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

No statistically significant differences were found in discrete plantar pressure variables between MTPJ1 OA and control groups across any of the four activities.

• Participants with MTPJ1 OA (n=22) and matched controls (n=21) were recruited for this case-control study.
• Four activities were assessed: standing, walking, stair ascent, and heel raise.
• Discrete pressure variables were analyzed at anatomical regions.
• The absence of differences in discrete variables is consistent with previous studies showing limited evidence of plantar pressure alterations during level walking.

Statistical parametric mapping revealed reduced loading under the distal first metatarsal head in the MTPJ1 OA group during walking.

• The reduction in loading under the distal first metatarsal head occurred during 60%–80% of stance phase.
• This finding was identified using statistical parametric mapping (SPM), a continuous analysis method, rather than discrete variable analysis.
• SPM detected differences that were not captured by traditional discrete variable analysis.

Statistical parametric mapping revealed increased midfoot pressures in the MTPJ1 OA group during stair ascent.

• Increased midfoot pressures occurred at 70%–80% of stair ascent stance phase.
• This finding was only detected using SPM and not by discrete variable analysis.
• Stair ascent was hypothesized to stress the MTPJ1 to a greater extent than standard level walking.

Statistical parametric mapping revealed decreased lateral forefoot pressure in the MTPJ1 OA group during heel raise.

• Decreased lateral forefoot pressure was identified during the heel raise activity.
• This finding was detected only through SPM analysis and not discrete variable analysis.
• Heel raise was included as an activity hypothesized to stress the MTPJ1 to a greater extent than standard gait.

The study hypothesized that activities stressing the MTPJ1 more than standard gait would reveal greater plantar pressure differences between MTPJ1 OA and healthy participants.

• Previous studies have presented limited evidence of alterations in plantar pressures during level walking in MTPJ1 OA.
• Four activities were selected to span a range of joint loading demands: standing, walking, stair ascent, and heel raise.
• The study was a case-control design with 22 OA participants and 21 matched controls.
• Both discrete pressure variable analysis and statistical parametric mapping were used to assess between-group differences.

The authors suggest that identified regions of plantar pressure difference in MTPJ1 OA may be targeted by interventions such as foot orthotics as part of a personalized treatment program.

• Regions of difference included under the distal first metatarsal head, the midfoot, and the lateral forefoot.
• The authors note that MTPJ1 OA contributes to activity restrictions and reduced quality of life along with biomechanical changes that affect the joint and beyond.
• The study was classified as Level IV evidence, case-control design.