The knee can take a great deal of abuse, thanks to the cartilage that cushions it. But if it’s not moved and exercised enough, the knee stiffens and has poor blood flow. The cartilage can degrade or tear, worsening any injury already there. So people with injured knees have to move in order to heal. The challenge is knowing how much exercise or movement is too much.

To answer that question, UConn College of Engineering professor Thanh Nguyen, along with Ph.D. student Jinyoung Park and other colleagues, developed a pressure sensor that can be placed inside the knee joint and then degrade harmlessly in the body when no longer needed.