Abstract:

Objective·To compare the pros and cons between digital simulation technology and conventional film template in predicting the prosthesis size before total knee arthroplasty (TKA) and provide evidence for perfect minimally invasive TKA. Methods·Sixty patients who underwent TKA from January 2015 to June 2015 were selected and assigned to the digital simulation group (DSG, n=30) and the conventional template group (CTG, n=30) based on a random number table method. In DSG, the prosthesis sizes were predicted by digital simulation of surgery, including osteotomy and placement of the prosthesis. In CTG, the comparisons between the film template and the knee X-ray radiographs were conducted to determine the prosthesis sizes. Predictive sizes and final sizes selected by surgeries were compared. The accuracies of prediction in the two groups were compared through statistical analysis of related data. Results·For the femoral prosthesis size prediction, there were 2 cases with a size difference of 1＃ and 1 case  with a size difference of 2＃ in DSG, and  7 cases with a size difference of 1＃ and 2 cases with a size difference of 2＃ in CTG. The accuracies for predicting femoral prosthesis size were 90.0% and 70.0% in DSG and CTG, respectively. For the tibial prosthesis size prediction, there were 2 cases with a size difference of 1＃ in DSG, and 8 cases with a size difference of 1＃ and 2 cases  with a size difference of 2＃ in CTG. The accuracies for predicting tibial prosthesis size were 93.3% and 66.7% in DSG and CTG, respectively. The differences between two groups were statistically significant. Conclusion·The prediction of prosthesis size with digital simulation technology is more accurate compared with conventional film template. This technology can provide evidence for preoperative planning, minimal invasion, and prosthesis preparation for TKA.

Key words: digital, total knee arthroplasty, prosthesis size, prediction