New data suggest electrical stimulation can defer total knee replacement surgery in patients with osteoarthritis

Townsend Letter for Doctors and Patients,  Jan, 2005  

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New data presented at the American Academy of Orthopaedic Surgeons annual meeting, in March 2004, suggest that a pulsed electrical stimulation device, the BioniCare(R) Model BIO-1000[TM] System, can defer total knee replacement surgery (total knee arthroplasty or TKA) by up to four years in patients with moderate to severe osteoarthritis (OA).

The BioniCare(R) Model BIO-1000[TM] System incorporates a soft Velcro wrap around the knee along with a signal generator which delivers a proprietary electrical stimulus.

Most Severe Patients Saw Greatest Benefit

"In this study, 62% of severe OA patients deferred TKA for four years versus seven percent in the control group. These patients had OA classified radiographically as Kellgren IV, which means bone-on-bone knee arthritis," said Michael A. Mont, MD, Director, Center for Joint Preservation and Reconstruction, Rubin Institute for Advanced Orthopedics at the Sinai Hospital of Baltimore, MD, and the study's first author. "Despite the increased severity of the disease, the Model BIO-1000[TM] System was able to deliver meaningful clinical benefits." Patients in the treated group also reported greater improvement in their evaluation of pain and symptoms, as well as in overall function, Dr. Mont added.

The prospective, open-label study involved 157 patients (48 men and 109 women ranging in age from 31 to 88) at 23 centers in the United States. All patients were diagnosed with moderate to severe OA of the knee aggravated by activity and relieved by rest. Patients in the study wore the Model BIO-1000[TM] System between six and 10 hours daily; most chose to do so at bedtime.

Data from these patients were compared to a control group of 101 patients who previously had a TKA on one knee and who reported moderate to severe pain in the other knee. This group was followed by Dr. Mont and David S. Hungerford, MD, another study author and Professor of Orthopaedic Surgery at the Johns Hopkins Medical Institutions in Baltimore, Maryland.

Additional data from this study showed that at the end of year one, 85% of patients treated with the BioniCare(R) Model BIO-1000[TM] System deferred total knee replacement surgery versus 67% of untreated patients. At year two, 75% of treated patients deferred TKA surgery against 51% of those in the control group. By the third year, 65% of study patients deferred surgery compared to 46% in the untreated group.

The BioniCare(R) Model BIO-1000[TM] System was well tolerated with no serious adverse events. Twenty percent of patients in the treated group reported mild and transient rashes. No patients dropped out of the study due to these adverse events.

About OA and Knee Surgery

Arthritis is the leading cause of disability in the United States, and affects approximately 38% of women and 26% of men.

More than 70 million Americans are currently diagnosed with some form of arthritis or chronic joint symptoms, according to the Centers for Disease Control and Prevention. The most prevalent forms are OA, affecting 20.7 million Americans, and rheumatoid arthritis, which affects an estimated 2.1 million Americans.

An estimated 10 million people in the United States currently suffer from OA of the knee. Orthopedic surgeons perform more than 275,000 TKAs a year to help alleviate pain and restore function. At a recent consensus conference, it was estimated that the cost of total replacement ranged as high as $32,000, not including rehabilitation and costs associated with complications.

Surgery is often considered a last resort in the treatment of OA knee pain and is recommended only after standard pharmacologic therapy, including COX-2 specific non-steroidal anti-inflammatory medications, has failed. Surgery may not restore function permanently, however. For younger patients in their 40s or 50s, for example, surgery may have to be repeated within 10-15 years. Frail and elderly patients with chronic heart, lung or metabolic disorders, such as diabetes or asthma, may be unable to tolerate the rigors of TKA surgery and rehabilitation. The BioniCare(R) Model BIO-1000[TM] System is designed to help fill the treatment gap between pharmacologic therapy and surgery.

Proposed Mechanism of Action for the BioniCare(R) System

This proprietary technology is related to findings in laboratory studies on human, rabbit, and bovine connective tissues, that specific electrical and magnetic fields positively influence the repair mechanisms of bone, cartilage, and other connective tissue.

"In animal studies, this particular electrical signal appears to stimulate the cartilage cell to regenerate itself and to proliferate," said Thomas Zizic, MD, a study co-author and Associate Professor of Medicine at the Johns Hopkins Medical School in Baltimore, MD. Dr. Zizic is also President, Chief Executive Officer and cofounder of BioniCare.

"It is our belief that the BioniCare(R) System produces an electrical field that may influence cartilage by a process that is similar to the endogenous fields that the body normally produces with movement and compression of cartilage. It is similar to the way that weight-bearing exercise helps produce bone," Dr. Zizic continued.