Repeatability and agreement of ultrasonography with computed tomography for evaluating forefoot structure in the coronal plane
© The Author(s). 2017
Received: 27 October 2016
Accepted: 18 March 2017
Published: 14 April 2017
Forefoot structure is important to understand some foot problems such as hallux valgus and metatarsalgia. Ultrasonography (US) is a highly portable, noninvasive, low cost, and fast imaging method, especially when compared to magnetic resonance imaging (MRI), computed tomography (CT), and radiography. As the use of US for evaluating forefoot bony structure has not been validated, except for the presence of synovitis, erosions and bursitis within the forefoot in people with inflammatory arthritis, the purpose of this study was to determine whether US is a reliable method for evaluating forefoot structure.
Sixty feet (30 women, age = 40.1 ± 11.8 years) were examined by US and CT to assess agreement with CT and repeatability of US evaluation of the 2nd metatarsal head height, length between the medial sesamoid bone and 5th metatarsal head, transverse arch height, transverse arch index, sesamoid rotation angle, and area under the transverse arch. The measurement data were evaluated for agreement with CT using the intra-class correlation coefficient (ICC)3, 1, Pearson correlation coefficient, and Bland-Altman plot, and with ICC1, 1 for repeatability.
The ICC3, 1 values of 0.78–0.89, Pearson correlation coefficient of 0.78–0.90, and Bland-Altman plots showed almost perfect agreements between the US and CT method for all parameters, except the area under the transverse arch (AUTA). The ICC1, 1 also showed perfect agreements (0.84–0.92) between two sets of US measurements in all parameters.
The US evaluation of forefoot structure in the coronal plane showed good agreement with CT and repeatability of two ultrasonograms in adult women. This reliable evaluation method of forefoot structure can contribute to a quick clinical assessment screening for risk factors of foot problems such as hallux valgus and metatarsalgia. However, because of some limitations such as a lack of inter-observer reliability, more research is needed to validate US evaluation of forefoot structure.
The current study (trial registration number: R0297) was approved by the Ethical Committee for Human Experiments of Kyoto University (http://www.ec.med.kyoto-u.ac.jp) on December 3, 2015. The first participant in this study was enrolled on November 17, 2015 and retrospectively registered.
KeywordsForefoot structure Ultrasound Agreement with CT Repeatability Coronal plane
The metatarsal and sesamoid bones of the forefoot bear most of the pressure on the plantar surface during gait [1, 2]. Many conditions such as hallux valgus, medial tibial stress syndrome, and diabetes affect the forefoot due to the loading and alignment of these bones [3–6]. Hallux valgus causes sesamoid bone pronation , and along with medial tibial stress syndrome , it affects transverse arch height  as well. In particular, sesamoid bones bear load of up to 300% of body weight , and sesamoid position contributes to the distribution of plantar pressure [8, 9], which is associated with foot pain . Metatarsal bones in the coronal plane form the transverse arch, which changes during gait; of these bones, the 2nd metatarsal absorbs the most shock during gait [11, 12]. This pressure on the 2nd and 3rd metatarsal heads (MTH) destabilizes the 2nd metatarsophalangeal joint and is recognized as a cause of metatarsalgia . Therefore, the 2nd MTH height is especially valuable in terms of foot function as a transverse arch and foot disease. Reduced plantar tissue thickness under the MTH has been found in patients with high peak plantar pressures in the high-risk diabetes population  and in patients with lesser toe deformities . These foot disorders often decrease quality of life due to pain; however, the mechanism of them are unknown. Evaluation of forefoot structure would provide insight into the mechanism underlying forefoot function and its relationship to foot disorders.
Diagnostic techniques such as magnetic resonance imaging (MRI), computed tomography (CT), and radiography have been used to evaluate forefoot structure. MRI has been used to assess the 1st metatarsophalangeal joint structure, including bone, tendon, and cartilage, and sesamoid bone alignment [16, 17]. CT and radiography have been used to evaluate sesamoid bone heights, metatarsal heads [11, 18], and sesamoid bone rotation angle . CT is especially effective for evaluating bony anatomy because of its high spatial and contrast resolutions for bone [19–21], and it is validated as having high accuracy and precision for foot measurements . However, these are relatively high-cost diagnostic methods, requiring large spaces for equipment and exposing patients to radiation.
