Orthopedic surgeons at the School of Medicine are testing an investigational treatment for heel pain that uses a technique developed in the early 1980s to eliminate kidney stones. Washington University is one of seven sites in the United States and the only site in the Midwest currently participating in the study.
The study's principal investigator at the St. Louis site is Jeffrey E. Johnson, M.D., associate professor and chief of the foot and ankle service in the Department of Orthopedic Surgery.
"Heel pain can be caused by a number of different problems," Johnson said. "Arthritic conditions can cause soft tissue inflammation. Some patients may have trauma or a stress fracture of the heel. Others have painful nerve entrapment, but the most common cause of heel pain is plantar fasciitis."
The plantar fascia is a ligament-like structure on the bottom of the foot that supports the arch. Patients with plantar fasciitis typically have pain and inflammation at the site where the plantar fascia attaches to the heel bone.
Traditional treatments for heel pain range from modifying activity to soft-soled shoes or heel pads to surgery for patients with persistent pain. Johnson said, however, that the surgery does not always solve the problem and causes complications because it involves cutting the plantar fascia. The complications led foot and ankle specialists to continue searching for a non-surgical treatment that would leave the plantar fascia intact while providing more effective relief than other traditional therapies.
Lithotripsy was developed originally as non-surgical treatment for kidney stones. The machines use shock waves to crush the stones. The waves pass through tissue into the area where the kidney stone is located, and their vibrations crush the stone and break it into tiny pieces, which then are passed.
The investigational lithotripsy treatment for heel pain also uses shock waves, but rather than crushing heel spurs like kidney stones, the orthopedic treatment attempts to create a small area of injury near the site where the plantar fascia attaches to the bone. That new injury is thought to attract new blood flow and other nutrients that promote healing and relieve pain.
To be eligible for the study, patients must have heel pain that has not responded to at least two prior treatments. The pain must have persisted for at least six months.
Patients in the study receive the shock wave treatment from a device called an OssaTron, a lithotripsy device manufactured by the HealthTronics company. The machine is owned by Midwest Stone Institute, a health-care company affiliated with the medical school.
Half of the patients get an actual treatment. The other half will be randomly selected to have a shield placed between the OssaTron machine and their foot so that the shock waves cannot enter the foot.
For more information about the study, call 1-800-371-9298.
