Objective: Mechanical strain on the hip can result from varus malalignment of the foot. This study was undertaken to explore the cross-sectional relationship between varus foot alignment and hip conditions in a population of older adults.
Methods: The Framingham Osteoarthritis Study cohort consists of a population-based sample of older adults. Within this sample, we measured forefoot and rearfoot frontal plane alignment using photographs of a non-weight-bearing view of both feet of 385 men and women (mean age 63.1 years). Each foot segment was categorized according to the distribution of forefoot and rearfoot alignment among cases of ipsilateral hip pain, trochanter tenderness, hip pain or tenderness, and total hip replacement (THR). The relationship of foot alignment to these conditions was examined using logistic regression and generalized estimating equations, adjusting for age, body mass index, sex, and physical activity.
Results: The mean +/- SD rearfoot varus alignment was 0.7 +/- 5.5 degrees, and the mean +/- SD forefoot varus alignment was 9.9 +/- 9.9 degrees. Subjects in the highest category of forefoot varus alignment had 1.8 times the odds of having ipsilateral hip pain (P for trend = 0.06), 1.9 times the odds of having hip pain or tenderness (P for trend < 0.01), and 5.1 times the odds of having undergone THR (P for trend = 0.04) compared with those in the lowest category. No significant associations were found between rearfoot varus alignment and any hip conditions.
Conclusion: Forefoot varus malalignment may be associated with ipsilateral hip pain or tenderness and THR in older adults. These findings have implications for treatment, since this risk factor is potentially modifiable with foot orthoses.