Foot orthoses: how much customisation is necessary?

Toward subtalar joint axis-driven computer-aided design and computer-aided manufacturing foot orthoses: Reliability of a noninvasive clinical scanning protocol

BACKGROUND

The subtalar joint axis (STJA) occupies a key role in the dynamics of the lower limb kinetic chain, and its location has a wide interindividual variability. It has been suggested that considering the STJA location when designing foot orthoses may help to apply the required mechanical dose. However, the evidence is more anecdotal than empirical.

OBJECTIVE

This study aimed to evaluate the reliability of the STJA digitization, a procedure combining the clinical determination of the functional STJA location and its subsequent 3-dimensional (3D) scanning.

STUDY DESIGN

Two examiners identified the posterior and anterior exit points of the functional STJA on the skin of 15 healthy participants using a clinical method in a repeated-measure design.

METHODS

A handheld 3D scanner was used to scan the feet and the skin markers. The 3D coordinates of the skin markers were subsequently quantified and (1) STJA digitization intratester within-session, (2) STJA digitization intratester between-session, and (3) STJA digitization intertester between-session reliabilities were evaluated.

RESULTS

When pooling all skin marker 3D coordinates, intraclass correlation coefficients (ICCs) for the STJA intratester within-session reliability ranged from 0.74 to 0.98. ICCs for the STJA digitization intratester between-session reliability ranged from 0.58 to 0.94. ICCs for the STJA digitization intertester reliability ranged from 0.56 to 0.81. Standard error of measurement for the mediolateral position of the talus marker (anterior exit point of the STJA) was substantially higher than that for the other coordinates.

CONCLUSIONS

Overall, the STJA digitization demonstrated a good intratester between-session reliability and may be used in a computer-aided design and computer-aided manufacturing workflow to create foot orthoses. However, further efforts should be considered to improve the scanning process and intertester reliability.

Understanding the role of foot biomechanics on regional foot orthosis deformation in flatfoot individuals during walking

BACKGROUND

Foot orthoses (FOs) are one of the most common interventions to restore normal foot mechanics in flatfoot individuals. New technologies have made it possible to deliver customized FOs with complex designs for potentially better functionalities. However, translating the individuals' biomechanical needs into the design of customized FOs is not yet fully understood.

RESEARCH QUESTION

Our objective was to identify whether the deformation of customized FOs is related to foot kinematics and plantar pressure during walking.

METHODS

The kinematics of multi-segment foot and FOs contour were recorded together with plantar pressure in 17 flatfoot individuals while walking with customized FOs. The deformation of FOs surface was predicted from its contour kinematics using an artificial neural network. Plantar pressure map and deformation were divided into five anatomically based regions defined by the corresponding foot segments. Forward stepwise linear mixed models were built for each of the four gait phases to determine the feet-FOs interaction.

RESULTS

It was observed that some associations existed between foot kinematics and pressure with regional FOs deformation. From heel-strike to foot-flat, longitudinal arch angle was associated with FOs deformation in forefoot. From foot-flat to midstance, rearfoot eversion accounted for variation in the deformation of medial FOs regions, and forefoot abduction for the lateral regions. From midstance to heel-off, rearfoot eversion, longitudinal arch angle, and plantar pressure played significant role in deformation. Finally, from heel-off to toe-off, forefoot adduction affected the deformation of forefoot and midfoot.

SIGNIFICANCE

This study provides guidelines for designing customized FOs. Flatfoot individuals with excessive rearfoot eversion or very flexible medial arches require more support on medial FOs regions, while the ones with excessive forefoot abduction need the support on lateral regions. However, a compromise should be made between the level of support and the level of increase in plantar pressure to avoid stress on foot structures.

Evidence for foot orthoses for adults with flatfoot: a systematic review

Background

Flatfoot is characterised by the falling of the medial longitudinal arch, eversion of the hindfoot and abduction of the loaded forefoot. Furthermore, flatfoot leads to a variety of musculoskeletal symptoms in the lower extremity, such as knee or hip pain. The standard conservative treatment for flatfoot deformity is exercise therapy or treatment with foot orthoses. Foot orthoses are prescribed for various foot complaints. However, the evidence for the provision of foot orthoses is inconsistent. The aim of this systematic review is to synthesize the evidence of foot orthoses for adults with flatfoot.

