Dynamic thoracohumeral kinematics are dependent upon the etiology of the shoulder injury

Abstract

Obtaining kinematic patterns that depend on the shoulder injury may be important when planning rehabilitation. The main goal of this study is to explore whether the kinematic patterns of continuous and repetitive shoulder elevation motions are different according to the type of shoulder injury in question, specifically tendinopathy or rotator cuff tear, and to analyze the influence of the load handled during its assessment. For this purpose, 19 individuals with tendinopathy and 9 with rotator cuff tear performed a repetitive scaption movement that was assessed with stereophotogrammetry. Furthermore, static range of motion (ROM) and isometric strength were evaluated with a goniometer and a dynamometer, respectively. Dynamic measurements of maximum elevation (Emax), variablility of the maximum angle (VMA), maximum angular velocity (Velmax), and time to maximum velocity (tmaxvel) were found to be significantly different between the tendinopathy group (TG) and the rotator cuff tear group (RTCG). No differences were found in the ROM assessed with goniometry and the isometric strength. The effect of increasing the load placed in the hand during the scaption movement led to significant differences in Emax, VMA, tmaxvel and repeatability. Therefore, only the dynamic variables showed sufficient capability of detecting differences in functional performance associated with structural shoulder injury. The differences observed in the kinematic variables between patients with tendinopathy and rotator cuff tear seem to be related to alterations in thoracohumeral rhythm and neuromuscular control. Kinematic analysis may contribute to a better understanding of the functional impact of shoulder injuries, which would help in the assessment and treatment of shoulder pain.

Three-Dimensional Kinematics during Shoulder Scaption in Asymptomatic and Symptomatic Subjects by Inertial Sensors: A Cross-Sectional Study

“…Their study included subjects suffering from rotator cuff tendinopathy (aged 46.89 (±10.69) years) and full-thickness RCT (aged 57 (±7.07) years), obtaining a value of 121.14 • (±6.51 • ) and 100.50 • (±9.46 • ), respectively. Differences found between shoulder damage were significant [40]. In both cases, maximum humeral elevation was higher than the sample of the present group (88.80 • in AB-AD plane and 38.62 in FL-EX plane).…”

“…One of the limitations of the present study is the inclusion of shoulder lesions of different etiologies in the symptomatic group, as kinematic variables from scaption motion assessment seem to depend on the etiology of the shoulder injury [40]. Another limitation is that pain was not measured, which has been shown to increase movement variability [56].…”

“…However, results are not comparable due to differences in methodology, the plane of motion analyzed, and age (subjects aged on average 74 years). Humerus elevation during scaption was recently studied by Pascual et al [40] using the Kinescan/IBV stereophotogrammetry system. Their study included subjects suffering from rotator cuff tendinopathy (aged 46.89 (±10.69) years) and full-thickness RCT (aged 57 (±7.07) years), obtaining a value of 121.14 • (±6.51 • ) and 100.50 • (±9.46 • ), respectively.…”

“…Furthermore, subjects were sitting, which may influence kinematics [41]. Pascual et al [40] also included maximum humeral velocity while holding 250 g weight, which was 96.79 • /s and 45.38 • /s for the rotator cuff tendinopathy group and full-thickness RCT group, respectively. Values were lower when performing scaption with kg: 76.04 • /s and 29.22 • /s, respectively.…”