Effect of Rotator Cuff Deficiencies on Muscle Forces and Glenohumeral Contact Force After Anatomic Total Shoulder Arthroplasty Using Musculoskeletal Multibody Dynamics Simulation.

Zhenxian Chen,Lei Guo,Xunjian Fan,Zhongmin Jin,Jing Zhang,Yongchang Gao,Shibin Chen

doi:10.3389/fbioe.2021.691450

Abstract

Anatomic total shoulder arthroplasty (ATSA) is widely used to treat the diseases of the glenohumeral (GH) joint. However, the incidence of rotator cuff tears after ATSA increases during follow-up. The effects of rotator cuff deficiencies after ATSA on the biomechanics of the GH joint are to be investigated. In this study, a musculoskeletal multibody dynamics model of ATSA was established using a force-dependent kinematics (FDK) method. The biomechanical effects were predicted during arm abduction under different rotator cuff deficiencies. The deltoid forces were increased under the rotator cuff deficiencies, the maximum deltoid forces were increased by 36% under the subscapularis deficiency and by 53% under the supraspinatus, infraspinatus, subscapularis, and teres minor deficiencies. The maximum GH contact forces were decreased by 11.3% under supraspinatus and infraspinatus deficiencies but increased by 24.8% under subscapularis deficiency. The maximum subscapularis force was decreased by 17% under only infraspinatus tear during arm abduction. The results suggested that the changes in the biomechanics of the GH joint induced by rotator cuff deficiencies after ATSA increase the deltoid muscle energy expenditure and joint instability, which result in postoperative less satisfactory clinical outcomes. The changes in rotator cuff muscle forces deserve more attention for understanding the evolution of rotator cuff tear after ATSA.

Highlights

Shoulder arthroplasty has become the third most common orthopedic procedure after hip and knee joint arthroplasties (Smith et al, 2015; Simovitch et al, 2017)
A generic upper extremity musculoskeletal model was extracted from Anybody Managed Model Repository (AMMR, V1.6.2) to establish the musculoskeletal multibody dynamics model of anatomic total shoulder arthroplasty (ATSA) in AnyBody Modeling System (AnyBody Technologies, Aalborg, Denmark, V6.0)
The maximum deltoideus_scapular forces were increased by 36% under the subscapularis deficiency (Q4) and by 53% under the supraspinatus, infraspinatus, subscapularis, and teres minor deficiencies (Q5) compared with the intact rotator cuff

Summary

Introduction

Shoulder arthroplasty has become the third most common orthopedic procedure after hip and knee joint arthroplasties (Smith et al, 2015; Simovitch et al, 2017). Two entirely different procedures with different implant designs, anatomic total shoulder arthroplasty (ATSA), and reverse total shoulder arthroplasty (RTSA), are widely used for a variety of joint diseases of the glenohumeral (GH) joint. The rotator cuff tear is the recognized complication following ATSA in addition to periprosthetic fracture, component loosening, and joint instability (Young et al, 2012; Sheth et al, 2019). A rate of 16.8% was reported at a mean follow-up of 8.6 years for secondary rotator cuff tears after primary ATSA (Young et al, 2012). The rotator cuff dysfunction rate is significantly increasing with the duration of follow-up (Young et al, 2012)

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