Point of care ultrasound imaging as a wound assessment tool in diabetic foot ulcers: a case series.

Foot ulceration is a common and devastating complication of diabetes. Traditionally, diabetic foot ulcers (DFU) are managed by multidisciplinary teams in tertiary hospital settings. Wound management decisions are based largely on visual observations at the point of care, using rudimentary evaluation of superficial tissues, such as wound tracings and photography combined with expert knowledge of the treating practitioners. Imaging based methods of assessment, such as X-ray, magnetic resonance imaging, scintigraphy or computed tomography are able to more comprehensively categorise wounds and to determine whether re-epithelialised wounds are in fact healed. Ultrasound has been advocated by the World Health Organization for the monitoring of chronic diseases and for screening because it is considered low risk, comfortable for patients and low cost. It can be performed in real time at the point of care and using B-mode, Doppler and elastography has the potential to provide clinically meaningful information for monitoring the status of hard-to-heal wounds, but to date this imaging technique has not been exploited in this field. This case series highlights the utility of diagnostic musculoskeletal ultrasound as an adjunct to traditional wound assessment that can provide diagnostically meaningful information to assist in clinical decision making. Future research will be needed to determine if routine incorporation of ultrasound in wound assessment improves patient outcomes.

Health professional views on the assessment and management of foot problems in people with psoriatic arthritis in Australia and New Zealand: a qualitative investigation.

BACKGROUND: Active foot disease persists in a high proportion of people with psoriatic arthritis despite the availability of pharmacological and non-pharmacological interventions to modify the course of the disease. Limited information exists on the provision of health care for foot disease in psoriatic arthritis. The objective of this study was to explore the views of health professionals on the assessment and management of people with psoriatic arthritis-related foot involvement. METHODS: Convenience sampling was used to recruit health professionals working in rheumatology outpatient clinics in Sydney, Australia and Auckland, New Zealand. Three focus groups were undertaken to explore the views and experiences of health professionals on the assessment and management of foot problems in people with psoriatic arthritis. All interviews were audio-recorded and transcribed verbatim. Qualitative data was analysed using a constant comparative analytic approach to identify themes. RESULTS: A total of seventeen health professionals participated including rheumatologists, podiatrists and a physiotherapist. Key themes derived from the focus groups suggest that health professionals perceived that people with psoriatic arthritis-related foot problems experience suboptimal management from symptom onset, to diagnosis and treatment. Frustration was expressed throughout discussions relating to lack of appropriate training and expertise required for the specialised management of foot problems typically encountered with psoriatic arthritis and poor access for patients to specialist podiatry services. CONCLUSIONS: This study provides new insight into the perspectives of health professionals on the management of foot problems related to psoriatic arthritis. Deficiencies in the diagnosis, assessment and treatment of foot problems were revealed. To meet the foot health needs of people with psoriatic arthritis, reducing diagnostic delay, improving knowledge and awareness about the disease among people with psoriatic arthritis and health professionals, and increasing specialist podiatry service provision may be required.

Metatarsophalangeal joint pain in psoriatic arthritis: a cross-sectional study.

OBJECTIVE: The aim of this study was to identify independent predictors of pain at the MTP joints in patients with PsA. METHODS: Thirty-four consecutive patients with PsA (mean age 45.3 years, 65% female, mean disease duration 9.9 years) and 22 control participants (mean age 37.9 years, 64% female) underwent clinical and US examination to determine the presence of pain, swelling, synovitis, erosions, effusions and submetatarsal bursae at the MTP joints. Mean barefoot peak plantar pressures were determined at each MTP joint. Levels of pain, US-determined pathology and peak pressures were compared between groups. Binary logistic regression was used to identify demographic, clinical examination-derived, US-derived and plantar pressure predictors of pain at the MTP joints in the PsA group. RESULTS: The presence of pain, deformity, synovitis, erosions (P < 0.001) and submetatarsal bursae and peak plantar pressure at MTP 3 (P < 0.05) were significantly higher in the PsA group. MTP joint pain in PsA was independently predicted by high BMI, female gender and the presence of joint subluxation, synovitis and erosion. CONCLUSION: These results suggest local inflammatory and structural factors, together with systemic factors (gender, BMI), are predominantly responsible for painful MTP joints in PsA, with no clear role for plantar pressure characteristics.

