The theory behind the all-metal hip implant was to allow those younger hip implant recipient patients to be able to go for a longer period of time before they were required to undergo revision surgery. The prior hip implant designs were primarily made from ceramic and polyethylene, and while these materials exhibited a reasonable success rate, they simply did not last long enough, with a typical length of time before revision surgery being approximately 8-10 years. The all-metal hip implants were expected to last almost double that amount of time, making them an exciting, innovative new development in hip implants. Problems soon began to arise with the metal-on-metal hip implants, with several models being recalled due to the risk of metallosis.