[Soft tissue balanced navigation of total knee arthroplasties]

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Medical imaging and navigation

Context:

• Symptomatic gonarthrosis often requires total knee arthroplasty (TKA) when conservative treatments fail.
• Achieving accurate component alignment and joint line restoration is crucial for TKA success.
• Imageless computer navigation systems offer potential for enhanced precision in TKA.

Purpose:

• To evaluate the accuracy of an imageless computer navigation system in achieving a correct mechanical axis, balanced joint gaps, and reconstructed joint line during TKA.
• To assess the incidence of joint gap instability and joint line malalignment following navigated TKA.

Summary:

• A consecutive series of 582 navigated TKAs were analyzed.
• The navigation system facilitated accurate restoration of the mechanical axis and joint line.
• Instability in extension and flexion gaps occurred in a small percentage of cases (0.2% and 1.4% respectively).
• Joint line reconstruction accuracy was high, with only 2.9% of cases showing elevation greater than 3mm.

Impact:

• This study validates the use of imageless computer navigation for precise TKA alignment.
• The findings suggest that computer-assisted surgery can lead to improved biomechanical outcomes in total knee replacement.
• Minimizing joint gap and joint line errors may contribute to better long-term function and patient satisfaction after TKA.