Kinematic, kinetic and electromyographic response to customized foot orthoses in patients with tibialis posterior tenosynovitis, pes plano valgus and rheumatoid arthritis.

OBJECTIVE: To describe the effect of customized foot orthoses (FOs) on the kinematic, kinetic and EMG features in patients with RA, tibialis posterior (TP) tenosynovitis and associated pes plano valgus. METHODS: Patients with RA and US-confirmed tenosynovitis of TP underwent gait analysis, including three-dimensional (3D) kinematics, kinetics, intramuscular EMG of TP and surface EMG of tibialis anterior, peroneus longus, soleus and medial gastrocnemius. Findings were compared between barefoot and shod with customized FO conditions. RESULTS: Ten patients with RA with a median (range) disease duration of 3 (1-18) years were recruited. Moderate levels of foot pain and foot-related impairment and disability were present with moderately active disease states. Altered timing of the soleus (P = 0.05) and medial gastrocnemius (P = 0.02) and increased magnitude of tibialis anterior (P = 0.03) were noted when barefoot was compared with shod with FO. Trends were noted for reduced TP activity in the contact period (P = 0.09), but this did not achieve statistical significance. Differences in foot motion characteristics were recorded for peak rearfoot eversion (P = 0.01), peak rearfoot plantarflexion (P < 0.001) and peak forefoot abduction (P = 0.02) in the shod with FOs compared with barefoot conditions. No differences in kinetic variables were recorded. CONCLUSION: This study has demonstrated, for the first time, alterations in muscle activation profiles and foot motion characteristics in patients with RA, pes plano valgus and US-confirmed TP tenosynovitis in response to customized FOs. Complex adaptations were evident in this cohort and further work is required to determine whether these functional alterations lead to improvements in patient symptoms.

Disabling foot pain and its impact on daily living among people with psoriatic arthritis in Singapore: a cross-sectional observational investigation.

BACKGROUND: Psoriatic Arthritis (PsA)-related foot involvement has been shown to have a profound impact on daily functioning, with most studies having focused on predominantly Caucasian populations. The aim was to describe disabling foot pain (DFP) and its impact on daily living in PsA in Singapore. METHODS: A cross-sectional, retrospective study was conducted using clinical data collected during a single-visit to a rheumatology clinic in Singapore. Records for adults with physician-diagnosed PsA were reviewed for sociodemographic information, disease characteristics, global disease activity and burden. Foot-specific measures included clinical assessment and the Manchester Foot Pain and Disability Index used to define DFP and evaluate between-group differences. RESULTS: Forty-two participants with PsA (83% female, 57% Chinese, 31% Malay, 9.5% Indian, mean (SD) age 54-years (16)) attended the rheumatology clinic over the study-period. The median (IQR) disease duration was 2-years (11) and all were taking current DMARDs. Global disease measures demonstrated mild-to-moderate global disease activity and mild functional impairment, and were significantly higher in those with DFP. Despite 90% reporting to be coping well with their condition, self-care and having emotional support (n = 38), this study sample demonstrated high levels of anxiety/depression (29%), sleep disturbance (34%) and fatigue (24%), and a lack of disease- and drug-specific knowledge (64%). Further management was indicated for medication adherence counselling (48%), occupational therapy (43%), physiotherapy (36%) and podiatry (30%). Nearly half had current foot pain with 40% reporting DFP (n = 17), which caused significantly greater difficulty walking 3 km than those without DFP (p < 0.05). Rearfoot enthesitis (plantar fasciitis, Achilles enthesitis) was the most common cause of DFP (67%) with pain lasting longer than 1-year. 72% were overweight or obese, with a high proportion not engaging in any cardiovascular exercise (70%). Three of 42 participants had previously seen a podiatrist. CONCLUSIONS: People with DFP in PsA experience more severe global disease activity, reduced mobility and higher levels of negative impact on their daily lives in Singapore. In the absence of working in a multidisciplinary-team, there is value in comprehensive assessments that have potential to capture a holistic view of personal impact and improve person-centred care in PsA.

