Abstract
Category:
Midfoot/Forefoot
Introduction/Purpose:
Metatarsalgia can result from both intrinsic and extrinsic causes of increased plantar pressure. The index patient in this study was a college professor with bilateral metarsalgia (and failed Morton’s neuroma surgeries). In clinic he was noted to be sitting with both feet positioned under his chair (Figure shows example of this position). He indicated that he sat in this position while using his computer for several hours at a time. He was counseled to sit with his feet flat and subsequently noted much improvement in his symptoms. Other patients were then noted to have metatarsalgia and similar computer use foot positions prompting this evaluation of forefoot plantar pressures in this sitting position.
Methods:
Fifteen patients (eight with computer foot and seven without) were seated in a chair that they could adjust to their normal sitting position. The patients wore socks of their choice but not shoes to avoid loading differences resulting from different types foot wear. A plexiglass plate portable pressure sensor was placed ln the floor. The pressure and contact area was measured for each foot with the foot flat and then the foot positioned with the foot directly under the edge of the chair.
Results:
The plantar pressures in the seated foot flat position ranged from 8-18 kg (some correlation with leg size/weight and self selected chair height). This pressure was fairly evenly distributed across the entire plantar foot. There were no right-left foot differences. The plantar pressures in the computer foot position (foot directly under the edge of the chair) increased by 40-60% while the contact area decreased by 50% or more. Positioning the foot as far under the chair as possible increased the pressures by an additional 10+%.
Conclusion:
Foot position while seated can result in increased loads on the plantar forefoot. Maintaining this position for long periods of time-as when working on a computer-can contribute to metatarsalgia . While rarely the only cause of metatarsalgia we have found that about 1/4 of patients with forefoot symptoms do acknowledge that they sit for periods of time in the computer foot position. Change in foot position commonly improves their foot symptoms