SACRAMENTO – A method for producing a type of natural stem-cell grout that can be used to treat patients whose fractured bones fail to fully heal is being tested as part of a clinical trial by UC Davis orthopaedic surgeons.

The surgeons are using a specialized syringe and new cell separation equipment to extract stem-cell-rich bone marrow from the pelvises of patients.

Called bone marrow aspiration, the surgical team considers it a less-invasive procedure for obtaining the stem cells needed to repair non-healing bones.

They say the technique could enable people to avoid the current standard procedure, which involves surgically removing bone and bone marrow from the pelvis and transplanting it to the fracture site.

“We are offering a promising new alternative for augmenting bone regeneration,” said Mark A. Lee, associate professor of orthopaedic surgery and principal investigator of the study. “Surgically removing bone and marrow from a patient’s hip can involve considerable pain and a long recovery. We’re hoping to avoid these problems while remaining at least as effective.”

For most people who have suffered a fracture in one of their long bones – the femur or tibia in the upper and lower leg, respectively, or the humerus in the upper arm – recovery normally takes from three to six months for the broken ends of the bone to grow back together.

Although most fractures respond well to surgery, some cases defy the best efforts of surgeons and do not fully heal, leaving a gap between the broken ends and causing serious complications.

According to the American Academy of Orthopaedic Surgeons, about six million individuals suffer fractures each year in North America.

In about 5 to 10 percent of cases, patients suffer either delayed healing or fractures that do not heal. The problem is especially troubling for the elderly, many of whom suffer from osteoporosis, a condition in which bones become weak and break more easily. For an older person, a fracture affects quality of life because it significantly reduces function and mobility, and requires an extended period of recuperation.

Lee and his colleagues are working with Rancho Cordova-based ThermoGenesis and Texas-based Celling Technologies to evaluate the effectiveness of a new cell processing device made by the companies that enables the sterile transfer of bone marrow during surgery.

The device separates out bone-forming cells – including stem cells – and produces a concentrated solution of cells the surgeons mix with tiny pieces of donor bone to create the grout-like mixture that serves as the framework for new bone formation. Surgeons pack the mixture into the fracture area before suturing the incision site closed.

“Dr. Lee’s clinical trial is the culmination of five years of collaboration with a high-tech firm, the UC Davis School of Veterinary Medicine and our Department of Orthopaedics,” said Jan Nolta, director of the UC Davis Institute for Regenerative Cures. “It is a great model for bringing together industry, academics and medicine to rapidly develop and test important new technology to improve clinical care for patients.”

According to Nolta, adult stem cells, such as those found in bone marrow, are analogous to paramedics because they respond rapidly to areas of tissue damage, enhancing repair, revascularization and blood flow while reducing inflammation and scarring.

Lee and his team are carefully analyzing the cellular composition of the concentrated bone-marrow mixture and correlating their findings to the degree of healing. They are using X-ray imaging, physical examinations and patient questionnaires to track patient progress and results.

“Bone marrow aspiration for treating non-healing fractures could potentially become an extremely important option as our population ages and we expect to see more broken bones,” said Lee, who also is exploring whether the bone-marrow cell mixture can be delivered to the fracture site through a minimally invasive incision rather than open surgery. “This study will help us determine the optimum therapy and technique for non-healing fractures, and we hope that this gentler approach really helps people get back on their feet faster.”

Lee’s co-investigator in the study, which is sponsored in part by ThermoGenesis and Celling Technologies, is Joel Williams, a fourth-year resident in the UC Davis Department of Orthopaedic Surgery who has been studying the use of stem cells in improving fracture repair.

The university currently has several other clinical trials using adult stem cells under way, including one for treating heart attack victims and another for people suffering from advanced peripheral vascular disease. The federal approval process also is under way to launch stem cell clinical trials for other diseases and conditions, including retinal occlusion (eye disease) and Huntington’s disease.

If the non-healing bone study provides positive results, Lee and his team plan to conduct a larger, more definitive multi-center clinical trial using this and similar cell-based technologies to demonstrate the true efficacy of using stem cells as an alternative to traditional bone grafting techniques.

“Our goal is to harness the tremendous healing potential of these cells to minimize pain and discomfort for our patients,” added Lee.