Gillian Crofts

Ultrasound evaluation of foot muscles and plantar fascia in pes planus

BACKGROUND Multiple intrinsic and extrinsic soft tissue structures that apply forces and support the medial longitudinal arch have been implicated in pes planus. These structures have common functions but their interaction in pes planus is not fully understood. The aim of this study was to compare the cross-sectional area (CSA) and thickness of the intrinsic and extrinsic foot muscles and plantar fascia thickness between normal and pes planus feet. METHODS Forty-nine adults with a normal foot posture and 49 individuals with pes planus feet were recruited from a university population. Images of the flexor digitorum longus (FDL), flexor hallucis longus (FHL), peroneus longus and brevis (PER), flexor hallucis brevis (FHB), flexor digitorum brevis (FDB) and abductor hallucis (AbH) muscles and the plantar fascia were obtained using a Venue 40 ultrasound system with a 5-13 MHz transducer. RESULTS The CSA and thickness of AbH, FHB and PER muscles were significantly smaller (AbH -12.8% and -6.8%, FHB -8.9% and -7.6%, PER -14.7% and -10%), whilst FDL (28.3% and 15.2%) and FHL (24% and 9.8%) were significantly larger in the pes planus group. The middle (-10.6%) and anterior (-21.7%) portions of the plantar fascia were thinner in pes planus group. CONCLUSION Greater CSA and thickness of the extrinsic muscles might reflect compensatory activity to support the MLA if the intrinsic foot muscle function has been compromised by altered foot structure. A thinner plantar fascia suggests reduced load bearing, and regional variations in structure and function in feet with pes planus.

Reliability of ultrasound for measurement of selected foot structures

BACKGROUND Understanding the relationship between the lower leg muscles, foot structures and function is essential to explain how disease or injury may relate to changes in foot function and clinical pathology. The aim of this study was to investigate the inter-operator reliability of an ultrasound protocol to quantify features of: rear, mid and forefoot sections of the plantar fascia (PF); flexor hallucis brevis (FHB); flexor digitorum brevis (FDB); abductor hallucis (AbH); flexor digitorum longus (FDL); flexor hallucis longus (FHL); tibialis anterior (TA); and peroneus longus and brevis (PER). METHODS A sample of 6 females and 4 males (mean age 29.1 ± 7.2 years, mean BMI 25.5 ± 4.8) was recruited from a university student and staff population. Scans were obtained using a portable Venue 40 musculoskeletal ultrasound system (GE Healthcare UK) with a 5-13 MHz wideband linear array probe with a 12.7 mm × 47.1mm footprint by two operators in the same scanning session. RESULTS Intraclass Correlation Coefficients (ICC) values for muscle thickness (ICC range 0.90-0.97), plantar fascia thickness (ICC range 0.94-0.98) and cross sectional muscle measurements (ICC range 0.91-0.98) revealed excellent inter-operator reliability. The limits of agreement, relative to structure size, ranged from 9.0% to 17.5% for muscle thickness, 11.0-18.0% for plantar fascia, and 11.0-26.0% for cross sectional area measurements. CONCLUSIONS The ultrasound protocol implemented in this work has been shown to be reliable. It therefore offers the opportunity to quantify the structures concerned and better understand their contributions to foot function.

‘Focus on feet’ – the effects of systemic lupus erythematosus: a narrative review of the literature

Background The manifestations of systemic lupus erythematosus (SLE) vary between individuals, from the severe and life-threatening renal and central nervous system involvement, to the involvement of skin, musculoskeletal and vascular system, and the complications of infection influencing the quality of life. However, as specific manifestations affecting the lower limb are perceived as receiving little focus, the purpose of this narrative literature review is to identify the specific factors associated with SLE that may have implications for lower limb and foot morbidity. Method A structured search of databases was conducted. The inclusion was restricted to publications in the English language, those that specifically investigate the feet as affected with SLE. No restriction on year of publication was imposed to reduce publication bias and to capture as many publication in relation to feet. Results Eleven papers fulfilled the inclusion criteria. There were seven additional papers that made observations related to the articular or vascular complications of the feet. This narrative review provides some information on how SLE affects the lower limb and foot in relation to the musculoskeletal and vascular systems. However, there is a lack of literature that specifically focuses on all the manifestations of SLE and the complications associated with its management. Discussion There are indications that SLE affects lower limb and foot morbidity but the scale of these problems is unclear and this is partly because of the absence of research and the lack of a ‘gold standard’ framework for the assessment of the lower limb and foot. In addition to clinical foot health assessment, ultrasonography may be a useful alternative to plain film radiography or magnetic resonance imaging (MRI) in capturing the extent of articular and extra-articular manifestations. Further, the Ankle Brachial Pressure Index (ABPI) may be useful in identifying those with atherosclerosis and ischaemia. Conclusion There are indications that SLE affects lower limb and foot morbidity but the scale of these problems and effective management of them is unclear. Therefore, further research is warranted in order to better understand the impact of SLE on the foot and lower limb and its impact on quality of life.

In vivo measurement of the biomechanical properties of plantar soft tissues under simulated gait conditions

Background In vivo biomechanical properties of plantar soft tissues have been assessed via manual indentation using simplified loading profiles [1], or in gait, with low image resolution/capture rates [2]. Since plantar soft tissue properties are highly rate dependent [3] these methods are potentially inadequate. The Soft Tissue Response Imaging Device (STRIDE) permits functionally relevant loading profiles to be applied to the plantar tissues.