Methods

A computerized search was conducted in August 2021, using the databases PubMed, Scopus, Pedro, Cochrane Library, and the Cochrane Central Register of Controlled Trials. Intervention studies of any design investigating the effects of foot orthoses were included, apart from case studies. Two independent reviewers assessed all search results to identify eligible studies and to assess their methodological quality.

Results

A total of 110 studies were identified through the database search. 12 studies met the inclusion criteria and were included in the review. These studies investigated prefabricated and custom-made foot orthoses, evaluating stance and plantar pressure during gait. The sample sizes of the identified studies ranged from 8 to 80. In most of the studies, the methodological quality was low and a lack of information was frequently detected.

Conclusion

There is a lack of evidence on the effect of foot orthoses for flatfoot in adults. This review illustrates the importance of conducting randomized controlled trials and the comprehensive development of guidelines for the prescription of foot orthoses. Given the weak evidence available, the common prescription of foot orthoses is somewhat surprising.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13047-021-00499-z.

The Effects of a Medial Heel Wedge on the Weight-Bearing Response of Hindfoot Valgus and the Total Weight-Bearing Responses of the Navicular and Talus Bones

OBJECTIVES Medial heel wedges are commonly prescribed to manage the weight-bearing response of hindfoot valgus and the total weight-bearing responses of the navicular and talus bones. Previous studies have reported that a medial heel wedge is effective in the management of musculoskeletal injuries. However, it remains unclear the effect of a medial heel wedge on the weight-bearing responses of footarch bones in vivo. To clarify the effects of a medial heel wedge on the weight-bearing response of hindfoot valgus and the total weight-bearing responses of the navicular and talus bones is necessary to understand how best to treat musculoskeletal injuries clinically. The purpose of our study was to clarify the effects of a medial heel wedge on the weight-bearing response of hindfoot valgus and the total weight-bearing responses of the navicular and talus bones.METHODS Twenty-five healthy males were analyzed. We obtained MRI scanning of the right foot under non-loading (NL) and full weight-bearing (FW) conditions. Participants wore two insole types, a flat insole and a medial heel wedge. To evaluate the weight-bearing response in hindfoot valgus, the hindfoot alignment view (HAV) was measured. We also measured navicular and talus bone positions and calculated the total positional changes of the navicular and talus bones (ΔTPCN, ΔTPCT) from the vertical and medial displacements using the Pythagorean theorem.RESULTS Significant interactions were observed with the HAV. Under both NL and FW conditions, the HAV was smaller on the medial heel wedge than on the flat insole. In addition, the ΔTPCN was significantly smaller on the medial heel wedge than on the flat insole. However, no significant differences were observed for ΔTPCT.CONCLUSIONS Our results suggest that use of a medial heel wedge decreases hindfoot valgus values under both NL and FW conditions and stabilizes the total weight-bearing response of the navicular bone.

Real-Time Analysis of the Dynamic Foot Function: A Machine Learning and Finite Element Approach

Finite element analysis (FEA) has been widely used to study foot biomechanics and pathological functions or effects of therapeutic solutions. However, development and analysis of such foot modeling is complex and time-consuming. The purpose of this study was therefore to propose a method coupling a FE foot model with a model order reduction (MOR) technique to provide real-time analysis of the dynamic foot function. A generic and parametric FE foot model was developed and dynamically validated during stance phase of gait. Based on a design of experiment of 30 FE simulations including four parameters related to foot function, the MOR method was employed to create a prediction model of the center of pressure (COP) path that was validated with four more random simulations. The four predicted COP paths were obtained with a 3% root-mean-square-error (RMSE) in less than 1 s. The time-dependent analysis demonstrated that the subtalar joint position and the midtarsal joint laxity are the most influential factors on the foot functions. These results provide additionally insight into the use of MOR technique to significantly improve speed and power of the FE analysis of the foot function and may support the development of real-time decision support tools based on this method.

Main types of insoles described in the literature and their applicability for musculoskeletal disorders of the lower limbs: A systematic review of clinical studies

The objective of this review was to identify the main types of insoles described in the literature that are used to treat musculoskeletal alterations of lower limbs and to analyze the existence of previous evaluation for the prescription of these insoles. To this end, two researchers, independently and blindly, searched the PubMed, SciELO, Bireme, MEDLINE, Lilacs, PEDro, Cochrane Library and Web of Science databases between June and July of 2018, from the free combination of the following descriptors: insoles, foot orthoses, foot, orthoses, musculoskeletal diseases and clinical trial. We included randomized or non-randomized clinical trials in which at least one intervention group used insoles and individuals with some type of musculoskeletal disorder had been sampled. Of the 227 documents identified in date bases, 20 were included in this review. In general, it is suggested to carry out more studies with more precise methods and that include evaluation before the prescription. This is a systematic review of clinical trials registered in PROSPERO (International Prospective Register of Systematic Reviews) under the protocol no. CRD42018099534e.