Development of a national survey on foot involvement among people with psoriatic arthritis in Australia using a best practice approach: a survey development protocol.

BACKGROUND: Limited research to date has defined the nature and extent of foot involvement in a psoriatic arthritis-specific population in Australia and the scale of the problem remains unclear. Survey research provides the ideal opportunity to sample a large population over a wide geographical area. Although quality criteria for survey research have been developed, research shows that adherence is low and that survey studies are poorly reported in peer-reviewed survey articles, which limits the ability to inform future survey design. The objective of this paper was to develop a national survey about foot involvement in people with psoriatic arthritis using a best practice approach. This is a methods paper for the development of survey research. METHODS: A systematic, multi-stage process of survey development was undertaken, which comprised 3 phases: 1) the generation of the conceptual framework and survey content; 2) the development of the survey and pre-testing and 3) development of the survey dissemination strategy. A survey best practice approach was adopted using iterative pre-testing techniques, which included; cognitive debriefing, cultural sensitivity review, survey design expert validation, subject expert validation and pilot testing. Targeted postal and online survey dissemination strategies were developed a priori to optimise the response rates anticipated. RESULTS: A 59-item survey with 8 sections was developed. Findings demonstrated a high survey response (n = 649), high data completeness (83% of respondents reached the end of the survey) and low rates of missing data (below 5% for 95% of respondents). Extensive survey pre-testing among the target population, health professionals and experts improved the overall quality, content validity, functioning and representativeness of the survey instrument, which optimised potential response rates. Clear audit trails that mapped the analytical process at each stage substantiated the rigour of the survey development methods. Robust strategies for sampling, survey dissemination and community engagement were deemed to have made a powerful contribution to response rates and the scale of information collected. CONCLUSIONS: Robust patient-centred methods in survey design were used to create a novel, high-quality survey to comprehensively evaluate psoriatic arthritis-related foot involvement. Transparent and precise description of the survey design and dissemination methods provides useful information to other researchers embarking on survey design in healthcare.

Linking the effect of psoriatic arthritis-related foot involvement to the Leeds Foot Impact Scale using the International Classification for Functioning, Disability and Health: a study to assess content validity.

BACKGROUND: Previous research to describe the impact of foot involvement in psoriatic arthritis has used the Leeds Foot Impact Scale in Rheumatoid Arthritis (LFIS-RA) in the current absence of any psoriatic arthritis foot-specific tools. However, the LFIS-RA is a rheumatoid arthritis disease-specific outcome measure and its content validity for evaluating the experiences of people with psoriatic arthritis-related foot involvement is unknown. The study objective was to determine the content validity of the LFIS-RA for assessing people with psoriatic arthritis, using the International Classification of Functioning, Disability and Health (ICF) as the frame of reference. METHOD: Concepts within each item of the LFIS-RA were linked to the best-matched ICF categories using established linking rules, which enable a systematic and standardised linking process. All concepts were independently linked to the ICF by 2 investigators with different professional backgrounds, which included occupational therapy and podiatry. The list of ICF categories derived from previous research that pertained to the foot in psoriatic arthritis was then compared with the ICF categories linked to the LFIS-RA. The comparison was undertaken in order to determine the extent to which concepts important and relevant to people with psoriatic arthritis-related foot involvement were addressed. RESULTS: Thirty-five distinct ICF categories were linked to the LFIS-RA, which related to body functions (44%), activities and participation (35%), environmental factors (16%) and body structure (5%). In comparison with the ICF categories derived from concepts of the foot in psoriatic arthritis previously defined, the LFIS-RA provided coverage of key constructs including pain, functioning, daily activities, footwear restrictions and psychological impact. Other concepts of importance in psoriatic arthritis such as skin and toenail involvement, self-management and paid employment were not addressed in the LFIS-RA. CONCLUSION: Content validity of the LFIS-RA to determine the impact of foot functional impairments and disability in people with psoriatic arthritis was not supported by the results of this study. Future work should consider the development of a psoriatic arthritis foot-specific patient reported outcome measure, using the LFIS-RA as an important foundation.

