Rejection rate, modifications, and turnaround time for patient specific instrumentation plans in total ankle replacement

Abstract

Patient specific instrumentation (PSI) in total ankle replacement (TAR) has been reported to be accurate and time saving. However, there has been criticism regarding accuracy and an overreliance on the preoperative plan. This is a retrospective review of a single surgeon's PSI plans from 2016-2024. We report rejection rates, modifications, and turnaround time. A total of 101 plans were reviewed and found an overall rejection rate of 17.8 %, with 18 reports rejected. Average turnaround time was 29:07 hours. When comparing the 1st half of the study period to the second half, a statistically significant increase in rejection rate was found, 0 % to 45 %, p < 0.0001. In addition, there was a higher rate of rejection on more complicated stemmed implants or revision implants compared to low profile implants. This report shows there is not a blind trust of the engineer's plan, and with experience with PSI rejection rate increases. Also, the engineer's understanding of complicated cases is addressed with higher rates of rejection in complicated cases. This report refutes charges that surgeons that use PSI for TAR are overly reliant on CT-derived engineer produced plans. Further studies with national data or multiple surgeons should be undertaken to explore this further.