Although bionics is really referring to the combination of biology with electronics, in today's culture it has come to mean anything artificial like joint replacements. Given this definition, it's likely that longer lifespan is a major contributing factor to the increasing number of bionic adults.
The World Health Organization (WHO) reports knee osteoarthritis as a common cause of disability in older adults around the world. With the aging of America, we are likely to see more of this over time.
But it isn't just Americans. Studies show an even larger number of people with knee OA in Asians than in Western groups. This is true even though Asian people have lower body weight. Being overweight or obese is a major risk factor for hip and especially knee arthritis.
According to a study in Thailand, Asian adults who squat or sit on the floor for long periods of time each day are at increased risk for knee OA. This is a common occupational hazard for the farming community in southeast Asia who often use the squatting position while working.