When patients with hip osteoarthritis (OA) complain of lower back pain, what is happening with certain muscles in the spine?
Elizabeth Hofheinz MPH MEd, Orthopedics This Week August 24 2018
Investigators from Canada have just published new work that attempts to answer that question. The study appears in the July 2018 edition of the Journal of Orthopaedic Research.
Janice Moreside PhD, assistant professor at the School of Health and Human Performance at Dalhousie University in Halifax, Nova Scotia, Canada and co-author on the study, explained the rationale behind the study to OTW. “As clinicians, we recognize that significant gait changes accompany increasing severity of hip OA. Anecdotally, we also know that many people with hip OA will report low back pain.”
“We wanted to delve into this a little deeper to understand what positional changes were occurring in the spine, as well as how the erector spinae (ES) muscles were being activated to either cause or react to positional changes, in a population with varying severities of unilateral hip OA.”
|Reproduction of a Gray’s anatomy plate with the muscles of the erector spinae muscle group highlighted. Henry Vandyke Carter – Henry Gray (1918) Anatomy of the Human Body Bartleby.com: Gray’s Anatomy, Plate 389. Wikipedia|
“To the best of our knowledge, no one had previously analyzed ES activation in such a population; increased or prolonged ES activity has implications for cumulative spine loading, which may be a factor in the development of back pain.”
The authors wrote, “Using a cross‐sectional cohort study, 3D trunk motions and ES surface electromyography were recorded on 19 individuals with severe OA (SOA), 20 with moderate hip OA (MOA), and 19 asymptomatic (ASYM) individuals during treadmill walking, using standardized collection and processing procedures. Principal component analysis was used to derive electromyographic amplitude and temporal waveform features. Three‐dimensional thoracic motion in a global system, and thoraco‐lumbar motion was calculated.”
“While we anticipated increased ES activity during the stance phase of gait (in keeping with increased frontal lean), we found this increase was also maintained during the swing phase of the OA hip,” commented Dr. Moreside to OTW. “Basically, ES was higher bilaterally throughout the entire gait cycle, and did not necessarily rise and fall with the different gait phases, as would be expected in someone with a healthy hip.”
“This increase in ES activity may help stiffen the spine, resulting in greater core stability on which to swing the affected leg. However, it will also result in greater cumulative lumbar compression, which could negatively affect spine health over time.”
“This increase in ES activity was seen in people with moderate and severe unilateral hip OA. Encouraging normal gait patterns by way of hip strengthening, pain relief and/or walking aides such as a cane may help reduce the likelihood that people with hip OA will develop low back pain.”
“When hip OA patients start to develop abnormal walking patterns, muscles are involved, and have a profound effect on joint compression. While some compression is a good thing, prolonged, unrelenting joint compression negatively impacts cartilage and joint health. In the case of hip OA, while it may be important to postpone hip surgery in some populations, it is also important to consider the long-term effects that pain and abnormal gait patterns have on other joints, such as the spine.”
Source Orthopedics This Week
Altered erector spinae activity and trunk motion occurs with moderate and severe unilateral hip OA, Moreside J, Wong I, Rutherford D. J Orthop Res. 2018 Jul;36(7):1826-1832. doi: 10.1002/jor.23841. Epub 2018 Jan 16.