Technique to study the biomechanical properties of the human calcaneal heel pad

Tong, J.; Lim, C. S.; Goh, O. L.

Affiliations

¹Podiatry Unit, Singapore General Hospital, Outram Road, Singapore 169608, Singapore

²Biomedical Engineering Research Centre, Nanyang Technological University, Singapore 639798, Singapore

³Sports Medicine, Singapore Sports Council, 15 Stadium Road, Singapore 397718, Singapore

Abstract and keywords

Background: The biomechanical properties of the human foot may depend on the health of the individual. Patients diagnosed with diabetes mellitus, for example, may suffer from observable change in biomechanical properties and subsequently result in foot ulceration. To date, only limited published studies have been carried out to show differences in heel pad mechanical properties of diabetic individuals and healthy individuals. It has been hypothesised that collagen septa of a diabetic’s heel fat pads are thicker and fat cells smaller, and that these occurrences could reduce their resilience, making the heel more vulnerable to ulceration. Furthermore, there is still not a clinical yet quantitative biomechanical tool that could provide an easy assessment on the heel pad stiffness in vivo. This paper reports the preliminary development of a test rig and subsequent protocol for its use to acquire the biomechanical properties of the human heel pad. The paper reports and discusses the results obtained from the test rig developed.

Objectives: The first objective of this work was to develop a suitable technique and protocol to acquire the biomechanical properties of the human heel pad. The second objective was to investigate the heel pad properties of healthy individuals and compare these with patients diagnosed with plantar heel pain (PHP) and diabetes mellitus.

Method: A test rig was designed and built by the authors for the purpose of acquiring the biomechanical properties of the human heel pad. A total of 17 heels (from 9 patients with diabetes), 17 heels (from 12 patients with PHP) and 21 heels (from 14 healthy subjects) were measured. All patients were of Asian descent. A convenience sample was recruited from both Type 1 and Type 2 diabetic patients, and patients diagnosed with PHP. The heel pad thickness (loaded and unloaded), compressibility index, strain and ultrasound images were acquired.

Results: The results revealed significantly lower loaded thickness and compressibility index, and significantly higher strain in the control group when compared with the two patient groups. The load deformation curve for the human heel pad showed non-linear characteristics indicating low initial stiffness and high final stiffness with an increasing deformation.

Conclusions: The dynamic characteristic of the human heel pad may depend on underlying pathology. The heel pad properties reveal that patients with plantar heel pain and diabetic patients were less compressible compared with those of healthy individuals.

Keywords: Ultrasound imaging; Calcaneal heel pad; Heel pad biomechanical properties; Plantar heel pain; Diabetes mellitus

Links

DOI: 10.1016/S0958-2592(02)00149-9

History

Received: 2002-04-17

Accepted: 2002-10-08

Cited Works (4)

Year	Entry
1994	De Clercq D, Aerts P, Kunnen M. The mechanical characteristics of the human heel pad during foot strike in running: an in vivo cineradiographic study. J Biomech. October 1994;27(10):1213-1222.
2001	Gefen A, Megido-Ravid M, Itzchak Y. In vivo biomechanical behavior of the human heel pad during the stance phase of gait. J Biomech. 2001;34(12):1661-1665.
2000	Hsu T-C, Wang C-L, Shau Y-W, Tang F-T, Li K-L, Chen C-Y. Altered heel-pad mechanical properties in patients with Type 2 diabetes mellitus. Diabetic Med. December 2000;17(12):854-859.
1980	Light LH, McLellan GE, Klenerman L. Skeletal transients on heel strike in normal walking with different footwear. J Biomech. 1980;13(6):477-480.

Cited By (7)

Year	Entry
2006	Spears IR, Miller-Young JE. The effect of heel-pad thickness and loading protocol on measured heel-pad stiffness and a standardized protocol for inter-subject comparability. Clin Biomech (Bristol, Avon). February 2006;21(2):204-212.
2012	Chokhandre S, Halloran JP, van den Bogert AJ, Erdemir A. A three-dimensional inverse finite element analysis of the heel pad. J Biomech Eng. March 2012;134(3):031002.
2010	Natali AN, Fontanella CG, Carniel EL. Constitutive formulation and analysis of heel pad tissues mechanics. Med Eng Phys. 2010;32(5):516-522.
2012	Fontanella CG, Matteoli S, Carniel EL, Wilhjelm JE, Virga A, Corvi A, Natali AN. Investigation on the load-displacement curves of a human healthy heel pad: in vivo compression data compared to numerical results. Med Eng Phys. November 2012;34(9):1253-1259.
2009	Sirimamilla PA. Elaborate Experimentation for Mechanical Characterization of Human Foot Using Inverse Finite Element Analysis [Master's thesis]. Cleveland, OH: Case Western Reserve University; January 2009.
2016	Grigoriadis G. Heel Biomechanics Under Blast Conditions [PhD thesis]. Imperial College London; June 2016.
2023	Marcallini AM Jr. PMHS Use as a Surrogate for Living Populations in Lower Extremity Research [Master's thesis]. The Ohio State University; 2023.