Reliability and relevance of radiographic measures of metatarsus primus elevatus and arch alignment in individuals with midfoot arthritis and controls

Risk Factors for Midfoot Arthritis Associated With Medical History by Weight Bearing Computed Tomography

Tarso-metatarsal joints and naviculocuneiform joints comprising midfoot is the second most commonly involved joints following the first metatarsophalangeal joint in the foot. However, related factors of midfoot arthritis (MA) have been rarely reported. The bony structure and alignment can be more precisely assessed using Weight-Bearing Computed Tomography (WBCT) than conventional radiographs. Therefore, the aim of this study was to investigate risk factors for MA related to medical history and comorbid foot deformities using WBCT. WBCT data from September 2014 to April 2022 were extracted from a single referral hospital. All cases were divided into two groups by the presence of MA. Twenty-five potential related factors including demographics, etiology, and common co-occurring foot deformities were collected for comparison. Six hundred six cases (247 males and 359 females) among consecutive 1316 cases between September 2014 to April 2022 were selected. One hundred thirty-nine male cases (56.3%) and 210 female cases (58.5%) showed MA. In stepwise multiple logistic regression analysis, 5 factors remained statistically significant. The multivariate-adjusted odds ratios for age, laterality, body mass index (BMI), Progressive Collapsing Foot Deformity (PCFD), and lesser toe deformities (LTD) were 1.08, 1.54, 1.05, 6.62, and 3.03 respectively. Risk factors for MA associated with medical history and foot deformities included age, laterality, BMI, PCFD, and LDT.

Structural Foot Characteristics in People With Midfoot Osteoarthritis: Cross-Sectional Findings From the Clinical Assessment Study of the Foot

OBJECTIVE

This study compared radiographic measures of foot structure between people with and without symptomatic radiographic midfoot osteoarthritis (OA).

METHODS

This was a cross-sectional study of adults aged 50 years and older registered with four UK general practices who reported foot pain in the past year. Bilateral weightbearing dorsoplantar and lateral radiographs were obtained. Symptomatic radiographic midfoot OA was defined as midfoot pain in the last 4 weeks, combined with radiographic OA in one or more midfoot joints (first cuneometatarsal, second cuneometatarsal, navicular-first cuneiform, and talonavicular). Midfoot OA cases were matched 1:1 for sex and age to controls with a 5-year age tolerance. Eleven radiographic measures were extracted and compared between the groups using independent sample t-tests and effect sizes (Cohen's d).

RESULTS

We identified 63 midfoot OA cases (mean ± SD age was 66.8 ± 8.0 years, with 32 male and 31 female participants) and matched these to 63 controls (mean ± SD age was 65.9 ± 7.8 years). There were no differences in metatarsal lengths between the groups. However, those with midfoot OA had a higher calcaneal-first metatarsal angle (d = 0.43, small effect size, P = 0.018) and lower calcaneal inclination angle (d = 0.46, small effect size, P = 0.011) compared with controls.

CONCLUSIONS

People with midfoot OA have a flatter foot posture compared with controls. Although caution is required when inferring causation from cross-sectional data, these findings are consistent with a pathomechanical pathway linking foot structure to the development of midfoot OA. Prospective studies are required to determine the temporal relationships between foot structure, function, and the development of this common and disabling condition.

Finite Element Modelling of Planus and Rectus Foot Types for the Study of First Metatarsophalangeal and First Metatarsocuneiform Joint Contact Mechanics

Evaluating the contact mechanics of human joints is an important element in understanding the pathomechanics of orthopaedic diseases. Although physical testing is essential in the evaluation process, reliable computational models can augment these experiments by non-invasive predictions of biomechanical or surgical variables. The objective of this study was to perform verification of a framework for developing a medial forefoot finite element. Verification was conducted by comparing computational predictions to experimental measurements of first metatarsophalangeal and first metatarsocuneiform joint contact mechanics. A custom-built force-controlled cadaveric test-rig was used to derive measurements of contact pressure, force, and area. A quasi-static finite element was developed and driven under the same boundary and loading conditions. Calibration of cartilage moduli and mesh sensitivity analyses were performed. Mean errors in contact pressures, forces, and areas were 24%, 4%, and 40% at the first metatarsophalangeal joint and 23%, 12%, and 19% at the first Metatarsocuneiform joint, respectively. Verification of a medial forefoot finite element model development framework was presented and found to be within 30% for contact pressure and contact force of both joints. This study presents a method to verify and simulate realistic physiological loading to investigate orthopaedic diseases of the medial forefoot.

