Background/Purpose: Osteoarthritis of the first metatarsophalangeal joint (1^st MTPJ OA) is a common and disabling condition characterised by symptoms of joint pain and stiffness, formation of a dorsal exostosis, and progressive reduction in range of motion of 1^st MTPJ dorsiflexion. Because the 1^st MTPJ plays an important role in transferring the body’s centre of mass over the foot during the propulsive phase of gait, individuals with 1^st MTPJ OA frequently adopt an apropulsive walking pattern. The objective of this study was to compare centre of pressure characteristics during walking in individuals with and without 1^st MTPJ OA, in order to provide insights into alterations in foot function associated with this condition.

Methods: Twenty people with 1^st MTPJ OA and 20 asymptomatic controls matched for age, sex and body mass index underwent gait analysis using the emed^®-x400 plantar pressure system (Novel GmbH, Germany). Average and maximum centre of pressure velocity and lateral-medial force index during loading, midstance, terminal stance and preswing were compared between the groups, adjusting for contact time.

Results: During the preswing phase of gait, maximum centre of pressure velocity was significantly slower in individuals with 1^st MTPJ OA (0.78 ± 0.19 vs 1.13 ± 0.36 m/sec; p=0.003), and both average and maximum lateral-medial force indices were significantly higher in individuals with 1^st MTPJ OA (0.98 ± 0.14 vs 0.82 ± 0.13; p<0.001 and 1.37 ± 0.29 vs 1.15 ± 0.15; p=0.008, respectively).  See Figures 1 and 2. Non-weightbearing 1^st MTPJ dorsiflexion range of motion was significantly associated with maximum centre of pressure velocity (r=0.54, p<0.001) and average lateral-medial force index (r=-0.44, p=0.004) during preswing.

Conclusion: These findings suggest that individuals with 1^st MTPJ OA may generate less forward momentum when walking due to a lateral transfer of force during propulsion, possibly due to decreased range of 1^st MTPJ dorsiflexion.