Recent technological advances have improved ultrasonography (US) imaging quality, which has enabled musculoskeletal ultrasonography to have diagnostic use . Given its low cost, portability, and real-time diagnostic power, its use has greatly increased. US is a non-invasive and non-ionizing imaging method unlike CT and radiography, which expose patients to radiation. Because of these advantages, US is a more convenient imaging technique, with less burden on patients than other methods. Therefore, it is meaningful that US could be an alternative to other imaging methods. Moreover, by taking advantage of its adaptability, US can be applied to various systems to evaluate forefoot structure with loading  and during gait .
As for the transverse arch, Kudo et al.  and Duerinck et al.  evaluated it in terms of the 2nd MTH height and length between the 1st MTH and 5th MTH. In their methods, the transverse arch, which is a bony alignment of MTHs and metatarsals, included the soft tissue since the measurement included the surface of the foot. Hence, the transverse arch should also be evaluated with bony alignment excluding soft tissue to clarify which factor of soft tissue or bony alignment affects the function of the transverse arch. Regarding the sesamoid position, it has been evaluated in the transverse or coronal plane using radiography or CT to study hallux valgus. Kuwano et al.  reported that the sesamoid rotation angle in the coronal plane had a higher correlation with the hallux valgus angle than other parameters used to evaluate the sesamoid position. Due to the association between these factors of forefoot plantar structure evaluated in static condition and foot disorder and forefoot function, especially in gait, it is meaningful to evaluate them statically.
Some studies have used US to evaluate plantar soft tissue thickness  and forefoot structure [24, 27, 28], such as the 2nd MTH height during gait with the original device which is a platform with an US probe underneath it , but its validity is not supported in the literature. The purpose of this study was to establish the agreement of US with CT as a validated method for evaluating forefoot structure. We compared US to CT to determine its reliability for evaluating bony anatomy, and examined the agreement with CT and repeatability of US evaluation of 2nd MTH height, medial sesamoid and 5th MTH (MS-5thMTH) length, transverse arch height (TAH), transverse arch index (TAI), sesamoid rotation angle (SRA), and area under the transverse arch (AUTA) in adult women because of the higher prevalence of foot problems in women [29, 30].
Demographic data of participants and feet
Participants (n = 30)
40.1 ± 11.8
161.6 ± 19.8
54.9 ± 8.8
21.5 ± 4.0
Feet (n = 60)
hallux valgus angle (°)
16.0 ± 8.4
hallux valgus foot
Participants lay in a supine position on the CT scanner bed (Aquilion TSX101A, Toshiba) without load on the plantar surface. Straps and a foot board fixed knees at full extension and ankles in resting position (Fig. 2). The field of view was approximately 320 mm, and 1.0-mm thick CT images of all MTHs were obtained in the coronal plane (120 kV × 300 mA, 512 × 512 matrix). A CT slice of each foot was selected from about 60 images with a 60-mm area and a focus on the center of medial sesamoid bones and the 5th MTH in accordance with the landmarks of US measurements, and it was imported into ImageJ software. These procedures for CT were standardized between participants. CT measurements were obtained within 3 weeks from the US measurements.
Agreement of US with the CT method was assessed by evaluating the relationship between CT and the average of two US measurements with the intra-class correlation coefficient (ICC3,1), Pearson correlation coefficient, and Bland-Altman plot . In particular, the Pearson correlation coefficient was used to show the proportional relationship between the two methods. For the Bland-Altman plot, differences between the two methods were plotted against their means. Most of the differences were within the limits of agreement (LoA), with a mean difference ± 1.96 standard deviation. The ICC1, 1 of two US measurements was evaluated for repeatability. The ICC and Pearson correlation coefficient were calculated using SPSS, version 20.0 software package (IBM Corp.). According to Landis et al., the ICC interpretation scale was classified as follows: below 0.4, poor to fair; 0.41–0.60, moderate; 0.61–0.80, excellent; and 0.81–1, almost perfect .
The sample size was calculated for an intra-class correlation coefficient (ICC) of 0.61 to detect at least a significantly moderate level with α error = 0.05 and power = 0.95 using G* power 3.1 software (Heinrich Heine University, Dusseldorf, Germany). As a result, at least 30 samples were needed.
