Strain on the repaired supraspinatus tendon during manual traction and translational glide mobilization on the glenohumeral joint: a cadaveric biomechanics study

There has been no report on the mechanical effects of joint mobilization on rotator cuffs. The purpose of this study was to determine whether it is safe to use grade 3 joint mobilization techniques after rotator cuff repair. Nine fresh frozen cadaveric shoulders were used in this study. The strains on the artificially repaired supraspinatus tendon during joint mobilization were measured at 0 degrees and 30 degrees of shoulder abduction and were compared with those at the maximal stretching position and relaxing position. Additionally, gap distances were measured during this experiment. The strain at 30 degrees of abduction of the repaired tendon during each joint mobilization was significantly smaller than that at 0 degrees abduction (P<0.05). At 30 degrees of abduction, the strain during joint mobilization was not statistically different from that of the shoulder in the relaxing position, except during the inferior glide technique. Gap distances were 0mm at 30 degrees , while the distances were 1.06-1.46 mm at 0 degrees. Our findings suggest that joint mobilization techniques, except inferior glide, can be performed safely without significantly straining the repaired tendon at 30 degrees of abduction, if rotator cuff repair is performed at 0 degrees of abduction.