Minimally invasive unicompartmental knee replacement with a nonimage-based navigation system.

Area of Science:

• Orthopedic Surgery
• Medical Technology
• Biomechanical Engineering

Background:

• Unicompartmental knee replacement (UKR) is a surgical procedure to address knee joint osteoarthritis.
• Accurate alignment of prosthetic components is crucial for optimal UKR outcomes and longevity.
• Minimally invasive techniques aim to reduce surgical trauma, but achieving precise alignment can be challenging.

Purpose of the Study:

• To compare the effectiveness of a CT-free navigation system versus conventional minimally invasive techniques in UKR.
• To evaluate the impact of computer-assisted surgery on postoperative alignment accuracy in UKR.

Main Methods:

• A prospective study involving two groups of 20 patients undergoing UKR.
• One group received UKR using a CT-free navigation system; the other used conventional minimally invasive surgery.
• Postoperative alignment was assessed using long-leg coronal and lateral radiographs.

Main Results:

• A significant difference in postoperative alignment was observed, favoring the navigation group.
• 95% of UKRs in the computer-assisted group achieved the desired varus alignment (mechanical axis), compared to 70% in the conventional group.
• The navigation group experienced a mean increase in operation time of 19 minutes.

Conclusions:

• CT-free navigation systems enhance precision in component orientation during UKR.
• Real-time leg axis information provided by navigation systems helps mitigate the risk of overcorrection.
• Computer-assisted navigation is a valuable tool for improving alignment accuracy in UKR surgery.