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Study suggests lubrication as a cause of squeaking in ceramic-on-ceramic hips
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KOHALA COAST, Hawaii — Recent research indicates that metal transfer may be the root cause of the squeaking phenomenon reported with ceramic-on-ceramic total hip constructs.
“We concluded that squeaking noise is a problem with ceramic-on-ceramic lubrication,” Robert T. Trousdale, MD, said during his presentation at Orthopedics Today Hawaii 2010, here. “The noise occurs, we think, when the fluid film between the two surfaces is disrupted and we feel this most commonly affected the area of material and metal transfer. Metal transfer is the primary mode leading to fluid lubrication disruption and may explain why squeaking is more common with certain designs.”
In an in vitro study, Trousdale and colleagues tested a ceramic-on-ceramic total hip using an automated hip simulator. The investigators tested the hip during the following situations twice in both a lubricated condition using a partial bovine serum and a dry condition:
- normal gait;
- extreme load;
- stripe wear;
- stripe wear and extreme load;
- edge wear and extreme load;
- metal transfer; and
- microfracture.
The tests were performed up to 11,000 cycles.
The investigators found that squeaking occurred in all of the testing done during dry conditions.
“If you add lubrication to all of the models, that squeak will go away,” Trousdale said. “Once that lubrication wears off, squeak returns.”
In addition, they discovered no cases of squeaking in nearly all testing conducted in lubricated conditions.
“The only thing that squeaks in the lubricated model was the metal or material transfers,” Trousdale said.
He also noted that a literature review of 196 documented patients with squeaking hips showed that 194 of these patients had the same cup design.
“So that implies that cup design can lead to a condition that makes the metal transfer a little bit easier to occur than with other designs,” Trousdale said.
- Reference:
Trousdale RT. The truth about ceramic squeaking. Presented at Orthopedics Today Hawaii 2010. Jan. 10-13, 2010. Kohala Coast, Hawaii.