AK Leung

AP McCormack

CW Imhauser

Erin D Ward

J Cohen

J Reeck

Timothy R Derrick

W Brent Edwards

English

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BioMed Central
Journal of Foot and Ankle Research
ssOpen AcceOral presentation
Foot joint pressures during dynamic gait simulation
W Brent Edwards*1, Erin D Ward2 and Timothy R Derrick1
Address: 1Department of Kinesiology, Iowa State University, Ames, IA, USA and 2Central Iowa Foot Clinic, Perry, IA, USA
Email: W Brent Edwards* - edwards9@iastate.edu
* Corresponding author    
Introduction
Adult acquired flatfoot deformity is a progressive loss of
normal function of the entire foot. A limited number of
studies concerning joint pressures [1,2] with adult
acquired flatfoot exist. Custom orthotics [3,4] are often
used for conservative treatment of adult acquired flatfoot.
Methods
5 fresh cadaveric specimens were connected to a dynamic
gait simulator. I-scan #6900 sensors® were calibrated and
surgically inserted into the subtalar (ST), naviculocunei-
form (NC) calcaneocuboid (CC), and talonavicular (TN)
joints using a joint spreader. Each foot was walked multi-
ple trials across a force platform for three conditions (nor-
mal, flatfoot, flatfoot-orthotic). The flatfoot condition
was created by detaching the posterior tibial tendon from
the simulator and surgically releasing the spring ligament
complex and the plantar fascia. Joint pressure data were
collected at 100 Hz. Peak pressures were averaged within
subjects and effect sizes were calculated between condi-
tions.
Results
Mean joint pressures ranged between 0.5 and 1.5 MPa
(Figure 1).
According to Cohen [5], effect sizes of .20, .50 and .80 rep-
resent small, medium and large differences, respectively.
Medium and large effect sizes were observed for the ST,
NC, and CC joint (Table 1). Compared to the normal con-
dition: ST pressures were lower during the orthotic condi-
tion, NC pressures were lower during the flatfoot and
orthotic conditions, and CC pressures were higher during
the flatfoot condition. Compared to the flatfoot condi-
tion: ST, NC, and CC pressures were all lower during the
orthotic condition.
from 1st Congress of the International Foot & Ankle Biomechanics (i-FAB) community
Bologna, Italy. 4–6 September 2008
Published: 26 September 2008
Journal of Foot and Ankle Research 2008, 1(Suppl 1):O21 doi:10.1186/1757-1146-1-S1-O21
<supplement> <title> <p>1st Congress of the International Foot &amp; Ankle Biomechanics (i-FAB) community</p> </title> <editor>Alberto Leardini, Chris Nester, Alex Stacoff and Dieter Rosenbaum</editor> <note>Meeting abstracts – A single PDF containing all abstracts in this Supplement is available <a href="http://www.biomedcentral.com/content/files/pdf/1757-1146-1-S1-full.pdf">here</a>.</note> <url>http://www.biomedcentral.com/content/pdf/1757-1146-1-S1-info.pdf</url> </supplement>
This abstract is available from: http://www.jfootankleres.com/content/1/S1/O21
© 2008 Edwards et al; licensee BioMed Central Ltd. 
Table 1: Measurements of effect size
ST NC CC TN
Normal vs Flatfoot -0.43 0.60* -2.62** -0.19
Normal vs Orthotic 3.40** 1.26** -0.46 -0.03
Flatfoot vs Othotic 2.17** 0.75* 3.96** 0.11
* medium effect, ** large effect.
Mean joint pressuresFigure 1
Mean joint pressures. Pressures for CC and TN were only 
available for two feet.Page 1 of 2
(page number not for citation purposes)
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Conclusion
Adult acquired flatfoot deformity appears to increase pres-
sure at the CC joint, and slightly decrease pressure at the
NC joint. The use of orthotics may be an effective method
to reduce joint pressures in both the normal foot and flat-
foot. The TN joint does not appear to be substantially
affected by flatfoot deformity or the use of orthotics.
Acknowledgements
Tekscan, Inc., South Boston, MA, USA. KLM Orthotics Laboratory, Valen-
cia, CA, USA
References
1. McCormack AP, et al.: Foot Ankle Int 1998, 19(7):452-461.
2. Reeck J, et al.: Foot Ankle Int 1998, 19(10):674-682.
3. Leung AK, et al.: Prosthet Orthot Int 1998, 22(1):25-34.
4. Imhauser CW, et al.: Foot Ankle Int 2002, 23(8):727-737.
5. Cohen J: Psychol Bull 1992, 112:155-159.Page 2 of 2
(page number not for citation purposes)


Foot joint pressures during dynamic gait simulation

Edwards W Brent

Ward Erin D

Derrick Timothy R

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Foot joint pressures during dynamic gait simulation

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