Narrow Results

Purpose: Component position is critical in knee arthroplasty. We propose using a navigated knee axis (NKA) that is kinematically determined using a navigation system as an alignment reference, instead of defining the transepicondylar axis (TEA) with bony landmarks. This paper investigates whether this NKA should be computed over small arc segments versus over a full range of motion. Methods: Twelve unembalmed cadaver knees were tested. A navigation system computed the NKA for segments and for the full arc of motion in multiple planes. Results: The NKA computed near extension was different from the plane perpendicular to the mechanical axis (P > 0.005), while the NKA computed in flexion matched the TEA. Conclusion: The NKA determined from the full arc of motion was more reproducible and more closely estimated important knee parameters.