Validation of a CT-free navigation system for the measurement of native acetabular alignment

Computer assisted surgery is becoming more frequently used in medical world. OrthoPilotTM Hip Suite CT-free navigation system (BBraun Aesculap) is one such computer assisted navigation system used for total hip replacement surgery. The validity of OrthoPilot system remains to be determined independent of the manufacturer. The main aims of this study were to investigate the accuracy of OrthoPilot data, while using surgical instruments and to confirm the suitability of the cup navigation algorithm. OrthoPilot was compared with the gold standard of a VICON movement analysis system. An aluminium pelvic phantom was machined with high accuracy to perform the experiments. Data were captured simultaneously from both OrthoPilot and VICON systems and acetabular angles were compared. Both systems produce comparable results for the distance between anatomical landmarks and acetabular angles. It can be concluded that data from OrthoPilot system, if used correctly, are sufficiently accurate for orthopaedic applications.