Cementless tibial components may lead to less TKR stability
The use of cementless tibial components in total knee replacement surgery led to a greater risk for subsidence in patients, according to published findings.
Nils Oscar Nivbrant, MBBS, of the department of surgical and perioperative sciences at Umea University in Sweden and the Fiona Stanley Hospital in Australia, and colleagues sought to compare tibial component stability, change in surrounding bone mineral density (BMD) and clinical outcomes of TKRs performed with posterior-stabilized Advanced Coated System knee prostheses (Implantcast) fixed with and without cement.
Nivbrant and colleagues analyzed data from a prospective single-center, blinded, clinical trial composed of 100 patients (mean age, 68 years). Two experienced arthroplasty surgeons split conducting patient operations.
Investigators stratified patients into either a cemented or cementless tibial fixation. Radiostereometric analysis and dual X-ray absorptiometry were performed during inpatient stay and between 3 and 24 months for monitoring of tibial component migration and periprosthetic BMD.
Nivbrant and colleagues observed late and continuing migration in patients with cementless fixation.
At 24 months follow-up, mean subsidence was greater in the cementless group compared with the cemented group (1.22 vs. 0.06 mm; P < .01), the results showed. Mean maximum total point motion at 24 months was greater in the cementless group compared with the cemented group (2.04 vs. 0.48 mm; P < .01).
The cemented group had greater BMD loss in the medial, lateral and anterior periprosthetic regions compared with the cementless group, researchers wrote.
Two tibial components required revision in the cementless group, including one for loosening. Clinical scores improved equally in both groups.
“Late ongoing subsidence and high maximum total point motion raise concerns about the fixation stability of cementless (advanced coated system) posterior stabilized knee replacements,” Nivbrant and colleagues wrote. “Cemented tibial fixation were stable despite BMD reduction surrounding the tibial components.”