International Foot and Ankle Osteoarthritis Consortium review and research agenda for diagnosis, epidemiology, burden, outcome assessment and treatment

OBJECTIVE

To summarise the available evidence relating to the diagnosis, epidemiology, burden, outcome assessment and treatment of foot and ankle osteoarthritis (OA) and to develop an agenda to guide future research.

METHOD

Members of the International Foot and Ankle Osteoarthritis Consortium compiled a narrative summary of the literature which formed the basis of an interactive discussion at the Osteoarthritis Research Society International World Congress in 2021, during which a list of 24 research agenda items were generated. Following the meeting, delegates were asked to rank the research agenda items on a 0 to 100 visual analogue rating scale (0 = not at all important to 100 = extremely important). Items scoring a mean of 70 or above were selected for inclusion.

RESULTS

Of the 45 delegates who attended the meeting, 31 contributed to the agenda item scoring. Nineteen research agenda items met the required threshold: three related to diagnosis, four to epidemiology, four to burden, three to outcome assessment and five to treatment.

CONCLUSIONS

Key knowledge gaps related to foot and ankle OA were identified, and a comprehensive agenda to guide future research planning was developed. Implementation of this agenda will assist in improving the understanding and clinical management of this common and disabling, yet relatively overlooked condition.

Effect of foot orthoses vs sham insoles on first metatarsophalangeal joint osteoarthritis symptoms: a randomized controlled trial

OBJECTIVES

To compare contoured foot orthoses to sham flat insoles for first MTP joint OA walking pain.

DESIGN

This was a participant- and assessor-blinded, sham-controlled, multi-centre randomized clinical trial set in community-based private practices. Eighty-eight adults aged ≥45 years with symptomatic radiographic first MTP joint OA were randomized to receive contoured foot orthoses (n = 47) or sham flat insoles (n = 41), worn at all times when wearing shoes for 12 weeks. Primary outcome was change in first MTP joint walking pain (11-point numerical rating scale (NRS), 0-10) over 12 weeks. Secondary outcomes included additional first MTP joint and foot pain measures, physical function, quality of life and physical activity. Separate linear regression models for primary and secondary outcomes on treatment group were fit, adjusting for the outcome at baseline and podiatrist. Other measures included adverse events.

RESULTS

88 participants were randomized and 87 (99%) completed the 12-week primary outcome. There was no evidence foot orthoses were superior to sham insoles for reducing pain (mean difference -0.3 NRS units (95% CI -1.2 to 0.6), p = 0.53). Similarly, foot orthoses were not superior to sham on any secondary outcomes. Sensitivity analyses yielded similar results. Adverse events were generally minor and transient.

CONCLUSION

Contoured foot orthoses are no more effective than flat sham insoles for the clinical management of first MTP joint OA. Given the dearth of evidence on treatments for first MTP joint OA, further research is needed to identify effective management approaches for this common and debilitating condition.

Shoe-stiffening inserts for first metatarsophalangeal joint osteoarthritis: a randomised trial

OBJECTIVE

To evaluate the efficacy of carbon-fibre shoe-stiffening inserts in individuals with first metatarsophalangeal joint osteoarthritis.

DESIGN

This was a randomised, sham-controlled, participant- and assessor-blinded trial. One hundred participants with first metatarsophalangeal joint osteoarthritis received rehabilitation therapy and were randomised to receive either carbon fibre shoe-stiffening inserts (n = 49) or sham inserts (n = 51). The primary outcome measure was the Foot Health Status Questionnaire (FHSQ) pain domain assessed at 12 weeks.

RESULTS

All 100 randomised participants (mean age 57.5 (SD 10.3) years; 55 (55%) women) were included in the analysis of the primary outcome. At the 12 week primary endpoint, there were 13 drop-outs (7 in the sham insert group and 6 in the shoe-stiffening insert group), giving completion rates of 86 and 88%, respectively. Both groups demonstrated improvements in the FHSQ pain domain score at each follow-up period, and there was a significant between-group difference in favour of the shoe-stiffening insert group (adjusted mean difference of 6.66 points, 95% CI 0.65 to 12.67, P = 0.030). There were no between-group differences for the secondary outcomes, although global improvement was more common in the shoe-stiffening insert group compared to the sham insert group (61 vs 34%, RR 1.73, 95% CI 1.05 to 2.88, P = 0.033; number needed to treat 4, 95% CI 2 to 16).

CONCLUSION

Carbon-fibre shoe-stiffening inserts were more effective at reducing foot pain than sham inserts at 12 weeks. These results support the use of shoe-stiffening inserts for the management of this condition, although due to the uncertainty around the effect on the primary outcome, some individuals may not experience a clinically worthwhile improvement.