US and CT measurement
2ndMTH height (mm)
21.2 ± 2.9
20.8 ± 2.8
21.0 ± 2.8
21.2 ± 2.6
MS-5thMTH length (mm)
62.6 ± 3.3
62.7 ± 3.3
62.7 ± 3.2
63.4 ± 2.8
13.4 ± 2.1
13.4 ± 2.2
13.4 ± 2.1
13.1 ± 2.2
21.6 ± 3.5
21.4 ± 3.6
21.5 ± 3.4
20.7 ± 3.6
16.1 ± 8.1
16.2 ± 7.1
16.1 ± 7.3
15.9 ± 8.1
902.0 ± 120
891.3 ± 112.7
896.7 ± 112.4
801.9 ± 111.4
Intra-rater agreement of the US measurement and agreement scores between US and CT measurements
Limits of agreement (95% CI)
ICC1,1 (95% CI)
ICC3,1 (95% CI)
Mean (95% CI)
Difference (95% CI)
2nd MTH height (mm)
0.88 (0.79, 0.92)
0.83 (0.74, 0.90)
21.13 (20.49, 21.77)
−0.18 (0.39, 1.53)
2.88 (3.27, 2.49)
MS-5thMTH length (mm)
0.92 (0.87, 0.95)
0.81 (0.70, 0.89)
63.05 (62.32, 63.78)
2.98 (2.48, 3.43)
0.84 (0.74, 0.90)
0.86 (0.78, 0.91)
13.26 (0.52, 2.06)
0.36 (0.64, 0.08)
2.62 (2.33, 2.90)
0.87 (0.80, 0.92)
0.85 (0.78, 0.91)
21.08 (20.23, 21.94)
0.86 (−2.94, 4.66)
4.66 (4.18, 5.14)
0.85 (0.76, 0.91)
0.89 (0.83, 0.93)
16.03 (14.15, 17.91)
0.19 (−0.71, 1.09)
7.27 (6.38, 8.17)
0.86 (0.78, 0.92)
0.78 (0.66, 0.86)
849.27 (822.76, 875.78)
94.82 (76.32, 113.32)
241.03 (222.53, 259.52)
Regarding the evaluation of forefoot structure, we investigated agreement between US and CT measurements for reliability and intra-rater agreement of two US scans taken at a single time point for repeatability. Based on this investigation, the most important finding of this study was demonstrating agreement with CT and repeatability of forefoot US evaluation (2ndMTH height, MS-5thMTH length, TAH, TAI, SRA, and AUTA) of the feet of adult women without a history of foot surgery, congenital disorders, or systemic diseases. Compared to CT, the LoA indicated good agreement and the ICC3, 1 indicated almost perfect correlation, and US showed almost perfect repeatability. Considering that CT evaluation of forefoot structure has been validated , US could be estimated to have good validity for evaluating forefoot structure. Some studies have explored the reliability of plantar musculoskeletal evaluations with US for muscles , bursitis, erosions, and synovitis ; this is the first study known to assess the reliability of US for evaluating bony forefoot structure alignment in detail. These results support the use of US in clinical practice to evaluate forefoot structure in real time, as it is less burdensome to patients than other methods. MRI and CT must be performed in enclosed spaces, which causes burden and stress to the patient, and they are expensive; MRI, especially, takes a long time, and CT emits radiation to patients.
A Bland-Altman plot demonstrated agreement of the US with CT method. Almost all points lay within the LoA, indicating good reliability of US methods for every parameter. Some points fell outside the LoA, likely because some images obtained from the same participant may have reflected different forefoot placement on US and CT. Despite using the same landmarks, spatial differences between the US probe contact angle and the CT scan angle could produce inaccurate measurements. In addition, it is undeniable that the scanned position of metatarsophalangeal joints was the same between US and CT scans, which might also lead to less agreement between US and CT scans because of the difference in the scanned position.
In studies measuring the 2ndMTH height and SRA, Wang et al.  and Gooding et al.  showed the 2ndMTH height was 13.6 and 14.2 mm, measured by US in an unloaded position; the 2ndMTH height values in our study were larger (21.1 mm by US, 21.3 mm by CT). In our method, the 2ndMTH height was measured at the more proximal part of the 2nd metatarsal because the imaging landmarks in the coronal plane were the 1stMTH and 5thMTH. The more proximal the metatarsal position measured, the higher the value, which produced our relatively higher values. It is also considered that 2ndMTH height might be affected by participants’ characteristics, such as fat volume, muscle volume and foot size, which could be associated with soft tissue thickness. Kuwano et al.  compared SRA in patients with hallux valgus to a control group using radiography, and they reported mean SRA values of 29.3° in the hallux valgus group (hallux valgus angle 20° or greater) and 7.4° in the control group. The mean SRA values in our study were 16.0° by US and 15.8° by CT, which were larger than those of the control group in Kuwano et al.’s study. As SRA is greater with hallux valgus  and 16 ft (26.7%) with a hallux valgus angle 20° or greater were found in our participants (Table 1), our SRA values were large.
