Low accuracy of stem implantation in THR using the CASPAR-system: anteversion measurements in 10 hips

Area of Science:

• Orthopedic surgery
• Medical device technology
• Radiological imaging

Background:

• Computer-assisted surgery (CAS) systems aim to improve surgical accuracy.
• The CASPAR-system is utilized for computer-assisted total hip replacement.
• Accurate implant positioning is crucial for successful total hip arthroplasty outcomes.

Purpose of the Study:

• To evaluate the accuracy of implant positioning in total hip replacement using the CASPAR-system.
• To compare postoperative implant anteversion angles and translational deviations with preoperative surgical plans.
• To assess the reliability of the CASPAR-system in achieving precise stem placement.

Main Methods:

• Pre- and postoperative computed tomography (CT) scans were used for analysis.
• Ten patients undergoing computer-assisted total hip replacement with the CASPAR-system were studied.
• Quantitative measurements of stem anteversion and translational deviations were performed.

Main Results:

• An average difference of 7.8 degrees (SD 6.3) was found in anteversion angles.
• Average medial translational deviation was 1.8 mm (SD 1.7).
• Average lateral translational deviation was 1.2 mm (SD 1.4).

Conclusions:

• The study did not confirm the accuracy of implant positioning claimed by the CASPAR-system manufacturer.
• Significant deviations in stem anteversion and translational placement were observed.
• Further investigation into the precision of CAS systems in total hip replacement is warranted.