Effects of First Metatarsophalangeal Osteoarthritis on Plantar Pressures Across Multiple Activities.

backgroundThe first metatarsophalangeal joint (MTPJ1) is one of the sites most often affected by osteoarthritis (OA). The condition contributes to activity restrictions and reduced quality of life along with biomechanical changes that affect the joint and beyond. Despite this, previous studies have presented limited evidence of alterations in plantar pressures during level walking. In this case-control study, we hypothesized that activities that may stress the joint to a greater extent than standard gait may reveal greater differences in plantar pressures between those with MTPJ1 OA and healthy feet.

methodsParticipants with MTPJ1 OA (n = 22) and matched controls (n = 21) were recruited for this study. All were asked to perform four activities while plantar pressures were measured: standing, walking, stair ascent, and heel raise. Analysis of discrete pressure variables at anatomical regions and statistical parametric mapping was used to determine if there were significant differences in pressures between MTPJ1 OA and control groups.

resultsNo differences were found for discrete variables across the activities, however, statistical parametric mapping revealed differences for the MTPJ1 OA group, including reduced loading under the distal first metatarsal head (60%-80% of stance), increased midfoot pressures at 70%-80% of stair ascent, and decreased lateral forefoot pressure during heel raise.

conclusionMTPJ1 OA is associated with limited changes in plantar pressures across different activities. These regions of difference may be targeted by interventions such as foot orthotics as part of a personalized treatment program. LEVEL OF EVIDENCE: Level IV, case control study.