• Biotherapeutics

    Regenerating diseased bones

Kendall Koens’ life is a dramatic reversal from what it was in 2006. Late stage cancer left him in a coma and on a ventilator fighting for survival. Aggressive chemotherapy was saving his life but slowly and silently destroying his hips joints. The financial planner from Rochester faced crippling pain typical of someone more than twice his age until a regenerative surgery pioneered at Mayo Clinic restored life to his bones.

Cancer leads to bone disorder

Mr. Koens was 26 years old when doctors discovered a grapefruit-size cancerous tumor in his chest. Chemotherapy and heavy steroids fought the germ cell cancer but left him with lung damage and a rare side effect that surfaced four years later. He developed avascular necrosis  of the hip, a condition in which blood stops flowing to the top of the hip joint known as the femoral head. Avascular necrosis, also called osteonecrosis, causes bone cells to die. Tiny fractures that result sometimes lead to a collapse of the joint.

Kendall Koens

“I was facing the possibility of needing a hip replacement. It was pretty concerning from a long term point of view,” says Kendall Koens. “Hip replacements only last so long. Being young, I knew that if I had a hip replacement, I might need a second or maybe even a third hip surgery over the course of my lifetime.”

Koens’ primary physician referred him to Rafael Sierra, M.D., a Mayo Clinic orthopedic surgeon who specializes in treating disorders of the hip, often with the newest regenerative treatments. 

Rafael Sierra, M.D.

“Avascular necrosis in the past has been described as one of the unsolved mysteries of orthopedics, because we really don’t have a way,  once it has started, of halting the process of the dying bone or even changing the natural history unless you catch it early,” says Dr. Sierra. “Without treatment, up to 90 percent of all people with this condition will need a hip replacement.”

Dr. Sierra recommended surgery that taps into the body’s healing powers to restore dead bone tissue. Mayo Clinic was one of the first medical centers in the United States to offer this regenerative treatment. It’s hip decompression surgery in which a small hole is drilled in the outside of the bone to access the femoral head to release pressure with the hopes of improving the blood flow to the damaged bone. This procedure is further fostered by a regenerative biotherapy.

“After the decompression, we take bone marrow from the pelvis that has the stem cells. We spin it in a centrifuge that separates red blood cells from the mononuclear cells that play a key role in healing. These mononuclear cells are then injected back into the hip where they act as healing agents,” says Dr. Sierra. “It is done as an outpatient procedure that takes about an hour. Generally there is very little pain and very low morbidity for the majority of patients.”

This type of modern hip decompression, with injection of bone marrow concentrate and bone graft done within the constraints of the operating room, is an approved therapy. The goal is to avoid or delay hip replacement for patients like Kendall Koens whose osteonecrosis is still in an early, treatable stage. Recovery time varies based on how far the bone decay has advanced prior to treatment. If caught early, recovery may be quicker than a hip replacement, but in later stages, if surgery is performed to save the femoral head, recovery could take more time. 

Although this was a new procedure, Koens decided it was worth the risk to avoid a hip replacement. In 2010, he became one of the first patients at Mayo Clinic to have the hip decompression surgery.

“After meeting with Dr. Sierra and hearing about this surgery, we were so excited and full of hope. At the time it felt like an unbelievable opportunity. I decided to have it done and take it a day at a time.  Here it is a decade later, and I’m doing well,” he says.

Koens’ life continues to take positive turns. His cancer is in remission. He lives an active lifestyle. Though cancer left him unable to have children, he and his wife became parents two years ago to two adopted daughters. He regularly takes walks with his family and has no problem chasing after two energetic preschoolers.

The Koens family

“I live a very normal life and don’t have any pain. I’m so grateful that I haven’t had to go through a life of hip replacements. I can’t imagine what that would mean for activity restrictions. My life would be so much different,” Koens says.  “Dr. Sierra told me to avoid running marathons and playing sports like basketball that have a heavy impact on the hips. I’m not a marathon runner anyway, so this recommendation didn’t change the course of my life.”

Helping hundreds avoid hip replacement

Dr. Sierra has performed as many as 300 hip decompression surgeries. Many of the patients are younger people like Kendall Koens who wanted an alternative to a total hip replacement.  

“Hip replacements are common and we love doing them.  However, if we can avoid them, it is in the patient’s best interest long term.

Dr. Sierra’s practice is based on scientific evidence. He regularly conducts research to improve surgery to treat avascular hip necrosis, an example of science-driven practice advancement at Mayo Clinic.

Mayo Clinic Center for Regenerative Medicine supports research and practice to advance therapies like modern hip decompression surgery that restore form and function to diseased cells, tissue or organs.


Links to Dr. Sierra’s research:

Facts about avascular necrosis
On average 6 out of 100 people on steroid therapy will develop avascular necrosis

Risk factors:
Steroid therapy
Sickle cell disease
Alcohol abuse
High cholesterol
Research is probing whether there is an underlying genetic mutation linked to the disease.