Accuracy of computer-navigated total hip arthroplasty

Area of Science:

• Orthopedic Surgery
• Medical Imaging
• Surgical Navigation

Background:

• Accurate acetabular cup positioning is critical for successful total hip arthroplasty (THA).
• Computer-assisted orthopedic surgery (CAOS) systems aim to improve surgical accuracy.
• Imageless navigation systems offer an alternative to traditional methods in THA.

Purpose of the Study:

• To assess the accuracy of an imageless computer navigation system in determining acetabular cup abduction and anteversion during THA.
• To compare intraoperative navigation measurements with postoperative radiographic findings.

Main Methods:

• Thirty-nine THA procedures utilizing an imageless computer navigation system were analyzed.
• Intraoperative cup abduction and anteversion measurements from the navigation system were recorded.
• These measurements were compared to cup orientation determined by follow-up radiographs.
• Statistical analysis included sensitivity, specificity, accuracy, and predictive values.

Main Results:

• The navigation system demonstrated high specificity (>90%) and positive predictive value (>94%) for identifying correct acetabular cup abduction and anteversion.
• However, the system showed limited sensitivity in detecting suboptimal cup positioning (abduction 50%, anteversion 33%).
• Intraoperative navigation readings within the 'safe zone' strongly indicated correct placement.

Conclusions:

• Imageless computer navigation in THA is reliable for confirming appropriate acetabular cup placement within the desired range.
• The system's low sensitivity necessitates supplementary diagnostic methods for intraoperative detection of malpositioned cups.
• Further advancements may be required to enhance the system's ability to identify and correct suboptimal cup orientations during surgery.