Until now, the transverse arch has been evaluated by measuring only soft tissue. The transverse arch height is affected by plantar muscle and fat pad thickness; however, the TAH indicates transverse arch bony alignment excluding soft tissue. The TAI indicates the transverse arch height adjusted for foot size in the coronal plane, which was defined as the MS-5thMTH length. Length parameters in the foot such as the TAH are affected by foot size; they need to show reliability of the MS-5thMTH length as a foot size in the coronal plane, which is useful to adjust foot structure parameter, and it is a constructional element that can contribute to better reliability of the TAH and TAI. The TAH and TAI are useful for evaluating the transverse arch bony structure and related hallux valgus . The AUTA indicates forefoot bony alignment and soft tissue thickness in the coronal plane for the overall transverse arch. Using the AUTA, it is possible to determine whether the transverse arch is collapsed or the soft tissue under the transverse arch is compacted. The former is when the AUTA has no changes between weight-bearing and non-weight-bearing, and the latter is when the AUTA becomes smaller in weight-bearing than in non-weight-bearing. Therefore, better accuracy of the AUTA measurement would offer a better understanding of the transverse arch function and structural forefoot change in foot deformities due to diabetes, which are associated with plantar soft tissue thickness. Evaluating the transverse arch using these parameters can clarify whether the bony structure or soft tissue affects the function of the transverse arch and foot disease associated with the transverse arch. We therefore propose using TAH, TAI, and AUTA as new parameters for transverse arch evaluation. As it is not yet known how these parameters compare with clinical assessments, these parameters could be tested in future work that assesses dynamic change during gait.
There were some limitations to this study. The interval was short between the two US scans, and the drawn landmark on the plantar surface for US scans was the same for both US scans. The short interval could increase the ICC1,1. Although the drawn landmark was only a reference of the initial placement of the US probe, the placement of the US probe and obtainment of the US image was conducted mainly with more attention paid to the screen image of US, regardless of the location of the landmark. Hence, the same landmark within both US scans had less impact on the intra-rater reliability of the US evaluation. There was a certain time gap between the US and CT examinations. However half of the participants were evaluated by both methods within a day, so the time gap was maximally 3 weeks, which might affect agreement between the two methods. This study was limited in that inter-observer reliability of US was not assessed. As US evaluation is dependent on the examiner’s skill, inter-observer reliability may be increased by well-trained examiners. Our research was insufficient to confirm the validity of US evaluation of the forefoot; however, agreement with CT evaluation was confirmed. Considering these limitations, more work needs to be undertaken in the future to determine the validity of US evaluation of the forefoot compared with a clinical assessment.
This study showed good agreement of US forefoot structure evaluation with CT as a gold standard in adult women. This has value as a non-invasive, convenient, and inexpensive forefoot evaluation in various fields with access to US. US could provide an opportunity to perform a forefoot evaluation that is less burdensome to patients in clinical practice, and it could be useful for foot screening for risk factors such as the SRA and TAH, and 2ndMTH height, which are indicative of hallux valgus and metatarsalgia, respectively. As this study had some limitations such as a lack of inter-observer reliability, short interval for repeatability, and lack of validity, more research should be performed to confirm US evaluation of the forefoot with a high reliability and validity.
Area under the transverse arch
Body mass index
Intra-class correlation coefficient
Limits of agreement
Lateral sesamoid bone
Magnetic resonance imaging
Medial sesamoid bone
- MS-5thMTH length:
The length between the medial sesamoid bone and 5th metatarsal head
Sesamoid rotation angle
Transverse arch height
Transverse arch index
The radiological technologist at Kyoto Hakuaikai Hospital conducted computed tomography scanning. We wish to thank the staff at the Kyoto Hakuaikai Hospital for their efforts in supporting our research. We would like to thank Editage (www.editage.jp) for English language editing.
No funding was received for this study.
Availability of data and materials
The dataset supporting the conclusions of this article is included within the article and its Additional file.
KM and TA designed the study. KM conducted echocardiography scan, image, and statistical analyses, and drafted the manuscript. YT, ST, TM, TS, YN, and YY assisted in performing the echocardiography scan. TM, YS and MK assisted in drafting the manuscript. All authors have read and approved the final manuscript.
The authors declare that they have no competing interests.
Consent for publication
Written informed consent for publication was obtained from all participants.
