LAUSR

PURPOSE Etiology of hallux valgus (HV) remains unclear and effective treatments and prophylaxis for this condition are lacking and conclusions of researches concerning HV are inconsistent. Recognition of the function-structure interrelation in foot at the early stage of valgus alignment of first metatarsophalangeus joint (1stMTPJ) would help explain the etiology of HV. METHODS The frequency of weight-shifting patterns during walking and the body mass index (BMI) were assessed relative to goniometric measurements of the 1stMTPJ angle in adolescents. Weight-shifting patterns were identified with a plantar pressure analysis, performed with the Gaitline- Maxline Distance method. RESULTS As the 1stMTPJ angle widened, the frequency distributions of identified weight-shifting patterns became increasingly lopsided, due to the favoring or disfavoring of one pattern at the expense of the other. The two sexes showed opposite trends in the weight-shifting patterns that were favored/disfavored, relative to participants with a 0º 1stMTPJ angle. The clear predominance of a central-shift pattern, at the expense of a medial-shift, occurred with the largest (20º) 1stMTPJ angle among girls. Additionally, the BMI distributions associated with 1stMTPJ angle characteristics showed opposite trends between the sexes. CONCLUSIONS Valgus alignment of 1stMTPJ among adolescents were associated with limitations in weight-shifting freedom of the foot during walking, that could be involved in maintaining balance. An 1stMTPJ angle of 20º, where distinct limitations were observed, might serve as a criterion of HV pathology.