A Comparison Between Preoperative and Intraoperative Measurement and Classification of the Size of Rotator Cuff Tears.

To evaluate the agreement in tear size obtained through preoperative imaging and intraoperative measurement, and to determine the accuracy of preoperative imaging in the classification of tear size and identification of tears in each rotator cuff tendon.  Data from 44 patients recruited to a randomized controlled trial were reviewed retrospectively. Size and location of the rotator cuff tears were confirmed by either ultrasound or magnetic resonance imaging scans preoperatively and evaluated during surgery. A -test and Bland and Altman plot were used to determine the agreement between the preoperative and intraoperative measurements. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for tear size and involvement of the rotator cuff tendon.  There was good agreement in terms of the measurements (91%) and classification (89%) of the tear size preoperatively and during surgery. When classifying tear size, the sensitivity and PPV were high for medium-sized tears (100%) and lower for large tears (75%), reflecting that all medium-sized tears but not all large tears were identified preoperatively. For the preoperative identification of the tears, the sensitivity and PPV were highest for the supraspinatus (84%), with progressively lower sensitivities and PPV for the infraspinatus (57%), subscapularis (17%) and teres minor (0%).  Through preoperative imaging, the measurement or classification of the tear size can be accurately performed. Where there is disagreement, it is unclear whether the tear size is either underestimated on the scan or overestimated during surgery. The high sensitivity demonstrates that a supraspinatus tear is usually detected by scan. The lower sensitivities for the infraspinatus and subscapularis indicate that the identification of tears in these tendons is less accurate.