Foot Orthoses in the Prevention of Injury in Initial Military Training: A Randomized Controlled Trial.
Franklin-Millar A, Wilson C, Bilzon J, McCrory. Am J Sports Med. 2011 39(1): 30-37.
The use of foot orthoses have been a topic of much debate. Both the literature and anecdotal findings often have mixed results for the prevention of lower extremity overuse injuries. Nonetheless, orthotics are prescribed for a variety of lower extremity injuries and biomechanical abnormalities. There have been no randomized-controlled trials to examine the effect of orthotics on preventing overuse lower-extremity injuries. This study attempted to fill that void and provided more evidence to aid clinicians in the prescription of orthotics. Four hundred military officer trainees volunteered for the study. Half were randomly placed in the orthotic group and the other half served as the non-orthotic control group. Plantar pressure recordings were performed during normal gait and a computerized system determined the number of recommended corrections; which represented a level of risk for overuse injuries: 1 being medium risk and 2 or higher being high risk (based on the manufacturer’s normal range). Participants identified as no risk were excluded from the study. All of the participants performed the same training over the course of the seven-week basic training. Overuse injuries were recorded by the medical personnel and an injury was defined as missing 2 or more days. They found that the orthotic group sustained 21 lower extremity overuse injuries while the control group sustained 61 injuries. The absolute risk reduction was 0.49 with the use of orthotics.
This was a very well conducted and planned out study and I congratulate the authors for all the hard work that went into completing this study. As in any clinical study it is difficult to control for every variable that may affect the results but I believe they did a considerable job. The use of a military group allowed the amount, duration, and intensity of exercise to be very tightly controlled. They indicated that the groups were significantly different for some of the anthropometric measurements. Specifically, height, weight, and shoe size, which is known to influence injury rates. However, when looking closely at the means, although they may be statistically significant, they may not be clinically significant, with only very small differences between groups. One thing that was not reported in the study was the number of corrections that the computerized system suggested for members each group (perhaps one group had a greater risk for injury based on the plantar pressure analysis). I would also like to see what the most common recommended corrections were and if these were different between groups. We may be able to take these results even further and identify those with specific abnormalities at a higher-injury risk (although more subjects would be needed). Clinically, we know there are an endless amount of abnormalities that can occur in the foot. However, it is very difficult to identify these abnormalities without the use of customized software or being a podiatric genius. It would be very useful to develop clinical measurements that correlate with the results this software program calculates so that clinicians can become more effective at prescribing orthotics for patients and not need to purchase expensive equipment. Does anyone disagree with the results? Does anyone have any clinical pearls to offer for measuring these corrections clinically? I would like to hear everyone’s thoughts.
Written by: Stephen Thomas
Reviewed by: Jeffrey Driban