Trabecular orientation in the human femur and tibia and the relationship with lower-limb alignment for patients with osteoarthritis of the knee.

Wolff׳s Law suggests that the orientation of trabeculae in human bone changes in response to altered loading patterns. The aim of this study was to investigate trabecular orientation in both the femur and tibia and to compare this with the mechanical axis of the leg. The study involved analysis of radiographs from patients with osteoarthritis of the knee (n=91).

Experience curve compared with manufacturing processes for TKA.

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 < .

Factors affecting the learning curve in Computer Assisted Total Knee Arthroplasty.

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.

The statistical relationship between varus deformity, surgeon's experience, BMI and tourniquet time for computer assisted total knee replacements.

The outcome of total knee arthroplasty (TKA) with severe pre-operative varus deformity is significantly worse than in well aligned knees. Computer navigated TKA has addressed some of the problems by ensuring accurate post-operative alignment. Our aims were to see if navigation could reproducibly correct a varus deformity to 3 degrees of the mechanical axis and to investigate the relationships between the tourniquet time and severity of the preoperative deformity, BMI and a surgeon's experience.