Comparative Reliability of a Novel Electromechanical Device and Handheld Ruler for Measuring First Ray Mobility

BACKGROUND

Quantifying first ray mobility is crucial to understand aberrant foot biomechanics. A novel device (MAP1^st) that can perform measurements of first ray mobility in different weightbearing conditions, foot alignments, and normalization was tested. The reliability of these measurement techniques was assessed in comparison to a handheld ruler considered representative of the common clinical examination.

METHODS

The study included 25 participants (50 feet). Two independent raters performed baseline, test-retest, and remove-replace measurements of first ray mobility with MAP1^st and the handheld device. The effects of non-, partial, and full weightbearing in subtalar joint neutral and the resting calcaneal stance position were assessed. Measurement normalization relative to foot size was also investigated. Intra- and interclass correlation coefficients (ICCs) were calculated for each device between the 2 raters. In addition, Bland-Altman plots were constructed to determine if fixed biases or substantial outliers were present.

RESULTS

Similar intrarater ICC values were found for both devices (≥0.85). However, interrater ICC values were substantially improved by MAP1^st compared with the handheld device (0.58 vs 0.06). Bland-Altman plots demonstrated biases of 1.27 mm for the handheld ruler, and 2.88 to 0.05 mm and -1.16 to 0.00 for linear and normalized MAP1^st measurements, respectively. Improved reliability was achieved with MAP1^st for normalized assessments of first ray mobility while the foot was placed in partial- and full-weightbearing resting calcaneal stance positions.

CONCLUSION

MAP1^st provided reliable assessments of partial- and full-weightbearing first ray mobility. It should help investigators to explore the potential relationships between first ray function and aberrant foot biomechanics in future research.

LEVEL OF EVIDENCE

Level II, prospective cohort study.

Foot structure and lower limb function in individuals with midfoot osteoarthritis: a systematic review

OBJECTIVE

To determine how foot structure and lower limb function differ between individuals with and without midfoot osteoarthritis (OA).

DESIGN

Electronic databases were searched from inception until May 2020. To be eligible, studies needed to (1) include participants with radiographically confirmed midfoot OA, with or without midfoot symptoms, (2) include a control group of participants without radiographic midfoot OA or without midfoot symptoms, and (3) report outcomes of foot structure, alignment, range of motion or any measures of lower limb function during walking. Screening and data extraction were performed by two independent assessors, with disagreements resolved by a third independent assessor. The methodological quality of included studies was assessed using the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies.

RESULTS

A total of 1,550 records were screened by title and abstract and 11 met the inclusion criteria. Quantitative synthesis indicated that individuals who had midfoot OA had a more pronated foot posture, greater first ray mobility, less range of motion in the subtalar joint and first metatarsophalangeal joints, longer central metatarsals and increased peak plantar pressures, pressure time integrals and contact times in the heel and midfoot during walking. Meta-analysis could not be performed as the data were not sufficiently homogenous.

CONCLUSIONS

There are several differences in foot structure and lower limb function between individuals with and without midfoot OA. Future research with more consistent case definitions and detailed biomechanical models would further our understanding of potential mechanisms underlying the development of midfoot OA.

Midfoot osteoarthritis: potential phenotypes and their associations with demographic, symptomatic and clinical characteristics

OBJECTIVE

To investigate the demographic, symptomatic, clinical and structural foot characteristics associated with potential phenotypes of midfoot osteoarthritis (OA).

DESIGN

Cross-sectional study of 533 community-dwelling adults aged ≥50 years with foot pain in the past year. Health questionnaires and clinical assessments of symptoms, foot structure and function were undertaken. Potential midfoot OA phenotypes were defined by the pattern of radiographic joint involvement affecting either the medial midfoot (talonavicular, navicular-1^st cuneiform, or cuneiform-1^st metatarsal joint), central midfoot (2^nd cuneiform-metatarsal joint), or both medial and central midfoot joints. Multivariable regression models with generalised estimating equations were used to investigate the associations between patterns of midfoot joint involvement and symptomatic, clinical and structural characteristics compared to those with no or minimal midfoot OA.

RESULTS

Of 879 eligible feet, 168 had medial midfoot OA, 103 central midfoot OA, 76 both medial and central midfoot OA and 532 no/minimal OA. Having both medial and central midfoot OA was associated with higher pain scores, dorsally-located midfoot pain (OR 2.54, 95%CI 1.45, 4.45), hallux valgus (OR 1.76, 95%CI 1.02, 3.05), flatter foot posture (β 0.44, 95%CI 0.12, 0.77), lower medial arch height (β 0.02, 95%CI 0.01, 0.03) and less subtalar inversion and 1^st MTPJ dorsiflexion. Isolated medial midfoot OA and central midfoot OA had few distinguishing clinical characteristics.