Linking the patient experience of foot involvement related to psoriatic arthritis to the International Classification of Functioning, Disability and Health.

OBJECTIVE: The aim was to categorize the patient experience of PsA-related foot involvement by linking it to the International Classification of Functioning, Disability and Health (ICF) framework. METHODS: Concepts, obtained from a previous qualitative investigation of people with PsA and health professionals into their perspective of PsA-related foot involvement, were linked to the full version of the ICF classification. Concepts were linked to the most appropriate ICF category using established linking rules, which enable a systematic and standardized linking process. All concepts were linked independently to the ICF by two investigators, followed by a third investigator for adjudication. The professional backgrounds of the investigators included occupational therapy and podiatry. RESULTS: More than 100 distinct ICF categories were linked to the interview concepts. The most represented ICF category was body functions (35%), followed by environmental factors (31%), activities and participation (19%) and body structure (15%). Concepts that could not be linked to the ICF were related to coping, aspects of time and knowledge. Health professionals identified a greater proportion of body functions and fewer activity and participation categories compared with patients, indicating a possible mismatch of key concerns. Interdisciplinary group analysis demonstrated merit. CONCLUSION: A list of ICF categories was generated, defining aspects of functioning important and relevant to the impact of PsA-related foot involvement. Despite the localized anatomical focus of this study, the effect of foot problems in PsA was linked to all components of the ICF, confirming the profound impact on functioning and daily life.

Perspectives of patients and health professionals on the experience of living with psoriatic arthritis-related foot problems: a qualitative investigation.

OBJECTIVE: The aim of the study was to explore how foot problems impact on the lives of people with psoriatic arthritis by interviewing patients and health professionals. METHOD: Participants were recruited from outpatient rheumatology clinics in Sydney, Australia, and in Auckland, New Zealand, using a convenience sampling strategy. People with psoriatic arthritis were asked questions in semi-structured interviews about their foot problems and the impact they have on daily living until qualitative data saturation. Focus groups were undertaken with health professionals to explore their understanding of the patient experience of psoriatic arthritis-related foot problems. All interviews were audio-recorded and transcribed verbatim. Constant comparative analysis was used to identify emerging themes from the data. RESULTS: Twenty-one people with psoriatic arthritis-related foot problems and 17 health professionals participated. Three overarching key themes were derived from patients and health professionals: (1) structural and functional foot manifestations, (2) impact on daily life leading to social withdrawal and reduced work productivity and (3) mediating factors influencing the severity of impact from foot problems on their lives such as social support, self-management strategies and experiences of health care. CONCLUSION: Foot problems caused functional disability and altered self-concept, which lead to a cascade of social, economic and psychological consequences. People with foot problems contend with profound disruption to their functioning and life roles. Whilst health professionals recognised the functional and visual impact that foot problems have on daily life, the emotional burden may be under-appreciated. Future work to determine the scale and types of foot problems in psoriatic arthritis is required.

Characterising the clinical and biomechanical features of severely deformed feet in rheumatoid arthritis.

