Clinical Orthopaedics and Related Research®

, Volume 470, Issue 1, pp 108–116

All-polyethylene and Metal-backed Tibial Components Are Equivalent With BMI of Less Than 37.5

Symposium: Papers Presented at the Annual Meetings of the Knee Society

DOI: 10.1007/s11999-011-2124-3

Cite this article as:
Toman, J., Iorio, R. & Healy, W.L. Clin Orthop Relat Res (2012) 470: 108. doi:10.1007/s11999-011-2124-3

Abstract

Background

Modular, metal-backed tibial (MBT) components are associated with locking mechanism dysfunction, breakage, backside wear, and osteolysis, which compromise survivorship. All-polyethylene tibial (APT) components eliminate problems associated with MBTs, but, historically, APT utilization has generally been limited to older, less active patients. However, it is unclear whether APT utilization can be expanded to a nonselected patient population.

Questions/purposes

We therefore determined the survivorship of APT components compared with MBT components in a non-age- or activity-selected population who underwent TKA.

Methods

Using a longitudinal database, we identified 775 patients with primary TKAs utilizing a single implant design between 1999 and 2007. Of these, 558 (72%) patients had APT components (APT2), while 217 (28%) patients with tibial bone loss or defects, contralateral MBT components, or a BMI of greater than 37.5 received MBT components. We determined the survivorship in the two groups. The minimum followup was 2 years for both groups (mean ± SD: MBT, 80 ± 29 months; APT, 63 ± 27 months). The APT group was older (average age: APT2, 70 years; MBT, 64.7 years) and had a lower BMI than the MBT group (APT2, 30.8; MBT, 33.8).

Results

Survivorship, as defined by revision for any reason, was 99% for the APT group and 97% for the MBT group. There were four (2%) tibial failures in the MBT group in patients with a BMI of greater than 40. There were no revisions for loosening or osteolysis in the APT group.

Conclusion

APT implants perform as well as MBT implants in a non-age- or activity-selected TKA population with a BMI of less than 37.5.

Level of Evidence

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Copyright information

© The Association of Bone and Joint Surgeons® 2011

Authors and Affiliations

  1. 1.Department of Orthopaedic SurgeryLahey Clinic Medical CenterBurlingtonUSA