Characteristics of general practitioner referrals to podiatrists in Australia, 2000-2016

OBJECTIVE

The aim of the study was to describe patterns of referral to podiatrists by general practitioners (GPs) in Australia.

STUDY DESIGN

This is a continuous cross-sectional study of Australian general practice activity.

METHODS

We analysed data from the Bettering the Evaluation and Care of Health program, collected from April 2000 to March 2016 inclusive. Data were summarised using descriptive statistics with 95% confidence intervals around point estimates. Multivariate logistic regression was used to identify GP and patient characteristics independently associated with referral.

RESULTS

The data set included 1,568,100 encounters, including 5,912 podiatry referrals. Referrals increased from 7.0 to 39.5 per 1000 population over the evaluation period. In multivariate analyses, female GPs were more likely than male GPs to refer, and GPs aged ≥55 years were less likely to refer. Patients referred to podiatrists were more likely to be aged ≥85 years, be Indigenous, be from an English-speaking background and have previously been seen at the practice. The problem generating the highest number of referrals was diabetes. After the introduction of Medicare funding, referred patients were more likely to be women, be aged >45 years, have a healthcare card, be socio-economically disadvantaged and have previously been seen at the practice.

CONCLUSIONS

GP referral to podiatrists in Australia increased markedly after the introduction of Medicare funding and appears to be targeted to those with the greatest need. Further research is required to determine whether this policy has improved outcomes and is cost-effective.

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.

Factors associated with prevalent and incident foot pain: data from the Tasmanian Older Adult Cohort Study

OBJECTIVES

To describe factors associated with prevalent and incident foot pain in a population-based cohort of older adults (n = 1092).

STUDY DESIGN

Longitudinal observational study.

MAIN OUTCOME MEASURES

Prevalent foot pain, incident foot pain after 5 years.

METHODS

Potential correlates included demographic factors, anthropometry, leg strength, metabolic factors, steps per day (using pedometer), pain at 6 other sites, and psychological wellbeing. Data were analysed using log binomial models.

RESULTS

Participants were aged 50-80 years (mean 63 years), 49% male, mean body mass index (BMI) 27.8 ± 4.7 at baseline. The prevalence of foot pain at baseline was 38% and the incidence of new pain over 5 years was 20%. BMI, pain at other sites (neck, hands, knees, pain at three or more sites), and poorer psychological wellbeing were independently associated with baseline foot pain. Baseline BMI and pain in the neck, hands, and knees were independently associated with incident foot pain; but change in weight or BMI, total number of painful joints and psychological wellbeing were not. Self-reported diabetes and cigarette smoking were not associated with prevalent or incident foot pain.

CONCLUSIONS

This study demonstrates that greater body weight and joint pain at multiple sites were consistently associated with prevalent foot pain and predict incident foot pain. Addressing excess body mass and taking a global approach to the treatment of pain may reduce the prevalence and incidence of foot pain in older adults.

Risk factors for lower limb injuries during initial naval training: a prospective study

Introduction

This study aimed to identify risk factors associated with the development of common lower limb injuries during initial defence training in naval recruits who were enrolled in a randomised trial.

Methods

Three-hundred and six naval recruits were randomly allocated flat insoles (n=153) or foot orthoses (n=153) while undertaking 11 weeks of initial training. Participant characteristics (including anthropometrics, general health, physical activity, fitness and foot characteristics) were collected at the baseline assessment and injuries were documented prospectively. Injury was defined as the combined incidence of participants with medial tibial stress syndrome, patellofemoral pain, Achilles tendinopathy and plantar fasciitis/plantar heel pain throughout the 11 weeks of training. A discriminant function analysis was used to explore the ability of baseline measures to predict injury.

Results

Overall, 67 (21.9%) participants developed an injury. Discriminant function analysis revealed that participants who sustained an injury were slightly younger (mean 21.4±SD 4.1 vs 22.5±5.0 years) and were less likely to be allocated to the foot orthosis group (40% vs 53%) compared with those who remained uninjured. The accuracy of these baseline variables to predict injury was moderate (78.1%).

Conclusions

Lower limb injury was not accurately predicted from health questionnaires, fitness results and clinical assessments in naval recruits undertaking initial defence training. However, although not reaching statistical significance, the use of foot orthoses may be protective against common lower limb injuries.

Trial registration number

ACTRN12615000024549; Post-results.

The relationship between foot and ankle symptoms and risk of developing knee osteoarthritis: data from the osteoarthritis initiative

OBJECTIVE

To investigate whether foot and/or ankle symptoms increase the risk of developing (1) knee symptoms and (2) symptomatic radiographic knee osteoarthritis (OA).

