the gait cycle. The mean intra-session ICC was 0.981 (±0.010), which was interpreted as excellent. The mean intra-session CMC was 0.948 (±0.027), which was interpreted as very good repeatability. The mean inter-session ICC was 0.886 (±0.047) and the mean inter-session CMC was 0.801 (±0.077), which were interpreted as excellent and good repeatability, respectively.

Conclusion

We demonstrated a MFM with a 15-marker set had high intra-session and inter-session repeatability, especially in sagittal plane motion. We thought this MFM would be applicable to evaluation of the segmental foot motion during gait.

Gait changes in individuals with bilateral hallux valgus reduce first metatarsophalangeal loading but increase knee abductor moments

Hallux valgus (HV), one of the most common foot pathologies in modern society, affects not only the foot itself, but also the other lower limb joints. The purpose of the study was to investigate the kinematic and kinetic changes in the lower limb joints in patients with bilateral HV during level walking. Twelve female patients with bilateral HV and 12 healthy female controls walked while three-dimensional kinematic and kinetic data were measured. Patients with HV were found to shift their center of pressure (COP) laterally away from the 1st metatarsophalangeal joint (MPJ), which helped unload the joint during late stance. The lateral shift of the COP in these patients was associated with the reduced toe-out angles of the foot as a result of increased internal rotation of the hip. However, this strategy increased the abductor moments at the knee, an index closely correlated with the medial load at the knee and a predictor of the onset and progression of medial OA. Early treatment of HV may be helpful not only for reducing foot pain and deformity, but also for preventing the potentially harmful loading at the knee, especially in those at risk of medial knee OA.

Hindfoot motion following STAR total ankle arthroplasty: a multisegment foot model gait study

BACKGROUND

One of the rationales for total ankle arthroplasty (TAA) is that it may retard the changes of hypermobility and accelerated arthritis in the hindfoot after ankle arthrodesis. Until recently, it has not been possible to quantify or even objectively demonstrate biomechanical findings to substantiate the theory that postsurgical biomechanical changes in the ankle produce changes in the kinematics of the hindfoot. Standard gait analysis has treated the foot as a single biomechanical unit. This study was undertaken to describe the hindfoot motion following Scandinavian Total Ankle Replacement (STAR) TAA by using multisegment foot model gait analysis.

METHODS

Forty-six patients with a mean age of 66 years underwent a 3D gait analysis following TAR. Mean interval between surgery and gait analysis was 4.9 years (range 2 to 9). The contralateral limb was used as control for each patient. Temporospatial variables and kinematic parameters were studied.

RESULTS

Temporospatial results showed statistically significant differences. Stance time on the affected side was 61.1% ± 2.2% of the gait cycle compared to 63.2% ± 2.1% for the unaffected side. Step length was 55.6 cm ± 10 on the affected side compared to 53.9 cm ± 10 for the unaffected side. Kinematics results were statistically significant: Ankle range of motion (ROM) on the arthroplasty side was 16.8 ± 4.5 degrees compared to 23.6 ± 5.0 on the unaffected side. Sagittal plane ROM was 12.7 ± 4.2 degrees on the arthroplasty side and 17.3 ± 3.5 degrees on the unaffected side. Coronal plane ROM was 4.7 ± 2.4 degrees on the arthroplasty side and 7.5 ± 2.4 degrees on the unaffected side. Transverse plane ROM on the arthroplasty side was 4.1 ± 1.5 degrees and 4.9 ± 1.6 on the unaffected side.

CONCLUSION

This study showed that, in addition to previously documented diminution in sagittal plane motion and gait velocity, some of the residual abnormalities of gait following TAR were comprised of differences in hindfoot function. These results relate to the growing recognition of the importance of understanding hindfoot mechanics apart from those of the tibiotalar joint.

LEVEL OF EVIDENCE

Level III, comparative case series.

Validation of the Foot and Ankle Outcome Score in adult acquired flatfoot deformity

INTRODUCTION

The American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score has been under recent scrutiny. The Foot and Ankle Outcome Score (FAOS) is an alternative subjective survey, assessing outcomes in 5 subscales. It is validated for lateral ankle instability and hallux valgus patients. The aim of our study was to validate the FAOS for assessing outcomes in flexible adult acquired flatfoot deformity (AAFD).

METHODS

Patients from the authors' institution diagnosed with flexible AAFD from 2006 to 2011 were eligible for the study. In all, 126 patients who completed the FAOS and the Short-Form 12 (SF-12) on the same visit were included in the construct validity component. Correlation was deemed moderate if the Spearman's correlation coefficient was .4 to .7. Content validity was assessed in 63 patients by a questionnaire that asked patients to rate the relevance of each FAOS question, with a score of 2 or greater considered acceptable. Reliability was measured using intraclass correlation coefficients (ICCs) in 41 patients who completed a second FAOS survey. In 49 patients, preoperative and postoperative FAOS scores were compared to determine responsiveness.

RESULTS

All of the FAOS subscales demonstrated moderate correlation with 2 physical health related SF-12 domains. Mental health related domains showed poor correlation. Content validity was high for the Quality of Life (QoL; mean 2.26) and Sports/Recreation subscales (mean 2.12). All subscales exhibited very good test-retest reliability, with ICCs of .7 and above. Symptoms, QoL, pain, and daily activities (ADLs) were responsive to change in postoperative patients (P < .05).

CONCLUSION

This study has validated the FAOS for AAFD with acceptable construct and content validity, reliability, and responsiveness. Given its previous validation for patients with ankle instability and hallux valgus, the additional findings in this study support its use as an alternative to less reliable outcome surveys.

LEVEL OF EVIDENCE

Level II, prospective comparative study.