Of the 315 feet treated in this study with severe HV deformity, the oblique shape of the first MTC joint was found in 165 or 52.4%, and the transverse shape in 145 feet or 46%. The oblique shape was dominated by moderate (46.1%) and severe (26.1%) degree of deformity measured by HVA in contrast to the transverse shape, which was dominated by mild deformity (44.1%). A statistically significant dependence of HVA and MTC joint shape was found (Sig. = 0.010). The influence of the shape of the joint on the value of HVA was investigated by one - factor analysis of variances. A statistically significant difference was found in the values of HVA in the three formed groups according to the form of the MTC joint, F (2,312) = 5,482, Sig. = 0.005 (Table 1). Subsequent comparison of Tukey's HSD test of the actual difference between the mean values of the groups showed that the mean value of HVU in feet with an oblique shape (N = 165, Me = 34.65, SD = 7.4, 95% Cl: from 33.51- 35.79, Min. = 18, Max. = 61) is statistically significantly different from the mean value of HVA in feet with the transverse shape (N = 145, Me = 32.59, SD = 7.106, 95% Cl: 31.43-33, 76, with Min. = 16, Max. = 50) with an average difference of R = -2.055, Sig. = 0.035, as well as the mean HVA in feet with a convex shape of the MTC joint (N = 5, Me = 26.6 , SD = 3,847,95Cl: from 21.82-31.38, and Min. = 22 and Max = 31) with average difference R = 8.048, Sig. = 0.039. These results are consistent with previously published 12,16 which found a significant dependence of HVA on the degree of stiffness and MTC of the joint.
The distribution of the subjects according to the severity of the deformity in relation to the IMA, in the oblique and the transverse shape is more even. However, the transverse shape is dominated by a mild degree (55.9%), and the oblique shape with a moderate degree of deformity (50.3%). Pearson's Chi square test showed that the relationship between IMA values and MTC joint shape was not statistically significant (Sig. = 0.105). The influence of MTC joint shape on IMA values was investigated by a one-factor analysis of variance. Differences in mean IMA values in the three groups were not statistically significant (F (2,312) = 2,636, Sig. = 0.073) (Table 2). Published results of previous studies10,12 that dealt with similar issues, found a significant correlation between IMA and the angle of medial angulation and MTC of the joint.
A statistically significant dependence of the position of the tibial sesamoid with HVA was found in both the transverse (Sig. = 0.002) and oblique shape of the MTC joint (Sig. = 0.000). One-factor analysis of variance of different groups showed the relationship between the position of the tibial sesamoid and HVA. A statistically significant difference was found between the average value of HVA formed groups according to the position of the tibial sesamoid both in the transverse (Sig. = 0.000, Eta squared = 0.188) and in the oblique shape (Sig. = 0.000 Eta squared = 0.172). (Table 3) Tukey's HSD test of actual differences showed a statistically significant difference in the mean value of HVA in cases of 'II' position of the tibial sesamoid in relation to 'III' in the oblique and transverse shape of the I MTC joint. (Sig. = 0.000). These results show that the form of the I MTC of the joint does not affect the ratio of the position of the tibial sesamoid to the corresponding HVU value.
The relationship between the value of IMA and the position of the tibial sesamoid differs depending on the form of the I MTC joint. Namely, in the oblique shape, a statistically significant dependence of IMA and tibial sesamoid position was found (Sig. = 0.002) and one-factor analysis determined a statistically significant difference in IMA values between the formed groups according to sesamoid position (Sig. = 0.000, Eta squared = 0.107). Pearson's Chi square test determined that in the transverse shape of the I MTC joint the described dependence was not statistically significant (Sig. = 0.102) while the one-factor analysis of variance showed the statistical significance of the difference between the formed groups (Sig. = 0.030, Eta square = 0.048). 4) Tukey's HSD test of actual differences showed a statistically significant difference in the mean value of IMA in cases of 'II' position of the tibial sesamoid in relation to 'III' in the oblique and transverse form of MTC joint (Sig. = 0.032).
The above results of the analysis show that in the transverse form of the MTC joint the position of the tibial sesamoid is not accompanied by the expected values of the IM angle. Dayton et al.6 indicate that pronation of the I MT bone significantly contributes to the positioning of the sesamoid mechanism on the AP radiograph. Most researchers agree that the pronation of the I MT bone is the result of movement in the frontal plane at the level of the MTC joint6,18,19,20 but the possibility of torsion as a structural change of the I MT bone is also investigated. 21 . This indicates the need to further examine the degree of pronation of the I MT bone in the transverse versus the oblique form and MTC joint.
HV deformity develops faster in the oblique form of the MTC joint, because in the first 15 years after the presence of the deformity, 94.55% occurred due to treatment, and in the transverse 82.76%. In the transverse shape of the MTC joint, a statistically significant dependence of HVA and the period of deformity development was found (Sig. = 0.013, Table 5), as well as IMA (Sig. = 0.049), while in other shapes this dependence was not statistically significant. One-factor analysis of variance showed that in the transverse shape there is a statistically significant difference in HVA values between the groups of the period of deformity development (F (4,140) = 4,507, Sig. = 0,002), while in the oblique shape this difference is not statistically significant (F (4,160) = 2.371, Sig. = 0.055) (Table 5).
Further analysis of the results showed that in persons under 18 years of age twice the prevalence of the oblique shape of the MTC joint (66.7%) compared to transverse (33.3%), and at the age of 60 and over where the oblique shape is also more prevalent (61.4%) compared to transversal (38.6%). In other age groups, the distribution is mostly even. Analyzing the dependence of HVA on the form of the first MTC joint in relation to the age of the subjects, we see that it is most pronounced in the age group from 33 to 46 years and that it is statistically significant (p = 0.016) (Fig. 3). One-factor analysis of variance showed that in the age group 33-46 years, the mean value of HVA in the oblique shape (N = 52, Me = 34.88, SD = 6.74.95% Cl: from 33.1 to 36.76) compared to transverse shape (N = 50, Me = 31.54, SD = 6.68.95% CL: from 29.64 to 33.44), statistically significantly different (Sig. = 0.013).