PURPOSE: Foot deformity is a well-recognised impairment in patients with rheumatoid arthritis (RA) which results in functional disability. Deformity can occur at the rearfoot, midfoot, forefoot or in combination and the impact that site-specific foot deformities has on functional disability is largely unknown. The aim of this study was to describe the clinical and biomechanical characteristics of patients with severe rearfoot, forefoot or combined deformities and determine localised disease impact. METHODS: Twenty-eight RA patients with severe forefoot (FF group n=12), rearfoot (RF group n=10) or combined deformities (COMB group n=6) were recruited. Each patient underwent 3D gait analysis and plantar pressure measurements. Localised disease impact and foot-specific disease activity were determined using the Leeds Foot Impact Scale and clinical examination respectively. Comparison was made against a normative control group (n=53). RESULTS: Patients in the COMB group walked slowest and the double-support time was longer in the RF and COMB groups compared to those in the FF group. Patients in the RF and COMB group had higher levels of foot-related disability and demonstrated excessive rearfoot eversion and midfoot collapse compared to those in the FF group. Forefoot deformity was associated with reduced toe contact, high forefoot pressures and delayed heel lift. CONCLUSIONS: Abnormal gait patterns were identified and were distinguishable among those patients with predominantly forefoot, rearfoot or combined foot deformity.

Methodological considerations for a randomised controlled trial of podiatry care in rheumatoid arthritis: lessons from an exploratory trial.

BACKGROUND: Whilst evidence exists to support the use of single treatments such as orthoses and footwear, the effectiveness of podiatry-led care as a complex intervention for patients with rheumatoid arthritis (RA) related foot problems is unknown. The aim of this study was to undertake an exploratory randomised controlled parallel arm clinical trial (RheumAFooT) to inform the design and implementation of a definitive trial and to understand the potential benefits of this care. METHODS: Patients with a definite diagnosis of RA, stable drug management 3 months prior to entry, and a current history of foot problems (pain, deformity, stiffness, skin or nail lesions, or footwear problems) were recruited from a hospital outpatient rheumatology clinic and randomised to receive 12 months of podiatry treatment or no care. The primary outcome was change in foot health status using the impairment/footwear (LFISIF) and activity limitation/participation restriction (LFISAP) subscales of the Leeds Foot Impact Scale. Disease Activity Score (DAS), Health Assessment Questionnaire (HAQ) score and walking speed (m/s) were also recorded. RESULTS: Of the 80 patients identified, 64 patients were eligible to participate in the pilot and 34 were recruited. 16 patients were randomised to receive podiatry led foot care and 18 received no care. Against a backdrop of stable disease (DAS and HAQ scores), there was a statistically significant between group difference in the change in foot health status for foot impairment (LFISIF) but not activity/participation (LFISAP) or function (walking speed) over 12 months. In the podiatry arm, 1 patient declined treatment following randomisation (did not want additional hospital visits) and 3 self-withdrew (lost to follow-up). Patients received an average of 3 consultations for assessment and treatment comprising routine care for skin and nail lesions (n = 3), foot orthoses (n = 9), footwear referral to the orthotist (n = 5), and ultrasound guided intra-articular steroid injection (n = 1). CONCLUSION: In this exploratory trial patients were difficult to recruit (stable drug management and co-morbid disease) and retain (lack of benefit/additional treatment burden) but overall the intervention was safe (no adverse reactions). Twelve months of podiatry care maintained but did not improve foot health status. These observations are important for the design and implementation of a definitive randomised controlled trial. TRIAL REGISTRATION: ISRCTN: 01982076.

