Evaluation of the inter and intraobserver reproducibility of the “defect coverage index method”, a new computed tomography assessment method of sagittal graft positioning in arthroscopic bone block procedures

PURPOSE: To assess the reproducibility of a new 2-dimensional computed tomography (CT) method of assessing graft positioning in arthroscopic bone block procedure. METHODS: This is a prospective observational study. Twenty-seven patients, (all men, mean [Standard deviation] age at surgery 30.9 [8.49] years) were included. Vertical graft position was assessed on the sagittal view by measuring the amount of glenoid bone defect covered by the graft. The length of the bone defect and the amount of graft covering the defect were measured. Positioning of the graft on the sagittal plane was classified as accurate if the graft covered at least 90% of the defect. Intraobserver and interobserver reproducibility was analyzed using intraclass correlation coefficients (ICC) and Kappa coefficient with 95% confidence. RESULTS: Excellent intraobserver reproducibility was found, with an ICC of 0.94 (CI 95%, 0.86-0.97). Interobserver reproducibility was good, with the ICC value of 0.71, ranging from 0.45 to 0.86 (CI 95%). CONCLUSION: This new method of assessing graft positioning in arthroscopic bone block procedures on 2-dimensional computed tomography scans is reliable, with an excellent intraobserver and good interobserver reproducibility. LEVEL OF EVIDENCE: III