DESIGN

1020 Osteoarthritis Initiative (OAI) participants who were at-risk of knee OA, but were without knee symptoms or radiographic knee OA, were investigated. Participants indicated the presence and laterality of foot/ankle symptoms at baseline. The main outcome was development of knee symptoms (pain, aching or stiffness in and around the knee on most days of the month for at least 1 month in the past year). A secondary outcome was development of symptomatic radiographic knee OA (symptoms plus Kellgren and Lawrence [KL] grade ≥2), over the subsequent 4 years. Associations between foot/ankle symptoms and study outcomes were assessed by logistic regression models.

RESULTS

Foot/ankle symptoms in either or both feet significantly increased the odds of developing knee symptoms (adjusted odds ratio (OR) 1.55, 95% confidence interval (CI) 1.10 to 2.19), and developing symptomatic radiographic knee OA (adjusted OR 3.28, 95% CI 1.69 to 6.37). Based on laterality, contralateral foot/ankle symptoms were associated with developing both knee symptoms (adjusted OR 1.68, 95% CI 1.05 to 2.68) and symptomatic radiographic knee OA (adjusted OR 3.08, 95% CI 1.06 to 8.98), whilst bilateral foot/ankle symptoms were associated with developing symptomatic radiographic knee OA (adjusted OR 4.02, 95% CI 1.76 to 9.17).

CONCLUSION

In individuals at-risk of knee OA, the presence of contralateral foot/ankle symptoms in particular increases risk of developing both knee symptoms and symptomatic radiographic knee OA.

Clinical diagnosis of symptomatic midfoot osteoarthritis: cross-sectional findings from the Clinical Assessment Study of the Foot

OBJECTIVE

To derive a multivariable diagnostic model for symptomatic midfoot osteoarthritis (OA).

METHODS

Information on potential risk factors and clinical manifestations of symptomatic midfoot OA was collected using a health survey and standardised clinical examination of a population-based sample of 274 adults aged ≥50 years with midfoot pain. Following univariable analysis, random intercept multi-level logistic regression modelling that accounted for clustered data was used to identify the presence of midfoot OA independently scored on plain radiographs (dorso-plantar and lateral views), and defined as a score of ≥2 for osteophytes or joint space narrowing in at least one of four joints (first and second cuneometatarsal, navicular-first cuneiform and talonavicular joints). Model performance was summarised using the calibration slope and area under the curve (AUC). Internal validation and sensitivity analyses explored model over-fitting and certain assumptions.

RESULTS

Compared to persons with midfoot pain only, symptomatic midfoot OA was associated with measures of static foot posture and range-of-motion at subtalar and ankle joints. Arch Index was the only retained clinical variable in a model containing age, gender and body mass index. The final model was poorly calibrated (calibration slope, 0.64, 95% CI: 0.39, 0.89) and discrimination was fair-to-poor (AUC, 0.64, 95% CI: 0.58, 0.70). Final model sensitivity and specificity were 29.9% (95% CI: 22.7, 38.0) and 87.5% (95% CI: 82.9, 91.3), respectively. Bootstrapping revealed the model to be over-optimistic and performance was not improved using continuous predictors.

CONCLUSIONS

Brief clinical assessments provided only marginal information for identifying the presence of radiographic midfoot OA among community-dwelling persons with midfoot pain.

The association between body composition and foot structure and function: a systematic review

The aim of this systematic review was to investigate the relationship between body composition and foot structure and function. Six electronic databases (Ovid MEDLINE, Ovid EMBASE, Ovid AMED, CINAHL, Scopus and The Cochrane Library) and reference lists from relevant papers were searched on 2 September 2013. Sixteen papers that reported on the association between body composition and foot structure and function met our inclusion criteria and were reviewed. The evidence indicates that obesity is strongly associated with planus (low-arched) foot posture, pronated dynamic foot function and increased plantar pressures when walking. However, there is limited evidence to support an association between other body composition measures, such as fat mass, with foot structure or function.

Fat mass is a predictor of incident foot pain

OBJECTIVE

Foot pain is a common complaint in adults. Increased BMI and fat mass have been linked only to foot pain prevalence. Therefore, a longitudinal study to examine the relationship between body composition and incident foot pain over 3 years was conducted.

DESIGN AND METHODS

Sixty-one community dwelling participants from a previous study of musculoskeletal health, who did not have foot pain at study inception in 2008, were invited to take part in this follow-up study in 2011. Current foot pain was determined using the Manchester Foot Pain and Disability Index, and body composition was measured using dual X-ray absorptiometry at study baseline.

RESULTS

Of the 51 respondents (84% response rate, 37 females and 14 males), there were 11 who developed foot pain. BMI ranged from underweight to morbidly obese (17-44 kg/m2), mean 27.0 ± 6.0 kg/m2. Incident foot pain was positively associated with both fat mass (odds ratio [OR] 1.11, 95% confidence interval [CI] 1.03-1.20) and fat-mass index (OR 1.28, 95% CI 1.04-1.57) in multivariate analysis.

