Effect of Coexisting Foot Deformity on Disability in Women with Knee Osteoarthritis

Abstract

Background: Knee osteoarthritis, a common musculoskeletal disorder, can cause considerable pain and disability. This study investigates the effect of certain foot deformities on the functional status of women with knee osteoarthritis. Methods: The common foot deformities pes planus and hallux valgus were evaluated in 115 women with knee osteoarthritis and Kellgren-Lawrence grade 2 and 3 osteoarthritis. Anteroposterior and lateral foot-ankle standard radiographs were obtained bilaterally. A lateral talometatarsal angle greater than 4° was defined as pes planus. A hallux valgus angle greater than 21° was defined as hallux valgus. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was used to objectively assess functional impairment. Knee pain intensity was measured with a visual analog scale. Results: Fifty-nine patients had bilateral pes planus, hallux valgus, or both. The mean visual analog scale value was higher for the deformity group, but the difference was not statistically significant. There was a significant difference in WOMAC scores between the group with foot deformities versus the group without (P = .000). Visual analog scale scores were positively correlated with WOMAC scores (r = 0.499, P = .000). Also, there was a significant correlation between WOMAC scores and lateral talometatarsal angle (r = 0.266, P = .004) and hallux valgus angle (r = 0.362, P = .000) values. Conclusions: There is a significant correlation between indicators of pain and disability (visual analog scale and WOMAC scores). Also, the presence of foot deformities increased disability levels in women with knee osteoarthritis. (J Am Podiatr Med Assoc 99(1): 23–27, 2009)