The future of orthopedic medical devices is small—microscopically small. Microelectromechanical systems, referred to as MEMS devices, are already used in a host of electronic devices, doing tasks that were previously only conceived of in science fiction. Sensors the size of a flea can now measure strain or temperature or resistivity. They can also measure acceleration, frequency, and electrical impulses. MEMS devices are used in microscopic gears for tuning hearing aids, capacitive rings embedded in contact lenses to measure glucose levels, and microfluidic pumps to deliver insulin to patients.