Pomeroy & Rhoads Orthopaedics PLLC
Zimmer’s Forever Hip is the only hip replacement implant that has been laboratory tested to mimic the number of walking steps a patient will typically take during their lifetime following total hip replacement surgery. The implants were tested for 80 million level walking cycles following a testing protocol intended to imitate the typical walking motion. A single test cycle is intended to be equivalent to the range of movement required for an average person to take a single step under typical conditions.
Why 80 million cycles of wear testing?
Zimmer’s Forever Hip has been lab tested to mimic the number of walking steps an implant will typically be subjected to during its lifetime. Based on the average American life expectancy of 78.7 years, a patient who undergoes hip replacement at the age of 45 would need their implant to last for 34 years. Depending on how active a person is, studies have shown that we typically take about 1.1 - 2.2 million walking steps per year. Therefore, the implant would be subjected to between 37 - 74 million steps during its lifetime.
Why is wear important?
Wear of a total hip prosthesis is a major clinical problem. A patient’s immune system may recognize the wear particles as foreign and generate an immune response, similar to an allergic reaction. This reaction can result in severe damage to the bone and bone loss around the hip implant, called osteolysis. If the damage to the bone is severe enough, the outer socket (shell) of the implant may become loose. The chance of re-operation may be reduced by improving a material’s wear resistance.
As a solution for the more demanding patients, Zimmer selected the more aggressive expectations as the appropriate simulated implant lifetime of wear and tested to 80 million cycles of simulated wear. Based on the results of this testing, Vivacit-E Vitamin E Technology shows improved wear performance in long-term 80 million cycle testing.
Information taken from Zimmer's webpage foreverhip.com