CONCLUSIONS

Fat mass is a predictor of incident foot pain. This study supports the notion that incident foot pain in overweight individuals is associated with fat mass rather than body mass alone.

The association between body mass index and musculoskeletal foot disorders: a systematic review

The primary aim of this systematic review was to investigate the relationship between body mass index (BMI) and foot disorders. The secondary aim was to investigate whether weight loss is effective for reducing foot pain. Five electronic databases (Ovid MEDLINE, Ovid EMBASE, Ovid AMED, CINAHL and The Cochrane Library) and reference lists from relevant papers were searched in April 2011. Twenty-five papers that reported on the association between BMI and musculoskeletal foot disorders met our inclusion criteria and were reviewed. The evidence indicates: (i) a strong association between increased BMI and non-specific foot pain; and (ii) a strong association between increased BMI and chronic plantar heel pain in a non-athletic population. The evidence is inconclusive regarding the relationship between BMI and the following specific disorders of the foot; hallux valgus, tendonitis, osteoarthritis and flat foot. With respect to our second aim, there were only two prospective cohort studies that reported a reduction in foot symptoms following weight loss surgery. In summary, increased BMI is strongly associated with non-specific foot pain in the general population and chronic plantar heel pain in a non-athletic population. However, there is currently limited evidence to support weight loss to reduce foot pain.

Greater peak rearfoot eversion predicts foot orthoses efficacy in individuals with patellofemoral pain syndrome

OBJECTIVE

There is growing evidence for the provision of foot orthoses when treating individuals with patellofemoral pain syndrome (PFPS), and prescription is frequently based on the assessment of foot posture/function. However, evaluation of the link between abnormal foot posture/function and foot orthoses outcomes has previously been limited to static alignment measures and has produced inconsistent findings. In this study, the ability of baseline foot kinematics associated with pronation to predict marked improvement 12 weeks following foot orthoses prescription in individuals with PFPS was evaluated.

METHODS

26 individuals with PFPS were issued with prefabricated foot orthoses, and patient-reported level of improvement was documented at 12 weeks. Potential predictors of marked improvement at 12 weeks were measured during walking at baseline and included forefoot dorsiflexion and abduction, and rearfoot eversion.

RESULTS

Of the 25 participants who completed the study, seven (28%) reported marked improvement with the foot orthoses after 12 weeks. Discriminant function analysis revealed a greater peak rearfoot eversion to be the only significant independent predictor of marked improvement.

CONCLUSION

These findings provide preliminary evidence that greater peak rearfoot eversion is predictive of marked improvement 12 weeks following prefabricated foot orthoses prescription in individuals with PFPS. Therefore, foot orthoses may be most effective in the subgroup of people with PFPS and increased dynamic foot pronation.

Foot structure and function in older people with radiographic osteoarthritis of the medial midfoot

OBJECTIVE

To investigate whether foot structure and dynamic foot function differ between older people with and without radiographically confirmed osteoarthritis (OA) of the talo-navicular joint (TNJ) and navicular-first cuneiform joint (N1(st)CJ).

METHOD

Dorso-plantar and lateral weighbearing foot radiographs (right feet) were obtained from 205 older people aged 61-94 years, and the presence of OA in the TNJ and N1(st)CJ was determined using a standardized atlas. Foot structure was assessed using a clinical measure (the arch index [AI]) and two radiographic measures (calcaneal inclination angle [CIA] and calcaneal-first metatarsal angle [C1MA]). Dynamic plantar pressure assessment during walking was undertaken using the Tekscan MatScan system.

RESULTS

Thirty-five participants exhibited radiographic OA in the TNJ and N1(st)CJ. There were no significant differences between the groups in relation to age, sex, weight or walking velocity. Compared to those without OA in these joints, those with OA had significantly flatter feet, as evidenced by larger AI (0.26+/-0.05 vs 0.25+/-0.05, P=0.02), smaller CIA (18.5+/-6.3 vs 21.3+/-5.4 degrees, P<0.01) and larger C1MA (137.0+/-9.3 vs 132.4+/-8.0 degrees, P<0.01), and exhibited significantly higher maximum forces in the midfoot (15.2+/-7.3 vs 11.2+/-7.0 kg, P<0.01; 36% increase).

CONCLUSION

Older people with radiographic OA of the TNJ and N1(st)CJ exhibit flatter feet and increased loading of the plantar midfoot when walking. Excessive loading of the midfoot may predispose to OA by increasing dorsal compressive forces, although prospective studies are required to confirm whether this relationship is causal.

Radiographic evaluation of foot osteoarthritis: sensitivity of radiographic variables and relationship to symptoms

OBJECTIVES

To evaluate a radiographic atlas for grading foot osteoarthritis (OA) in relation to the relative sensitivity of different radiographic and views and features, and to examine the relationship between radiographic OA and foot symptoms.

