| BackgroundRotator cuff disease(RCD)is one of the most common musculoskeletal diseases in orthopedics and sports medicine.Magnetic Resonance Imaging(MRI)is the most often used method in evaluating the degree of rotator cuff injury[1-3],and X-ray is commonly used to evaluate the acromion morphology and subacromial space(SAS)before shoulder arthroscopy[4,5]However,MRI has various deficiencies including costliness,consuming time,contraindication,and insufficience in primary hospitals.X-ray is radioactive,and it may lead to difficulty for regional measurement due to the overlap of shoulder soft tissue and skeleton.In re-cent years,ultrasound(US)has been widely used in the diagnosis of shoulder joint diseases due to its low cost,radiation free,popularity,convenience,real time and dynamic nature.Hereby,this study aims to evaluate the value of ultrasound before shoulder arthroscopy,by assessing the degree of Rotator cuff injury(RCI)and SAS by dynamic ultrasound,and compared to MRI,X-ray and arthroscopy.Objective:1.To evaluate the sensitivity,specificity and Youden’s index of ultrasonography in the diagnosis of RCD.2.To assess the accuracy of ultrasonography in measuring subacromial space of patients with RCI.3.To evaluate the dynamic changes of subacromial space examined by ultrasound in patients with RCI when the shoulder is in the active abduction state.4.To investigate the dynamic changes of supraspinatus tendon length examined by ultrasound in patients with RCI when the shoulder is in the active abduction state.Methods:It’s a prospective single-blind cross-sectional study.Thirty three patients suffering unilateral RCD confirmed by arthroscopic were enrolled in the study,and the contralateral asymptomatic shoulders were compared as control group.The SAS was imaged with ultrasound using a 6-18MHz linear transducer,which was placed in the coronal plane over the anterior aspect of the acromion.All patients were examined by the same physician.The SAS outlet was measured via the acromiohumeral distance(AHD),which was defined as the shortest distance between the acromion and the humerus head.The supraspinatus tendon length(STL)was measured between acromion and greater tuberosity of humerus head.The AHD and STL was measured in 2 trials at 4 angles(0 degrees,30 degrees,60 degrees and 90 degrees)when the shoulder is in the active abduction state,and averaged for data analysis.All of thirty three patients had MRI and US examination before surgery.The RCI pattern was recorded.The preoperative results were compared with the findings during the arthroscopy to assess the sensitivity,specificity and Youden’s index of the two methods.Ultrasound and X-ray were used respectively to measure SAS in patients with RCI.Data was statistically analyzed by another doctor without knowledge of the experiment.Results:1.Thirty three patients completed the study.SAS of all subjects could be well shown to measure AHD and STL by ultrasound.2.Surgery showed unilateral partial-thickness supraspinatus tendon tears in 20 cases,full-thickness tears in 10 cases,and calcified supraspinatus tendinitis in 3 cases.Took arthroscopy as the gold standard,the sensitivity,specificity,and Youden’s index of the diagnosis of partial-thickness RCT was 100%(20/20),93%(13/14),0.93 respectively in US,and 100%(20/20),87%(13/15),0.87 respectively in MRI,the difference was not significant(P>0.05).For the assessment of full-thickness RCT,the sensitivity,specificity and Youden’s index was 90%(9/10),100%(23/23),0.90 respectively in US,and 80%(8/10),100%(23/23),0.80 respectively in MRI,the differrrence was not statistically significant(P>0.05).For the diagnosis of calcified supraspinatus tendinitis,the sensitivity,specificity and Youden’s index was 100%(3/3),100%(30/30),1 respectively in US and 0%(0/3),100%(30/30),0 respectively in MRI,the sensitivity and Youden’s index of US was significantly higher than MRI(P<0.001).The sensitivity,specificity,and Youden’s index of the diagnosing joint bursa effusion was 100%(30/30),100%(3/3),1 respectively in US and 100%(30/30),100%(3/3),1 respectively in MRI,the difference was not statistically significant(P>0.05).For the assessment of synovial hyperplasia,sensitivity,specificity and Youden’s index was 28%(5/18),100%(15/15),0.28 respectively in US and 22%(4/18),100%(15/15),0.22 respectively in MRI,the difference was not significant(P>0.05).3.Average value of SAS in all patients measured by US and X-ray was 8.98±2.46mm and 7.81±1.75mm respectively,the difference was not statistically significant(P>0.05).4.The mean value of AHD in all subjects reached maximum at 0 degrees in active abduction,while minimum at 60～90 degrees in active abduction.A decrease in the SAS was observed in all subjects when the shoulder was in active abduction from 0 degrees to 90 degrees(P<0.001).5.Ultrasonographic measurements demonstrated that unilateral full-thickness RCT patients presented statistically smaller AHD and STL compared to partial-thickness RCT and control shoulders at 4 angles(0 degrees,30 degrees,60 degrees and 90 degrees)in active abduction(P<0.05).There was no statistically significant difference in AHD and STL between partial-thickness RCT and control shoulders(P>0.05).Conclusion:1.US and MRI have similar high accuracy for detecting RCI and joint bursa effusion.For diagnosing calcific tendinitis,US is more sensitive than MRI.For diagnosing synovial hyperplasia,sensitivity of US and MRI is poor.2.Ultrasound and X-ray have similar value for measuring the subacromial space.3.AHD and STL is decreasing in unilateral RCT patients during the active abduction of the glenohumeral joint.Reduction in AHD and STL in patients with unilateral RCT significantly relates to the severity of RCT.4.US performed dynamically by a well-trained radiologist is an ideal tool for RCD and SAS assessment.Ultrasound can be used as the first choice of imaging examination before shoulder arthroscopy. |
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