Joint gap measurement in total knee arthroplasty using a tensor device with the same articulating surface as the...

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Surgical Instrumentation

Background:

• Total knee arthroplasty (TKA) requires precise measurement of joint gap for optimal outcomes.
• Existing methods may not accurately reflect intraoperative conditions post-implantation.
• A novel tensor was developed to mimic tibial liner geometry for accurate gap assessment.

Purpose of the Study:

• To evaluate the precision and reproducibility of a newly developed tensor for measuring the joint gap during TKA.
• To assess the intra-observer and inter-observer error associated with the tensor's measurements.
• To analyze joint gap changes throughout knee flexion after TKA implantation.

Main Methods:

• TKA was performed on four cadaveric knees using a modified gap technique.
• The novel tensor was employed to measure joint gaps at various flexion angles.
• Intra-observer and inter-observer errors were calculated from 168 measurements by two surgeons.

Main Results:

• The tensor demonstrated high precision with low inter-observer (0.8 mm) and intra-observer (0.3 mm) errors.
• Pre-implantation gaps were consistent (12.1 mm at extension, 12.5 mm at 90° flexion).
• Post-implantation gaps varied significantly with knee flexion, ranging from 9.1 mm to 13.8 mm.

Conclusions:

• The developed tensor offers precise and reproducible joint gap measurements in TKA.
• Joint gap dimensions change dynamically throughout knee flexion following TKA.
• Surgeons should account for this variability in joint gap during TKA procedures.