Application Of Ultrasonography In The Hierarchical Diagnosis Of The Anterior Talofibular Ligament Injury Of Ankle Joint

Part 1Objective: The hierarchical diagnostic results of the anterior talofibular ligament(ATFL)injuries derived from the MRI were taken as a standard.The accuracy of the hierarchical diagnostic results by ultrasound was evaluated.Methods: A total of 49 patients with lateral ankle joint injuries,who underwent ultrasound and MRI examinations were included.All the patients were male,with an average age of(26 ± 6)years.The general features of the lateral ankle were recorded by ultrasound and MRI,including ATFL’s thickness,shape,fiber continuity,echo(signal)intensity and changes of soft tissues in and around the joint cavity.The ligament injuries were classified into three categories based on the characteristics of ultrasound and MR images together.Based on the hierarchical diagnostic results of the ligaments derived from MRI,the hierarchical diagnostic results of high-frequency ultrasound and MRI were compared.Results:1.Findings of high-frequency ultrasound about ATFLAccording to the ultrasonic findings,the ligament was divided into four categories:normal ligament,grade Ⅰ injury(contusion),grade Ⅱ injury(incompletely torn)and grade Ⅲ injury(completely torn).2.Comparisons of general dataNo significant difference was found in the ligament shape,fiber continuity,echo(signal)intensity and changes of soft tissues in and around the joint cavity between high-frequency ultrasound and MRI(all P > 0.05).3.Comparison of ligament thickness measurement consistencyNo significant difference was found in the ligament thickness between the high-frequency ultrasound(0.31 ± 0.09cm)and MRI(0.32 ± 0.10cm).The interclass correlation coefficient(ICC)of ligament measurement was 0.780.4.Assessment of the accuracy of high-frequency ultrasonic hierarchical diagnosis of ATFL injuriesThe hierarchical diagnostic results of the ligaments derived from the MRI were taken as a standard.The sensitivity,specificity and accuracy of high-frequency ultrasound in the diagnosis of ligament injuries above grade Ⅰ were 100%,100% and100% respectively.The sensitivity,specificity and accuracy of high-frequency ultrasound in the diagnosis of ligament injuries above grade Ⅱ were 85%,91% and88% respectively.The sensitivity,specificity and accuracy of high-frequency ultrasound in the diagnosis of ligament injuries above grade Ⅲ were 44%,98% and88% respectively.These two methods had moderate to high agreement[the Cohen’s kappa(k)= 0.736,P < 0.001].Part 2Objective: The results observed in the operation or ankle arthroscopy examination were taken as a standard.The accuracy of the hierarchical diagnostic results of the ATFL injuries by ultrasound and MRI was evaluated.Methods: A total of 22 patients with lateral ankle joint injuries,who underwent operation or ankle arthroscopy examinations were included.All the patients were male,with an average age of(25 ± 6)years.The general features of the lateral ankle were recorded by ultrasound,MRI and operation/ankle arthroscopy,including ATFL’s thickness,shape,fiber continuity and changes of soft tissues in and around the joint cavity.The ligament injuries were classified into three categories based on the characteristics of ultrasound,MR images and operation together with the patient’s medical history.Taking the hierarchical diagnostic results of the ligaments observed from the operation as a standard,the hierarchical diagnostic results of high-frequency ultrasound and MRI were compared respectively.Results:1.Comparisons of general dataNo significant difference was found in the ligament shape,fiber continuity and changes of soft tissues in and around the joint cavity among high-frequency ultrasound,MRI and operation(all P > 0.05).2.Comparison of ligament thickness measurement consistencyNo significant difference was found in the ligament thickness between the high-frequency ultrasound(0.27 ± 0.10 cm)and operation(0.27 ± 0.09 cm).The ICC of ligament measurement was 0.868.No significant difference was found in the ligament thickness between the MRI(0.29 ± 0.11cm)and operation.The ICC of ligament measurement was 0.723.3.Assessment of the accuracy of high-frequency ultrasonic hierarchical diagnosis of ATFL injuriesThe status of the ligaments observed during the operation/ankle arthroscopy were taken as a standard.The sensitivity,specificity and accuracy of high-frequency ultrasound in the diagnosis of ligament injuries above grade Ⅰ were 100%,100% and100% respectively.The sensitivity,specificity and accuracy of high-frequency ultrasound in the diagnosis of ligament injuries above grade Ⅱ were 100%,83% and95% respectively.The sensitivity,specificity and accuracy of high-frequency ultrasound in the diagnosis of ligament injuries above grade Ⅲ were 100%,89% and91% respectively.These two hierarchical diagnostics had high agreement(k = 0.849,P< 0.001).The sensitivity,specificity and accuracy of MRI in the diagnosis of ligament injuries above degree I were 100%,100% and 100% respectively.The sensitivity,specificity and accuracy of MRI in the diagnosis of ligament injuries above degree Ⅱ were 100%,83% and 95% respectively.The sensitivity,specificity and accuracy of MRI in the diagnosis of ligament injuries above degree Ⅲ were 100%,95% and 95%respectively.These two hierarchical diagnostics had high agreement(k = 0.844,P <0.001).Conclusion:High-frequency ultrasound has a high accuracy in the hierarchical diagnosis of ankle ATFL injuries.High-frequency ultrasound and MRI have similar diagnostic efficiency in determining the degree of ankle ATFL injuries.