The Achilles heel gets all the ink, but in fact the body’s real Achilles heel is its next-door neighbor, the ankle—the body part more injured than any other. In the late 1990s, the science of rehabilitating ankles got a leg up from Dr. Greg Burdea’s Human-Machine Interface Lab at Rutgers, which in 2000 patented a device called the Rutgers Ankle Robotic Interface, or Rutgers Ankle for short. From the patient’s perspective, the system is not only more effective but a lot more fun than the usual regimen of toe raises, lateral resistance exercises, and the like. With the injured foot strapped into the device, the patient flies an airplane on a video screen by tilting and turning the foot in different directions; the amount of resistance is set by the therapist. There is also a boat-piloting simulation.
Only about 30 people so far have used the Rutgers Ankle, which is still considered a prototype. The virtual reality system can also be adapted to other joints and has been used experimentally in the rehabilitation of stroke patients and those with cerebral palsy.
1. FEEL THE FORCE
The patient’s shod foot is strapped into a holder connected to a disc that measures in real time the forces and torques exerted by the patient as the foot moves.
2. PISTONS RESISTIN’
Beneath the force sensor, a device called a Stewart platform offers variable amounts of resistance through six linked pneumatic pistons. The platform enables the ankle to move in every direction a healthy ankle can.
3. PLAYING FOOTSIE
The Rutgers Ankle is a video game. By moving his or her foot, the patient maneuvers an airplane, seen on a video screen, through a series of colored rectangles that appear in the sky. Not only are the required movements more complex than those of traditional physical therapy, but the challenge of the game, with the patient scoring points, adds interest. “You’re more engaged,” says Dr. Greg Burdea, “so you push yourself harder.”
4. THE BRAIN
A control box coordinates the inputs from the force sensor and Stewart platform with parameters set by the therapist; it projects the plane’s movement onto the screen and records the patient’s progress. One potential of virtual reality systems like the Rutgers Ankle is to make remote therapy feasible. Burdea envisions a day when patients from around the world can meet on a cloud-computing server for virtual soccer or basketball matches. “It’s a big shift,” he says. “Therapy has become games.”