Learning curve for the two-incision total hip replacement.

Recently there has been increased interest in doing total hip replacement through small incisions. One such technique is the two-incision approach. After initial investigations into its feasibility, Zimmer developed a training program for surgeons interested in doing the so called MIS 2-Incision Hip Procedure. An "index case" study was initiated to track the early experiences of trained surgeons, which includes 159 surgeons who have completed such training and recorded data on their initial cases. The purpose of this report is to present the data available from this index case study regarding the process of developing proficiency with the two-incision total hip replacement. We found a significant decrease in the mean operative time and fluoroscopy time from the first to tenth case. Key complications did not show a systematic decrease as a function of case number for the first ten cases. Clarification of the entire learning curve for this technique requires further investigation but may last beyond case ten for many surgeons. In addition, data from this study suggests that patient characteristics and surgeon experience have a significant effect on the prevalence of complications with the two-incision technique. The evolution of minimally invasive joint replacement is clearly in its infancy. Complication rates and the demonstrated learning curve may be altered by changes in training and surgical techniques.