Changes in foot pressure distribution in pre-obese patients can potentially identify patients who are predisposed to foot complications should they eventually develop diabetes, according to a study recently published in Foot.

“A preliminary observation was done to see the effect of pressure distribution in the foot when normal subjects were asked to carry extra weight of 5 kilograms and 10 kilograms,” R. Periyasamy, study author and a research scholar and PhD candidate at the Indian Institute of Technology Delhi Center for Biomedical Engineering and India Institute of Medical Science, New Delhi, told O&P Business News. “The initial study showed that the estimation of the foot pressure distribution parameter-power ratio (PR) goes up in some areas primarily, but the pressure normalized once the weight increased to 10 kg.”

The researchers speculated the normalization was a result of the body adapting to the increased pressure.

“It is possible that any biological system where there is compensation can break down,” Periyasamy said. “We therefore wanted to know if there was a difference among the pre-obese subjects and non-obese subjects as far as the pressure distribution was concerned.”

Pressure distribution

The study included 11 non-obese and 11 pre-obese participants, which was determined by the patient’s body mass index (BMI). Static foot pressure images were obtained during standing on the right and left foot using a portable Pedopowergraph.

The researchers found a significant difference in PR in the midfoot region of the pre-obese participants when compared with the non-obese group.

“We found significant variation in PR value in midfoot and plantar ground contact area of pre-obese subjects compared to non-obese subject during standing because plantar pressure increase begins from the mid foot in low grade obese subjects (ie, pre-obese) due to an increase in midfoot contact area,” the authors wrote in the study.

However, they did not find any change in PR for the hindfoot and forefoot for the pre-obese group, which they attributed to the increase in BMI value.

“Increase in plantar pressure distribution over midfoot region among pre-obese subjects during static measurement demonstrates early changes in the biomechanical properties of the foot sole,” Periyasamy said. “It was surprising that the findings of the loading PR and results seen there were similar to what is seen in obese subjects.”

Foot complication indicators

According to Periyasamy, this is the first study that looked at pressure distribution while standing in a pre-obese population. These changes in midfoot PR values could indicate whether a patient is more likely to develop foot complications if they eventually develop diabetes.

“In pre-obese subjects, there is an increase in midfoot PR value compared with non-obese subjects,” Periyasamy said. “This implies if pre-obese subjects develop diabetes and subsequent neuropathy, then they may have a high predisposition to foot complications.”

Periyasamy said understanding the pressure distributions from image data of entire points on the plantar surfaces of both feet can provide suitable guidelines for corrective methods to offload the area of excessively high pressure and mitigate the risk for foot complications in pre-obese patients.

“Changes in pre-obese subjects may [reveal] important insights in the development of foot problems at an early stage,” Periyasamy said. “Documentation, surveillance and intervention may possibly prevent progression of foot deformities seen in obese subjects.” — by Megan Gilbride

For more information:
Periyasamy R et al. Foot. 2012. doi: 10.1016/j.foot.2012.08.009

Disclosure: The authors have no relevant financial disclosures.

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