Foot orthoses for people with rheumatoid arthritis: a survey of prescription habits among podiatrists

Background

Guidelines recommend foot orthoses for people with both early (< 2 years) and established rheumatoid arthritis (RA). While prefabricated foot orthoses are cheaper and can exhibit comparable effects to customised devices, the available evidence for their effectiveness is inconsistent. Little is known about what types of foot orthoses clinicians prescribe. This study describes the foot orthoses prescription habits of podiatrists for people with rheumatoid arthritis.

Methods

One hundred and eighty-three podiatrists from the United Kingdom (UK) (n = 88), Australia (n = 68) and New Zealand (n = 27) completed a self-administered, online survey regarding the types of foot orthoses prescribed in clinical practice for people with RA. This study forms part of a wider international survey exploring foot orthosis prescription habits.

Results

UK respondents were more likely to prescribe prefabricated orthoses for early RA (n = 47, 53%) and customised orthoses for established RA (n = 47, 53%). Respondents in Australia were more likely to prescribe customised orthoses for both early (n = 32, 47%) and established (n = 46, 68%) RA, whilst respondents in New Zealand were more likely to prescribe prefabricated orthoses for both early (n = 16, 59%) and established (n = 10, 37%) disease.

Irrespective of disease stage, the use of foam impression boxes was more prevalent in the UK and New Zealand when capturing a model of the feet prior to manufacturing customised orthoses. In contrast, electronic scanning and plaster of Paris were more common in Australia. Computer aided manufacture was utilised more frequently among respondents in Australia than in the UK and New Zealand. Respondents in all three countries specified more flexible shell materials for established RA, compared to early disease. Cushioning top covers (e.g. PORON® or polyurethane) were most frequently specified in all countries for both disease stages.

Conclusions

Considerable variation was seen in the self-reported foot orthoses prescription habits of respondents for people with RA. Variation between countries and disease stage was seen in type of orthoses, specific brands, manufacturing methods, and materials prescribed. The results allow podiatrists and broader health service providers to compare their practice against reported national and international patterns.

Electronic supplementary material

The online version of this article (10.1186/s13047-019-0314-5) contains supplementary material, which is available to authorized users.

A survey of foot orthoses prescription habits amongst podiatrists in the UK, Australia and New Zealand

Background

Foot orthoses are frequently used but little is known about which types are used in contemporary practice. This study aimed to explore the types of foot orthoses currently used by podiatrists and the prescription variations in a range of conditions.

Methods

A web-based, cross-sectional survey was distributed through professional bodies in the United Kingdom (UK), Australia, and New Zealand. Questions focussed on foot orthosis prescription habits in relation to 26 conditions affecting the back and lower limb.

Results

Two hundred and sixty-four podiatrists practising in 19 different countries completed the survey; the majority practised in the UK (47%, n = 124), Australia (30%, n = 79) and New Zealand (12%, n = 32). Respondents qualified between 1968 and 2016, and 147 (56%) were female. Respondents worked in different healthcare sectors and this varied between countries: 42 (34%) respondents in the UK worked solely in the public sector, compared to 3 (4%) in Australia and 2 (6%) in New Zealand. Forty-four (35%) respondents in the UK worked solely in private practice, compared to 64 (81%) in Australia and 14 (44%) in New Zealand.

UK respondents prescribed more prefabricated orthoses per week (mean 5.5 pairs) than simple insole-type devices (±2.7) and customised devices (±2.9). Similarly, respondents in New Zealand prescribed more prefabricated orthoses per week (±7.7) than simple (±1.4) and customised (±2.8) devices. In contrast, those in Australia prescribed more customised orthoses per week (±4.4) than simple (±0.8) and prefabricated (±1.9) orthoses. Differences in the types of orthoses prescribed were observed between country of practice, working sector, and the condition targeted. Generally, prefabricated orthoses were commonly prescribed for the 26 highlighted conditions in the UK and New Zealand. Australian podiatrists prescribed far fewer devices overall, but when they did prescribe, they were more likely to prescribe custom devices. Respondents in all three countries were more likely to prescribe customised orthoses for people with diabetes complicated by peripheral neuropathy than for diabetes without this complication.

