Osteoporosis Drug, Forteo, Appears to Heal Common
Injury to Senior Citizens From Falls
Newly approved drug improves healing after rotator
cuff surgery; common problem for falling seniors and young athletes
March 10, 2010 - Tears in the shoulder's rotator
cuff, a common injury among senior citizens due to falls, are painful
and restricting. Surgery to repair the damage is successful for pain
management, but in many patients it does not result in full recovery of
function due to poor healing. New research shows an approved therapy for
osteoporosis, Forteo
(teriparatide), may speed healing and improve patient outcomes.
The preliminary study from Hospital for Special
Surgery in New York is being presented at the American Academy of
Orthopaedic Surgeons (AAOS) meeting in New Orleans, which runs March
9-13.
"According to a previous study, only 69 percent of
rotator cuff repairs were completely healed when evaluated two years
after the surgery," said Scott Rodeo, M.D., co-chief of the Sports
Medicine and Shoulder Service at Hospital for Special Surgery and senior
author on the study.
"Although not all of the patients with failed
rotator cuff tendon healing had poor clinical outcomes, we wanted to
look for ways to further improve patient outcomes."
The rotator cuff is a set of four smaller muscles
in the shoulder that rotate the upper arm. A rotator cuff tear happens
when the tendon part of the muscle tears away from the bone of the upper
arm. The repair surgery reattaches the tendon to the bone, but the
success depends on how well the interface between the tendon and bone
heals.
Much of the time scar tissue forms at that
interface, which is not as strong as the original tissue and can lead to
a failed repair.
"The healing process occurs from both the bone and
the tendon, which is made up of collagen," said Carolyn Hettrich, M.D.,
MPH, fifth year resident in orthopedic surgery at Hospital for Special
Surgery and lead author.
"We knew the drug Forteo is osteogenic and can
stimulate bone growth, but we found reports in the literature that it is
also chondrogenic, so it can promote cartilage formation as well."
Forteo is a synthetic version of parathyroid
hormone, which is the body's primary regulator of calcium and phosphate
levels in bone. Recently approved by the FDA, it is prescribed for
osteoporosis as it not only stimulates bone growth but it also slows the
rate of bone loss.
The researchers hypothesized that because Forteo
stimulated both bone and cartilage formation, it might enhance the
healing process after rotator cuff surgery. Using a rat model, they
performed the surgery and then gave some rats Forteo injections in
amounts comparable to human doses.
Initially, at two weeks after the surgery, the
repair was not as strong in the rats who received the Forteo.
But when the researchers looked at weeks four
through eight, the tendon to bone interface in those rats appeared much
more like normal tissue.
Shoulder
Injuries and Disorders (MedlinePlus)
Your
shoulders are the most movable joints in your body. They can
also be unstable because the ball of the upper arm is larger
than the shoulder socket that holds it. To remain in a stable or
normal position, the shoulder must be anchored by muscles,
tendons and ligaments. Because the shoulder can be unstable, it
is the site of many common problems. They include
sprains, strains,
dislocations, separations,
tendinitis,
bursitis, torn rotator cuffs, frozen shoulder, fractures and
arthritis.
Usually
shoulder problems are treated with RICE. This stands for Rest,
Ice, Compression and Elevation. Other treatments include
exercise, medicines to reduce pain and swelling, and surgery if
other treatments don't work.
National
Institute of Arthritis and Musculoskeletal and Skin Diseases
Closer examination showed that not only had those
rats that received Forteo produced more bone and cartilage cells, but
the organization of the tissue was better and more closely resembled
normal tissue.
The tendon was also significantly stiffer, a sign
of proper healing, at 8 weeks.
"The results are positive, but now we want to
understand why at week two the tendon wasn't healing as well," said Dr.
Hettrich.
"Our next experiments will look to pinpoint these
causes and determine the optimum delivery time of the drug after
surgery."
The researchers caution that it would be risky to
use Forteo in patients undergoing rotator cuff surgery just yet as
further studies are needed. Instead, they encourage patients to talk to
their surgeons about other steps they can do to improve healing, such as
not smoking after the surgery to optimize their biology.
Athletes who use overhead movements, like baseball
or tennis players, are prone to this injury.
It is also common in adults over 40 because the
tendons begin to degenerate and weaken.
"In some instances, the body's own healing process
does not produce ideal results," said Dr. Rodeo. "We are trying to find
ways to improve tendon to bone healing – ways to augment the healing
process and go beyond what the body can do on its own. Although
preliminary, the results here are promising and may eventually be
applied to other tendon to bone surgeries, such as bicep tears or
patellar tendon tears in the knee."
Founded in 1863, Hospital for Special Surgery (HSS)
is a world leader in orthopedics, rheumatology and rehabilitation. HSS
is nationally ranked No. 2 in orthopedics, No. 3 in rheumatology and No.
24 in neurology by U.S. News & World Report (2009), and has received
Magnet Recognition for Excellence in Nursing Service from the American
Nurses Credentialing Center, and has one of the lowest infection rates
in the country.
From 2007 to 2010, HSS has been a recipient of the
HealthGrades Joint Replacement Excellence Award. A member of the NewYork-Presbyterian
Healthcare System and an affiliate of Weill Cornell Medical College, HSS
provides orthopedic and rheumatologic patient care at New
York-Presbyterian Hospital at New York Weill Cornell Medical Center. All
Hospital for Special Surgery medical staff are on the faculty of Weill
Cornell Medical College. The hospital's research division is
internationally recognized as a leader in the investigation of
musculoskeletal and autoimmune diseases. Hospital for Special Surgery is
located in New York City and online at
www.hss.edu.
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