Shoulder pain is a common reason for people to seek medical care and is the third most common site of musculoskeletal pain, after the lower back and knee (1,2). In the United States alone, the direct cost of treatment for shoulder dysfunction in 2000 was estimated to be $7 billion. 1-2% of the population is estimated to experience shoulder pain each year. Beyond direct costs, regional pain in the shoulder can also evolve into more generalized pain syndromes, and pain can lead to limitations in range of motion (ROM), subsequently impairing functional activities (1,2). As a result, it is necessary to investigate whether existing treatments for improving shoulder range of motion and pain, such as spinal manipulation, are effective.
Chiropractic care frequently draws on the theory of regional interdependence, which posits that deficiencies in one area of the body may be associated with primary symptoms in another area, despite being apparently unrelated (2). Previous studies found a decrease in shoulder pain immediately after thoracic manipulation but did not find changes in scapular kinematics or muscle activity (3). Due to the importance of shoulder ROM to daily life, a study by Silva et al. sought to investigate the effect of thoracic spinal manipulation (SM) on shoulder range of motion in people with chronic shoulder pain, with a secondary goal of decreasing pain levels (2).
The study examined 60 participants who presented with shoulder pain for at least 6 months and who showed clinical signs of rotator cuff tendinopathy, through a combination of positive Hawkins, Neer, or Jobe tests; or pain/weakness with external rotation of the arm. The study excluded patients with contraindications to SM (such as a history of cancer, osteoporosis, or fracture), a pacemaker, or clinical signs of complete rotator cuff tear. On average, participants had experienced nearly four years of pain before entering the study (2).
Participants were assigned to either the manipulation group or placebo group but were blinded to which group they belonged to. The manipulation group received two high-velocity low-amplitude thrusts between the T4 and T5 vertebrae, while the placebo group received a constant, low pressure contact while assuming the same prone position. Researchers evaluated three key metrics before and after the intervention: the degree of shoulder flexion, the degree of shoulder abduction, and self-reported shoulder pain (2).
After thoracic spinal manipulation, participants demonstrated a statistically significant increase in both flexion and abduction range of motion in the painful shoulder, as well as a significant increase in abduction of the nonpainful shoulder. The improvement in abduction in the painful shoulder was also above the calculated minimal detectable change, giving this effect clinical significance as well. However, the placebo group also demonstrated a statistically significant improvement in shoulder ROM after receiving the placebo intervention. Both groups reported less pain after their respective interventions (p < 0.01), but this change was not clinically significant (2).
This study demonstrated that thoracic spinal manipulation clinically improved abduction, one aspect of range of motion, in the painful shoulder, but that thoracic SM did not improve flexion or pain levels (2). Future research should include a true control group in order to test for a placebo effect, which is a potential explanation for changes experienced by the placebo group, as well as investigate other treatment techniques for shoulder pain.
References
1. Silva ACD, Santos GM, Marques CMG, Marques JLB. Immediate Effects of Spinal Manipulation on Shoulder Motion Range and Pain in Individuals With Shoulder Pain: A Randomized Trial. J Chiropr Med. 2019;18(1):19-26. doi:10.1016/j.jcm.2018.10.001
2. Tekavec, E., Jöud, A., Rittner, R. et al. Population-based consultation patterns in patients with shoulder pain diagnoses. BMC Musculoskelet Disord. 2012;13(238). doi:10.1186/1471-2474-13-238
3. Haik MN, Alburquerque-Sendín F, Silva CZ, et al. Scapular Kinematics Pre- and Post-Thoracic Thrust Manipulation in Individuals With and Without Shoulder Impingement Symptoms: A Randomized Controlled Study. J Orthop Sports Phys Ther. 2014;44(7):475-487. doi:10.2519/jospt.2014.4760