Conclusions

Foot orthosis prescription habits vary between countries. Prefabricated orthoses were frequently prescribed in the UK and New Zealand, and customised orthoses in Australia. Prescriptions for people with diabetes differed depending on the presence of neuropathy, despite a lack of robust evidence supporting these decisions. This study provides new insight into contemporary practice.

Electronic supplementary material

The online version of this article (10.1186/s13047-018-0304-z) contains supplementary material, which is available to authorized users.

A protocol for a randomised controlled trial of prefabricated versus customised foot orthoses for people with rheumatoid arthritis: the FOCOS RA trial [Foot Orthoses - Customised v Off-the-Shelf in Rheumatoid Arthritis]

BACKGROUND

Foot pain is common in rheumatoid arthritis and appears to persist despite modern day medical management. Several clinical practice guidelines currently recommend the use of foot orthoses for the treatment of foot pain in people with rheumatoid arthritis. However, an evidence gap currently exists concerning the comparative clinical- and cost-effectiveness of prefabricated and customised foot orthoses in people with early rheumatoid arthritis. Early intervention with orthotics may offer the best opportunity for positive therapeutic outcomes. The primary aim of this study is to evaluate the comparative clinical- and cost-effectiveness of prefabricated versus customised orthoses for reducing foot pain over 12 months.

METHODS/DESIGN

This is a multi-centre two-arm parallel randomised controlled trial comparing prefabricated versus customised orthoses in participants with early rheumatoid arthritis (< 2 years disease duration). A total of 160 (a minimum of 80 randomised to each arm) eligible participants will be recruited from United Kingdom National Health Service Rheumatology Outpatient Clinics. The primary outcome will be foot pain measured via the Foot Function Index pain subscale at 12 months. Secondary outcomes will include foot related impairments and disability via the Foot Impact Scale for rheumatoid arthritis, global functional status via the Stanford Health Assessment Questionnaire, foot disease activity via the Rheumatoid Arthritis Foot Disease Activity Index, and health-related quality of life at baseline, 6 and 12 months. Process outcomes will include recruitment/retention rates, data completion rates, intervention adherence rates, and participant intervention and trial participation satisfaction. Cost-utility and cost-effectiveness analyses will be undertaken.

DISCUSSION

Outcome measures collected at baseline, 6 and 12 months will be used to evaluate the comparative clinical- and cost- effectiveness of customised versus prefabricated orthoses for this treatment of early rheumatoid arthritis foot conditions. This trial will help to guide orthotic prescription recommendations for the management of foot pain for people with early rheumatoid arthritis in future.

TRIAL REGISTRATION

ISRCTN13654421. Registered 09 February 2016.

The effectiveness of non-surgical intervention (Foot Orthoses) for paediatric flexible pes planus: A systematic review: Update

Background

Flexible pes planus (flat feet) in children is a common presenting condition in clinical practice due to concerns amongst parents and caregivers. While Foot Orthoses (FOs) are a popular intervention, their effectiveness remains unclear. Thus, the aim of this systematic review was to update the current evidence base for the effectiveness of FOs for paediatric flexible pes planus.

Methods

A systematic search of electronic databases (Cochrane, Medline, AMED, EMBASE, CINHAL, SportDiscus, Scopus and PEDro) was conducted from January 2011 to July 2017. Studies of children (0–18 years) diagnosed with flexible pes planus and intervention to be any type of Foot Orthoses (FOs) were included. This review was conducted and reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. McMaster critical review form for quantitative studies, was used to assess the methodological quality of the included studies. Given the heterogeneity of the included studies, a descriptive synthesis of the included studies was undertaken.

Results

Out of 606 articles identified, 11 studies (three RCTs; two case-controls; five case-series and one single case study) met the inclusion criteria. A diverse range of pre-fabricated and customised FOs were utilised and effectiveness measured through a plethora of outcomes. Summarised findings from the heterogeneous evidence base indicated that FOs may have a positive impact across a range of outcomes including pain, foot posture, gait, function and structural and kinetic measures. Despite these consistent positive outcomes reported in several studies, the current evidence base lacks clarity and uniformity in terms of diagnostic criteria, interventions delivered and outcomes measured for paediatric flexible pes planus.

