No abstract

In the experience curve concept set forth by the National Aeronautics and Space Administration (NASA), production time falls by a set percentage every time cumulative production doubles. NASA has established benchmark figures for different manufacturing processes, and we have used these figures in analyzing our first 240 navigated total knee arthroplasties for varus knees. Our experience curve was 93% (P < .001), which is similar to the experience curve (90%) for processes consisting of 25% hand assembly and 75% machining. We suggest that the experience curve may provide a guide for comparing different surgical teams and navigation systems and for resource allocation.

Mathematical modeling of learning curves have been used in industry since 1936. The advent of Computer Assisted Total Knee Arthroplasty allows the collection of hard data. We present our finding of a statistically significant mathematical model relating operative time, body mass index, experience of the surgeon and preoperative varus deformity in a prospective study of 241 computer assisted total knee arthroplasties. To the best of our knowledge, such a model has not been described before.