Reliability and Agreement of Four Patellar Height Measurement Methods in Knee Radiographs

Authors : Mehmet Barış Ertan, Volkan Büyükarslan, Murat Yüncü, Emre Mücahit Kartal, Koray Kaya Kılıç, Özkan Köse

Pages : 111-118

Doi:10.32708/uutfd.1634452

View : 44 | Download : 76

Publication Date : 2025-05-27

Article Type : Research Paper

Abstract :This study aimed to evaluate and compare the reliability and agreement of four commonly used methods for patellar height measurement: Insall-Salvati (IS), Modified Insall-Salvati (mIS), Caton-Deschamps (CD), and Blackburne-Peel (BP) indices, using standardized lateral knee radiographs. This prospective study included seventy adult patients with standardized lateral knee radiographs. Radiographs met strict criteria for true-lateral views and appropriate knee flexion angles. Three observers independently measured patellar height using the four methods, each performing two rounds of measurements at a 15-day interval. Intraclass Correlation Coefficients (ICC) were calculated for intra-observer and interobserver reliability. Pairwise agreements between methods were analyzed using Cohen’s kappa with 95% confidence intervals (CI). Correlation coefficients (Pearson’s r) were computed to assess the relationships between the methods. The BP method exhibited the highest inter-observer reliability (ICC = 0.848, 95% CI: 0.754–0.910) and intra-observer reliability (average ICC = 0.908, 95% CI: 0.829–0.986). This was followed closely by the CD method, while the IS and mIS methods demonstrated moderate reliability. Correlation analysis revealed strong relationships between the BP and CD methods (r = 0.871, p < 0.01) but weaker correlations between IS and the other methods. Despite high correlation coefficients, agreement in classification was poor, particularly between IS and BP (κ = -0.131) and IS and mIS (κ = -0.047).The Blackburne-Peel method is the most reliable and reproducible for patellar height measurement under standardized conditions, making it a robust tool for clinical and research applications. However, the methods were not interchangeable, emphasizing the need for consistent imaging protocols and method selection tailored to clinical objectives.
Keywords : Patellar yükseklik, Güvenilirlik, Blackburne-Peel indeksi, Caton-Deschamps indeksi, Insall-Salvati oranı, Modifiye Insall-Salvati oranı

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