Regionalised centre of pressure analysis in patients with rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis patients alter their gait pattern to compensate for painful foot symptoms. The centre of pressure may be a useful indicator of these altered loading patterns. Our purpose was to undertake a comparison of the regionalised duration and velocity of the centre of pressure between rheumatoid arthritis patients with foot impairments and healthy able-bodied adults. METHODS: The progression of the centre of pressure through the foot, heel, midfoot, forefoot and toe regions was measured using an EMED-ST pressure platform. Patients walked at self selected cadence. Variables analysed were the average and maximum velocity and the duration of the centre of pressure (as % stance). RESULTS: In comparison with able-bodied adults, rheumatoid arthritis patients had a statistically significant decrease in the average velocity of the centre of pressure in the total foot (P<0.001), heel (P=0.001) and midfoot (P<0.001) regions. The maximum velocity of the centre of pressure was slower in rheumatoid arthritis patients in only the midfoot region (P=0.002). During stance, the duration of the centre of pressure was longer in the midfoot (P<0.001) and shorter in the forefoot (P=0.001) in the rheumatoid arthritis patients. INTERPRETATION: Alteration of the foot loading patterns in patients with rheumatoid arthritis can be characterised by changes to the centre of pressure patterns. Off-loading the painful and deformed forefoot was a characteristic feature in this patient cohort.

The impact of rheumatoid arthritis on foot function in the early stages of disease: a clinical case series.

BACKGROUND: Foot involvement occurs early in rheumatoid arthritis but the extent to which this impacts on the structure and function leading to impairment and foot related disability is unknown. The purpose of this study was to compare clinical disease activity, impairment, disability, and foot function in normal and early rheumatoid arthritis (RA) feet using standardised clinical measures and 3D gait analysis. METHODS: Twelve RA patients with disease duration < or =2 years and 12 able-bodied adults matched for age and sex underwent 3D gait analysis to measure foot function. Disease impact was measured using the Leeds Foot impact Scale (LFIS) along with standard clinical measures of disease activity, pain and foot deformity. For this small sample, the mean differences between the groups and associated confidence intervals were calculated using the t distribution RESULTS: Moderate-to-high foot impairment and related disability were detected amongst the RA patients. In comparison with age- and sex-matched controls, the patients with early RA walked slower (1.05 m/s Vs 1.30 m/s) and had a longer double-support phase (19.3% Vs 15.8%). In terminal stance, the heel rise angle was reduced in the patients in comparison with normal (-78.9 degrees Vs -85.7 degrees). Medial arch height was lower and peak eversion in stance greater in the RA patients. The peak ankle plantarflexion power profile was lower in the patients in comparison with the controls (3.4 W/kg Vs 4.6 W/kg). Pressure analysis indicated that the RA patients had a reduced lesser toe contact area (7.6 cm2 Vs 8.1 cm2), elevated peak forefoot pressure (672 kPa Vs 553 kPa) and a larger mid-foot contact area (24.6 cm2 Vs 19.4 cm2). CONCLUSION: Analysis detected small but clinically important changes in foot function in a small cohort of RA patients with disease duration <2 years. These were accompanied by active joint disease and impairment and disability.

The relationship between hallux dorsiflexion and ankle joint complex frontal plane kinematics: a preliminary study.

BACKGROUND: It has been suggested that the function of the first metatarsophalangeal joint may be related to the motion of the ankle joint complex. OBJECTIVE: This study explored the relationship between ankle joint complex and first metatarsophalangeal joint motion during gait in a group of 14 who demonstrated clinically limited passive hallux dorsiflexion in quiet standing (cases), and 15 matched controls. METHOD: An electromagnetic tracking system was used to measure the ankle joint complex frontal plane motion and first metatarsophalangeal joint sagittal plane motion during gait, in both cases and controls. The case group was then evaluated further to investigate the effect of an orthosis on first metatarsophalangeal joint motion. FINDINGS: The correlation between maximum ankle joint complex eversion and maximum first metatarsophalangeal joint dorsiflexion during gait was r=0.471. Within the case group, maximum rearfoot eversion was reduced following the application of the orthoses, but there was no change in sagittal first metatarsophalangeal joint rotations. INTERPRETATION: The relationship between maximum ankle joint complex eversion and first metatarsophalangeal joint dorsiflexion kinematics found in this study was moderate, and decreasing maximum ankle joint complex eversion with an orthosis did not result in any increase in first metatarsophalangeal joint dorsiflexion during gait in patients with functional first metatarsophalangeal joint limitation. These results do not support the assumption that ankle joint complex eversion influences first metatarsophalangeal joint motion substantially.

