Foot deformities: biomechanical and pathomechanical changes associated with aging, Part I

Prevalence of midfoot arthritis and lesser toe deformities

BACKGROUND

The aim of this study was to investigate the epidemiology of Midfoot Arthritis (MA) and Lesser toe deformity (LTD) using Weight-Bearing Computed Tomography (WBCT).

METHODS

606 cases (247 male, 359 female) among 1316 consecutive cases with WBCT data from September 2014 to April 2022 were retrospectively reviewed at a single referral institution. The Cochran-Armitage test was performed to evaluate the trend of prevalence with respect to age group and obesity classification.

RESULTS

139 male (56.3%) and 210 female cases (58.5%) showed MA. 157 male (63.6%) and 222 female cases (61.6%) showed LTD. 115 male (19.0%) and 157 female cases (25.9%) showed both MA and LTD. The prevalence of MA and LTD increased with age in both genders. The incidence of MA in males showed an increasing tendency until obesity class II and then was slightly decreased in obesity class III. This is contrary to females whose prevalence increased with increasing obesity groups. LTD had a similar pattern in both genders to obesity classification.

CONCLUSIONS

The prevalence of MA and LTD increased with age and increasing obesity groups for both genders.

LEVEL OF EVIDENCE

Level III, Retrospective Comparative Study.

Degree of Impact of Tailor's Bunion on Quality of Life: A Case-Control Study

Tailor’s bunion (TB) disease should be considered one of the foot injuries that causes disability in feet as well as general health. This case–control descriptive study investigated and contrasted the effects of different TB types in a sociodemographic population using the Foot Health Status Questionnaire (FHSQ). A sample of 100 subjects with a mean age of 51.70 ± 17.78 years was recruited and requested to reply to a foot health survey. Results were self-reported. Subjects were scored. Participants with TB type III (TB3) registered lower scores for foot pain, foot function, footwear, and foot health. Physical activity and social capacity had higher scores, and vigor and general health were lower. A Kruskal–Wallis test was used for systematic differences between the FHSQ and different TB types. In all analyses, statistical significance was considered a p-value <0.05 with a 95% confidence interval. Statistically significant differences were found between all domains of the FHSQ and TB, except for the social capacity domain and vigor. The FHSQ is an important measurement tool in TB subjects, showing that factors such as sex, age, and footwear used throughout an individual’s life are significantly associated with the development of TB3 and its influence on foot pain and foot health.

Medium-Long-Term Clinical and Radiographic Outcomes of Minimally Invasive Distal Metatarsal Metaphyseal Osteotomy (DMMO) for Central Primary Metatarsalgia: Do Maestro Criteria Have a Predictive Value in the Preoperative Planning for This Percutaneous Technique?

Background

The purpose of this prospective study was first to evaluate the safety and effectiveness of Minimally Invasive Distal Metatarsal Metaphyseal Osteotomy (DMMO) in treating central metatarsalgia, identifying possible contraindications. The second objective was to verify the potential of DMMO to restore a harmonious forefoot morphotype according to Maestro criteria.

Methods

A consecutive series of patients with metatarsalgia was consecutively enrolled and treated by DMMO. According to Maestro criteria, preoperative planning was carried out by both clinical and radiological assessment. Patient demographic data, AOFAS scores, 17-FFI, MOXFQ, SF-36, VAS, and complications were recorded. Maestro parameters, relative morphotypes, and bone callus formation were assessed. Statistical analysis was carried out (p < 0.05).

Results

Ninety-three patients (93 feet) with a mean age of 62.4 (31-87) years were evaluated. At mean follow-up of 58.7 (36-96) months, all of the clinical scores improved significantly (p < 0.0001). Most of the osteotomies (76.3%) had healed by 3-month follow-up, while ideal harmonious morphotype was restored only in a few feet (3.2%). Clinical and radiological outcomes were not different based on principal demographic parameters. Long-term complications were recorded in 12 cases (12.9%).

Conclusion

DMMO is a safe and effective method for the treatment of metatarsalgia. Although Maestro criteria were useful to calculate the metatarsal bones to be shortened and a significant clinical improvement of all scores was achieved, the ideal harmonious morphotype was restored only in a few feet. Hence, our data show that Maestro criteria did not have a predictive value in clinical outcomes of DMMO.

