A new total wrist replacement device just approved by the U.S. Food and Drug Administration (FDA) will hopefully bring relief to people living with arthritis.
Almost five million people in the U.S. suffer from wrist arthritis. Fusion of the wrist bones and wrist joint replacement surgery are often recommended to treat it, however, they offer limited results.
A team effort, Scott Wolfe, M.D., a hand surgeon at Hospital for Special Surgery (HSS) and Joseph J. Crisco, III, Ph.D., director of the Bioengineering Laboratory at Brown University and Rhode Island Hospital, have spent 30 years researching and developing the new total wrist implant.
The HSS Innovation Institute worked with them to obtain a patent which is now licensed to Extremity Medical, LLC, a New Jersey medical device company.
“We believe the new wrist replacement, known as the KinematX Total Wrist Implant, has advantages over traditional implants,” said Dr. Wolfe, chief emeritus of the Hand and Upper Extremity Service at HSS.
“Most people are familiar with total joint replacement in the knee or hip, which is much more common and highly successful,” he said. “Total wrist joint replacement has not enjoyed the same degree of success. Historically, some studies demonstrate failure rates of near 50% within 5 to 10 years, mainly due to loosening of implant components.”
In their effort to better understand how the bones move in the wrist when injured compared to how they move in a healthy wrist, Drs. Wolfe and Crisco designed a noninvasive three-dimensional motion analysis system to measure wrist kinematics.
They discovered that the wrist does not move the hand either just up and down or side to side like previously thought. Instead it can move the hand in different directions simultaneously for actions like throwing a ball or pouring a glass of water.
“Traditional wrist replacements often constrain the wrist to move in one plane at a time, and this puts stress on surrounding joints,” Dr. Wolfe explained. “The increased loads in the implant bone interface often lead to prosthesis loosening and mechanical failure. In addition, traditional implants often make it difficult or impossible to return to some activities, such as tennis or golf.”
The KinematX is the only wrist replacement that is computer-designed to mimic the actual kinematics of the human wrist, which should make it more durable than traditional wrist replacements, he said.
“Our extensive research into how the wrist moves helped us design a replacement that more closely matches the anatomy and motion of a normal wrist. This should allow for more natural motion and increased durability compared to currently available implants.”
Doug Leach, managing director of Biomechanical Innovation at the HSS Innovation Institute added that they believe that KinematX will be a “game changer” when it comes to wrist replacement surgery.
“Current wrist replacement devices are relatively dated. The new implant design leverages the clinical and bioengineering experience of Drs. Wolfe and Crisco, their seminal research, and modern-day engineering and design principals of total joint replacement in general.”
Surgery with KinematX involves replacing the proximal carpal row bones of the wrist. The surgery will be performed on an outpatient basis.
