Comparison of extramedullary versus intramedullary referencing for tibial component alignment in total ankle arthroplasty.


BACKGROUND: The majority of total ankle arthroplasty (TAA) systems use extramedullary alignment guides for tibial component placement. However, at least 1 system offers intramedullary referencing. In total knee arthroplasty, studies suggest that tibial component placement is more accurate with intramedullary referencing. The purpose of this study was to compare the accuracy of extramedullary referencing with intramedullary referencing for tibial component placement in total ankle arthroplasty. METHODS: The coronal and sagittal tibial component alignment was evaluated on the postoperative weight-bearing anteroposterior (AP) and lateral radiographs of 236 consecutive fixed-bearing TAAs. Radiographs were measured blindly by 2 investigators. The postoperative alignment of the prosthesis was compared with the surgeon's intended alignment in both planes. The accuracy of tibial component alignment was compared between the extramedullary and intramedullary referencing techniques using unpaired t tests. Interrater and intrarater reliabilities were assessed with intraclass correlation coefficients (ICCs). RESULTS: Eighty-three tibial components placed with an extramedullary referencing technique were compared with 153 implants placed with an intramedullary referencing technique. The accuracy of the extramedullary referencing was within a mean of 1.5 ± 1.4 degrees and 4.1 ± 2.9 degrees in the coronal and sagittal planes, respectively. The accuracy of intramedullary referencing was within a mean of 1.4 ± 1.1 degrees and 2.5 ± 1.8 degrees in the coronal and sagittal planes, respectively. There was a significant difference (P < .001) between the 2 techniques with respect to the sagittal plane alignment. Interrater ICCs for coronal and sagittal alignment were high (0.81 and 0.94, respectively). Intrarater ICCs for coronal and sagittal alignment were high for both investigators. CONCLUSIONS: Initial sagittal plane tibial component alignment was notably more accurate when intramedullary referencing was used. Further studies are needed to determine the effect of this difference on clinical outcomes and long-term survivability of the implants. LEVEL OF EVIDENCE: Level III, retrospective comparative study.





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Publication Info

Adams, Samuel B, Constantine A Demetracopoulos, Nicholas A Viens, James K DeOrio, Mark E Easley, Robin M Queen and James A Nunley (2013). Comparison of extramedullary versus intramedullary referencing for tibial component alignment in total ankle arthroplasty. Foot Ankle Int, 34(12). pp. 1624–1628. 10.1177/1071100713505534 Retrieved from

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Samuel Bruce Adams

Associate Professor of Orthopaedic Surgery

James Keith DeOrio

Professor of Orthopaedic Surgery

Mark Erik Easley

Associate Professor of Orthopaedic Surgery

James Albert Nunley

Goldner Jones Distinguished Professor of Orthopaedic Surgery

My current research interests are both clinical and basic science. Currently, in the Orthopaedic Research Laboratory, we are investigating the biomechanical properties of the deltoid ligament in the ankle. This is a clinically relevant problem and we will hopefully identify ways to improve the correction of the adult relaxed flat foot. We are also performing a preliminary investigation into the blood supply of the distal tibia to look for a vascularized bone transfer.

We have recently completed a biomechanical study looking at the strength of fixation for proximal metatarsal osteotomies in the correction of hallux valgus and that information has been submitted for publication.

Clinical projects have looked into nerve palsies after total elbow replacement and to reconstructive upper and lower extremity surgery.

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