The Effect of Toe Flexion Exercises on Grip

BACKGROUND

Weakness of the toe flexor muscles has been attributed to the development of toe pathologies, and it responds well in the clinic to toe grip exercises. However, it is unknown whether exercising the toe flexor muscles improves the ability to grip and alter function. The aim of this study was to assess the effect of toe flexor exercises on apical plantar pressure, as a measure of grip, while seated and during gait.

METHODS

Twenty-three individuals with no known toe pathologies were recruited. Static peak pressure, time spent at peak pressure, and pressure-time integral while seated, as well as dynamic forefoot maximal force, contact area, and percentage contact time, were recorded before and after exercise. Toe grip exercises with a therapy ball were completed daily for 6 weeks.

RESULTS

Static peak pressure significantly increased after exercise on the apex of the second and third digits, as did the pressure-time integral. Dynamic peak force and contact area did not alter after exercise around the metatarsals and toes, yet percentage contact time significantly increased for each metatarsal after completing daily toe grip exercises.

CONCLUSIONS

Exercises to improve the grip ability of the toes increased the static peak pressure on the apex of the second and third digits as well as the percentage contact time of the metatarsals during gait. The ability to increase apical peak pressure and contact time after exercises could assist in improving forefoot stability and gait efficiency and in reducing toe pathology progression.

Dynamic rheological comparison of silicones for podiatry applications

PURPOSE

This work shows an effective methodology to evaluate the dynamic viscoelastic behavior of silicones for application in podiatry. The aim is to characterize, compare their viscoelastic properties according to the dynamic stresses they can be presumably subjected when used in podiatry orthotic applications. These results provide a deeper insight which extends the previous creep-recovery results to the world of dynamic stresses developed in physical activity. In this context, it shoulod be taken into account that an orthoses can subjected to a set of static and dynamic shear and compressive forces.

METHODS

Two different podiatric silicones, Blanda-blanda and Master, from Herbitas, are characterized by dynamic rheological methods. Three kinds of rheological tests are considered: shear stress sweep, compression frequency sweep and shear frequency sweep, all the three with simultaneous control of the static force at three different levels. The static force represents a static load like that produced by the weight of a human body on a shoe insole. In a practical sense, dynamic stresses are related to physical activity and are needed to evaluate the frequency effect on the viscoelastic behavior of the material. It is considered that the dynamic stresses can be applied in compression and shear since, in practice, the way the stresses are applied in real life depends on the orthoses geometry and its exact location with respect to the foot and shoe. The effects of static and dynamic loads are individualized and compared to each other through the relations between the elastic constants for isotropic materials.

CONCLUSIONS

The overall proposed experimental methodology can provide very insightful information for better selection of materials in podiatry applications. This study focuses on the rheological characterization to choose the right silicone for each podiatric application, taking into account the dynamic viscoelastic requirements associated to the physical activity of user. Accordingly, one soft and one hard silicones of common use in podiatry were tested. Each of the two silicones exhibit not only different moduli values, but also, a different kind of dependence of the dynamic moduli with respect to the static load. In the case of the soft sample a linear trend is observed but in the case of of the hard one the dependence is of the power law type. Moreover, these samples exhibit very different Poisson's coefficient values for compression stresses lower than 20 kPa, and almost the same values for stresses above 40 kPa. That different dependence of the Poisson's ratio on the static load should also be taken into account for material selection in customized podiatry applications, where static and dynamic loads are strongly dependent on the individual weight and activity.

Foot health-related quality of life among elderly with and without lesser toe deformities: a case-control study

PURPOSE

The aim of this study was to compare the health-related quality of life impact related to foot health and health in general in older adults with lesser toe deformities (LTD) and without any foot conditions.

METHODS

A case-control observational study was carried out following the Strengthening the Reporting of Observational Studies in Epidemiology criteria. A total of 100 older adults with a mean age of 74.39±6.02 years were recruited at an outpatient clinic; 50 of these subjects had LTD (case group) and 50 subjects were without any foot conditions (control group). Presence of LTD was determined in both feet using the Kelikian push-up test, and the Foot Health Status Questionnaire scores were self-reported.

