Total knee replacement with an accelerometer-based, hand-held navigation system improves knee alignment: reliable in...

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Radiology

Background:

• Achieving optimal mechanical alignment is crucial for long-term implant survival in total knee arthroplasty (TKA).
• Accelerometer-based navigation (ABN) systems offer a potential solution for precise alignment.
• Limited evidence exists on ABN accuracy, particularly in younger patients (<65 years) with diverse arthritis etiologies.

Purpose of the Study:

• To evaluate the precision of a specific ABN system in restoring the mechanical axis during TKA.
• To analyze surgical variables and complication rates associated with ABN use.
• To specifically assess ABN performance in patients under 65 years of age.

Main Methods:

• Retrospective review of 310 primary TKAs performed using ABN between May 2016 and February 2021.
• Analysis of preoperative and postoperative radiological data, including mechanical axis, component alignment, and outliers.
• Collection of data on patient demographics (age, BMI), surgical time, follow-up duration, length of stay, pain, ROM, complications, and reoperations.

Main Results:

• 98% of TKAs achieved postoperative mechanical axis alignment within ±3° of neutral.
• Only 2% of knees fell outside the ±3° alignment range; 1.5% were outside ±5°.
• Factors like younger age, posttraumatic arthrosis, or prior surgery did not increase alignment outliers. No ABN-related complications were observed.

Conclusions:

• The ABN system is user-friendly and accurate in reducing coronal and sagittal alignment outliers in TKA.
• It provides a precise navigation solution that preserves surgeon autonomy and traditional instrumentation.
• Integration of this ABN system is recommended to improve TKA surgical precision across all patient groups.