METHODS

Weightbearing dorso-plantar (DP) and lateral foot radiographs were obtained from 197 people (126 women and 71 men) aged 62-94 years (mean age 75.9, standard deviation [SD] 6.6). The prevalence of OA in five joints (the first metatarsophalangeal joint [1st MPJ], the first cuneo-metatarsal joint [1st CMJ], the second cuneo-metatarsal joint [2nd CMJ], the navicular-first cuneiform joint [N1st CJ] and the talo-navicular joint [TNJ]) was then determined using both views in combination (as recommended in the atlas), or by using either view in isolation. Associations between radiographic OA in individual foot joints and symptoms were then explored.

RESULTS

Joint-specific prevalence of OA using both DP and lateral views was 1st MPJ (42.4%), 1st CMJ (22.6%), 2nd CMJ (60.2%), N1st CJ (39.1%) and TNJ (32.7%). Using only the DP view detected almost all cases of 1st MPJ OA (94.6%), however, the sensitivity was lower for the other joints (31.0-60.7%). Using only the lateral view detected almost all cases of OA (83.8 to 86.9%), with the exception of the 1st MPJ and 1st CMJ (50.9% and 60.7%, respectively). Using either osteophytes (OP) alone or joint space narrowing (JSN) alone showed low sensitivity for all joints (14.3-63.0%), with the exception of OP alone in the DP view for the 1st MPJ and JSN in the lateral view for the 2nd CMJ (83.8% and 84.0%, respectively). Radiographic OA in individual foot joints and the total number of joints affected were both moderately associated with foot symptoms.

CONCLUSION

Epidemiological and clinical studies should incorporate observation of both OP and JSN from both DP and lateral views to determine the presence of OA in the foot, as the number of cases detected is reduced if only one radiographic feature or view is used. Radiographic foot OA is common in older people and is moderately associated with foot symptoms.

Radiographic classification of osteoarthritis in commonly affected joints of the foot

OBJECTIVE

To develop a radiographic atlas for the classification of osteoarthritis (OA) in commonly affected joints of the foot based on observations of osteophytes and joint space narrowing, and to assess its intra- and inter-examiner reliability.

DESIGN

Weightbearing dorso-plantar and lateral foot radiographs from people aged over 65 years were examined, and an atlas was developed incorporating characteristic OA features of five foot joints: the first metatarsophalangeal joint, the first cuneo-metatarsal joint (1(st) CMJ), the second cuneo-metatarsal (2(nd) CMJ), the navicular-first cuneiform joint and the talonavicular joint. To assess the reliability of the atlas, two examiners independently rated 50 radiographs on two separate occasions.

RESULTS

Observations using the atlas demonstrated moderate to excellent reliability within examiners (percentage agreement from 86 to 99% and weighted kappa from 0.45 to 0.95), and, with the exception of joint space narrowing of the 2(nd) CMJ from the lateral projection, fair to excellent reliability between examiners (percentage agreement from 86 to 97% and weighted kappa from 0.32 to 0.87). Intra-class correlation coefficients for the overall foot OA score (representing the sum of observations for all joints from both feet) ranged between 0.83 and 0.89 for intra-examiner comparisons, and between 0.72 and 0.74 for inter-examiner comparisons.

CONCLUSION

Radiographic features of OA in commonly affected foot joints can be documented with high levels of agreement within examiners and moderate levels of agreement between examiners. Provided single examiners or consensus gradings are used, the atlas appears to be a useful tool to assist in the standardization of foot OA assessment for epidemiological and clinical studies.

Plantar pressures are higher under callused regions of the foot in older people

BACKGROUND

Mechanically induced hyperkeratotic lesions (corns and calluses) are among the most common foot problems in older people. However, their aetiology is not well understood.

AIM

To compare the magnitude of pressures generated under the foot when walking in older people with and without plantar calluses.

METHODS

Peak plantar pressure measurements were obtained from 292 participants (99 men and 193 women) aged 62-96 years (mean +/- SD 77.6 +/- 6.9) recruited from a retirement village and a university health sciences clinic. Comparisons were then made between callused and noncallused regions of the foot.

RESULTS

In total, 151 participants (52%) had at least one plantar callus. Those with plantar calluses were more likely to be female, have moderate to severe hallux valgus, and at least one lesser toe deformity. Regional peak plantar pressures were significantly higher in people with calluses under the second metatarsophalangeal joint (2.34 +/- 0.46 vs. 2.12 +/- 0.51 kg/cm(2), P = 0.001), the third to fifth metatarsophalangeal joints (1.71 +/- 0.46 vs. 1.50 +/- 0.51 kg/cm(2), P = 0.009) and the hallux (1.40 +/- 0.34 vs. 1.23 +/- 0.47 kg/cm(2), P = 0.007) compared with people without calluses under these sites.

