Table 2.

Temporal analysis of the CN-THA learning curve

Study (year)	LC analysis	Key findings
Inori et al. (2012) [21]	Initial 40 cases compared: A. Cases 1–20 B. Cases 21–40	After 20 cases, cup medialization showed marked improvement with a decreased mean discrepancy from 3.1° to 1.6 mm. No difference in deviation from planned cup height, anteversion, inclination, or LLD
Kamenaga et al. (2019) [27]	Initial 75 cases compared: A. Cases 1–25 B. Cases 26–50 C. Cases 51–75	Operative time and navigation time showed a marked decrease after 5 cases and then remained stable for the remaining 70 cases. No difference in deviation from planned cup inclination or anteversion between groups
Najarian et al. (2009) [29]	Initial 96 cases compared: A. Cases 1–49 B. Cases 50–96	Deviation from planned anteversion decreased after 49 cases (1.04° vs 0.85°). Deviation from planned inclination also decreased from 0.88° to 0.69°. Mean blood loss decreased from 520 to 356 mL No difference in operative time
Thorey et al. (2009) [25]	Initial 60 cases compared: A. Cases 1–30 B. Cases 31–60	Navigation time was significantly lessened in the latter 30 cases (13 vs 5 min). The first 30 cases showed a significant difference between intraoperatively planned and postoperative radiographic inclination (43.7° vs 47.3°) and anteversion (15.2° vs 20.9°). However, in the latter 30 cases, there was no difference in intraoperative and postoperatively measured inclination or anteversion, demonstrating improved placement accuracy after 30 cases
Wixson et al. (2005) [28]	Initial 82 cases compared: A. Cases 1–20 B. Cases 21–82	After 20 cases, cup anteversion and inclination accuracy showed marked improvement with experience, as 44% of cups were placed in the combined target zone in the first 20 cases, compared to 87% in the remaining cases
Kolodychuk et al. (2022) [23]	Learning curve was considered completed when the 5-case mean operative time was maintained within the 95% confidence interval of the mean operative time for conventional direct anterior THA	There was a learning curve of 31–35 cases based on operative time

CN-THA computer-navigated total hip arthroplasty, mm millimeters, LLD leg length discrepancy, mL milliliters, THA total hip arthroplasty