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Advanced wear-reducing hip replacements

What are some of the advanced wear-reducing materials available for revision hip surgery?

  • OXINIUM◊ Oxidized Zirconium
  • Ceramic on ceramic
  • Metal on metal

A surgeon’s main long-term goal for the procedure is for the hip replacement to last many years. In recent years, advanced, wear-reducing materials have been introduced that may extend the life of hip replacements. These material options include OXINIUM◊ Oxidized Zirconium balls on cross-linked polyethylene plastic liners, ceramic balls on ceramic liners and metal balls on metal liners.

OXINIUM◊ Oxidized Zirconium

OXINIUM◊ material is a metal alloy whose surface has been transformed into smooth, hard, black ceramic. This remarkable surface reduces wear like a ceramic but beneath the surface it is still solid metal and thus retains all of the metal component’s strength characteristics.

The ceramic surface makes OXINIUM◊ implants 4,900 times more abrasion resistant than standard cobalt chrome. It also reduces friction between the implant and the plastic or cartilage surfaces. The result is superior durability over time.

With an OXINIUM◊ hip replacement, the ball is replaced with an OXINIUM◊ femoral head and the socket is replaced with cross-linked plastic. This reduces wear by 98%1, 2 in laboratory testing when compared to traditional metal on plastic hip replacements. The OXINIUM◊ surface also reduces the concern for metal wear particles that can occur from metal on metal hip replacements and brittle fractures which sometimes occur with ceramic on ceramic hip replacement. Talk with your orthopaedic surgeon to learn more about OXINIUM◊ hip replacements and to find out if they are right for you.

Ceramic on ceramic

Another option for extending the life of your hip replacement is ceramic on ceramic. These implants reduce wear by 99%3 in laboratory testing when compared to traditional metal on plastic. With ceramic on ceramic hip replacements, both the ball and socket are replaced with ceramic.

These implants have an excellent reputation for reducing wear, but have limited flexibility in design options due to manufacturing limitations of the ceramic material. Therefore these implants are not suited for all patients. Talk with your surgeon about this technology and if it is right for you.

Metal on metal

Metal on metal hip implants have shown to reduce wear by 97%3 in laboratory testing as compared with traditional metal on plastic. As with ceramic implants, metal sometimes limits flexibility in design. The metal on metal design also involves some potential health risks due to more metal wear particles (ions).

Some studies have shown that ions in the body of patients with metal on metal hip replacements are up to 29 times the normal level.4 These levels were measured by testing the patient’s blood and urine ion levels before and after total hip replacement surgery.  High ion levels can be especially harmful to women of child bearing age or persons with poor kidney function.

 REFERENCES

1. Good V, Ries M, Barrack RL, Widding K, Hunter G, Heuer D, Reduced Wear with Oxinium Ziconium Femoral Heads, JBJS in print, 2003.

2. Scott M, Morrison M, Mishra SR, Jani S, A Method to Quantify Wear Particle Volume Using Atomic Force Microscopy. ORS Transactions Vol. 27 2002 (Dallas, Texas) 132.

3. Clarke IC, Good P, Schroeder D, Anissan L, A. Stark, Oonishi H, Schuldies J, and Gustafson G. Ultra-low wear rates for rigid-on-rigid bearings in total hip replacements. Proc Inst Mech Eng [H]. 2000; 214(4):331-47.

4. MacDonald, S.J. MD, McCalden, R.W. MD, Chess D.G. MD, Bourne, R.B. MD, Rorabeck, C.H. MD, Cleland, D. BScN; Leung, F. PhD +: Metal-on-Metal Versus Polyethylene in Hip Arthroplasty: A Randomized Clinical Trial. Clinical Orthopaedics & Related Research. 1(406):282-296, January 2003.