Conclusion

There continues to remain uncertainty on the effectiveness of FOs for paediatric flexible pes planus. Despite a number of methodological limitations, FOs show potential as a treatment method for children with flexible pes planus.

PROSPERO registration number

CRD42017057310.

Comparison of plantar pressure distribution in CAD-CAM and prefabricated foot orthoses in patients with flexible flatfeet

BACKGROUNDS

The effect of foot orthoses on plantar pressure distribution has been proven by researchers but there are some controversies about advantages of custom-made foot orthoses to less expensive prefabricated foot orthoses.

METHODS

Nineteen flatfeet adults between 18 and 45 participated in this study. CAD-CAM foot orthoses were made for these patients according to their foot scan. Prefabricated foot orthoses were prepared according to their foot size. Plantar pressure, force and contact area were measured using pedar^®-x in-shoe system wearing shoe alone, wearing CAD-CAM foot orthoses and wearing prefabricated foot orthoses. Repeated measures ANOVA model with post-hoc, Bonferroni comparison were used to test differences.

RESULTS

CAD-CAM and prefabricated foot orthoses both decreased pressure and force under 2nd, 3-5 metatarsal and heel regions comparing to shoe alone condition. CAD-CAM foot orthosis increased pressure under lateral toe region in comparison to shoe alone and prefabricated foot orthosis. Both foot orthoses increased pressure and contact area in medial midfoot region comparing to shoe alone condition. Increased forces were seen at hallux and lateral toes by prefabricated foot orthoses in comparison with CAD-CAM foot orthoses and control condition, respectively.

CONCLUSION

According to the results, both foot orthoses could decrease the pressure under heel and metatarsal area. It seems that the special design of CAD-CAM foot orthoses could not make great differences in plantar pressure distribution in this sample. Further research is required to determine whether these results are associated with different scan systems or design software.

Custom-made foot orthoses: an analysis of prescription characteristics from an Australian commercial orthotic laboratory

BACKGROUND

Foot orthoses are widely used in the prevention and treatment of foot disorders. The aim of this study was to describe characteristics of custom-made foot orthosis prescriptions from a Australian podiatric orthotic laboratory.

METHODS

One thousand consecutive foot orthosis prescription forms were obtained from a commercial prescription foot orthosis laboratory located in Melbourne, Victoria, Australia (Footwork Podiatric Laboratory). Each item from the prescription form was documented in relation to orthosis type, cast correction, arch fill technique, cast modifications, shell material, shell modifications and cover material. Cluster analysis and discriminant function analysis were applied to identify patterns in the prescription data.

RESULTS

Prescriptions were obtained from 178 clinical practices across Australia and Hong Kong, with patients ranging in age from 5 to 92 years. Three broad categories ('clusters') were observed that were indicative of increasing 'control' of rearfoot pronation. A combination of five variables (rearfoot cast correction, cover shape, orthosis type, forefoot cast correction and plantar fascial accommodation) was able to identify these clusters with an accuracy of 70%. Significant differences between clusters were observed in relation to age and sex of the patient and the geographic location of the prescribing clinician.

CONCLUSION

Foot orthosis prescriptions are complex, but can be broadly classified into three categories. Selection of these prescription subtypes appears to be influenced by both patient factors (age and sex) and clinician factors (clinic location).

The effect of foot orthoses with forefoot cushioning or metatarsal pad on forefoot peak plantar pressure in running

Background

Foot orthoses are frequently used in sports for the treatment of overuse complaints with sufficient evidence available for certain foot-related overuse pathologies like plantar fasciitis, rheumatoid arthritis and foot pain (e.g., metatarsalgia). One important aim is to reduce plantar pressure under prominent areas like metatarsal heads. For the forefoot region, mainly two common strategies exist: metatarsal pad (MP) and forefoot cushioning (FC). The aim of this study was to evaluate which of these orthosis concepts is superior in reducing plantar pressure in the forefoot during running.

