Evaluation of Functional and Biomechanical Deficiency in the Shoulder Joint: a Prospective Cohort Study of 119 Patients with Rotator Cuff Injury

Abstract

AIM. To assess the degree of change in functional and biomechanical characteristics of the shoulder joint in patients with rotator cuff injury. MATERIAL AND METHODS. The study included 119 patients, 59 patients with rotator cuff injury and 60 practically healthy volunteers with no history of injuries and shoulder disorders, aged 18 to 66 years. All patients completed DASH questionnaires and underwent clinical examination by a traumatologist, neurologist and physical therapist, as well as a biomechanical examination of the shoulder joint. The biomechanical parameters of the shoulder joint were studied using the «Con-Trex MJS» (Physiomed, Germany) computerized isokinetic dynamometer. We chose the inward/outward rotation test as the diagnostic test. The inward/outward rotation test was performed lying on the back. The elbow was bent at an angle of 90º, the upper limb was moved 90º at the shoulder joint. The handle of the dynamometer was set individually according to the patient’s limb length. The axis of rotation of the dynamometer coincided with the axis of rotation in the shoulder joint. The maximum allowable amount of motion in the test was limited to 90º movement of the external rotation and 80º internal rotation. The neutral position of the shoulder joint retraction equal to 90 ° and the elbow joint flexion at 90 ° were taken as the zero point of reference. RESULTS AND DISCUSSION. Patients with rotator cuff injury have a high shoulder pain level, 6.00 [5.00;7.00] VAS, a severe degree of functional limitations 63.33 [55.92;66.67] scores on the DASH questionnaire, a pronounced decrease in shoulder range of motions, as well as a significant deficit in dynamic strength and endurance indices and muscle performance. CONCLUSION. Patients with shoulder rotator cuff injury experience extensive functional limitations expressed in a high level of pain in the shoulder joint, high points of the questionnaire of the upper limb functioning (DASH, more – worse) and a significant decrease in the biomechanical indicators of the shoulder joint and upper limb in general, which ultimately leads to a serious limitation of functional activity, a decrease in the working capacity and, consequently, a decrease in the quality of life.