Measurement of functional heel pad behaviour in-shoe during gait using orthotic embedded ultrasonography.

The ability to measure the functional behaviour of the plantar heel pad is clinically relevant in dystrophic or pathological heel conditions and may help to inform the design and development of interventions that attempt to restore normal function. In this study we present a novel technique which utilises orthotic heel inserts with an embedded ultrasound (US) transducer to allow the functional, dynamic behaviour of the heel pad to be measured in-shoe during gait. The aim of this study was to demonstrate feasibility of the technique, determine the reproducibility of measurements, and to compare the effects of two orthotic inserts: (i) a flat orthotic heel raise and (ii) a contoured heel cup insert on the behaviour of the heel pad during gait. Dynamic compression of the heel pads of 16 healthy participants was recorded during treadmill walking and combined with plantar pressure measurements to allow stiffness and energy disappation ratio (EDR) to be estimated. Inter-session reliability of the US measurements was found to be excellent (ICC2,1=0.94-0.95), as was inter-rater reliability (ICC2,1=0.89). Use of the heel cup insert significantly reduced the maximum compression of the heel pad (p<0.0001) as well as the overall stiffness of the pad (p<0.001). There was no change in EDR (p=0.949). In-shoe embedded US is a reliable method to establish person-specific functional geometry of plantar soft tissues. Use of a contoured heel cup reduces the compression of the mid portion of the heel pad.

An ultrasound based non-invasive method for the measurement of intrinsic foot kinematics during gait.

Soft tissue artefact (STA) and marker placement variability are sources of error when measuring the intrinsic kinematics of the foot. This study aims to demonstrate a non-invasive, combined ultrasound and motion capture (US/MC) technique to directly measure foot skeletal motion. The novel approach is compared to a standard motion capture protocol. Fourteen participants underwent instrumented barefoot analysis of foot motion during gait. Markers were attached to foot allowing medial longitudinal arch angle and navicular height to be determined. For the US/MC technique, the navicular marker was replaced by an ultrasound transducer which was secured to the foot allowing the skeletal landmark to be imaged. Ultrasound cineloops showing the location of the navicular tuberosity during the walking trials were synchronised with motion capture measurements and markers mounted on the probe allowed the true position of the bony landmark to be determined throughout stance phase. Two discrete variables, minimum navicular height and maximum MLA angle, were compared between the standard and US/MC protocols. Significant differences between minimum navicular height (P=0.004, 95% CI (1.57, 6.54)) and maximum medial longitudinal arch angle (P=0.0034, 95% CI (13.8, 3.4)) were found between the measurement methods. The individual effects of STA and marker placement error were also assessed. US/MC is a non-invasive technique which may help to provide more accurate measurements of intrinsic foot kinematics.

Dynamic plantar loading index detects altered foot function in individuals with rheumatoid arthritis but not changes due to orthotic use.

BACKGROUND: Altered foot function is common in individuals with rheumatoid arthritis. Plantar pressure distributions during gait are regularly assessed in this patient group; however, the association between frequently reported magnitude-based pressure variables and clinical outcomes has not been clearly established. Recently, a novel approach to the analysis of plantar pressure distributions throughout stance phase, the dynamic plantar loading index, has been proposed. This study aimed to assess the utility of this index for measuring foot function in individuals with rheumatoid arthritis. METHODS: Barefoot plantar pressures during gait were measured in 63 patients with rheumatoid arthritis and 51 matched controls. Additionally, 15 individuals with rheumatoid arthritis had in-shoe plantar pressures measured whilst walking in standardized footwear for two conditions: shoes-only; and shoes with prescribed custom foot orthoses. The dynamic plantar loading index was determined for all participants and conditions. Patient and control groups were compared for significant differences as were the shod and orthosis conditions. FINDINGS: The patient group was found to have a mean index of 0.19, significantly lower than the control group's index of 0.32 (p>0.001, 95% CI [0.054, 0.197]). No significant differences were found between the shoe-only and shoe plus orthosis conditions. The loading index was found to correlate with clinical measures of structural deformity. INTERPRETATION: The dynamic plantar loading index may be a useful tool for researchers and clinicians looking to objectively assess dynamic foot function in patients with rheumatoid arthritis; however, it may be unresponsive to changes caused by orthotic interventions in this patient group.

