Isometric Strenght of the Small Tears of the Rotator Cuff

Abstract

The purpose of this study was to clarify the isometric strength of ashoulderabduction and external rotation in small tears of the rotator cuff.
Among 18 symptomatic shoulders w ith small tears of the rotator cuff (area<4cm²on MRI ),11Shoulders (11 patients ) without a history of shoulder pain on the contralateral side were enrolled in this study. The patients were groupedaccording to the location of the tear; six had the isolated supraspinatus (SSP ) tears (mean age 61 years, mean size 1.31cd) and six had the SSP-infrspinatus (ISP ) tears (mean age 65 years, mean size 1.52cm²). We measured the isometric strength of abduction and external rotation of both shoulders using a Micro FET II (Nihon medics). A preliminary session was followed by three maximum efforts after injectina 5? of 1 % mepivacaine into the subacromial bursa ofthe tear side to relieve pain. The peak torque which was the highest torque value seen from all repetitions were measured and expressed percentages of thoseof the contralateral side.
The external rotation strength of the isolated SSP tears was almost equal tothe SSP-ISP tears (100.3±11.0%,107.8 ±12.6%, respectivly ). On the other hand, the abduction strength of the isolated SSP tears was significantly smaller than the SSP-ISP tears (65.0±30.3%129.3 ±26.4%, respectively; p=0.042). The abduction strength in small teats was affected by the location of the tear.