Acute Measurement of Developmental Dysplasia of the Hip: Comparing Two Approaches for Measuring the Alpha Angle Using the Graf Technique

Objective: The Graf method, in ultrasonography screening of developmental hip dysplasia, is based on angle measurements. Using different reference points may cause varied results. The aim of this study was to investigate to what extent the alpha angle obtained, varied at different reference points. Materials and Methods: There were 178 hips evaluated by two trained observers. Both measured the alpha angle with different reference points and these were labeled as methods A and B, for all the hips evaluated. The statistical analysis was performed with SPSS Version 21. Results: The average of observer 1, based on measurements with method A, were 65.63 (SD ±5.95) and based on method B were 73.39 (SD ±6.29). The average of the measurements of observer 2, utilizing method A were 64.39 (SD ±4.85) and based on method B were 69.92 (SD ±6.08). It was observed that method B showed higher mean and variability compared to method A. The agreement between observers was moderate in method A and poor in method B. The intraobserver correlation coefficient (ICC) was 0.69 for method A and 0.47 for method B. The ICC was considered good (e.g., 95%) for both observers in terms of using methods A and B. Conclusion: The use of ultrasonography still maintains its place in the diagnosis of developmental hip dysplasia. The Graf method is based on precise measurements, and the most decisive parameter is the alpha angle. Reference points in method A would be more useful in patient management and may increase the diagnostic accuracy.