RESULTS

The case group showed lower scores in quality of life in relation to health in general and to foot health specifically. Statistically significant differences (p<0.05) between case and control groups were shown by means of the Wicoxon test.

CONCLUSION

A negative impact in quality of life in relation to foot health should be considered in older adults with LTD, regardless of gender.

Age- and sex-associated morphological variations of metatarsal torsional patterns in humans

It has been demonstrated that the torsional patterns of the metatarsal heads are associated with the presence or absence of the medial longitudinal arch in hominoid feet. The relatively untwisted second metatarsal is unique in humans, but that of the African apes is much more inverted, suggesting that the torsion of the second metatarsal might represent the overall shape and flatness of the foot. Some clinical studies have recently argued that the onset of foot pathologies such as hallux valgus might be related to the torsional pattern of the metatarsals. However, to date, no studies have systematically investigated the morphological variations of the torsional patterns of human metatarsals. In this study, therefore, the aim was to clarify the age- and sex-associated variations in the torsional patterns of human metatarsals using three-dimensional computed tomography. The torsion angles of the five metatarsals were calculated by defining the dorsopalmar vector of the metatarsal base and the vector corresponding to the rotational axis of the metatarsal head. The present result demonstrated that the second metatarsals of females were significantly more inverted with increasing age. Flat foot is known to be most common in elderly women. Whether there is a cause-effect relationship between second metatarsal torsion and flattening of the medial longitudinal arch has yet to be answered, but this study suggested that torsion of the second metatarsal might possibly be used as an indicator for the early diagnosis of flat foot and associated foot pathologies. Clin. Anat. 30:1058-1063, 2017. © 2017 Wiley Periodicals, Inc.

Reliability of metatarsophalangeal and ankle joint torque measurements by an innovative device

The toe flexor muscles maintain body balance during standing and provide push-off force during walking, running, and jumping. Additionally, they are important contributing structures to maintain normal foot function. Thus, weakness of these muscles may cause poor balance, inefficient locomotion and foot deformities. The quantification of metatarsophalangeal joint (MPJ) stiffness is valuable as it is considered as a confounding factor in toe flexor muscles function. MPJ and ankle joint stiffness measurement is still largely depended on manual skills as current devices do not have good control on alignment, angular joint speed and displacement during measurement. Therefore, this study introduces an innovative dynamometer and protocol procedures for MPJ and ankle Joint torque measurement with precise and reliable foot alignment, angular joint speed and displacement control. Within-day and between-day test-retest experiments on MPJ and ankle joint torque measurement were conducted on ten and nine healthy male subjects respectively. The mean peak torques of MPJ and ankle joint of between-day and within-day measurement were 1.50±0.38Nm/deg and 1.19±0.34Nm/deg. The corresponding torques of the ankle joint were 8.24±2.20Nm/deg and 7.90±3.18Nm/deg respectively. Intraclass-correlation coefficients (ICC) of averaged peak torque of both joints of between-day and within-day test-retest experiments were ranging from 0.91 to 0.96, indicating the innovative device is systematic and reliable for the measurements and can be used for multiple scientific and clinical purposes.

Relationship between foot posture measurements and force platform parameters during two balance tasks in older and younger subjects

[Purpose] The aim of this study was to compare age-related differences in balance and anthropometric posture measurements of the foot and to determine any relationship between them. [Subjects and Methods] Sixty-eight older and 42 younger adults participated in this study. Foot posture was tested for four domains: 1) hallux flexion and extension range of motion using a goniometer, 2) navicular height and 3) length of the foot using a pachymeter, and 4) footprint (width of forefoot, arch index and hallux valgus). Balance was tested under two conditions on a force platform: bipodal in 60-s trials and unipodal in 30-s trials. The sway area of the center of pressure and velocity in the anteroposterior and mediolateral directions were computed. [Results] Older individuals showed significantly poorer balance compared with younger adults under in the unipodal condition (center of pressure area 9.97 vs. 7.72 cm(2)). Older people presented a significantly lower hallux mobility and higher values for width of the forefoot and transverse arch index than younger adults. The correlations between all foot posture and center of pressure parameters varied across groups, from weak to moderate (r -0.01 to -0.46). Low hallux mobility was significantly related to higher center of pressure values in older people. [Conclusion] These results have clinical implications for balance and foot posture assessments.

