Multibody System of the Upper Limb Including a Reverse Shoulder Prosthesis

Abstract

The reverse shoulder replacement, recommended for the treatment of several shoulder pathologies such as cuff tear arthropathy and fractures in elderly people, changes the biomechanics of the shoulder when compared to the normal anatomy. Although several musculoskeletal models of the upper limb have been presented to study the shoulder joint, only a few of them focus on the biomechanics of the reverse shoulder. This work presents a biomechanical model of the upper limb, including a reverse shoulder prosthesis, to evaluate the impact of the variation of the joint geometry and position on the biomechanical function of the shoulder. The biomechanical model of the reverse shoulder is based on a musculoskeletal model of the upper limb, which is modified to account for the properties of the DELTA® reverse prosthesis. Considering two biomechanical models, which simulate the anatomical and reverse shoulder joints, the changes in muscle lengths, muscle moment arms, and muscle and joint reaction forces are evaluated. The muscle force sharing problem is solved for motions of unloaded abduction in the coronal plane and unloaded anterior flexion in the sagittal plane, acquired using video-imaging, through the minimization of an objective function related to muscle metabolic energy consumption. After the replacement of the shoulder joint, significant changes in the length of the pectoralis major, latissimus dorsi, deltoid, teres major, teres minor, coracobrachialis, and biceps brachii muscles are observed for a reference position considered for the upper limb. The shortening of the teres major and teres minor is the most critical since they become unable to produce active force in this position. Substantial changes of muscle moment arms are also observed, which are consistent with the literature. As expected, there is a significant increase of the deltoid moment arms and more fibers are able to elevate the arm. The solutions to the muscle force sharing problem support the biomechanical advantages attributed to the reverse shoulder design and show an increase in activity from the deltoid, teres minor, and coracobrachialis muscles. The glenohumeral joint reaction forces estimated for the reverse shoulder are up to 15% lower than those in the normal shoulder anatomy. The data presented here complements previous publications, which, all together, allow researchers to build a biomechanical model of the upper limb including a reverse shoulder prosthesis.

Computational reverse shoulder prosthesis model: Experimental data and verification

“…The biomechanical model of the upper limb used here consists in an inverse dynamic model, based on multibody methodologies (Quental et al, 2012(Quental et al, , 2013(Quental et al, , 2015. The skeletal model includes seven rigid bodies, namely the thorax, rib cage, clavicle, scapula, humerus, ulna, and radius.…”

“…The relative motion between these is constrained by 6 anatomical joints: the sternoclavicular (SC), acromioclavicular (AC), and GH joints, each represented by a 3 degrees-of-freedom ball-and-socket joint; the ST joint, defined by 2 holonomic constraints; and the humeroulnar (HU) and radioulnar (RU) joints, each modeled by a one degree-of-freedom hinge joint. For the reverse shoulder anatomy, the biomechanical model was modified according to the configurations of the Delta prostheses implanted, which are described in Table 1, to take into account the changes in the GH joint geometry and position (Quental et al, 2013). The muscular system is composed of 21 muscles, which are mainly based on the data of Garner and Pandy (2001).…”

“…Clearly, it is essential to understand the biomechanical changes introduced by the reverse design in order to achieve the best possible outcome (SanchezSotelo, 2009). So far, only a few computational studies have analyzed the shoulder function after a reverse shoulder replacement (Kontaxis and Johnson, 2009;Johnson, 2010a, 2010b;Quental et al, 2013;Terrier et al, 2008). Although these studies provide valuable information regarding changes in muscle moment arms and lengths, and on the range of motion free of impingement, their results regarding muscle and joint reaction forces must be analyzed with caution due to the kinematic data Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jbiomech www.JBiomech.com considered.…”

“…Although these studies provide valuable information regarding changes in muscle moment arms and lengths, and on the range of motion free of impingement, their results regarding muscle and joint reaction forces must be analyzed with caution due to the kinematic data Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jbiomech www.JBiomech.com considered. In particular, the scapular motion pattern was either estimated using regression equations (Kontaxis and Johnson, 2009;Johnson, 2010a, 2010b;Terrier et al, 2008), which are specific for healthy subjects, or acquired for healthy subjects using video-imaging (Quental et al, 2013). Consequently, the scapulohumeral rhythm of the reverse shoulder anatomy has been disregarded, limiting the practical use of these results.…”

“…For this purpose, a musculoskeletal model of the upper limb (Quental et al, 2012), already modified to account for the properties of the Delta reverse shoulder anatomy (Quental et al, 2013), was applied. The model input comprised the kinematics of standardized tasks measured for 2 patients with 3 Delta reverse shoulder prostheses and a healthy control group.…”