Squeaking hip arthroplasties: a tribological phenomenon

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Tribology

Background:

• Increasing reports of squeaking in hip arthroplasty, especially with ceramic-on-ceramic bearings.
• Squeaking is a concerning phenomenon affecting patient satisfaction and implant longevity.
• Understanding the underlying mechanisms is crucial for improving implant design and performance.

Purpose of the Study:

• To investigate the potential causes of squeaking in hard-on-hard hip bearings.
• To determine the influence of bearing clearance and third-body particles on squeaking.
• To correlate squeaking incidence with tribological factors like friction.

Main Methods:

• Two sets of experimental conditions were employed to simulate hip arthroplasty environments.
• Metal-on-metal surface arthroplasties were tested to evaluate the effect of bearing clearance.
• Total hip arthroplasties were subjected to the addition of third-body particles to assess their impact.

Main Results:

• Bearing clearance was found to influence the incidence of squeaking in metal-on-metal bearings.
• The presence of third-body particles at the bearing interface also affected squeaking occurrence.
• A strong correlation was observed between squeaking incidence and elevated friction in both experimental setups.

Conclusions:

• Adverse tribological conditions, specifically suboptimal lubrication, are likely causes of squeaking in hip arthroplasty.
• Multiple factors can contribute to suboptimal lubrication, making a single cause for squeaking improbable.
• Further research into lubrication dynamics and material interactions is warranted to mitigate squeaking.