Assessment of within- and between-rater Reliability for Soft Tissue Laxity during image-based robotic assisted Total
Henriëtte M Eijking1,2, Emil H van Haaren1, Roel Hendrickx1
1Excellence Center for Hip & Knee Arthroplasty, Department of Orthopeadic Surgery, Zuyderland Medical Center, the Netherlands.
Background:
Despite developments in the prosthetic design, surgical techniques and instrumentation including the incorporation of robotic-assistance for total knee arthroplasty (RATKA), the success rate of total knee arthroplasty has not markedly improved over the past decade. Recent advancements emphasize the importance of the soft tissue and the data-driven restoration of the native anatomy. In this study, we aim to evaluate the reliability of robotically captured data on soft tissue assessment by measuring the within- and between-rater reliability of gap assessment.
Methods:
From an ongoing randomized controlled trial, gap laxity was assessed in 26 patients undergoing RATKA by the operating senior surgeon (twice) and the orthopeadic surgeon in training (once). Soft tissue laxity was evaluated instrument-assisted and manually in both full extension and 90-degrees of flexion for varus and valgus stress. Reliability was determined using intraclass correlation coefficients (ICC). Bland-Altman plots were employed to assess agreement between observers.
Results:
The reliability of gap assessment was excellent when performed instrument-assisted for both within- and between rater reliability. When gap assessment was performed manually in full extension, both lateral and medial, between-rater reliability was good (0,875 and 0,756 respectively) as was within-rater (0,842 and 0,825 respectively). In 90-degrees flexion, lateral and medial between-rater reliability was poor (0,079 and 0,303 respectively), as was within-rater reliability (-0,412 and 0,080 respectively). The Bland-Altman plot demonstrated good agreement.
Conclusion:
The findings suggest that soft tissue laxity assessment during RATKA is reliable when performed instrument-assisted. Manual gap assessment remains challenging in 90-degrees flexion. Variability in 90-degree flexion assessment may impact perioperative planning and joint balancing. Discrepancies with prior studies underscore the need for further investigation into assessment techniques and potential sources of variability. Accordingly, the development of a gap assessment tool with integrated force measurement is recommended.