CONCLUSION

Plantar pressures are significantly higher under callused regions of the foot in older people. Raised pressure may play a role in the development of plantar calluses by accelerating the turnover rate of keratinocytes in the epidermis. Future studies should focus on evaluating the efficacy of pressure-relieving interventions in the prevention and treatment of keratotic disorders in older people.

Factors associated with chronic plantar heel pain: a systematic review

Chronic plantar heel pain (CPHP) is one of the most common soft tissue disorders of the foot, yet its aetiology is poorly understood. The purpose of this systematic review was to examine the association between CPHP and the various aetiological factors reported in the literature. Seven electronic databases and the reference lists of key articles were searched in August 2005. The resulting list of articles was assessed by two independent reviewers according to pre-determined selection criteria and a final list of articles for review was created. The methodological quality of the included articles was assessed and the evidence presented in each of the articles was descriptively analysed. From the 16 included articles, body mass index in a non-athletic population and the presence of calcaneal spur were the two factors found to have an association with CPHP. Increased weight in a non athletic population, increased age, decreased ankle dorsiflexion, decreased first metatarsophalangeal joint extension and prolonged standing all demonstrated some evidence of an association with CPHP. Evidence for static foot posture and dynamic foot motion was inconclusive and height, weight and BMI in an athletic population were not associated with CPHP. The findings of this review should be used to guide the focus of prospective cohort studies, the results of which would ultimately provide a list of risk factors for CPHP. Such a list is essential in the development of new and improved preventative and treatment strategies for CPHP.

Foot pain in community-dwelling older people: an evaluation of the Manchester Foot Pain and Disability Index

OBJECTIVES

The objectives of this study were (i) to examine the psychometric properties of the Manchester Foot Pain and Disability Index (MFPDI) in community-dwelling older people, and (ii) to determine the correlates of disabling foot pain in this age-group.

METHODS

A questionnaire consisting of medical history, the MFPDI, the Goldberg Anxiety and Depression Scale (GADS) and the Medical Outcomes Study Short Form 36 (SF-36) was administered to a sample of 301 community-dwelling people (117 men, 184 women) aged between 70 and 95 yr (mean 77.2, s.d. 4.9), who also underwent a clinical assessment of foot problems.

RESULTS

Using the MFPDI case definition, 108 people (36%) were found to have disabling foot pain. Within this subgroup, the MFPDI had high internal consistency (Cronbach's alpha=0.89). Principal components analysis revealed a four-factor structure representing the constructs of functional limitation, pain intensity, concern about appearance, and activity restriction, which explained 62% of the variance in the original items. Participants with disabling foot pain were more likely to report pain in the back, hips, knees and hands or wrists, and exhibited flatter feet and less range of motion in the ankle joint. The MFPDI and its subscales were significantly associated with scores on the GADS depression subscale and the general health and mental health components of the SF-36.

CONCLUSIONS

These findings confirm the high prevalence of disabling foot pain in older people, and suggest that the MFPDI is a suitable tool for assessing foot pain in this population.

The contribution of foot problems to mobility impairment and falls in community-dwelling older people

OBJECTIVES

To investigate the relationship between foot problems, balance, and functional ability in community-dwelling older people and to determine whether older people with a history of multiple falls exhibit greater foot impairment than those who have not fallen or who have fallen once only.

DESIGN

A cross-sectional, retrospective study.

SETTING

Falls and Balance Laboratory, Royal North Shore Hospital, Sydney, Australia.

PARTICIPANTS

One hundred thirty-five community-dwelling men and women age 75 to 93 (mean age +/- standard deviation, 79.8 +/- 4.1).

MEASURES

Foot problem score; postural sway; coordinated stability; stair ascent and descent; an alternate stepping test; timed 6-meter walk; and tests of vision, sensation, strength, and reaction time.

RESULTS

Eighty-seven percent of the sample had at least one foot problem. Women had a significantly higher foot problem score than did men. The foot problem score was significantly associated with performance on the coordinated stability test, stair ascent and descent, alternate stepping test, and timed 6-meter walk. Multiple regression analyses revealed that the foot problem score was a significant independent predictor of performance in the coordinated stability test, stair ascent and descent, and the alternate stepping test. Subjects with a history of multiple falls had a significantly higher foot problem score than did those who had not fallen or who had fallen once only, but the prevalence of individual foot conditions or the presence of foot pain did not differ between these groups.

CONCLUSIONS

Foot problems are common in older people and are associated with impaired balance and performance in functional tests. Furthermore, older people with a history of multiple falls have greater foot impairment than non- or once-only fallers. These findings provide further evidence that foot problems are a falls risk factor and suggest that the cumulative effect of multiple foot problems is more important in increasing falls risk than the presence or absence of individual foot conditions.

