Pre- and Postoperative Isokinetic Strength Test in Rotator Cuff Tear

Abstract

PURPOSE: This study investigated whether (i) isokinetic muscle strength correlated with (ii) anatomical assessment of rotator cuff tear size, fatty degeneration of the supraspinatus muscle or postoperative cuff integrity.MATERIALS & METHODS: Among patients who underwent arthroscopic rotator cuff repair, 32 patients in whom magnetic resonance imaging (MRI) and isokinetic muscle strength tests were performed preoperatively and, at an average of 10 months after repair, took part in this study. We measured the isokinetic strength (peak torque and total work) deficit in external rotation and internal rotation at a 60degrees/sec load.RESULTS: Preoperative isokinetic strength deficits correlated with tear size (p<0.001) but correlated weakly with fatty degeneration of supraspinatus muscle (p<0.001). In patients with healed rotator cuffs, preoperative peak torque and total work deficits were 39% and 62% for external rotation. At final follow up, they were decreased to 17% and 32%, respectively. In the re-tear group, preoperative peak torque and total work deficit were 44% and 61% in external rotation. At final follow up, they were decreased to 23% and 35%, respectively. But there was no significant difference between the two groups (p>0.05).CONCLUSION: Preoperative isokinetic strength correlates with tear size but not fatty degeneration of the supraspintus muscle or postoperative cuff integrity. Postoperative cuff integrity did not have an effect on postoperative isokinetic strength.