Reference values for toe grip strength among Japanese adults aged 20 to 79 years: a cross-sectional study

Background

No standardised method has been adopted for measuring toe-grip strength (TGS), and no reference values have been established for evaluating it. The present study investigated age-related changes in TGS and the association of TGS with various descriptive characteristics.

Methods

TGS was measured in both feet of 1842 community-dwelling individuals aged 20–79 years using a toe-grip dynamometer. The participants were classified by decade into six age groups: 20–29, 30–39, 40–49, 50–59, 60–69, and 70–79 years. Correlations for TGS between the dominant and non-dominant sides were analysed according to decade and sex using Pearson’s correlation coefficient. The mean TGS and TGS-to-weight ratio (TGS/Wt%) were compared between sexes by each decade and among all decades by sex using two-way analysis of variance with post-hoc tests. To assess relationships between mean TGS and various descriptive characteristics, we determined Pearson’s correlation coefficient by sex and performed a stepwise multiple-regression analysis. Significance was set at 5%.

Results

Correlations for TGS between the dominant and non-dominant sides were significant in all decades by sex, ranging from 0.73 for men in their 70s to 0.91 for women in their 50s. Mean TGS and TGS/Wt% significantly differed between the sexes in all decades and in all decades except the 40s, respectively. In men, the mean TGS and TGS/Wt% significantly decreased with aging after the 50s and 60s, respectively. In women, both the mean TGS and TGS/Wt% significantly decreased between the 40s and 50s and between the 60s and 70s. TGS significantly correlated with age, height, and weight in both sexes. The stepwise multiple-regression analysis revealed TGS was significantly associated with sex, age, height, and weight (adjusted R² = 0.31).

Conclusions

TGS was closely correlated between the dominant and non-dominant sides. TGS and TGS/Wt were significantly reduced with aging after the 50s in men and significantly reduced between the 40s and 50s and between the 60s and 70s in women. Age, sex, height, and weight accounted for only 30.8% of the variance in TGS. Therefore, other factors (e.g. toe flexibility, structural characteristics) should be considered for improving the accuracy of predicting TGS.

Revisiting the tailor's bunion and adductovarus deformity of the fifth digit

Correction of the fifth digit deformity and Tailor's Bunion can be rewarding as well as challenging for a foot and ankle surgeon. Immense care should be taken when performing these reconstructive surgical procedure, especially to avoid and minimize complication rates and mainly to prevent neurovascular damage. Appropriate surgical procedure selection for the fifth digit deformity and Tailor's Bunion is necessary in order to obtain a long term predictable outcome.

Effect of a metatarsal pad on the forefoot during gait

BACKGROUND

Metatarsal pads are frequently prescribed for patients with metatarsalgia to reduce pain under the distal metatarsal heads. Several studies showed reduced pain and reduced plantar pressure just distal to the metatarsal pad. However, only part of the pain reduction could be explained by the decrease in plantar pressure under the forefoot. Therefore, an alternative hypothesis is proposed that pain relief is related to a widening of the foot and the creation of extra space between the metatarsal heads. This study focused on the effect of a metatarsal pad on the geometry of the forefoot by studying forefoot width and the height of the second metatarsal head.

METHODS

Using a motion analysis system, 16 primary metatarsalgia feet and 12 control feet were measured when walking with and without a metatarsal pad.

RESULTS

A significant mean increase of 0.60 mm in forefoot width during the stance phase was found when a metatarsal pad was worn. During midstance, the mean increase in forefoot width was 0.74 mm. In addition, walking with a metatarsal pad revealed an increase in the height of the second metatarsal head (mean, 0.62 mm). No differences were found between patients and controls.

CONCLUSIONS

The combination of increased forefoot width and the height of the second metatarsal head produced by the metatarsal pad results in an increase in space between the metatarsal heads. This extra space could play a role in pain reduction produced by a metatarsal pad.

[The association between foot problems and falls in older adults -a covariance structure analysis-]

AIM

To investigate the manner in which community-dwelling older adults' foot problems affect their history of falls.

