変形性膝関節症に対するステム付き人工関節抜去後の骨欠損に対する新規分類の外部検証
Johannes M Herold1, Jonggu Shin1, Young Dong Song2
1Stavros Niarchos Foundation Complex Joint Reconstruction Center, Hospital For Special Surgery, New York, NY 10021, United States.
Background:
Evaluation and management of bone loss in revision total knee arthroplasty (rTKA) poses a demanding challenge. The rising number of knee revisions and re-revisions has led to increasing bone loss severity, and previous bone loss classification systems fail to provide adequate assessment of the diaphysis. The Scuderi Classification was recently introduced to better assess diaphyseal bone loss and underwent internal validation. The purpose of this study was to perform an external validation using preoperative radiographs of failed stemmed rTKA and describe the interobserver and intraobserver reliability.
Methods:
From our institutional database, 128 preoperative radiographs of failed rTKAs with stemmed prostheses awaiting re-revision were identified. There were 120 stemmed femoral prostheses (60 cemented, 60 hybrid fixation) and 120 stemmed tibial prostheses (60 cemented, 60 hybrid fixation) that were subject to analysis. There were two readers who had similar experience levels who scored the cases according to the Scuderi classification, and each reader performed two independent reads at least two weeks apart from the first read. The levels of interobserver and intraobserver reliability were determined by the intraclass correlation coefficients (ICC).
Results:
Strong ICC for both femur (total: 0.96) and tibia (total: 0.89) has been demonstrated among the graders. Intraobserver reliability of 0.86 (grader one) and 0.79 (grader two) for femur and 0.8 (grader one) and 0.71 (grader two) for tibia demonstrated satisfactory agreement. Absolute score congruency between the readers was 86.7% for the femur and 89.2% for the tibia, showing excellent grading reproducibility for this new classification.
Conclusion:
This study provided an external validation of this bone loss classification in revision prosthesis with strong to near-perfect interobserver and intraobserver reliability. Based on our reported results, we advocate the use of this intuitive grading scheme, which can facilitate bone loss evaluation and may provide a future foundation to assist with implant selection in these complex cases.
