Cementless Versus Cemented Tibial Fixation in Posterior Stabilized Total Knee Replacement: A Randomized Trial

Area of Science:

• Orthopedic Surgery
• Biomaterials Engineering
• Medical Imaging Analysis

Background:

• Limited literature exists on cementless tibial fixation for posterior stabilized total knee replacements.
• This study addresses the comparative efficacy of cemented versus cementless fixation in this specific prosthesis design.

Purpose of the Study:

• To compare component migration, bone remodeling, and clinical outcomes between cemented and cementless tibial fixation in posterior stabilized total knee replacements.
• To evaluate the long-term stability and safety of cementless fixation for the Advanced Coated System (ACS) prosthesis.

Main Methods:

• A prospective, single-center, blinded, randomized clinical trial involving 100 patients undergoing total knee replacement with the ACS prosthesis.
• Radiostereometric analysis (RSA) and dual x-ray absorptiometry (DXA) were used to assess component migration and bone mineral density over 24 months.
• Clinical outcomes were evaluated using the Oxford Knee Score and Short Form-12.

Main Results:

• Cementless fixation exhibited significant late and ongoing subsidence (mean 1.22 mm at 24 months) compared to cemented fixation (0.06 mm).
• Mean maximum total point motion was substantially higher in the cementless group (2.04 mm) versus the cemented group (0.48 mm).
• The cemented group experienced greater periprosthetic bone mineral density loss; however, two cementless components required revision, one for loosening.

Conclusions:

• Cementless tibial fixation in ACS posterior stabilized total knee replacements is associated with concerning fixation instability.
• Cemented tibial components demonstrated stable fixation and are recommended for the ACS posterior stabilized total knee replacement.
• Caution is advised when considering cementless tibial components for this specific implant.