# Obstacle Crossing in Older Adults with Total Knee Arthroplasty at the Initial Swing Phase
## 3 Results  
### Participant Characteristics and Gait Parameters  
Forty participants took part in the study. Twenty underwent TKA before surgery and they visited the lab for check-ups until their sixth postoperative month. Excluding the three who withdrew from participation, the final analysis engaged thirty-seven participants. The control group included twenty healthy participants. Table 1 shows the characteristics of all participants. There were no significant differences in age, height, and skeletal muscle mass. However, body weight and body mass index had differences as the preoperative TKA was usually heavier. According to the severity of knee OA, participants with KL grades 3 and 4 represented 70% and 30% of all participants, respectively (Table 1). Thirteen patients were concerned with the right knee, whereas the remaining seven with the left knee. Of those with radiographic knee OA, 75% exhibited a varus knee and 25% a valgus knee. Table 2 shows clinical and gait parameters at the level walk. At six months postoperatively, significant differences were mostly found in the five subscales of the KOOS (symptoms, pain, activity daily living, sport and recreation function and QOL) among the patient groups (\(p<0.05\)). The global satisfaction with five subscales was improved especially the quality of life. For level walking, the spatiotemporal parameters of TKA at six months had a significant difference compared to the control group. However, no difference was found among groups of TKA patients in terms of all parameters, except the gait speed of TKA at six months. This parameter indicates that TKA at six months walked faster than TKA at three months (0.73 \(\pm\) 0.12 m/s vs. 0.61 \(\pm\) 0.12 m/s; \(p<0.05\)). In addition, the six months of TKA exhibited the same vertical position as the control group (2.43 \(\pm\) 0.72 cm vs. 2.22 \(\pm\) 0.67 cm, \(p=0.347\)), which occurred at around 50% of the swing phase (Table 2, Figure 3a). At the time of TC, the preoperative TKA exhibited significantly greater hip flexion than the three-month postoperative TKA (\(p<0.05\)). The knee flexion and ankle dorsiflexion were not different among the TKA patients (\(p=0.464\), \(p=0.386\)). In addition, the hip flexion and the knee flexion of the TKA at six months were found to be significantly lower than that of the controls (\(p<0.05\)) and ankle dorsiflexion was not significantly different between the groups (\(p=0.692\)). Table 2 presents the active joint position sense of the knee. The AE values did not differ significantly within pre-TKA and post-TKA groups. Similar results were demonstrated in AE between the TKA groups and control groups. Regarding the lower limb strength, there was no significant difference in quadriceps muscle strength between pre-TKA and \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameters** & **Preoperative TKA (\(n=20\))** & **Control (\(n=20\))** & \(p\)**-Value** \\ \hline Demographic & & & \\ Age (year) & 71.65 (5.90) & 70.40 (3.69) & 0.427 \\ Height (cm) & 150.30 (6.16) & 153.33 (4.44) & 0.083 \\ Body weight (kg) & 61.43 (10.69) & 54.34 (8.08) & 0.023 \({}^{\ast}\) \\ Body mass index (kg/m\({}^{2}\)) & 27.09 (3.63) & 22.99 (2.80) & 0.001 \({}^{\ast}\) \\ Skeletal muscle mass (kg) & 18.91 (2.54) & 18.92 (2.06) & 0.995 \\ \hline \hline \multicolumn{4}{c}{The knee characteristics} \\ K/L grade, number (\%) & & \\ Grade 3 & 14 (70\%) & - & \\ Grade 4 & 6 (30\%) & - & \\ Knee OA localization, number (\%) & & \\ Right & 13 (65\%) & - & \\ Left & 7 (35\%) & - & \\ Knee alignment, number (\%) & & \\ Varus & 15 (75\%) & - & \\ Valgus & 5 (25\%) & - & \\ \hline \hline \end{tabular} Values are reported as mean \(\pm\) SD, or \(n\) (\(\%\)). \({}^{\ast}\) Significance value set at \(p<0.05\).  
\end{table} 
Table 1: Participant demographics and clinical characteristics. post-TKA groups. The TKA groups had considerably less knee extensor strength than the control group. In the hamstring muscle, a comparable result was obtained.