Volume 7 Supplement 1

4th Congress of the International Foot and Ankle Biomechanics Community

Open Access

A novel technique of quantifying first metatarsophalangeal (1stMPJ) joint stiffness

Journal of Foot and Ankle Research20147(Suppl 1):A32

DOI: 10.1186/1757-1146-7-S1-A32

Published: 8 April 2014

The first metatarsophalangeal joint (1st MPJ) mobility is usually described by (i) range of motion in degrees (°) or (ii) stiffness based on an experienced tester’s subjective feel, ie. hypermobile, normal or stiff. Approximately 65° of 1st MPJ dorsiflexion is required for normal effective walking [1]. Visual estimation of 1st MPJ range of motion is often used in current practice [2], reflecting the absence of a reliable and practical method for clinicians to quantify 1st MPJ stiffness. This study presents a novel technique to measure joint stiffness using a tactile pressure sensing system (Figure 1A) together with simple video analysis.
Figure 1

A. Finger sleeve with pressure pad (circled) on tip of thumb to measure force applied to move the 1st MPJ. B. Moment arm (length of proximal phalanx) from joint fulcrum to point of force application. C. Displacement force applied to proximal phalanx, dorsiflexing 1st MPJ through its range of motion.

To illustrate the method, data were collected on one female flat-footed subject with posterior tibial tendon dysfunction (age 25 yr, body mass index 20.6 kg/m2). The moment arm was measured from the tuberosity of the first metatarsal head to just beneath the tuberosity of the 1st distal phalanx (Figure 1B). A qualified podiatrist moved the 1st MPJ of the subject through its full range of motion before data collection. For each trial, joint movement is paused briefly at 3 interval points between the resting and maximally dorsiflexed position. At each interval point, the corresponding force applied was measured using a tactile pressure sensing system (Figure 1C). The procedures were recorded by a synchronised webcam such that the angular displacement of the 1st MPJ can be quantified using video analysis. A total of 3 trials were taken, resulting in nine sets of data points to plot a torque-angular displacement graph (Figure 2). The joint stiffness was then calculated as the slope of the line of best fit as 3.8 Nmm/deg. The R2 indicates that 61% of variability can be explained by this model.
Figure 2

Plot of torque (Nmm) against angular displacement (degrees) of the 1st MPJ to determine joint stiffness from the slope.

The proposed method of quantifying 1st MPJ stiffness is potentially useful for measuring small joint stiffness in clinical practice. Quantified joint stiffness provides greater accuracy to facilitate clinicians in their diagnoses and prescription of treatment.

Authors’ Affiliations

(1)
Physical Education & Sports Science Academic Group, National Institute of Education, Nanyang Technological University
(2)
Podiatry Department, Singapore General Hospital

References

  1. Hopson MM, McPoil TG, Cornwall MW: Motion of the first metatarsophalangeal joint. Reliability and validity of four measurement techniques. Journal of the American Podiatric Medical Association. 1995, 85 (4): 198-204.View ArticlePubMedGoogle Scholar
  2. Jones AM, Curran SA: Intrarater and interrater reliability of first metatarsophalangeal joint dorsiflexion. Goniometry versus visual estimation. Journal of the American Podiatric Medical Association. 2012, 102 (4): 290-298.View ArticlePubMedGoogle Scholar

Copyright

© Heng and Kong; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 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.

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