Ethics approval and consent to participate
This study was performed in accordance with the current local guideline and the Declaration of Helsinki, and it was approved by the Ethical Committee for Human Experiments (R0297) of Kyoto University. Written informed consent was obtained from all participants in this study.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
- Kanatli U, Yetkin H, Bolukbasi S. Evaluation of the transverse metatarsal arch of the foot with gait analysis. Arch Orthop Trauma Surg. 2003;123:148–50.PubMedGoogle Scholar
- Dedmond BT, Cory JW, McBryde A. The hallucal sesamoid complex. J Am Acad Orthop Surg. 2006;14:745–53.View ArticlePubMedGoogle Scholar
- Guiotto A, Sawacha Z, Guarneri G, Cristoferi G, Avogaro A, Cobelli C. The role of foot morphology on foot function in diabetic subjects with or without neuropathy. Gait Posture. 2013;37:603–10.View ArticlePubMedGoogle Scholar
- Mueller MJ, Hastings M, Commean PK, Smith KE, Pilgram TK, Robertson D, et al. Forefoot structural predictors of plantar pressures during walking in people with diabetes and peripheral neuropathy. J Biomech. 2003;36:1009–17.View ArticlePubMedGoogle Scholar
- Suzuki J, Tanaka Y, Takaoka T, Kadono K, Takakura Y. Axial radiographic evaluation in hallux valgus: evaluation of the transverse arch in the forefoot. J Orthop Sci. 2004;9:446–51.View ArticlePubMedGoogle Scholar
- Kudo S, Hatanaka Y. Forefoot flexibility and medial tibial stress syndrome. J Orthop Surg (Hong Kong). 2015;23:357–60.View ArticleGoogle Scholar
- Kuwano T, Nagamine R, Sakaki K, Urabe K, Iwamoto Y. New radiographic analysis of sesamoid rotation in hallux valgus: comparison with conventional evaluation methods. Foot Ankle Int. 2002;23:811–7.View ArticlePubMedGoogle Scholar
- Koller U, Willegger M, Windhager R, Wanivenhaus A, Trnka HJ, Schuh R. Plantar pressure characteristics in hallux valgus feet. J Orthop Res. 2014;32:1688–93.View ArticlePubMedGoogle Scholar
- Cavanagh PR, Morag E, Boulton AJM, Young MJ, Deffner KT, Pammer SE. The relationship of static foot structure to dynamic foot function. J Biomech. 1997;30:243–50.View ArticlePubMedGoogle Scholar
- Martinez-Nova A, Sanchez-Rodriguez R, Perez-Soriano P, Llana-Belloch S, Leal-Muro A, Pedrera-Zamorano JD. Plantar pressures determinants in mild hallux valgus. Gait Posture. 2010;32:425–7.View ArticlePubMedGoogle Scholar
- Simonsen O, Vuust M, Understrup B, Hojbjerre M, Bottcher S, Voigt M. The transverse forefoot arch demonstrated by a novel X-ray projection. Foot Ankle Surg. 2009;15:7–13.View ArticlePubMedGoogle Scholar
- Duerinck S, Hagman F, Jonkers I, Van Roy P, Vaes P. Forefoot deformation during stance: does the forefoot collapse during loading? Gait Posture. 2014;39:40–7.View ArticlePubMedGoogle Scholar
- Dreeben SM, Noble PC, Hammerman S, Bishop JO, Tullos HS. Metatarsal osteotomy for primary metatarsalgia: radiographic and pedobarographic study. Foot Ankle. 1989;9:214–8.View ArticlePubMedGoogle Scholar
- Abouaesha F, van Schie CHM, Griffths GD, Young RJ, Boulton AJM. Plantar tissue thickness is related to peak plantar pressure in the high-risk diabetic foot. Diabetes Care. 2001;24:1270–4.View ArticlePubMedGoogle Scholar
- Mickle KJ, Munro BJ, Lord SR, Menz HB, Steele JR. Soft tissue thickness under the metatarsal heads is reduced in older people with toe deformities. J Orthop Res. 2011;29:1042–6.View ArticlePubMedGoogle Scholar
- Dietrich TJ, da Silva FLF, de Abreu MR, Klammer G, Pfirrmann CWA. First metatarsophalangeal joint- MRI findings in asymptomatic volunteers. Eur Radiol. 2015;25:970–9.View ArticlePubMedGoogle Scholar