A Methodology for Biomedical Ontology Reuse

The abundance of biomedical ontologies is beneficial to the development of biomedical related systems. However, existing biomedical ontologies such as the National Cancer Institute Thesaurus (NCIT), Foundational Model of Anatomy (FMA) and Systematized Nomenclature of Medicine-Clinical Terms (SNOMED CT) are often too large to be implemented in a particular system and cause unnecessary high usage of memory and slow down the system’s processing time. Developing a new ontology from scratch just for the use of a particular system is deemed as inefficient since it requires additional time and causes redundancy. Thus, a potentially better method is by reusing existing ontologies. However, currently there are no specific methods or tools for reusing ontologies. This paper aims to provide readers with a step by step method in reusing ontologies together with the tools that can be used to ease the process.

A framework for guiding learning in ultrasound scanning

Ultrasound scanning is provided by a range of health professionals who need to be trained to a proficient level. In respect of education and training in ultrasound scanning, little attention has been given to how scanning skills are acquired and what assists and hinders the learning process. This study aims to develop a framework for guiding learning in ultrasound scanning. Overt participant observation and semi-structured interviews generated data on four learners undertaking a 12-month postgraduate ultrasound programme. Narrative analysis of the interview data was used to reveal dominant themes related to stages in learning to scan. Dominant themes associated with learning to scan were communication with the patient, navigation skills, image interpretation skills, observation of expert practice, feedback on performance and random practise. Detailed interpretation of the themes through narrative analysis provided characteristics of learning for each stage of a four staged process. This study provides an insight into the key features of scan performance and how scanning skills are acquired over a four-staged approach. These themes and characteristics are presented in a framework for guiding learning in ultrasound scanning.

A device for characterising the mechanical properties of the plantar soft tissue of the foot

The plantar soft tissue is a highly functional viscoelastic structure involved in transferring load to the human body during walking. A Soft Tissue Response Imaging Device was developed to apply a vertical compression to the plantar soft tissue whilst measuring the mechanical response via a combined load cell and ultrasound imaging arrangement. Accuracy of motion compared to input profiles; validation of the response measured for standard materials in compression; variability of force and displacement measures for consecutive compressive cycles; and implementation in vivo with five healthy participants. Static displacement displayed average error of 0.04 mm (range of 15 mm), and static load displayed average error of 0.15 N (range of 250 N). Validation tests showed acceptable agreement compared to a Houndsfield tensometer for both displacement (CMC > 0.99 RMSE > 0.18 mm) and load (CMC > 0.95 RMSE < 4.86 N). Device motion was highly repeatable for bench-top tests (ICC = 0.99) and participant trials (CMC = 1.00). Soft tissue response was found repeatable for intra (CMC > 0.98) and inter trials (CMC > 0.70). The device has been shown to be capable of implementing complex loading patterns similar to gait, and of capturing the compressive response of the plantar soft tissue for a range of loading conditions in vivo.

An Architecture to Support Ultrasound Report Generation and Standardisation

Ultrasound reports are developed in different ways by clinicians and radiologists. These variations in reporting style, content and format could impact on the value of the report and the way it is interpreted, which in turn have implications on patient management and decision making. There are many reasons for the poor success rate of some reporting systems which is usually down to poor adaptability and the main one being the human factor. In this paper, we present a system architecture model for a proposed medical ultrasound reporting system that attempt to address some of these problems. In this system, we propose a solution where humans will not need to adapt to the system, instead the system acknowledge the various styles, contents and format being produced by the humans and uses an ontology to standardise the terminology and Natural Language Processing techniques to transform free text reports to the preferred proposed model of a structured and standardised report.

Plantar fascia segmentation and thickness estimation in ultrasound images

Ultrasound (US) imaging offers significant potential in diagnosis of plantar fascia (PF) injury and monitoring treatment. In particular US imaging has been shown to be reliable in foot and ankle assessment and offers a real-time effective imaging technique that is able to reliably confirm structural changes, such as thickening, and identify changes in the internal echo structure associated with diseased or damaged tissue. Despite the advantages of US imaging, images are difficult to interpret during medical assessment. This is partly due to the size and position of the PF in relation to the adjacent tissues. It is therefore a requirement to devise a system that allows better and easier interpretation of PF ultrasound images during diagnosis. This study proposes an automatic segmentation approach which for the first time extracts ultrasound data to estimate size across three sections of the PF (rearfoot, midfoot and forefoot). This segmentation method uses artificial neural network module (ANN) in order to classify small overlapping patches as belonging or not-belonging to the region of interest (ROI) of the PF tissue. Features ranking and selection techniques were performed as a post-processing step for features extraction to reduce the dimension and number of the extracted features. The trained ANN classifies the image overlapping patches into PF and non-PF tissue, and then it is used to segment the desired PF region. The PF thickness was calculated using two different methods: distance transformation and area-length calculation algorithms. This new approach is capable of accurately segmenting the PF region, differentiating it from surrounding tissues and estimating its thickness.

Effects of age on strength of the toe flexor muscles

Abstract of paper that presented at the Eleventh Footwear Biomechanics Symposium, Natal, Brazil, 2013.