Spine alignment influences shoulder range of motion and scapular orientation: A systematic review from the FP-UCBM Shoulder Study Group.

Abstract

<h4>Purpose</h4>The relationship between spine orientation and the shoulder active range of motion (ROM) has been an ever-growing topic in the last few years. This systematic review aimed to assess the epidemiological association between spine morphology and shoulder function.<h4>Methods</h4>The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. A literature search was performed on PubMed, Scopus, and Cochrane library. Randomised controlled trials (RCTs) and cross-sectional studies, analysing the correlation between shoulder ROM and Cobb angle, kyphosis index, scapular tilt, forward scapular posture, functional scores in adults were selected. Finally, data of interest were extracted and analysed.<h4>Results</h4>A total of five studies were included in this study. The study included a total number of 624 participants and 887 shoulders. The mean age 40 years old, ranging from 17.1 to 67. The most significant correlations (<i>p</i> < 0.0003) were that greater thoracic kyphosis was associated with increased scapular internal rotation (<i>R </i>= Left -0.081 Right = -0.065) (<i>p</i> < 0.0003), and that greater scapular anterior tilt was associated with increased scapular internal rotation (<i>R</i> = 0.29, <i>p</i> < 0.001). Higher thoracic kyphosis was correlated with reduced shoulder abduction (<i>R</i> = -0.163, <i>p</i> < 0.005) and flexion (<i>R</i> = -0.118, <i>p</i> < 0.05), whereas greater lumbar ROM was associated with increased abduction and flexion (<i>R</i> = 0.119, <i>p</i> < 0.05 and <i>R</i> = 0.166, <i>p</i> < 0.005). In addition, higher thoracic kyphosis was correlated with reduced shoulder adduction (<i>R</i> = -0.72, <i>p</i> < 0.05).<h4>Conclusions</h4>Sagittal spine morphology shows frequent and significant correlations with shoulder active ROM. In particular, greater thoracic kyphosis is associated with increased scapular internal rotation and reduced shoulder abduction, adduction and flexion, while higher lumbar mobility correlates with improved shoulder elevation. These findings confirm the biomechanical interdependence between spinal alignment and shoulder kinematics.<h4>Level of evidence</h4>Level III.