CONCLUSIONS

Distinct phenotypes of midfoot OA appear challenging to identify, with substantial overlap in symptoms and clinical characteristics. Phenotypic differences in symptoms, foot posture and function were apparent in this study only when both the medial and central midfoot were involved.

Metatarsus Primus Elevatus Resolution After First Metatarsophalangeal Joint Arthroplasty

BACKGROUND

Hallux limitus (HL) is the second-most common pathology associated with the first metatarsophalangeal joint. A common etiology believed to be associated with HL is metatarsus primus elevatus (MPE), although causation has been unsubstantiated by evidence. Historically, correction of MPE is surgically addressed with an osteotomy. However, some believe MPE is a secondary manifestation of HL due to retrograde pressure and lack of dorsiflexion at the first metatarsophalangeal joint. This study sought to determine whether MPE resolves spontaneously after first metatarsophalangeal joint arthroplasty and reinstitution of normal joint dorsiflexion.

METHODS

Twenty-seven weightbearing lateral radiographs from patients with HL were reviewed before and after nonimplant first metatarsophalangeal joint arthroplasty. Radiographs were taken preoperatively and at postoperative visits 1 (mean, 2 weeks) and 2 (mean, 10 weeks). Measurements included first to second metatarsal elevation, Seiberg Index, first to fifth metatarsal distance, sagittal plane first to second metatarsal angle, Meary's angle, metatarsal declination angle, and hallux equinus angle.

RESULTS

Statistically significant improvement was seen at both postoperative visits in all of the previously mentioned measurements except first to fifth metatarsal distance, which was reduced but was not statistically significant.

CONCLUSIONS

Metatarsus primus elevatus was reduced significantly after first metatarsophalangeal joint arthroplasty. Resolution occurred rapidly and was maintained at the final postoperative visit. This could be due to MPE being a manifestation of HL and not a cause. Based on the results of this study, osteotomies may be unnecessary to surgically address MPE because it can spontaneously correct after reinstitution of first metatarsophalangeal joint motion.

Ankle-Dorsiflexion Range of Motion After Ankle Self-Stretching Using a Strap

CONTEXT

A variety of ankle self-stretching exercises have been recommended to improve ankle-dorsiflexion range of motion (DFROM) in individuals with limited ankle dorsiflexion. A strap can be applied to stabilize the talus and facilitate anterior glide of the distal tibia at the talocrural joint during ankle self-stretching exercises. Novel ankle self-stretching using a strap (SSS) may be a useful method of improving ankle DFROM.

OBJECTIVE

To compare the effects of 2 ankle-stretching techniques (static stretching versus SSS) on ankle DFROM.

DESIGN

Randomized controlled clinical trial.

SETTING

University research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Thirty-two participants with limited active dorsiflexion (<20°) while sitting (14 women and 18 men) were recruited.

MAIN OUTCOME MEASURE(S)

The participants performed 2 ankle self-stretching techniques (static stretching and SSS) for 3 weeks. Active DFROM (ADFROM), passive DFROM (PDFROM), and the lunge angle were measured. An independent t test was used to compare the improvements in these values before and after the 2 stretching interventions. The level of statistical significance was set at α = .05.

RESULTS

Active DFROM and PDFROM were greater in both stretching groups after the 3-week interventions. However, ADFROM, PDFROM, and the lunge angle were greater in the SSS group than in the static-stretching group (P < .05).

CONCLUSIONS

Ankle SSS is recommended to improve ADFROM, PDFROM, and the lunge angle in individuals with limited DFROM.

Midfoot and forefoot osteoarthritis

BACKGROUND

Foot osteoarthritis (OA) is linked with chronic foot pain and functional impairment.

OBJECTIVE

To review the current knowledge on midfoot and forefoot OA.

METHODS

PubMed, CINAHL, PEDro, and the ISI Web of Science databases (1950-2013) were searched for keywords: foot OA, midfoot OA, forefoot OA and metatarsal OA. The search was limited to reports in human subjects and English language. Published cohort, cross-sectional studies and clinical trials relating to epidemiology, clinical features, functional impairment, risk factors and treatment were included.

RESULTS

We found heterogeneity in the design, radiographic views and grading systems used among studies. Most of the literature focused on radiographic OA, being the prevalence between 0.1% and 61%, depending on gender, age and joint evaluated. The age and female gender were the main associated factors, whereas structural (bone length) and mechanical factors (hypermobility, altered tarso-metatarsal stress, etc.) seemed to be related. Various treatments are widely used, i.e. physical therapy, orthotics, steroid injection, analgesics and arthrodesis. However, scarce research supports their efficacy.

CONCLUSION

Most of the current knowledge comes from observational and small case-control studies. Future population-based studies as well as controlled studies are essential to understand the risk factors and to evaluate the effectiveness of treatment options.