ABSTRACTIntroductionOptimal outcomes in total hip arthroplasty are dependent on appropriate placement of femoral and acetabular components, with technological advances providing a platform for guiding component placement to reduce the risk of malpositioned components during surgery. This study will validate the intraoperative data captured using a handheld imageless THA navigation system against postoperative measurements of acetabular inclination, anteversion, leg length, and femoral offset on CT radiographs.Methods and analysisThis is a prospective observational cohort study conducted within a single-centre, single-surgeon private practice. Data will be collected for 35 consecutive patients (>18years) undergoing elective THA surgery, from the research registry established at the surgeon’s practice. The primary outcome is the agreement between intraoperative component positioning data captured by the navigation system compared to postoperative measurements using computed tomography (CT). A total of ten CT scans will be re-assessed for inter- and intra-observer reliability. The influence of patient and surgical factors on the accuracy of component position will also be examined with multivariable linear regression.Ethics and disseminationEthics approval for this study was provided through a certified ethics committee (Bellberry HREC approval number 2017-07-499). The results of this study will be disseminated through peer-reviewed journals and conference presentations.Strengths and limitations of this studyThis study will assess the accuracy of an imageless THA navigation system for measurement of component positioning against postoperative computed tomography analysis as gold standard.A sample size of n=35 participants will ensure adequate power to detect differences between intraoperative navigation results and postoperative CT measurements.A sample size of n=10 will provide adequate confidence to establish intra and inter-observer reliability of postoperative measurements of component positioning via CT analysis.This study will enable a mechanism to detect potential discrepancies between the component positioning measurement methods intrinsic to the Naviswiss™ device and postoperative CT analysis method and identify any corrective factors required for direct comparison of the two methods.
Validity of intraoperative imageless navigation (Naviswiss) for component positioning accuracy in primary total hip arthroplasty: protocol for a prospective observational cohort study in a single-surgeon practice
