Abstract
Soft-tissue balancing is an important factor in primary total knee arthroplasty (TKA),
with 30 to 50% of TKA revisions attributed to technical operative factors including
soft-tissue balancing. Robotic-assisted TKA (RATKA) offers opportunities for improved
soft-tissue balancing methods. This study aimed to evaluate the repeatability and
reproducibility of ligamentous laxity assessments during RATKA using a digital tensioner.
Three experienced RATKA surgeons assessed preresection and trialing phases of 12 human
cadaveric knees with varying degrees of arthritis. Ligamentous laxity was assessed
with manual varus and valgus stresses in extension and flexion, with a digital tensioner
providing feedback on the change of laxity displacement. Intraclass correlation coefficient
(ICC) analyses were used to determine the repeatability within a single surgeon and
reproducibility between the three surgeons.
The results showed excellent repeatability and reproducibility in ligamentous laxity
assessment during RATKA. Surgeons had excellent repeatability for preresection and
trialing assessments, with median ICC values representing excellent reproducibility
between surgeons. Surgeons were repeatable within 1 or 1.5 mm for preresection and
trialing assessments. On average, the variation within a surgeon was 0.33 ± 0.26 mm
during preresection and 0.29 ± 0.28 mm during trialing. When comparing surgeons to
each other, they were reproducible within an average of 0.69 ± 0.33 mm for preresection
and 0.65 ± 0.31 mm for trialing.
This study demonstrated the reliability of robotic-assisted soft-tissue balancing
techniques, providing control over ligamentous laxity assessments, and potentially
leading to better patient outcomes. The digital tensioner used in this study provided
excellent repeatability and reproducibility in ligamentous laxity assessment during
RATKA, highlighting the potential benefits of incorporating robotics in TKA procedures.
Keywords
orthopaedic surgery - adult reconstruction - total knee arthroplasty - Mako
