Precise pre- and postoperative anatomic measurements are necessary to plan, perform, and evaluate total knee arthroplasty
(TKA). We evaluated the relationship between radiographic and navigation alignment measurements, identified sources of error
in radiographic and navigated alignment assessment, and determined the differences between desired and clinically accepted
alignment. Fifty-eight computer-assisted TKAs were performed and limb alignment measurements were recorded both pre- and postoperatively
with standard radiographs and with an intraoperative navigation system. Intraoperative navigation produced consistent navigation-generated
alignment results that were within 1° of the desired alignment. The difference between preoperative radiographic and navigation
measurements varied by as much as 12° and the difference between postoperative radiographic and navigation measurements varied
by as much as 8°. This discrepancy depended on the degree of limb deformity. Postoperative radiographic measurements have
inherent limitations. Navigation can generate precise, accurate, and reproducible alignment measurements. This technology
can function as an effective tool for assessing pre- and postoperative limb alignment and relating intraoperative alignment
measurements to clinical and functional outcomes.
Level of Evidence: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
One or more of the authors (SDS) has received funding from Aesculap.
Each author certifies that his or her institution has approved the human protocol for this investigation, that all investigations
were conducted in conformity with ethical principles of research, and that informed consent for participation in the study
was obtained.