Orthoses alter in vivo segmental foot kinematics during walking in patients with midfoot arthritis.

OBJECTIVE To assess the effect of a 4-week intervention with a full-length carbon graphite (FL) orthosis on pain and function in patients with midfoot arthritis, and to identify alterations in in vivo foot kinematics accompanying FL use in patients with midfoot arthritis. These results have immediate application for enhancing patient care through effective orthotic recommendations. DESIGN Experimental laboratory study supplemented by a case series. SETTING University based clinical research laboratory. PARTICIPANTS Patients (n=30) with midfoot arthritis and age-, sex-, and body mass index-matched control subjects (n=20). INTERVENTION Four-week intervention with FL orthoses. MAIN OUTCOME MEASURES Pain and function were assessed using the Foot Function Index-Revised (FFI-R). In vivo foot kinematics were quantified as peak and total range of calcaneal eversion, forefoot abduction, first metatarsal plantarflexion, and first metatarsophalangeal joint dorsiflexion during walking in 2 conditions: with FL orthoses and with shoes only. A paired t test and repeated-measures analysis of variance were used to assess statistical significance (alpha=.05) of change in FFI-R score and in vivo foot kinematics, respectively. RESULTS Significant improvements in pain and function, discerned as lower FFI-R scores (P<.001), were noted after the 4-week intervention with FL orthoses. During walking, FL orthosis use resulted in decreased first metatarsophalangeal joint dorsiflexion (P=.024) and first metatarsal plantarflexion range of motion (P=.038), compared with the shoe-only condition. CONCLUSIONS Orthotic intervention emphasizing a "stiffening" strategy of the first metatarsal and first metatarsophalangeal joint may be valuable in patients with midfoot arthritis and early degenerative changes.