Prosthetic Categories

Effects of Prefabricated and Customized Insoles

    Lower-limb amputees sometimes develop foot pronation, a condition where most of the weight is on the inside of the foot when walking. Overpronation increases an individual’s risk of injury in the foot or the leg, so correcting it with exercise and using orthotic insoles is imperative.

     Researchers sought to determine the effects of prefabricated and customized insoles.

    However, podiatrists prescribe different insoles to reduce foot pronation; some prescribe prefabricated insoles, while others prescribe custom-made insoles. But what are the differences between these insole types?

    Researchers conducted a study to compare the effects of three types of insoles:

    1. Flat insole, which we’ll refer to in this article as the “control.”

    2. Prefabricated insole with arch support, which we’ll refer to in this article as “prefabricated.”

    3. Prefabricated insole with arch support plus a 6-degree inside wedge, which we’ll refer to in this article as “customized.”

    The effects of these three insoles were tested by study participants during walking and stepping up and down using statistical parametric mapping (SPM).  

    The study  

    Researchers analyzed the data of study participants aged 18 to 45 with a body mass index (BMI) of 28 kg/m² and a foot posture index of ≥ 6. Potential participants who reported discomfort or pain when using the insoles were excluded from the study. So, only a total of 10 women and nine men were able to complete the study.

    The researchers tested three insole conditions: control, customized, and prefabricated. The customized insole is essentially a prefabricated insole but added with a 6-degree inside wedge under the rear foot. The addition of the wedge is influenced by another study that found the wedge helped improve the movement of the lower limbs when running and walking.

    The results  

    During the walking test, the researchers found that both the customized and prefabricated insoles reduced the ankle eversion moment, which occurs when the ankle rolls outward, compared to the control insole.

    During the stepping up and down tasks, the researchers found that the customized insole increased the knee adduction moment, which reflects the inside-to-outside load distribution at the knee joint during walking. The researchers also found that the customized insole decreased the internal rotation of the hip joint during the stepping-down task.

    Therefore, the researchers noted that if the goal is to reduce foot pronation, it’s best to consider customized and prefabricated insoles. However, if the issue is in the knees or the hips, they recommend using the customized insole.

    The bottom line  

    Excessive foot pronation can lead to injuries. Therefore, reducing the foot eversion, increasing knee adduction moment, and decreasing medial rotation of the hip can help reduce pain and even improve function. Getting customized and prefabricated insoles reduce foot pronation, while the customized insole works best for those with knee or hip issues.