# Learning Curve in Robotic-Assisted Total Knee Arthroplasty: A Systematic Review of the Literature
## 4 Discussion  
The use of raTKA is steadily increasing in everyday surgical practice leading to several advantages, such as the reduction of radiographic outliers and risks of atrogenic soft tissue injuries [14]. Nevertheless, these advantages must be related to higher costs, increased surgical time, and a long learning curve [8,14]. This systematic review aims to evaluate data on the raTKA learning curve in three different areas: surgical time, lower limb alignment, and complications. The main findings of this paper are focused on surgical time. In most cases, the inflection point was recorded between the first 5 and 20 cases, regardless of the surgeon's experience. The first and last cases reported a significant reduction in surgical time [22, 23, 24, 25, 26, 27, 28]. Additionally, few studies report the raTKA learning curve regarding lower limb alignment, component position, and intraoperative and postoperative complications [21,23,24]. The main finding of this systematic review is that the inflection points in raTKA range from 5 to 43 cases, with a mean of 14.9 cases. In addition, an average decrease in surgical time of 23.9 min was described between the initial and proficiency phases; the average surgical time in the two phases was 98.8 min and 74.4 min, respectively [21, 22, 23, 24, 25, 26, 27]. [PERSON] et al., in their study, reported that an experienced surgeon could flatten the learning curve, suggesting that companies should provide surgical support from trained personnel during initial cases [21]. Surgical time may be considered an evaluation index of the learning process for surgical procedures. Multiple factors, such as familiarity with displays, landmark registration, and resection techniques, were related to surgical time procedures [38, 39, 40]. Several studies included in this review reported improved surgical time in the latter cases compared with the first cases [22, 23, 24, 25, 26, 27, 28]. [PERSON] et al. reported that the average surgical time improved significantly between the first and last 50 cases [22]. Similarly, [PERSON] et al. [23] and [PERSON] et al. [27] reported a statistically significant reduction in surgical time in their respective studies. [PERSON] et al. [28] reported a significant improvement in surgical time for only one of the two surgeons involved in their research. Controversially, the results compare the average intervention time of raTKA and mTKA. [PERSON] et al. [24] and [PERSON] et al. [32] reported that the overall time of raTKA was \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Author and Publication Year** & **raTKA** & **Learning/Proficiency Phase** & **Complications Related to raTKA** & **Complications Not Related to raTKA** \\  & **N\({}^{\circ}\)** & **N\({}^{\circ}\)** & N\({}^{\circ}\)** & N\({}^{\circ}\) \\ \hline \hline [PERSON] et al. & \multirow{4}{*}{90} & One complication during the learning phase (1 arthritis). & \multirow{4}{*}{0} & 2 arthritis fibrosis, 1 surgical site infection, 1 deep vein thrombosis \\ (2021) [23] & & Three complications after reaching the proficiency phase & & & \\  & & (1 arthritis fibrosis, 1 surgical site infection, 1 deep vein thrombosis) & & \\  & & infection, 1 deep vein thrombosis). & & & \\ \hline [PERSON] et al. & \multirow{4}{*}{604} & N/A & N/A & N/A \\ (2022) [22] & & & & \\ \hline [PERSON] et al. (2022) [27] & 58 & N/A & 0 & N/A \\ \hline [PERSON] et al. [32] & 40 & N/A & 0 & N/A \\ \hline [PERSON] et al. [30] & 202 & N/A & 0 & N/A \\ \hline [PERSON] et al. [28] & 120 & N/A & N/A & 2 arthritis fibrosis, 1 celluitis, 1 acute kidney injury, 1 congestive heart failure \\ \hline \hline \end{tabular}
\begin{tabular}{c c c} \hline \hline  & & 2 arthritis fibrosis, 1 intraoperative tibial \\  & & 1 fatal pulmonary embolism \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._significantly higher than mTKA. On reaching the inflection point, the average surgical time did not differ between mTKA and raTKA [24; 29; 35]. [PERSON] et al.