Tibialis posterior tenosynovitis and associated pes plano valgus in rheumatoid arthritis: electromyography, multisegment foot kinematics, and ultrasound features.

OBJECTIVE: To compare electromyographic (EMG), kinematic, kinetic, and ultrasound (US) features of pes plano valgus associated with US-confirmed tibialis posterior (TP) tenosynovitis in rheumatoid arthritis (RA) and healthy control subjects. METHODS: In this cross-sectional study, patients with RA and US-confirmed tenosynovitis of TP underwent gait analysis, including 3-dimensional kinematics, kinetics, and intramuscular EMG of TP, and findings were compared with a group of healthy individuals. The RA group also underwent B mode and power Doppler US scanning of the TP tendon to assess and score levels of pathology. RESULTS: Ten patients with RA, median (range) disease duration of 3 years (1-18 years), and 5 control subjects were recruited. Compared to control subjects, the RA patients walked slower and presented with moderate levels of foot-related disability. The mean ± SD Disease Activity Score in 28 joints was 4.6 ± 1.6. Increased magnitude of TP activity was recorded in the RA group compared to controls in the contact period of stance (P = 0.007), in conjunction with reduced ankle joint power (P = 0.005), reduced navicular height in the medial arch (P = 0.023), and increased forefoot dorsiflexion (P = 0.027). TP tendon thickening, fluid, and power Doppler signal were observed in the majority of patients. CONCLUSION: This study has demonstrated, for the first time, increased TP EMG activity in the presence of US-confirmed TP tenosynovitis in RA. Altered muscle function occurred in conjunction with suboptimal mechanics, moderate levels of tendon pathology, and active disease. Targeted therapy may be warranted to reduce inflammation and mechanically off-load diseased tendon states.

Reliability study of tibialis posterior and selected leg muscle EMG and multi-segment foot kinematics in rheumatoid arthritis associated pes planovalgus.

OBJECTIVE: To determine within- and between-day reliability characteristics of electromyographic (EMG) activity patterns of selected lower leg muscles and kinematic variables in patients with rheumatoid arthritis (RA) and pes planovalgus. METHODS: Five patients with RA underwent gait analysis barefoot and shod on two occasions 1 week apart. Fine-wire (tibialis posterior [TP]) and surface EMG for selected muscles and 3D kinematics using a multi-segmented foot model was undertaken barefoot and shod. Reliability of pre-determined variables including EMG activity patterns and inter-segment kinematics were analysed using coefficients of multiple correlation, intraclass correlation coefficients (ICC) and the standard error of the measurement (SEM). RESULTS: Muscle activation patterns within- and between-day ranged from fair-to-good to excellent in both conditions. Discrete temporal and amplitude variables were highly variable across all muscle groups in both conditions but particularly poor for TP and peroneus longus. SEMs ranged from 1% to 9% of stance and 4% to 27% of maximum voluntary contraction; in most cases the 95% confidence interval crossed zero. Excellent within-day reliability was found for the inter-segment kinematics in both conditions. Between-day reliability ranged from fair-to-good to excellent for kinematic variables and all ICCs were excellent; the SEM ranged from 0.60° to 1.99°. CONCLUSION: Multi-segmented foot kinematics can be reliably measured in RA patients with pes planovalgus. Serial measurement of discrete variables for TP and other selected leg muscles via EMG is not supported from the findings in this cohort of RA patients. Caution should be exercised when EMG measurements are considered to study disease progression or intervention effects.