Prediction and portrayal of repetitive stress-induced lower limb pain disorders among soldiers in basic training using videothermography

Thermography has been widely espoused for both detecting and portraying pain problems. Development of repetitive stress-induced lower limb pain during army basic training is a relatively common occurrence. This study was designed to assess the usefulness of thermography for differentiating soldiers who developed lower limb pain during training from those who did not. This information was intended to be used to determine the usefulness of pretraining thermograms taken just as people came into the army in predicting which trainees would develop these conditions during training.

Videothermographic pictures were taken of the lower limbs of 639 newly enlisted soldiers who had just arrived at a large U.S. Army base but had not yet begun basic training. The amount of symmetry was correlated with the development of lower limb pain. Each soldier reporting lower limb pain and "controls" with nonpain problems (usually minor colds) received a thermographic evaluation identical to the original evaluation when they came for their medical examination.

Among prebasic trainees, 37% showed 1.0 degrees C of asymmetry somewhere in their lower limbs, 14% were asymmetrical by between 1.1 degrees and 2.0 degrees C, 5% by 3.0 degrees C and 4% by 4.0 degrees C or more. Thus, only 40% of the prebasic trainees were within accepted "normal" limits before participating in training. Thirty-nine percent of those with asymmetrical thermograms developed lower limb pain compared with 28% of those with symmetrical thermograms (significant at p < 0.05). It was impossible to predict from any thermographic measurement on the lower limbs which soldiers were most likely to develop lower limb pain. This held true even for those pretrainees with the greatest asymmetries. Eighty-four percent of trainees reporting lower limb pain produced abnormal thermograms regardless of whether or not they produced abnormal thermograms prior to training.

Thermograms were of little value for either predicting or portraying repetitive stress-induced lower limb pain in this population.