Are Pressure Time Integral and Cumulative Plantar Stress Related to 1(st) Metatarsophalangeal Joint Pain: The Multicenter Osteoarthritis Study.

OBJECTIVE: To examine the relationship between plantar stress over a step, cumulative plantar stress over a day and 1(st) metatarsophalangeal (MTP) joint pain among older adults. METHODS: Plantar stress and 1(st) MTP pain were assessed within the Multicenter Osteoarthritis Study (MOST). All included participants were asked if they had pain, aching or stiffness at the 1(st) MTP joint on most days for the past 30 days. Pressure time integral (PTI) was quantified as participants walked on a pedobarograph, and mean steps per day were obtained using an accelerometer. Cumulative plantar stress was calculated as the product of regional PTI and mean steps per day. Quintiles of hallucal and 2(nd) metatarsal PTI and cumulative plantar stress were generated. The relationship between predictors and the odds ratio of 1(st) MTP pain was assessed using a logistic regression model. RESULTS: Feet in the quintile with the lowest hallux PTI had 2.14 times increased odds of 1(st) MTP pain (95% confidence interval [95% CI]:1.42-3.25, p