Methods

Twenty-three (13 female, 10 male) asymptomatic runners participated in this cross-sectional experimental trial. Participants ran in a randomised order under the two experimental (MP, FC) conditions and a control (C) condition on a treadmill (2.78 ms⁻¹) for 2 min, respectively. Plantar pressure was measured with the in-shoe plantar pressure measurement device pedar-x®-System and mean peak pressure averaged from ten steps in the forefoot (primary outcome) and total foot was analysed. Insole comfort was measured with the Insole Comfort Index (ICI, sum score 0–100) after each running trial. The primary outcome was tested using the Friedman test (α = 0.05). Secondary outcomes were analysed descriptively (mean ± SD, lower & upper 95%-CI, median and interquartile-range (IQR)).

Results

Peak pressure [kPa] in the forefoot was significantly lower wearing FC (281 ± 80, 95%-CI: 246–315) compared to both C (313 ± 69, 95%-CI: 283–343; p = .003) and MP (315 ± 80, 95%-CI: 280–350; p = .001). No significant difference was found between C and MP (p = .858). Peak pressures under the total foot were: C: 364 ± 82, 95%-CI: 328–399; MP: 357 ± 80, 95%-CI: 326–387; FC: 333 ± 81 95%-CI: 298–368. Median ICI sum scores were: C 50, MP 49, FC 64.

Conclusions

In contrast to the metatarsal pad orthosis, the forefoot cushioning orthosis achieved a significant reduction of peak pressure in the forefoot of recreational runners. Consequently, the use of a prefabricated forefoot cushioning orthosis should be favoured over a prefabricated orthosis with an incorporated metatarsal pad in recreational runners with normal height arches.

Electronic supplementary material

The online version of this article (doi:10.1186/s13047-016-0176-z) contains supplementary material, which is available to authorized users.

Adults with flexible pes planus and the approach to the prescription of customised foot orthoses in clinical practice: A clinical records audit

A clinical records audit of the University of South Australia's podiatry clinic clients attending in 2010 was undertaken to determine prevalence of symptomatic flexible pes planus, presenting reasons and treatment options most frequently used. Analysis of rearfoot measures (resting calcaneal stance position, subtalar joint range of motion) between those prescribed a vertical (heel) or inverted (heel) cast pour and a medial heel (Kirby) skive was undertaken. Of 223 clinical records audited, 50% (111/223) of clients were assessed with flexible pes planus, 77% (86/111) of clients with pes planus presented with back or lower limb pain and 58% (64/111) were prescribed customised foot orthoses. Of 42 prescriptions for customised foot orthoses audited; 64% (27/42) were prescribed a vertical (heel) cast pour, 36% (15/42) an inverted (heel) cast pour and 19% (8/42) received a medial heel (Kirby) skive. Those prescribed a medial heel (Kirby) skive had a more everted resting calcaneal stance position than those that were not (mean -8.6±2.8° vs. -5.5±3.4°, p=0.02). Those prescribed an inverted (heel) cast pour had a greater range of subtalar joint motion than those prescribed a vertical (heel) cast pour (median 36.0±10.0° vs. 29.0±5.0°, p=0.01).

Consensus-based recommendations of Australian podiatrists for the prescription of foot orthoses for symptomatic flexible pes planus in adults

BACKGROUND

Foot orthoses are commonly used for symptomatic flexible pes planus in adults. However, there are no clinical guidelines for the prescription of customised foot orthoses that are specific to this population. The aim of this study was to investigate prescription habits of Australian podiatrists for customised foot orthoses for symptomatic flexible pes planus in adults and to develop consensus-based practice recommendations for the prescription of these foot orthoses.

METHODS

A four round Delphi survey was undertaken with 24 podiatric experts to establish current use and rationale for individual prescription variables of customised foot orthoses for symptomatic flexible pes planus in adults. Round one determined prescription use (consensus) and rounds two, three and four determined the rationale for use (agreement) of prescription variables across the rearfoot, midfoot, forefoot, as well as accommodation and materials used. For consensus and agreement to be accepted, 70% of the respondents were required to use or agree on the rationale for use of individual prescription variables.

RESULTS

Consensus was reached in round one for two variables, choice of shell material (polyolefin) and when to prescribe a forefoot post balanced to perpendicular. In rounds two, three and four, agreement was reached for 52 statements related to the rationale for use of individual prescription variables, including when to prescribe: an inverted cast pour [heel in an inverted position], an inverted rearfoot post, a medial heel (Kirby) skive, minimal/maximum arch fill, a medial flange, a forefoot post and common orthotic accommodations.

