Pedographic analysis of hallux valgus deformity

Abstract

Hallux valgus (HV) deformity exhibits a typical loading pattern of the forefoot characterized by a medio-lateral load transfer from the first metatarsal to the lesser metatarsals. The aim of this study was to determine the influence of radiologic characteristics of a HV deformity on the loading conditions of the forefoot. Eighty-two feet with a HV deformity have been evaluated. A dorsoplantar weight-bearing radiograph of the forefoot was used to determine the radiologic parameter (hallux abductus valgus angle and 1/2 intermetatarsal angle). Pedobarographic data was collected by the use of a capacitive pressure measurement platform. For each proband 10 acceptable trials were collected. The distribution of the peak pressure and pressure time integral showed the greatest values for the lateral forefoot (PP: 47.76 N/cm 2, P/T Int.: 17.81 N/cm 2∗ s), second for the medial toe (PP: 38.67 N/cm 2, P/T Int.: 12.53 N/cm 2∗ s), third for the medial forefoot (PP: 23.88 N/cm 2, P/T Int.: 9.44 N/cm 2∗ s), fourth for the lateral toes (PP: 18.77 N/cm 2, P/T Int.: 6.48 N/cm 2∗ s). Regarding the medio-lateral load transfer the following pressure variables were calculated: peak pressure (PP: 9.93 N/cm 2), pressure time integral (PT Int.: 5.33 N/cm 2 s) and force time integral ((BW ∗s: 23.4%). Radiologic parameter did neither correlate with pressure characteristics of the forefoot nor with the degree of the medio-lateral load transfer ( p<0.5). In HV deformity radiologic characteristics alone do not determine the loading parameters of the forefoot. Only the addition of radiologic characteristics and other varieties such as hindfoot alignment, hypermobility and sufficiency of the plantar fascia would be able to explain the typical pressure distribution of the forefoot.