Mobile bearings in primary knee arthroplasty

Area of Science:

• Orthopedic surgery
• Biomaterials engineering
• Biomechanics

Background:

• Mobile-bearing knee arthroplasty (MBKA) allows axial rotation, potentially improving articular conformity and reducing polyethylene wear compared to fixed-bearing total knee arthroplasty (TKA).
• This design aims to minimize stress on polyethylene components, reducing wear and fatigue failure, and allows for self-correction of tibial component alignment.

Purpose of the Study:

• To compare the theoretical advantages of MBKA with its actual long-term clinical performance against conventional TKA.
• To evaluate the clinical outcomes, potential benefits, and drawbacks of MBKA in total knee replacement.

Main Methods:

• Review of existing literature comparing MBKA and TKA.
• Analysis of clinical results, focusing on implant survival, wear characteristics, and adverse events associated with both arthroplasty types.

Main Results:

• Despite theoretical benefits, current long-term clinical results for MBKA are comparable to well-designed fixed-bearing TKA.
• MBKA presents disadvantages including bearing dislocation, breakage, soft-tissue impingement, and concerns regarding volumetric wear.

Conclusions:

• Current long-term data does not demonstrate the superiority of MBKA over fixed-bearing TKA.
• Further long-term follow-up is needed to ascertain if MBKA's theoretical advantages in mitigating polyethylene fatigue failure will manifest over extended periods.