METHODS

This study included 112 community-dwelling older adults. Foot problems (e.g., inflammation, ingrown nails, and pain while walking), self-rated physical ability (e.g., gait, tripping over, and balance), history of falls within a year, and physical ability (e.g., walking speed, Timed Up & Go test, and one leg balance test) were measured during a routine health checkup. Of these, five subjects were excluded due to incomplete all the measurement. Thus, the subjects eligible for analysis were 107 older adults (mean age±standard deviation=73.0±5.5 years). Covariance structure analysis was used to identify the inter-relationships among all measurements.

RESULTS

The covariance structure analysis showed that foot problems negatively influenced participants' self-rated physical ability, and this relationship was also linked to history of falls. The overall fit of this model was judged to be statistically satisfactory (GFI=0.959, AGFI=0.912, CFI=0.981, RMSEA=0.043).

CONCLUSIONS

Our model indicated that the association between foot problems and history of falls was affected by self-rated physical ability. Furthermore, in order to prevent falls, the current results suggest that foot care could be an important intervention in older adults to prevent decline in their overall physical ability.

Mallet toe deformity

Mallet toe is one of the most common deformities encountered by orthopedic surgeons. Care needs to be taken to ascertain whether it is a primary condition or secondary to a systemic disease, especially if multiple deformities are present. There are numerous operative strategies available, but each has its specific indications. If the indications are followed, highly successful outcomes may be achieved.

A clinical classification system for rheumatoid forefoot deformity

BACKGROUND AND PURPOSE

In the present study a classification system for the rheumatoid forefoot is reported with its intra- and interobserver reliability and clinical relevance. The classification is based on the sequence of anatomical changes resulting from the loss of integrity of the MTP joints, loss of motion and changes regarding the quality and position of the plantar soft tissues. It is hypothesized that with progression of the amount of deformity of the MTP joint(s), patients have more pain and functional loss.

PATIENTS AND METHODS

In total 94 patients were included in the study following precise inclusion criteria. The forefeet of the patients were classified according to the introduced classification system by two observers in order to determine the intra- and interobserver reliability. The relation of the suggested classification between pain, function scores, and plantar foot pressure measurements was examined.

RESULTS AND CONCLUSION

According to the Cohen's kappa and the ICC, the intra- and inter-observer reliability were high. Despite the large variation between subjects in a certain grade, a clear trend was found between increase in classification and VAS for pain, FFI difficulty with activities, and plantar peak pressure under the metatarsals. The suggested classification is of clinical relevance and can be used to develop therapeutical algorithms and to test interventions.

Hallux valgus and the first metatarsal arch segment: a theoretical biomechanical perspective

Hallux valgus is a progressive foot deformity characterized by a lateral deviation of the hallux with corresponding medial deviation of the first metatarsal. Late-stage changes may render the hallux painful and without functional utility, leading to impaired gait. Various environmental, genetic, and anatomical predispositions have been suggested, but the exact cause of hallux valgus is unknown. Evidence indicates that conservative intervention for hallux valgus provides relief from symptoms but does not reverse deformity. Part 1 of this perspective article reviews the literature describing the anatomy, pathomechanics, and etiology of hallux valgus. Part 2 expands on the biomechanical initiators of hallux valgus attributed to the first metatarsal. Theory is advanced that collapse of the arch with vertical orientation (tilt) of the first metatarsal axis initiates deformity. To counteract the progression of hallux valgus, we use theory to discuss a possible mechanism by which foot orthoses can bolster the arch and reorient the first metatarsal axis horizontally.

ISB Clinical Biomechanics Award 2009: toe weakness and deformity increase the risk of falls in older people

BACKGROUND

Hallux valgus and lesser toe deformities are highly prevalent foot problems in older people. One factor contributing to the development of these toe deformities is reduced toe flexor strength. As adequate toe flexor strength is also crucial in maintaining balance, it was hypothesised that poor toe flexor strength and toe deformities would increase the risk of falls in community-dwelling older people.

METHOD

The feet of 312 men and women aged 60-90 years were assessed for the presence of lesser toe deformities and hallux valgus. Hallux and lesser toe flexor strength were assessed using an emed AT-4 pressure platform and novel test protocol. Participants were then followed prospectively to determine their falls incidence over 12 months.

