Three-dimensional scapular kinematics during commonly used rehabilitation exercises in patients 12 weeks after reverse shoulder arthroplasty.

Abstract

Reverse shoulder arthroplasty (rTSA) is often used to restore functionality in patients with joint arthropathy and dysfunctional rotator cuff. As rTSA changes the biomechanical properties of the shoulder, an altered movement pattern of the arm and scapula is to be expected. Previous studies focused on changes of the scapulohumeral rhythm during functional elevation tasks. To our knowledge, no study exists examining scapular kinematics during rehabilitation exercises in a patient population with rTSA. Therefore, this study aimed to analyze 3-dimensional scapular kinematics during 3 commonly used rehabilitation exercises 12 weeks after rTSA surgery. It was hypothesized that scapular kinematics would be different between the horizontal and the vertical plane. Secondly, differences in scapular kinematics in the vertical plane between the open and closed chain were hypothesized. In this cross-sectional study, 48 patients (55 shoulders) aged 69 ± 7.4 years participated. Scapular kinematics in terms of anterior/posterior tilt, external/internal rotation, and upward/downward rotation were registered during 3 rehabilitation exercises. Exercises varied based on the plane (horizontal or vertical) and the modality (closed or open chain). Data were analyzed using statistical parametric mapping (SPM). Post hoc pairwise analysis within SPM (SPM(t)) revealed no significant differences among the exercises regarding posterior tilt. During vertical plane exercises (standing wall slide 120° [WS] and standing reach 120° [REACH]), the scapula was more upwardly rotated for most of the time (14.93%-74.63%, P < .001) than during the exercise in the horizontal plane (seated bench slide). No statistically significant differences were found between the vertical open chain (REACH) and the vertical closed chain exercise (WS). For the internal/external rotation, significant differences were found between the horizontal (seated bench slide) and the vertical plane (WS and REACH) (0%-100%, P < .001), and between the open (REACH) and closed chain (WS) vertical exercises (3.0%-91.5%, P < .001), with more external rotation when performing the movement in the vertical plane, and in the closed chain compared with the horizontal plane and the open chain, respectively. Scapular kinematics during rehabilitation exercises after rTSA differ, depending on the plane and modality of the exercise. Insight into the impact of changing the plane (horizontal/vertical), and training in open vs. closed chain, may assist physical therapists in the choice of exercises.