- Schweitzer ME, Maheshwari S, Shabshin N. Hallux valgus and hallux rigidus: MRI findings. Clin Imaging. 1999;23:397–402.View ArticlePubMedGoogle Scholar
- Weijers RE, Walenkamp G, Kessels AGH, Kemerink GJ, van Mameren H. Plantar pressure and sole thickness of the forefoot. Foot Ankle Int. 2005;26:1049–54.View ArticlePubMedGoogle Scholar
- Kuo GP, Carrino JA. Skeletal muscle imaging and inflammatory myopathies. Curr Opin Rheumatol. 2007;19:530–5.View ArticlePubMedGoogle Scholar
- Guldner C, Heinrichs J, Weiss R, Zimmermann AP, Dassinger B, Bien S, et al. Visualisation of the Bonebridge by means of CT and CBCT. Eur J Med Res. 2013;18:30.View ArticlePubMedPubMed CentralGoogle Scholar
- Sievers KW, Greess H, Baum U, Dobritz M, Lenz M. Paranasal sinuses and nasopharynx CT and MRI. Eur J Radiol. 2000;33:185–202.View ArticlePubMedGoogle Scholar
- Smith KE, Commean PK, Robertson DD, Pilgram T, Mueller MJ. Precision and accuracy of computed tomography foot measurements. Arch Phys Med Rehabil. 2001;82:925–9.View ArticlePubMedGoogle Scholar
- Rezaei H, Torp-Pedersen S, Af Klint E, Backheden M, Kisten Y, Gyori N, van Vollenhoven RF. Diagnostic utility of musculoskeletal ultrasound in patients with suspected arthritis - a probabilistic approach. Arthritis Res Ther. 2014;16:448.View ArticlePubMedPubMed CentralGoogle Scholar
- Wang CL, Hsu TC, Shau YW, Shieh JY, Hsu KH. Ultrasonographic measurement of the mechanical properties of the sole under the metatarsal heads. J Orthop Res. 1999;17:709–13.View ArticlePubMedGoogle Scholar
- Cavanagh PR. Plantar soft tissue thickness during ground contact in walking. J Biomech. 1999;32:623–8.View ArticlePubMedGoogle Scholar
- Telfer S, Woodburn J, Turner DE. Measurement of functional heel pad behaviour in-shoe during gait using orthotic embedded ultrasonography. Gait Posture. 2014;39:328–32.View ArticlePubMedGoogle Scholar
- Bowen CJ, Dewbury K, Sampson M, Sawyer S, Burridge J, Edwards CJ, et al. Musculoskeletal ultrasound imaging of the plantar forefoot in patients with rheumatoid arthritis: inter-observer agreement between a podiatrist and a radiologist. J Foot Ankle Res. 2008;1:5.View ArticlePubMedPubMed CentralGoogle Scholar
- Gooding GAW, Stess RM, Graf PM, Moss KM, Louie KS, Grunfeld C. Sonography of the sole of the foot. Evidence for loss of foot pad thickness in diabetes and its relationship to ulceration of the foot. Invest Radiol. 1986;21:45–8.View ArticlePubMedGoogle Scholar
- Menz HB, Jordan KP, Roddy E, Croft PR. Characteristics of primary care consultations for musculoskeletal foot and ankle problems in the UK. Rheumatology (Oxford). 2010;49:1391–8.View ArticleGoogle Scholar
- Thomas MJ, Roddy E, Zhang WY, Menz HB, Hannan MT, Peat GM. The population prevalence of foot and ankle pain in middle and old age: a systematic review. Pain. 2011;152:2870–80.View ArticlePubMedGoogle Scholar
- Hammond AW, Phisitkul P, Femino J, Amendola A. Arthroscopic debridement of the talonavicular joint using dorsomedial and dorsolateral portals: a cadaveric study of safety and access. Arthroscopy. 2011;27:228–34.View ArticlePubMedGoogle Scholar
- Rullan M, Cerda L, Frontera G, Mast-Niquel L, Llobera J. Treatment of chronic diabetic foot ulcers with bemiparin: a randomized, triple-blind, placebo-controlled, clinical trial. Diabet Med. 2008;25:1090–5.View ArticlePubMedGoogle Scholar
- Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986;1:307–10.View ArticlePubMedGoogle Scholar
- Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33:159–74.View ArticlePubMedGoogle Scholar
- Mickle KJ, Nester CJ, Crofts G, Steele JR. Reliability of ultrasound to measure morphology of the toe flexor muscles. J Foot Ankle Res. 2013;6:12.View ArticlePubMedPubMed CentralGoogle Scholar