Porous metal tibial components seen as durable as traditional cemented models

Researchers discovered similar rates between the groups for re-operation, revision and complications.

Issue: September 2013

In a randomized clinical trial, researchers discovered uncemented highly porous metal tibial components performed as well as cemented modular tibial components in patients who underwent total knee arthroplasty.

“At 5 years, uncemented monoblock highly porous metal tibial components are as durable and clinically reliable as cemented modular tibial components,” Matthew P. Abdel, MD, of Mayo Clinic, Rochester, Minn., said during his presentation at a recent meeting. “No single uncemented highly porous metal tibial component was revised for aseptic loosening.”

Unilateral TKA

According to Abdel, the authors of previous published studies noted concern about the durability and clinical reliability of uncemented tibial components for total knee arthroplasty (TKA). However, he said uncemented highly porous metal tibial components have multiple advantages, including the potential for increased biologic fixation and stability.

To test the durability and reliability of these components, Abdel and colleagues performed a prospective randomized trial at the Mayo Clinic of 246 patients who underwent unilateral TKA and had a preoperative diagnosis of osteoarthritis. The researchers included patients aged 20 years to 85 years. There were 117 patients who received an uncemented monoblock highly porous metal tibial component and 129 patients who had a cemented modular tibial component. The researchers analyzed the groups’ Knee Society Scores (KSS), range of motion (ROM), complications, reoperations and survivorship. There were no significant differences between the groups for age, gender, body mass index, and preoperative ROM and KSS for pain or function. The researchers had 98% clinical follow-up for their 5-year study. The statisticians of the study completed a power analysis prior to initiation of the study to avoid type 2 error.

No significant differences

The researchers saw no significant differences between the groups regarding the postoperative KSS and ROM measures. Using revision for any reason as an endpoint, the researchers found a 5-year survivorship of 96% for both groups. The overall rate of re-operation was 3.5% in both groups. The rate of aseptic tibial revision was 3.1% in the cemented modular group and 1.7% in the uncemented monoblock group. The primary cause of failure in the uncemented monoblock highly porous metal group was deep infection.

“We completed a per protocol analysis, and no uncemented monoblock highly porous metal tibial component was revised for aseptic loosening,” Abdel said. They found five instances of aseptic loosening in the cemented group.

“We found that an uncemented monoblock highly porous metal tibial component was as durable as a cemented modular tibial component as judged by survivorship at 5 years,” Abdel said. – by Renee Blisard Buddle

Reference:

Pulido L. Paper #357. Presented at: American Academy of Orthopaedic Surgeons Meeting; March 19-23, 2013; Chicago.

For more information:

Matthew P. Abdel, MD, can be reached at the Mayo Clinic, 200 First St., SW, Rochester, Minnesota 55905; email: abdel.matthew@mayo.edu.
Disclosure: Abdel has no relevant financial disclosures. His institution received research support from Stryker, DePuy, Zimmer and Biomet.