CONCLUSION

This study found consensus or agreement for the use of several prescription variables for customised foot orthoses for symptomatic flexible pes planus in adults. The findings were used to develop the Foot orthosis Prescription Recommendations for symptOmatic flexible Pes planus in adults (FootPROP) proforma, to guide clinicians and researchers in the prescription of customised foot orthoses for this population.

Foot orthoses for adults with flexible pes planus: a systematic review

BACKGROUND

Foot orthoses are widely used in the management of flexible pes planus, yet the evidence to support this intervention has not been clearly defined. This systematic review aimed to critically appraise the evidence for the use of foot orthoses for flexible pes planus in adults.

METHODS

Electronic databases (Medline, CINAHL, Cochrane, Web of science, SportDiscus, Embase) were systematically searched in June 2013 for randomised controlled, controlled clinical and repeated measure trials where participants had identified flexible pes planus using a validated and reliable measure of pes planus and the intervention was a rigid or semi-rigid orthoses with the comparison being a no-orthoses (shoes alone or flat non-posted insert) condition. Outcomes of interest were foot pain, rearfoot kinematics, foot kinetics and physical function.

RESULTS

Of the 2,211 articles identified by the searches, 13 studies met the inclusion criteria; two were randomised controlled trials, one was a controlled trial and 10 were repeated measure studies. Across the included studies, 59 relevant outcome measures were reported with 17 calculated as statistically significant large or medium effects observed with use of foot orthoses compared to the no orthoses condition (SMD range 1.13 to -4.11).

CONCLUSIONS

No high level evidence supported the use of foot orthoses for flexible pes planus. There is good to moderate level evidence that foot orthoses improve physical function (medial-lateral sway in standing (level II) and energy cost during walking (level III)). There is low level evidence (level IV) that foot orthoses improve pain, reduce rearfoot eversion, alter loading and impact forces; and reduce rearfoot inversion and eversion moments in flexible pes planus. Well-designed randomised controlled trials that include appropriate sample sizes, clinical cohorts and involve a measure of symptom change are required to determine the efficacy of foot orthoses to manage adult flexible pes planus.

Clinical efficacy and cost-effectiveness of bespoke and prefabricated foot orthoses for plantar heel pain: a prospective cohort study

BACKGROUND

Plantar heel pain is a common reason for referral to podiatric practice, and one of the key interventions is the use of orthoses. The aim of the present study was to compare the clinical efficacy of bespoke, casted foot orthoses and prefabricated foot orthoses for plantar heel pain.

METHODS

People with plantar heel pain were included if, following initial assessment, foot orthoses were indicated and participants received either bespoke, casted foot orthoses or prefabricated semi-rigid orthoses (Powerstep™). Clinical efficacy was assessed at eight weeks using the Manchester Foot Pain and Disability Questionnaire (MFPDQ).

RESULTS

A total of 67 patients completed the trial and at baseline there were no appreciable differences in the two groups of patients in terms of the MFPDQ score; however, at eight weeks post-treatment both had significantly reduced foot pain and disability (both p < 0.0001). There was no significant difference in effectiveness between the bespoke or prefabricated orthoses. However, prefabricated devices were 38% cheaper per patient compared with the average costs of casted devices.

CONCLUSION

For most patients with plantar heel pain, prefabricated semi-rigid insoles such as the Powerstep™ devices used in the present trial provide short-term benefit equivalent to that of bespoke, casted foot orthoses, but at considerably reduced costs.

The use of 'off-the-shelf' foot orthoses in the reduction of foot symptoms in patients with early rheumatoid arthritis

BACKGROUND

Foot pain in patients diagnosed with early rheumatoid arthritis is common.

OBJECTIVES

To investigate effects of off-the-shelf foot orthoses on outcomes of swollen and tender joints, and pain, in patients with early rheumatoid arthritis.

METHODS

Thirty-five patients with painful and swollen foot joints were recruited. None had previously used foot orthoses or had contraindications to their use. Any patients with concomitant musculoskeletal disease, endocrine disorders, and neurological disease, were excluded. At baseline, participants were prescribed a customised off-the-shelf foot orthosis with chair-side modifications. Data was collected at baseline, three and six months. Foot pain (using Visual Analogue Scale) and the number of tender and swollen foot joints was measured.

RESULTS

There was a trend towards a reduction in the number of swollen and tender joints by 3 months with a further improvement by 6 months. Statistically (p<0.05) and clinically significant reductions in pain levels were also noted.

