Shiro Imagama (Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan) report, in the European Spine Journal, that their study provides the first evidence that increased thoracic kyphosis, increased spinal inclination and weak back muscle strength are risk factors for limited shoulder range of motion.
Imagama et al comment that spinal diseases and limited shoulder range of motion (ROM) are common orthopaedic problems among elderly people and add that both influence activities of daily living, which can cause loss of independence (leading to increased nursing care and medical costs). They state: “Therefore, it is important to determine the relationship of the spine with shoulder function. However, influences between the spine and the shoulder disabilities are still not well understood.” As several studies have indicated a possible relationship between the spine and shoulder motion, the authors conducted the current study to “clarify the influence of the spine on shoulder range of motion through evaluation of spinal alignment, spinal angles, spinal range of motion, and shoulder range of motion in a prospective cohort of participants who underwent a health checkup.”
Imagama et al identified 317 participants (average age 67 years) from healthy volunteers who attended the checkup. They performed lumbar lateral standing radiographs, used the SpinalMouse (Idiag) device to measure spinal angle, sagittal balance, spinal mobility, and also assessed shoulder range of motion. They found that 29 participants had shoulder pain (average Visual Analogue Scale score 3.7), 35 had limited shoulder flexion and 50 had limited shoulder abduction. The authors comment: “Thoracic kyphosis angle and spinal inclination angle, as well as age, 10m gait time, and shoulder pain had significant negative correlations with shoulder range of motion. Back muscle, strength, lumbar lordosis angle and lumbar range of motion had significant positive correlations with shoulder range of motion.” Also, after adjusting for age, shoulder pain and other variables, Imagama et al identified that increased thoracic kyphosis angle and increased spinal inclination angle were “significant risk factors for limited shoulder flexion; and the increased thoracic kyphosis angle and weak back muscle strength were significant risk factors for limited shoulder abduction (p<0.05).”
Concluding their study, the authors state: “These results suggest that the maintenance of spinal alignment and back muscle strength may be important for better shoulder range of motion.”