This article is more than 5 years old. Information may no longer be current.
Navigation yielded reliable implant placement for ankle arthroplasty
Click Here to Manage Email Alerts
Total ankle arthroplasty performed with patient-specific surgical guides and preoperative computer-assisted navigation produced reliable and reproducible implant placement, based on preliminary results of the first study on the use of computer navigation for this procedure.
“Deviation was less than 2° in all planes of measurement, which was greater accuracy than 3° used in knee studies to determine when implants can cause increasing wear across that interface,” study investigator and president of the American Orthopaedic Foot and Ankle Society, Steven L. Haddad, MD, said at a recent meeting. “This reduces intraoperative fluoroscopy time, which helps us all as surgeons, and it creates less patient-specific alignment once it is done.”
Steven L. Haddad
Haddad and colleagues took CT scans of the distal tibia, proximal tibia, ankle and knee. They imported the data into a computer-aided design system to create anatomic landmarks and performed a virtual total ankle arthroplasty (TAA) in which they used commercially available implants. They reverse engineered a surgical guide using the anatomy of the cadaver.
Orthopedic surgeons who were experienced in TAA, but who had no experience using computer navigation, placed the guides. The procedure was repeated four times to test variability. The researchers tracked the tibia and talus using the Optitrack motion capture system (NaturalPoint; Corvallis, Ore.). The final position of the implants were confirmed by radiographs and 3-D CT scans.
“The guide in the tibia was accurate [less] than 1 mm and less than 1° in all circumstances amongst these surgeons, on average,” Haddad said. “Looking at the talar guide variation…we have less than 1 mm and less than 1° of improper accuracy placed across this region, i.e., this guide is completely accurate. We compared this to the Prophecy advanced knee system [Wright Medical Technology], finding in this case it is a validated system.”
Preoperative and postoperative implant positioning was within 2° and 1.4 mm of each other in all planes. The intra-observer tibia and talus guide variation was 0.25°±0.13° and 0.47°±0.51° in flexion/extension. Varus and valgus was measured at 0.50°±0.39° and 0.45°±0.34°, respectively, and internal and external rotation variation was measured at 0.92°±0.74° and 0.98°±0.54°, respectively, according to the abstract. – by Renee Blisard Buddle
Reference:
Disclosure: Haddad receives royalties from Wright Medical Technology is on the speaker’s bureau or performs paid presentations for Olympus BioTech; is a paid consultant for Arthrex Inc. and Wright Medical Technology; owns stock in Tornier and receives research support from Biomimetic.