IMPACT OF ROTATOR CUFF AND SUPERIOR LABRAL PATHOLOGY ON SHOULDER BIOMECHANICS: (EXAMINATION UNDER ANESTHESIA)

Abstract

There is an association between SLAP lesions and laxity of the shoulder. The relationship between rotator cuff disease and hypermobility has also been implied. The purpose of this case-control study was to assess the impact of rotator cuff and superior labral pathologies on degree of glenohumeral translation and range of motion of the shoulder in comparison with individuals with normal shoulders.

This study involved individuals with asymptomatic shoulders (control group), and individuals with Rotator Cuff (RC) and Superior Labral Anterior and Posterior (SLAP) pathologies who underwent a repair. Subjects were matched by age, gender and hand dominance side. To assess laxity, all subjects including the control group were examined under anesthesia. The degree of humeral head translation was recorded in three (anterior, posterior and inferior) directions. Range of motion was documented in five directions.

Forty-six females and forty-four males with RC pathology and twenty-seven men with SLAP pathology were compared with the age and gender matched control group. The number of women with SLAP pathology was not sufficient for analysis. Rotator cuff pathology reduced range of motion of the affected side in all directions including flexion, elevation in scapular plane, internal rotation at ninety degrees of abduction and external rotation at zero and ninety degrees of abduction (p=0.02 to p< 0.001) as compared to normal population. Men with SLAP pathology had reduced range of motion in all directions (p< 0.001) except external rotation at ninety degrees of abduction. There were no statistically significant differences in glenohumeral glides between the normal group and SLAP group. However, the affected side of the patients with RC pathology had less laxity than normal population in anterior and posterior directions.

Presence of rotator cuff and superior labral pathologies affect biomechanics and consequently range of motion and accessory movements of the glenohumeral joint. We were unable to confirm a positive relationship between laxity and SLAP and RC pathologies. Prolonged disuse of the shoulder in these pathologies might have played a role in our findings.