Accelerometer-Based Portable Navigation System Is Useful for Tibial Bone Cutting in Modified Kinematically Aligned...

Area of Science:

• Orthopedics
• Surgical Navigation
• Biomechanics

Background:

• Kinematically aligned total knee arthroplasty (KA-TKA) shows promising clinical outcomes compared to mechanical alignment.
• Accurate tibial bone resection is crucial for consistent KA-TKA reproduction.
• Computer navigation systems aid in achieving precise bone cuts.

Purpose of the Study:

• To compare an accelerometer-based portable navigation system (iASSIST) with a conventional navigation system (OrthoPilot) for tibial bone resection in KA-TKA.
• To evaluate the impact of these navigation systems on accuracy of bone cuts and clinical outcomes.

Main Methods:

• 60 patients undergoing primary KA-TKA were randomized into OrthoPilot and iASSIST groups.
• Tibial bone cuts were standardized (3° varus, 7° posterior slope).
• Accuracy was assessed by tibial component angle (TCA) and posterior slope angle (PSA) via radiography; outliers were defined as >2° deviation. Clinical outcomes included range of motion (ROM) and 2011 Knee Society Score (KSS) at 1 year.

Main Results:

• No significant differences were found between the OrthoPilot and iASSIST groups regarding mean TCA, PSA, number of outliers, ROM, or KSS categories.
• Both navigation systems demonstrated comparable accuracy in achieving the desired tibial bone cuts.
• Clinical outcomes at one year postoperation were similar between the two groups.

Conclusions:

• The accelerometer-based iASSIST system is a simple and useful navigation tool for kinematically aligned total knee arthroplasty.
• Both tested navigation systems provide comparable accuracy and clinical results for KA-TKA.
• Accurate tibial bone resection is achievable with both conventional and portable navigation systems in KA-TKA.