The Usefulness and Indications of Arthrosonography to Differentiate Full-thickness Tears from Partial-thickness Tears of the Rotator Cuff

ABSTRACT

OBJECTIVE: To investigate the usefulness and indications of arthrosonography by testing if the new technique could provide additional information on the degrees of rotator cuff tears when compaired to the findings of conventional ultrasonographic examinations. METHOD: Thirty six patients, who were identified to have partial or full-thickness rotator cuff tears by conventional ultrasonography, were included. Intraarticular injection of 15 ml of fluid was performed via posterior approach under ultrasound-guidance, which was followed by arthrosonography. RESULTS: Among 26 patients with partial-thickness tear which was detected by the conventional ultrasonography, eight were identified to have full-thickness tears by the arthrosonography. Although the difference was not significant, the grade 3 partial-thickness tear in the conventional sonography had a higher rate of being identified as full- thickness tear in the arthrosonography than the grade 2 partial-thickness tears. The size of partial-thickness tear was increased after instillation of fluid in the arthrosonography. CONCLUSION: Arthrosonography would be useful in differentiating partial- and full-thickness tears. When a tear of the rotator cuff tendon, especially a grade 3 partial-thickness tear, is detected in the conventional sonographic examination, an obscured full-thickness tear should be suspected and subsequent arthrosonographic procedure could be administered to clarify the extent of the lesion. Moreover, arthrosonography might be helpful in detecting partial-thickness tears by making them appear larger after instillation of fluid.