Evaluation of plantar pressures in people with hallux valgus using principal component analysis.

BACKGROUND: Foot deformities are serious problems in the elderly as they increase the risk of falling.

OBJECTIVE: This study aimed to examine the relationship between foot plantar pressure during gait and hallux valgus (HV).

METHODS: Foot-pressure data were recorded using an F-scan II system. We analyzed the entire waveform of plantar pressure during gait from 37 healthy adults using principle component analysis (PCA), conducted using a 370 × 357 matrix of time-normalized plantar data of 7 areas during gait (5 gait trials × 2 (both feet) of 37 participants × 51 data points × 7 plantar areas). Two-way (plantar pressure × presence or absence of HV) analyses of variance were conducted on the principal component scores (PCSs) of principal component vectors (PCVs) 1 through 5, each of which exhibited more than 5% variance.

RESULTS: The PCA clarified that the 2nd, 3rd, and 5th PCVs (PCV 2, 3, and 5) were related to HV (p< 0.01). These PCVs exhibit a significant interaction between plantar pressure area and HV presence.

CONCLUSIONS: The larger plantar pressure of the HV group around the hallux area during walking compared with the non-HV group is a dominant difference in plantar pressure features due to HV.