Is TKA using patient-specific instruments comparable to conventional TKA? A randomized controlled study of one system

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Medical Device Technology

Background:

• Patient-specific instrumentation (PSI) in total knee arthroplasty (TKA) aims to reduce malpositioning and improve alignment.
• The clinical benefit of PSI over conventional instrumentation remains uncertain.

Purpose of the Study:

• To compare the precision of PSI-TKA versus conventional TKA by analyzing postoperative alignment outliers.
• To assess the intraoperative reliability of PSI by determining if surgery can be completed using PSI alone.

Main Methods:

• A randomized controlled trial compared PSI-TKA (n=50) with conventional TKA (n=50).
• Postoperative alignment (hip-knee-ankle angle, component rotation, sagittal alignment) was measured.
• Intraoperative validity of PSI was assessed; conversion to conventional instruments was recorded if PSI failed.

Main Results:

• Outlier rates for hip-knee-ankle angle were similar between PSI and conventional groups (12% vs. 10%).
• No significant differences in outliers for sagittal alignment or femoral component rotation were observed.
• PSI guides were abandoned in 16% of cases due to malrotation or improper tibial slope, requiring conversion to conventional instruments.

Conclusions:

• The accuracy of TKA is comparable between PSI and conventional instrumentation.
• Frequent intraoperative abandonment of PSI procedures incurred additional costs without patient benefit.
• Current PSI systems may not offer a significant advantage over conventional methods in TKA.