The effects of rotator cuff tear on shoulder proprioception

To evaluate the effects of rotator cuff tear (RCT) and its severity on shoulder proprioception. We studied 132 consecutive patients (67 M-65 F; mean age ± SD, 66.03 ± 9.04; range, 43–78) who underwent arthroscopic rotator cuff repair. Tear size was determined intra-operatively. The control group included 82 subjects (38 M-44 F; mean age ± SD, 65.87 ± 8.06; range, 41–75) with no RCT. All participants, wearing an eye mask, were submitted to the evaluation of the joint position sense (JPS) at 30°, 60°, 90°, 120°, and 150° of shoulder forward flexion during the sitting position, using a digital inclinometer securely attached to the subject’s arm using hook-and-loop straps. The passive placement and active replacement method was used; the order of the tested angles was randomly selected. The entire test was repeated three times. The error score, by averaging the three trials, was measured as the absolute difference between the target angle and the observed angle. Statistics were performed. The intraclass correlation coefficient for all degrees of flexion movement measured was > 0.90, exhibiting a very high correlation. We found significant differences between cases and controls regarding the results of joint position sense error at all measurements (p < 0.05). According to RCT size, we found significant differences between groups at 30° (F = 27.27, p < 0.001), 90° (F = 5.37, p = 0.006), 120° (F = 10.76, p < 0.001), and 150° (F = 30.93, p < 0.001) of shoulder flexion; in details, patients with massive RCT showed greater absolute error value than those with both small and large RCT at 30°, 90°, 120°, and 150° of shoulder flexion (p < 0.05). RCT provokes an alteration of shoulder proprioception, evaluated as the loss of joint position sense, and the impairment is related to tear severity.