Bone defects in knee revision arthroplasty—a therapy-oriented classification

• DOI: 10.1007/s00402-025-05759-2
• Publication Date: 2025-04-03T09:47:11Z
• Authors: Max Jaenisch; Elias Hoven; Martin Gathen; Frank Sebastian F...; Adnan Kasapovic; Charlotte Rommels...; Andreas Christian...; Dieter Christian ...
• Keywords: Kappa; Cohen's kappa; Intra-rater reliability; Inter-Rater Reliability; Guideline

Abstract

Introduction The complex field of revision knee arthroplasty displays a lack of standardized, intuitive pre- and intraoperative assessment of bone defects. In clinical practice revision surgeries are a common sight presenting with increasingly complex cases of bone loss and ligamentary dysfunction. To address these issues the Knee Defect Classification (KDC) is introduced to offer a reliable, reproducible and an intuitive classification system with a clear therapeutic guideline.

Materials and methods Reliability was evaluated through comparison between intraoperative findings and preoperative gradings of 218 patients. To account for reproducibility inter- and intra-rater agreement was assessed.

Results The mean agreement between intraoperative and radiographic grading of femoral and tibial defects was evaluated with a Cohens kappa of 0.79, representing a good agreement. For interrater reliability a mean Fleiss kappa of 0.71 could be evaluated for femoral and tibial defects falling into the good agreement range. In the subgroup analysis femoral defects presented with a Fleiss kappa of 0.652 ± 0.026 (good agreement), while tibial defects presented with a Fleiss kappa of 0.768 ± 0.024 (good agreement). For intrarater reliability a mean Cohens kappa was evaluated at 0.78 indicating good agreement.

Conclusion The KDC is a reliable and reproducible classification system. Through its structured design it facilitates intuitive use and allows for consistent preoperative planning and intraoperative guidance. A therapeutic algorithm is provided based on a review of the literature in combination with expert opinion.