CONCLUSION

Patients diagnosed with early RA may benefit from using off-the-shelf foot orthoses with the majority of their pain reduction occurring within the first 3 months of use, but with some small further symptomatic improvement up to 6 months. There was a tendency to a reduction in swollen and tender joints although more studies are required to substantiate these findings.

Dose-response effects of customised foot orthoses on lower limb muscle activity and plantar pressures in pronated foot type

Customised foot orthoses (FOs) featuring extrinsic rearfoot posting are commonly prescribed for individuals with a symptomatic pronated foot type. By altering the angle of the posting it is purported that a controlled dose-response effect during the stance phase of gait can be achieved, however these biomechanical changes have yet to be characterised. Customised FOs were administered to participant groups with symptomatic pronated foot types and asymptomatic normal foot types. The electromyographic (EMG) and plantar pressure effects of varying the dose were measured. Dose was varied by changing the angle of posting from 6° lateral to 10° medial in 2° steps on customised devices produced using computer aided orthoses design software. No effects due to posting level were found for EMG variables. Significant group effects were seen with customised FOs reducing above knee muscle activity in pronated foot types compared to normal foot types (biceps femoris p=0.022; vastus lateralis p<0.001; vastus medialis p=0.001). Interaction effects were seen for gastrocnemius medialis and soleus. Significant linear effects of posting level were seen for plantar pressure at the lateral rearfoot (p=0.001), midfoot (p<0.001) and lateral forefoot (p=0.002). A group effect was also seen for plantar pressure at the medial heel (p=0.009). This study provides evidence that a customised FOs can provide a dose response effect for selected plantar pressure variables, but no such effect could be identified for muscle activity. Foot type may play an important role in the effect of customised orthoses on activity of muscles above the knee.

Dose-response effects of customised foot orthoses on lower limb kinematics and kinetics in pronated foot type

Despite the widespread use of customised foot orthoses (FOs) for the pronated foot type there is a lack of reliable information on the dose-response effect on lower limb mechanics. This study investigated these effects in subjects with normal and pronated foot types. Customised FOs were administered to 12 participants with symptomatic pronated foot type and 12 age and gender matched controls. A computer-aided design (CAD) software was used to design nine FOs per participant with dose incrementally changed by varying only the rearfoot post angle. This was done in 2° increments from 6° lateral to 10° medial posting. A 3D printing method was used to manufacture the FOs. Quantification of the dose-response effect was performed using three-dimensional gait analyses for selected rearfoot and knee kinematics and kinetics. Under these experimental conditions, significant and linear effects of posting were seen for the peak (p<0.001) and mean (p<0.001) rearfoot eversions, peak (p=0.003) and mean (p<0.001) ankle eversion moments and peak (p=0.017) and mean (p=0.005) knee adduction moment variables. Group effects were observed for the peak (p=0.007) and mean (p=0.007) forefoot abduction and for the peak (p=0.007) knee adduction moment. A significant interaction between posting and group was seen for internal tibial rotation (p=0.004). These data indicate that a dose-response effect, with a linear trend for both the rearfoot and knee, exists for customised FOs used to treat pronated foot type.

Embracing additive manufacture: implications for foot and ankle orthosis design

Background

The design of foot and ankle orthoses is currently limited by the methods used to fabricate the devices, particularly in terms of geometric freedom and potential to include innovative new features. Additive manufacturing (AM) technologies, where objects are constructed via a series of sub-millimetre layers of a substrate material, may present the opportunity to overcome these limitations and allow novel devices to be produced that are highly personalised for the individual, both in terms of fit and functionality.

Two novel devices, a foot orthosis (FO) designed to include adjustable elements to relieve pressure at the metatarsal heads, and an ankle foot orthosis (AFO) designed to have adjustable stiffness levels in the sagittal plane, were developed and fabricated using AM. The devices were then tested on a healthy participant to determine if the intended biomechanical modes of action were achieved.

Results

The adjustable, pressure relieving FO was found to be able to significantly reduce pressure under the targeted metatarsal heads. The AFO was shown to have distinct effects on ankle kinematics which could be varied by adjusting the stiffness level of the device.

Conclusions

The results presented here demonstrate the potential design freedom made available by AM, and suggest that it may allow novel personalised orthotic devices to be produced which are beyond the current state of the art.