Full Hip Joint Replacement Description
[Continued from above] . . . worked loose and required more surgery. Some joints didn't work very well because they were designed like hinges that just opened one way.
Later, when the designers realized the knee needed to rotate (a knee replacement also requires a ball-and-socket joint), they produced a joint that would fulfill these movements as well. Medical pioneers finally overcame bodily rejection by making the joints out of nonirritating, man-made materials. They have now perfected hip replacements so that recipients are relieved of pain and can walk at a smoother pace.