Specific structures may contribute to limb-length discrepancies (LLDs), such as differences in length or shape between the right and left femur or tibia contractures or differences in alignment at the hip, knee and ankle; or joint space narrowing at one or more specific joints of the lower extremity.
A simple measurement, termed the total foot height (TFH), can be used to accurately determine the foot’s contribution to limb-length discrepancy.
Standard full weightbearing lateral view radiographs are taken of both feet.
On each of these images, a horizontal line is drawn tangential to the most inferior point of the calcaneal tuberocity (Line A).
A vertical line is then drawn from this tangent point (Line B).
From where this vertical line intersects with the skin under the calcaneal fat pad, another horizontal line is drawn tangential to the skin line (Line C).
A horizontal line is then drawn tangential to the most superior aspect of the talar dome (Line D).
The measurement of the distance between the intersection of lines B and D (Point 1), and the intersection of lines B and C (Point 2), is defined as the TFH.
The measured difference between the right TFH and left TFH is the foot’s contribution to the limb-length discrepancy.
The findings from such an evaluation have practical applications; specifically, they can contribute to the method of treatment selected, as well as the effects of treatment.
Total foot height measurements can be useful in tracking potential changes over time attributable to Charcot’s foot deformity or adult acquired flatfoot.
This measurement has the potential to be an additional useful parameter for clinicians and researchers to consider when evaluating outcomes of particular surgical procedures such as flatfoot or Charcot foot reconstructions.
Copyright 2017 MASS4D® All rights reserved.