Abstract
Category:
Ankle Arthritis
Introduction/Purpose:
Preoperative navigation and patient-specific instrumentation has many theoretical benefits in total ankle arthroplasty (TAA). Potential benefits over standard instrumentation include decreased surgical time, improved implant alignment, decreased surgical complexity, and decreased fluoroscopy exposure. The purpose of this study was to compare the differences of operative time and fluoroscopy exposure between two total ankle arthroplasty techniques utilizing the same implant, one using an intramedullary referencing system and the other a computed tomography (CT) scan-derived guide.
Methods:
Between 2011-2013, 74 TAA cases in 73 patients were retrospectively reviewed from a single foot and ankle fellowship-trained orthopaedic surgeon at a single center. TAA implants used included 65 intramedullary referencing implants (INBONE II, Wright Medical Technology) and 9 CT scan-derived patient-specific plans and guides (PROPHECY, Wright Medical Technology). Patients with the custom guide had a standardized preoperative CT scan before surgery that was used to create a custom surgical plan and 3-dimensional cutting guide. Patient demographics and the reason for TAA were recorded. Total anesthetic/surgical/tourniquet time and the number of fluoroscopy shots taken during the case were compared. This study also recorded additional procedures performed at the time of the TAA.
Results:
Average age for all patients was 62.7. This included 38 males and 35 females, most commonly having a TAA for osteoarthritis (N=34) closely followed by post-traumatic arthritis (N=33). When comparing all patients in the INBONE II to the PROPHECY group, surgical time was 151.6 vs 129 minutes (p-value 0.056) and fluoroscopy exposure was 38 vs 30 shots (p-value 0.01). There were 5 additional procedures (average 0.55 per case) in the PROPHECY group compared to 75 additional procedures (average 1.2 per case) in the INBONE II group. In a subset group of patients without additional bone work, comparing the INBONE II (N=25) and the PROPHECY group (N=8), fluoroscopy exposure was 31.3 vs 29 shots (p-value 0.2), respectively. In patients without any additional procedures, the average surgical time and fluoroscopy exposure of INBONE II (N=8) compared to PROPHECY (N=4) group was 125.3 vs 125.5 minutes and 32.8 vs 29.1 shots.
Conclusion:
Results from this study suggest that there are no statistically significant differences between surgical time and fluoroscopy exposure, when comparing the INBONE II and PROPHECY TAA techniques. In one instance there was a statistically significant difference between fluoroscopy exposure, however, this compared groups with additional bone procedures, more likely to occur in the INBONE II group. Future studies are warranted to investigate larger sample sizes without co-founding variables and whether increased surgeon experience with the PROPHECY system will affect surgical time and fluoroscopy exposure, as it is a newer implant and our data could reflect the learning curve.