To evaluate the strength of association between standard pre & postoperative radiographic & intraoperative navigation coronal alignment measurements

Abstract

Background: Precise pre- and postoperative measurements of limb alignment are necessary to plan and evaluate the success of TKA. There is a wealth of published literature attesting to the precision of intraoperative navigation systems over radiographic measurement as ― gold standard for TKA alignment. Aims and Objectives: (1) To evaluate the strength of the association between standard pre- and postoperative radiographic and intraoperative navigation alignment measurements; (2) To determine the potential sources of error inherent to the process of radiographic and navigated alignment assessment; and (3) To examine the subtle differences that exist between desired alignment (anteroposterior [AP] mechanical axis and clinically accepted alignment (final alignment after the bone cuts were made and implants placed) as assessed through an intraoperative navigation system.Material and Methods: The study was conducted from April 2015 to May 2017. Data from a total of 60 consecutive total knee arthroplasties were included. Clinical measurement, radiographic measurement, computer navigation system measurement were carried out. BrainLab IV navigator was used in all cases.Results: Prior to surgery: The mean varus deformity as assessed on navigation was significantly lower in the navigation in comparison to the clinical assessment as well as by x-ray (p0.05).After surgery: The mean deformity was significantly higher on clinical assessment and X-ray (valgus) in comparison to the navigation (varus) (p