AB161. SOH26AB_0311. A retrospective analysis of the learning curve for total knee replacement for a newly appointed orthopaedic consultant: accumulative sum analysis

Background: Total knee replacement (TKR) is the most common large joint arthroplasty and presents a learning curve for new consultants. The cumulative sum (CUSUM) method is a statistical tool that visualises this curve, with the point of inflection indicating when operative efficiency is achieved. We aimed to apply the CUSUM score for a single consultant orthopaedic surgeon.

Methods: We reviewed the first 77 elective TKR procedures performed by a consultant orthopaedic surgeon in his initial post across public and private practice. Tourniquet time in minutes was recorded and ordered chronologically. A Mann-Whitney U test compared mean tourniquet times between the first 38 and the second 39 cases. CUSUM analysis was used to determine the learning curve and point of inflection.

Results: The overall mean tourniquet time was 68.23±22.24 minutes. Mean operative time for the first 38 cases was 68.84±14.68 minutes, compared with 57.27±8.95 minutes for the second 39, a significant difference (P=0.001). CUSUM analysis identified the point of inflection at case 32. There was also a significant difference in mean tourniquet time between public (76.53±29.09 minutes) and private (62.53±13.68 minutes) cases. Separate learning curves for public and private practice were generated.

Conclusions: The early portion of the learning curve showed fluctuation, suggesting an initial adjustment period as the surgeon adapted to new roles and environments. Efficiency was reached after approximately 33 cases. Public and private operative times differed significantly. Factors affecting the learning curve likely included case volume, adaptation to different hospital settings, and familiarity with the TKR procedure gained during fellowship.

Keywords: Cumulative sum (CUSUM); total knee replacement (TKR); learning curve; public; private