Steroids and Exercise May Improve Recovery of Rotator Cuff Tears
July 15, 2004
By Stephanie Riesenman for Shoulder1
In a novel study, a combination of anabolic steroids and exercise has been shown to speed up and improve recovery of bioengineered rotator cuff tendons, leading researchers to believe the same regimen could improve surgical repair of massive or recurrent rotator cuff tears of the shoulder.
Such injuries are common in high-performance athletes, but also in the so-called "weekend warriors," particularly older athletes.
"Give the difficulty attaining uniformly good results in massive or recurrent postsurgical rotator cuff tears, it is reasonable to consider adjunctive methods to enhance the repair and healing process in these difficult clinical problems," wrote the researchers.
Their study is published in the June issue of the American Journal of Sports Medicine.
The research was conducted at the University of North Carolina, Chapel Hill and was led by Dr. Spero Karas, assistant professor of orthopedic surgery in UNC’s School of Medicine. Dr. Karas extracted samples of tendon from 6 patients — 5 men and 1 woman — with an average age of 52 years, while surgically repairing tears of their shoulders’ rotator cuff tendons. In a lab, the tissues were ground up to release the cells, which were put in a plate of collagen gel and allowed to grow.
Next, the bioengineered tendons were tested under 4 different conditions. No steroid was added to the first tissue group, and it was not manipulated to limit exercise. The second group was treated with the steroid, nandrolone decoanate, but again was not allowed to exercise. The thirds group underwent stretch to simulate exercise, but was not treated with the steroid. Finally, the fourth group of artificial tendon was treated with the steroid and was stretched to simulate exercise.
The bioengineered tendons were examined daily for 7 days to estimate their rate of growth and remodeling. During the first 2 days all samples showed a rapid decrease in width and surface area. By the fourth day the steroid-exercise group showed a much greater decrease in width compared to the other groups. And by the seventh day the steroid-exercise group had the lowest values for surface area and the greatest decrease in width.
The highest level of actin fiber elongation—which maintains the tendon’s integrity was highest in the steroid-exercise group. This tissue also had a more organized cytoskeleton—which makes up the structure of the tendon and maintains its flexibility.
MMP-3 is an important enzyme in tissue degradation, re-growth, and repair. High levels of MMP-3 have been associated with cartilage destruction in osteoarthritis. In the study, the steroid-exercise group demonstrated the earliest increase and highest levels of MMP-3, suggesting accelerated tissue repair. However, by the sixth day, levels of MMP-3 in all 4 groups returned to baseline.
When the researchers ran biomechanical tests on the tendon samples they found that the steroid-exercise group demonstrated significantly greater stress and strain and had higher energy absorption that the other groups.
Overall, the researchers concluded that the bioartificial tendon, treated with steroids and then mechanical strain, were smaller, stronger, denser, and more elastic and had better biomechanical and remodeling properties than untreated artificial tendon. They also said they formed a more normal looking tendon than the untreated group, which had a more disorganized structure.
The clinical application of this research is that the synergistic effect of steroids and exercise may improve the characteristics of tendon—particularly in shoulders that have atrophied tendons or rotator cuffs that have been torn for a long time. Dr. Karas also suggested the possibility of using bioengineered tendon when human tissue is deficient following large rotator cuff tears.
Future studies will examine the long term effects of steroids and exercise on tendon stability, said the researchers.
"Increasing the time between treatment and analysis, or increasing the time of treatment with anabolic steroid and load (exercise), will be another avenue of study to determine whether the effects will remain significant over a long period of time," wrote the researchers.
Last updated: 15-Jul-04