## 3 Results  
We obtained an intra-observer error in the preoperative right knee measurements for MBE = 0.41\({}^{\circ}\), SD = 0.14\({}^{\circ}\), and 95% CI: 0.36\({}^{\circ}\)-0.46\({}^{\circ}\) and MBE = 0.42\({}^{\circ}\), SD = 0.12\({}^{\circ}\), and 95% CI: 0.38\({}^{\circ}\)-0.46\({}^{\circ}\) for the left knee. We obtained an inter-observer error in the preoperative right knee measurements for MBE = 0.5\({}^{\circ}\), SD = 0.17\({}^{\circ}\), and 95% CI: 0.43\({}^{\circ}\)-0.57\({}^{\circ}\) and MBE = 0.49\({}^{\circ}\), SD = 0.12\({}^{\circ}\), and 95% CI: 0.38\({}^{\circ}\)-0.53\({}^{\circ}\) for the left knee. Table 1 shows the different comparisons' MBE values for intra- and inter-observer errors. Table 1 shows the values of the mean bias error (MBE); the reliability or standard deviation (SD), which described the variability within a single sample; the sample standard error (SEM), which estimated the variability across multiple samples; and the SEM for a 95% confidence interval (CI). T2T1 corresponds to the pair of measurements used to obtain the intra-observer error between the second and the first measurement rounds, T3T2 refers to that between the third and the second, and T3T1 refers to that between the third and the first. T1 shows the inter-observer error in the first round of measurements, T2 shows that in the second, and T3 shows that in the third. No significant differences were found when analysing the intra-observer error distributions by ANOVA (\(p\) = 0.205). When analysing the inter-observer error distributions, we also found no significant differences (\(p\) = 0.215), and so we accepted the hypothesis of the equality of the means. However, in the post hoc rank test (Tukey's test), when comparing the differences in the inter-observer error MBE values for each pair of distributions, we \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{6}{c}{**Right Knee Intra-Observer Error**} & \multicolumn{6}{c}{**Left Knee Intra-Observer Error**} \\ \hline  & **T2T1** & **T3T2** & **T3T1** & **T2T1** & **T3T2** & **T3T1** \\ \hline MBE & 0.43\({}^{\circ}\) & 0.37\({}^{\circ}\) & 0.43\({}^{\circ}\) & MBE & 0.45\({}^{\circ}\) & 0.40\({}^{\circ}\) & 0.40\({}^{\circ}\) \\ SD & 0.19\({}^{\circ}\) & 0.10\({}^{\circ}\) & 0.12\({}^{\circ}\) & SD & 0.10\({}^{\circ}\) & 0.14\({}^{\circ}\) & 0.12\({}^{\circ}\) \\ SEM & 0.04\({}^{\circ}\) & 0.02\({}^{\circ}\) & 0.02\({}^{\circ}\) & SEM & 0.02\({}^{\circ}\) & 0.03\({}^{\circ}\) & 0.02\({}^{\circ}\) \\
95\% CI & 0.36\({}^{\circ}\)-0.50\({}^{\circ}\) & 0.33\({}^{\circ}\)–0.41\({}^{\circ}\) & 0.38\({}^{\circ}\)–0.48\({}^{\circ}\) & 95\% CI & 0.41\({}^{\circ}\)–0.49\({}^{\circ}\) & 0.35\({}^{\circ}\)–0.45\({}^{\circ}\) & 0.36\({}^{\circ}\)–0.44\({}^{\circ}\) \\ \hline \multicolumn{6}{c}{**Right Knee Inter-Observer Error**} & \multicolumn{6}{c}{**Left Knee Inter-Observer Error**} \\ \hline  & **T1** & **T2** & **T3** & **T1** & **T2** & **T3** \\ \hline MBE & 0.49\({}^{\circ}\) & 0.50\({}^{\circ}\) & 0.49\({}^{\circ}\) & MBE & 0.54\({}^{\circ}\) & 0.50\({}^{\circ}\) & 0.43\({}^{\circ}\) \\ SD & 0.18\({}^{\circ}\) & 0.17\({}^{\circ}\) & 0.16\({}^{\circ}\) & SD & 0.12\({}^{\circ}\) & 0.13\({}^{\circ}\) & 0.11\({}^{\circ}\) \\ SEM & 0.04\({}^{\circ}\) & 0.03\({}^{\circ}\) & 0.03\({}^{\circ}\) & SEM & 0.02\({}^{\circ}\) & 0.03\({}^{\circ}\) & 0.02\({}^{\circ}\) \\
95\% CI & 0.52\({}^{\circ}\)–0.56\({}^{\circ}\) & 0.43\({}^{\circ}\)–0.57\({}^{\circ}\) & 0.43\({}^{\circ}\)–0.55\({}^{\circ}\) & 95\% CI & 0.49\({}^{\circ}\)–0.59\({}^{\circ}\) & 0.45\({}^{\circ}\)–0.55\({}^{\circ}\) & 0.39\({}^{\circ}\)–0.47\({}^{\circ}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Mean bias errors for the intra- and inter-observer errors (n = 26 and n = 26). obtained a significant difference (\(p\) = 0.002) at a confidence level of at least 95% in the analysis of tests 1 (T1) and 3 (T3) of the left lower extremity.