FINDINGS

During the 12 month follow-up, 107 (35%) participants experienced a fall. Compared to non-fallers, fallers displayed significantly less strength of the hallux (11.6 (SD 6.9) versus 14.8 (SD 7.8)% BW, P<0.01) and lesser toes (8.7 (SD 4.7) versus 10.8 (SD 4.5)% BW, P<0.01), and were more likely to have hallux valgus (relative risk [RR]=2.36; 95% CI=1.03-5.45; P<0.01) and lesser toe deformity (RR=1.32; 95% CI=1.04-1.69; P<0.01).

INTERPRETATION

Reduced toe flexor strength and the presence of toe deformities increase the risk of falling in older people. To reduce this risk, interventions designed to increase strength of the toe flexor muscles combined with treatment of those older individuals with toe deformities may be beneficial.

The impact of rheumatoid foot on disability in Colombian patients with rheumatoid arthritis

BACKGROUND

Alterations in the feet of patients with rheumatoid arthritis (RA) are a cause of disability in this population. The purpose of this research was to evaluate the impact that foot impairment has on the patients' global quality of life (QOL) based on validated scales and its relationship to disease activity.

METHODS

This was a cross-sectional study in which 95 patients with RA were enrolled. A complete physical examination, including a full foot assessment, was done. The Spanish versions of the Health Assessment Questionnaire (HAQ) Disability Index and of the Disease Activity Score (DAS 28) were administered. A logistic regression model was used to analyze data and obtain adjusted odds ratios (AORs).

RESULTS

Foot deformities were observed in 78 (82%) of the patients; hallux valgus (65%), medial longitudinal arch flattening (42%), claw toe (lesser toes) (39%), dorsiflexion restriction (tibiotalar) (34%), cock-up toe (lesser toes) (25%), and transverse arch flattening (25%) were the most frequent. In the logistic regression analysis (adjusted for age, gender and duration of disease), forefoot movement pain, subtalar movement pain, tibiotalar movement pain and plantarflexion restriction (tibiotalar) were strongly associated with disease activity and disability. The positive squeeze test was significantly associated with disability risk (AOR = 6,3; 95% CI, 1.28-30.96; P = 0,02); hallux valgus, and dorsiflexion restriction (tibiotalar) were associated with disease activity.

CONCLUSION

Foot abnormalities are associated with active joint disease and disability in RA. Foot examinations provide complementary information related to the disability as an indirect measurement of quality of life and activity of disease in daily practice.

Brazilian version of the foot health status questionnaire (FHSQ-BR): cross-cultural adaptation and evaluation of measurement properties

OBJECTIVE

To conduct a cross-cultural adaptation of the Foot Health Status Questionnaire into Brazilian-Portuguese and to assess its measurement properties.

INTRODUCTION

This instrument is an outcome measure with 10 domains with scores ranging from 0-100, worst to best, respectively. The translated instrument will improve the examinations and foot care of rheumatoid arthritis patients.

METHODS

The questions were translated, back-translated, evaluated by a multidisciplinary committee and pre-tested (n = 40 rheumatoid arthritis subjects). The new version was submitted to a field test (n = 65) to evaluate measurement properties such as test-retest reliability, internal consistency and construct validity. The Health Assessment Questionnaire, Numeric Rating Scale for foot pain and Sharp/van der Heijde scores for foot X-rays were used to test the construct validity.

RESULTS

The cross-cultural adaptation was completed with minor wording adaptations from the original instrument. The evaluation of measurement properties showed high reliability with low variation coefficients between interviews. The alpha-Cronbach coefficients varied from 0.468 to 0.855, while correlation to the Health Assessment Questionnaire and Numeric Rating Scale was statistically significant for five out of eight domains.

DISCUSSION

Intra- and inter-observer correlations showed high reliability. Internal consistency coefficients were high for all domains, revealing higher values for less subjective domains. As for construct validity, each domain revealed correlations with a specific group of parameters according to what the domains intended to measure.

CONCLUSION

The FHSQ was cross-culturally adapted, generating a reliable, consistent, and valid instrument that is useful for evaluating foot health in patients with rheumatoid arthritis.