Reliability of Patient Specific Instrumentation in Total Knee Arthroplasty

The aim of this study is to evaluate the precision of a patient specific instrumentation (PSI) system as determined by pinless navigation system. Eighty patients were included in our prospective comparative study and they were divided into two homogeneous groups. The first group consisted of the patients that were operated by the PSI and the second group with the usual instrumentation. We defined an original score (maximum 30 points) to evaluate the accuracy of the cuts. This score is based on 6 objective criteria. The analysis indicated that the PSI was not superior to the conventional (p=0.434). However, we observed that the reliability of the femoral cuts was undermined in the PSI group compared to the UT group and a statistically significant difference for the mechanical axis (p=0.035) and for the thickness cut (p=0.025).