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Researchers investigate impact of grown hormone on ACL tears

Despite advances in surgical techniques and accelerated rehabilitation,
the nearly quarter of a million patients who suffer ACL tears each year
still experience permanent weakness and muscle loss. This weakness
largely limits their ability to return to the same level of sport
performance, and can increase their chances of developing painful
osteoarthritis later in life.

The clinical trial, which opened June 1st, will study if growth hormone
can safely improve recovery and help to prevent long-term osteoarthritis
and knee joint weakness after an ACL tear.

“There is a large body of research on growth hormone, and our study will
be the first of its kind to explore whether it may aid recovery from an
ACL tear. We think that a brief treatment with growth hormone around
the time of surgery will help to limit some of the otherwise
irreversible loss in muscle mass and strength that occurs after these
injuries,” said principal investigator Christopher Mendias, assistant
professor of Orthopaedic Surgery and Molecular & Integrative
Physiology at the University of Michigan Medical School and MedSport
researcher.

The study will be a two-year, double-blinded, placebo controlled trial.
Neither the patients nor their doctors will know whether they are taking
the drug or an inactive placebo until after the study has been
completed. A safety committee composed of UM physicians will closely
monitor patient health and safety throughout the study. The trial will
evaluate whether patients restore full knee strength within six months
after surgery.

Growth hormone (somatropin) is a prescription medication that has been
used to prevent muscle atrophy and wasting in patients with HIV and
other severe illnesses. Recent work from the University of Copenhagen
has also shown that growth hormone can prevent muscle loss in otherwise
healthy individuals who are immobilized for a brief period of time.
However, when abused and taken at a very high dose for prolonged periods
of time, it can lead to large gains in muscle mass. Because of the
potential for abuse, most professional sports leagues throughout the
world currently ban growth hormone.

“There are a lot of assumptions about how growth hormone may impact
athletic performance and sports injuries but these claims are not
supported by strong scientific evidence,” Mendias said.

“We hope our findings will help professional sports organizations make
more informed decisions about whether growth hormone should remain a
banned substance or be used as treatment that can safely aid healing in
players, return them to their pre-injury strength levels and reduce
other long-term musculoskeletal risks which result from these injuries.
The dose and timing of growth hormone in this study was carefully chosen
to prevent the loss in muscle mass following ACL tear and
reconstruction, but not lead to muscle gains elsewhere in the body.”

ACL tears strike nearly 250,000 people a year and are especially
notorious among professional athletes. Almost a quarter of NBA players
and a third of NFL players who suffer an ACL tear do not return to
professional sports. The athletes who do return typically miss over
three quarters of the regular season and require over a year of recovery
time.

“Improving the recovery of professional athletes with ACL tears will
likely have an important short term impact on their playing careers but
also help avoid long term health problems like osteoarthritis that can
diminish quality of life and limit how active they can be as older
adults,” said Mendias.

Mendias and colleagues at UM’s MedSport clinic have long had a special
interest and expertise in sports medicine therapies, conducting several
studies over the years to improve the treatment of patients that suffer
from muscle loss after rotator cuff tears or ACL tears.

“We hope our results bring new insight into the field of sports medicine
and the quest to help both recreational and professional athletes more
easily return to the activities they enjoyed before, and improve their
long-term quality of life.”

This trial has been reviewed and approved by the U.S. Food and Drug Administration.

The study investigators report no financial conflicts of interest related to this study.

For more information about the trial: clinicaltrials.gov/ct2/show/NCT02420353