Fixed or mobile-bearing total knee arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Knee Arthroplasty

Background:

• Total knee arthroplasty (TKA) designs, specifically fixed-bearing and mobile-bearing, remain a subject of ongoing debate.
• Understanding the biomechanical and clinical differences is crucial for optimizing patient outcomes.

Purpose of the Study:

• To review and compare the biomechanical and clinical aspects of fixed-bearing versus mobile-bearing total knee arthroplasty.
• To evaluate the evidence regarding wear, contact stresses, kinematics, and long-term survivorship.

Main Methods:

• Review of biomechanical studies examining tibiofemoral contact stresses and wear rates.
• Analysis of clinical data on axial tibiofemoral rotation during gait and deep knee bending.
• Evaluation of mid-term and long-term survivorship data for both implant designs.

Main Results:

• Mobile-bearing designs demonstrate reduced tibiofemoral contact stresses and lower wear rates in vitro.
• Increased axial tibiofemoral rotation was observed in mobile-bearing knees during dynamic activities.
• No significant superiority in mid-term or long-term survivorship was found for mobile-bearing designs compared to fixed-bearing designs.

Conclusions:

• While mobile-bearing TKA offers theoretical biomechanical benefits, these have not translated into proven long-term clinical advantages.
• Fixed-bearing designs are suggested for less active, elderly patients; mobile-bearing designs may suit younger, higher-demand individuals.
• Surgical technique familiarity is emphasized over implant design choice for surgeons.