Madsen, Maja M.

Matteoli, Sara

Torp-Pedersen, Søren T.

Virga, Antonio

Wilhjelm, Jens E.

Online Research Database In Technology

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Downloaded from orbit.dtu.dk on: Dec 20, 2017Investigations on in vivo human heel pad thicknessMatteoli, Sara; Madsen, Maja M. ; Virga, Antonio; Wilhjelm, Jens E.; Torp-Pedersen, Søren T.Published in:Journal of BiomechanicsPublication date:2012Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Matteoli, S., Madsen, M. M., Virga, A., Wilhjelm, J. E., & Torp-Pedersen, S. T. (2012). Investigations on in vivohuman heel pad thickness. Journal of Biomechanics, 45(Supplement 1), S196.INVESTIGATIONS ON IN VIVO HUMAN HEEL PAD THICKNESS Sara Matteoli(1), Maja M. Madsen(1), Antonio Virga(2), Jens E. Wilhjelm(1), Søren T. Torp-Pedersen(3)  1. Department of Electrical Engineering, Technical University of Denmark, DK;  2. Department of Mechanics and Industrial Technologies, University of Florence, IT; 3. The Parker Institute, Frederiksberg Hospital, DK  Introduction The human heel pad thickness is one of the intrinsic factors which must be taken into account when investigating the biomechanics of the heel pad [Rome, 1998; Uzel, 2006]. In fact, heel pad thickness has been reported to be an important factor in determining stresses observed in healthy as well as pathological feet [Rome, 1998; Uzel, 2006]. Furthermore, the heel pad compressibility index (HPCI), indicating the ability of the heel pad to be compressed, is also an important parameter.  Methods 134 healthy subjects (66F, 68M) were enrolled in the present study. All participants were volunteers. The subject characteristics are shown in Table 1. For each subject the dominant foot was scanned, in both loaded and unloaded conditions with a 14 MHz 3D US (LogicE9, GE Healthcare). In unloaded condition the subject was lying down. In loaded condition the subject was standing on a Plexiglas platform with all the body weight on the dominant foot. The scan was made through the Plexiglas plate. The heel pad thickness was measured from 3D-block in the acquisition plane. The HPCI was then found as [Kanatli, 2001, Prichasuk, 1994; Prichasuk et al., 1994]:  HPCI= LHPT/UHPT                     (1)  The statistical analysis was performed with the program R. A linear regression model was fitted to the data to investigate whether there was a correlation between HPCI and the intrinsic factors: age, gender, weight, height and duration of physical activity. The model included HPCI as a response variable and the intrinsic factors as explanatory variables. In the linear regression model the significance of each factor was evaluated by using the sum of squares. A P-value <0.05 was chosen as significant.   All Females Males Age (years) 36.0±14.4 36.7±14.4 36.6±14.4 Weight (kg) 71.7±13.7 64.2±9.2 79.2±12.8 Height (m) 173.7±9.8 166.8±5.7 180.4±8.3 BMI (kg/m2) 23.6±3.1 23.0±2.7 24.3±3.3 Sport (h/week) 3.9±3.9 4.7±4.1 3.3±3.6  Table 1: Characteristics grouped according to the gender given as mean ± SD.  Results The linear regression model showed that gender (P-value=0.048) and interaction between gender and age (P-value=0.029) were statistically significant, while age was not a significant variable (P-value= 0.444). Table 2 shows results for UHPT, LHPT and HPCI. A statistically significant difference between males and females was found in weight, height and hours of physical activity (P-value<0.05), while no statistically significant difference in age and BMI was found (P-value>0.05). A statistically significant difference between males and females was found in UHPT and LHPT (P-value=0.0006 and 0.007, respectively), while no statistically significant difference was found in HPCI (P-value= 0.889).   Females Males UHPT (mm) 14.59±2.02 15.80±1.88 LHPT (mm) 8.65±1.55 9.35±1.47 HPCI (%) 59.29±6.94 59.30±7.38  Table 2: Results grouped according to the gender given as mean ± SD.  Discussion Literature shows discordant results when dealing with heel pad biomechanics. The main reasons are the different methodologies applied and the different number of subjects investigated. Our study confirms that the interaction between gender and age plays a significant role on HPCI, as indicated by [Ozdemir, 2004]. [Prichasuk, 1994; Prichasuk et al., 1994; Hsu, 1998; Turgut, 1999] reported that age has a significant effect on HPCI, while [Prichasuk et al., 1994; Turgut, 1999; Ozdemir, 2004] indicated the weight as a significant factor.  References Kanatli U et al, Foot Ankle Int, 22(8):662-5, 2001. Prichasuk S, J Bone Joint Surg Br, 76B(1):140-142, 1994. Prichasuk S et al, Clin Orthop Relat Res, 300:197-200, 1994. Rome K et al, Br J Rad, 71:1149-1152, 1998. Ozdemir H et al, J Am Podiatr Med Assoc, 94(1):47-52, 2004. Turgut A et al, Clin Orthop Relat Res, 360:191-196, 1999. Uzel M et al, Joint Bone Spine, 73:196-199, 2006. S196 Presentation 1392 − Topic 17. Foot and ankle biomechanicsJournal of Biomechanics 45(S1) ESB2012: 18th Congress of the European Society of Biomechanics

Investigations on in vivo human heel pad thickness

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Investigations on in vivo human heel pad thickness

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