Learning curve of the 67 steps of conventional total knee replacement: an experimental study.

The instrumentation system for total knee replacement (TKR) has been there since the 1970s. The many steps and instruments are the main features despite several modifications over the last 50 years. This may lead to the accumulation of errors as certain steps are dependent on others. This study aimed to identify the errors while performing TKR by three trainees at different levels of training. Methods: Three trainees with different expertise performed the steps of TKR on bone models. One senior supervisor recorded the outcomes, including operative time and errors made during the experiment. Errors were further categorized into correctable and uncorrectable ones. Results: Most of the errors were made by the trainee with the least experience during the stages of femoral cutting, sizing, and rotation. The first-year resident has taken 1.25 times longer than the fellow in preparing the femur and 1.11 times in preparing the tibia. The recorded mistakes were 28, 8, and 3 for the first-year resident, the second-year resident, and the fellow surgeon, respectively. Fifteen of the mistakes were uncorrectable, and none of them were from the senior surgeon. Conclusion: The results of this study highlight the type of errors made by different trainees. This shows the steep learning curve of conventional instrumentation systems for trainees. Increasing cognitive skills and applying computer-assisted technologies may help trainees overcome this steep learning curve.