Teaching Tip: Using Knee Surgery to Illustrate Learning Curves

One of my favorite OM topics is learning curves (covered in Module E).  It takes only an hour of class time to cover well and it’s also a subject that is very motivational. When I tell students that understanding learning curves may save their lives one day, it catches their attention.

While  learning curves originated in the aircraft industry– and continue to drive production rates at Boeing today– an equally important application is in surgical procedures. I usually mention my friend the urologist, who has done thousands of kidney transplants. Who would you rather have operating on you?  A rookie on his or her 3rd or 6th transplant–or someone who is well down the experience curve?

In the text, we discuss one -year death rates for heart transplant patients, which follow  a 79% learning rate. Yesterday’s Wall Street Journal (Feb.14, 2012) provides a second medical example, with an article titled “Study Shows Knee Surgeons Have a Learning Curve”.  Here we find that if a patient’s ACL (anterior cruciate ligament) surgery was among the first 10 such cases of a surgeon’s career, the patient had 5 times the risk of having another ACL repair within a year as a patient whose doctor had performed more than 150 of the operations.

While it isn’t surprising that there is a learning curve, “it was striking to see the figures shown in such a dramatic way,” says the orthopedic professor who did the study.  ACL surgery, while routine, he adds, “is fairly complex.”  Potential pitfalls include incorrectly placing the graft, not fixing it solidly, and not dealing with other damaged ligaments in the area. Given that the learning curve is inevitable, what can be done? Two solutions are: have an experienced doctor supervise surgeries early in a new surgeon’s career, or use medical simulators in training.

Meanwhile, my 1st question is always: “How many times have you done this procedure?”