Reliability of navicular displacement measurement as a clinical indicator of foot posture

This study evaluated two methods for quantifying foot posture: navicular drop and navicular drift. Five clinicians measured 20 nonpathological participants on two occasions. Intraclass correlation coefficients ranged from 0.33 to 0.76 for navicular drop and from 0.31 to 0.62 for navicular drift. The standard error of measurement, as a 95% confidence interval, ranged from +/-1.5 mm to +/-3.5 mm for navicular drop and +/-3 mm to +/-5 mm for navicular drift. Intratester reliability was slightly better than intertester reliability for both measurements. These results indicate that both techniques are only moderately reliable, and physicians using these measurements in clinical practice should interpret the values in light of the magnitude of error associated with them.

Slip resistance of casual footwear: implications for falls in older adults

BACKGROUND

A large proportion of falls in older people are caused by slipping. Previous occupational safety research suggests that inadequate footwear may contribute to slipping accidents; however, no studies have assessed the slip resistance of casual footwear.

OBJECTIVE

To evaluate the slip resistance of different types of casual footwear over a range of common household surfaces.

METHODS

The slip resistance of men's Oxford shoes and women's fashion shoes with different heel configurations was determined by measuring the dynamic coefficient of friction (DCoF) at heel contact (in both dry and wet conditions) on a bathroom tile, concrete, vinyl flooring and a terra cotta tile using a specially-designed piezoelectric force plate apparatus.

RESULTS

Analysis of variance revealed significant shoe, surface, and shoe-surface interaction effects. Men's Oxford shoes exhibited higher average DCoF values than the women's fashion shoes, however, none of the shoes could be considered safe on wet surfaces. Application of a textured sole material did not improve slip resistance of any of the shoes on wet surfaces.

CONCLUSION

Heel geometry influences the slip resistance of casual footwear on common household surfaces. The suboptimal performance of all of the test shoes on wet surfaces suggests that a safety standard for casual footwear is required to assist in the development of safe footwear for older people.

Foot pain impairs balance and functional ability in community-dwelling older people

Foot problem assessments were performed on 135 community-dwelling older people in conjunction with clinical tests of balance and functional ability. Eighty-seven percent of the sample had at least one foot problem, and women had a higher prevalence than men of foot pain, hallux valgus, plantar hyperkeratosis, lesser digital deformity, and digital lesions. Postural sway did not differ between older people with and without each of these foot conditions. However, the presence of specific foot conditions impaired performance in a more challenging balance test and in some functional tests. In particular, older people with foot pain performed worse in a leaning balance test, stair ascent and descent, an alternate step-up test, and a timed six-meter walk. Furthermore, multiple regression analyses revealed that foot pain was a significant independent predictor of performance in each of these tests. These results show that the presence of foot problems, particularly foot pain, impairs balance and functional ability. As foot pain is amenable to treatment, podiatric intervention has the potential to improve mobility and independence in older people.

Publication patterns and perceptions of the Australian podiatric medical faculty

Despite the wide range of publication opportunities in podiatric medicine, little is known about how podiatric authors select journals in which to publish or their perceptions of journals currently available. To investigate these issues, a survey of publication patterns and perceptions of full- and part-time academic staff members at podiatric medical schools in Australia was undertaken. Most of the papers by Australian podiatric medical faculty members have been published in "local" journals, such as the Australasian Journal of Podiatric Medicine (38%) and the British Journal of Podiatry (17%). However, an increasing number of papers are being published in JAPMA (14%). In addition, a large proportion of papers have been published in a variety of journals that are not specific to podiatric medicine, particularly in the areas of biomechanics and diabetic medicine. The number of publications per faculty member was associated with the highest qualification obtained, academic rank, and the number of years of employment in higher education. The most important factors in selecting the journal in which to publish were the journal's inclusion in MEDLINE, the perceived prestige of the journal, and the quality of the journal's peer-review panel and editor.

Effects of prefabricated foot orthoses and soft insoles on postural stability in professional soccer players

Postural stability is an important component of skilled athletic activity. However, the effects of foot orthoses on stability have not been adequately addressed. This study measured postural sway in 30 asymptomatic professional soccer players in three standing positions and four underfoot conditions. The results revealed that the underfoot condition had no significant effect on sway in the mediolateral or anteroposterior planes; however, there was a trend toward less mediolateral sway when subjects stood in a unipedal position with prefabricated orthoses. These results suggest that insoles and foot orthoses have no significant beneficial or detrimental effects on postural stability in asymptomatic subjects. Clinically, this suggests that no improvements in balance performance could be expected with prophylactic use of insoles or orthoses but that clinicians may prescribe insoles and foot orthoses without fear of impairing postural performance in elite athletes.

The Footwear Assessment Form: a reliable clinical tool to assess footwear characteristics of relevance to postural stability in older adults

OBJECTIVE

Falls in older adults are common and may result in serious injury. Inappropriate footwear has been suggested to be a contributing factor to many falls. However no studies have been undertaken to determine whether clinicians can reliably assess footwear variables thought to influence postural stability in older adults. The aim of this study was therefore to develop a simple clinical footwear assessment form and assess its reliability, both between examiners and with repeated assessments over time.

DESIGN

Two examiners assessed seven footwear variables (shoe type, heel height, heel counter stiffness, longitudinal sole rigidity, sole flexion point, tread pattern and sole hardness) in 12 different shoes, and repeated the measurements three weeks later. The examiners were blinded to each other's and their own previous results.

RESULTS

Analysis using the kappa (kappa) and percentage agreement statistics revealed the examiners' footwear assessments to be generally highly reliable (kappa = 0.47-1.00 for inter-tester comparisons, kappa = 0.40-1.00 for intra-tester comparisons), with the exception of inter-tester assessment of sole hardness (kappa = 0.03-0.48).

CONCLUSION

The Footwear Assessment Form is a reliable clinical tool for the assessment of shoe type, heel height, heel counter stiffness, longitudinal sole rigidity and tread pattern; however, a more objective protocol may be required to improve the reliability of sole hardness evaluation. The Footwear Assessment Form can now be used with confidence in the clinical setting and in future investigations to determine the contribution of footwear characteristics to instability and falls in older adults.

Visual contributions to postural stability in older adults

BACKGROUND

With advancing age, there is a generalized reduction in visual functioning which has been associated with impaired postural stability and increased risk of falls. However, little is known about which visual abilities are the most important in the control of postural sway when standing.

OBJECTIVE

To determine whether specific visual abilities predict stability when standing on firm and compliant surfaces.

METHODS

Tests of visual function, peripheral sensation, strength, reaction time and sway were administered to 156 community-dwelling men and women aged 63-90 years. The visual tests included high- and low-contrast visual acuity, contrast sensitivity, depth perception, stereopsis and lower visual field size. Postural sway was measured with eyes open on a firm and a compliant foam rubber surface.

RESULTS

On the firm surface, sway was significantly associated with only one sensorimotor measure: proprioception in the lower limbs. In contrast, on the compliant surface, sway was associated with all of the visual measures, quadriceps strength and reaction time. Multiple regression analysis revealed that contrast sensitivity, stereopsis and quadriceps strength were significant independent predictors of total sway when subjects stood on the compliant surface.

CONCLUSION

The study findings confirm the importance of vision, in particular contrast sensitivity and stereopsis, in the control of posture under challenging conditions, and suggest some mechanisms for the association between impaired vision and falls in older people.

Foot problems, functional impairment, and falls in older people

Falls in older people are common and may lead to considerable disability. Although a number of risk factors for falling have been identified, the role of foot problems has received relatively little attention in the literature. This article reviews the literature pertaining to the prevalence of foot problems in older people and discusses the relationship of foot problems to functional impairment and falls. In addition, a number of theoretical considerations regarding specific foot conditions and postural instability are outlined.

The effect of pregnancy on footprint parameters. A prospective investigation

Pregnancy produces significant alterations in the posture of the pregnant woman; however, gait changes that occur during pregnancy have not been adequately evaluated in the literature. This prospective investigation of the footprints of 25 pregnant women from early pregnancy to just prior to parturition revealed a significant increase in the base of gait during walking. This change in gait function may be a compensatory mechanism to improve locomotor stability, and may have important implications for foot function and development of lower-extremity pathology in pregnant women.

Footwear and postural stability in older people

Accidental falls in the older population are common and often result in serious injury. Although a number of factors have been recognized as risk factors for falling, the effect of footwear on postural stability is often overlooked. This article reviews the literature on the effect of various footwear features on postural stability and suggests areas that warrant further investigation.

Alternative techniques for the clinical assessment of foot pronation

Clinical measurement is a fundamental component of podiatric biomechanics. However, recent research has seriously questioned the reliability and validity of the commonly used approaches to clinical measurement of foot posture. A reevaluation of foot-morphology measurement is therefore warranted. This article discusses alternative clinical techniques of measuring foot type reported in the literature (arch height, footprint indices, the valgus index, and navicular drop) that may prove to be superior to the commonly used podiatric measurement system. On the basis of a critical evaluation of the literature, it would appear that arch height and footprint indices are invalid as means of categorizing foot morphology, while the valgus index and navicular drop offer a number of benefits over traditional frontal-plane measurements. An additional clinical measurement suggested by the author, navicular "drift," is also introduced. The advantages, disadvantages, and clinical application of each of these approaches are discussed in detail.