Effects of cement creep on stem subsidence and stresses in the cement mantle of a total hip replacement

✍ Scribed by Lu, Z. ;McKellop, H.

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 353 KB
• Volume: 34
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/(sici)1097-4636(199702)34:2<221::aid-jbm11>3.0.co;2-l

✦ Synopsis

In cemented total hip prostheses, the role of creep of the occurred with all three bonding conditions, allowing addiacrylic cement (polymethyl methacrylate, [PMMA]) in in-tional subsidence of the stem and a decrease in the stress creasing or decreasing the chance of failure of the cement components within the cement. During the unloaded period mantle is a subject of ongoing controversy. In the present the full recovery of the preload conditions could be reached study we used a three-dimensional finite-element model of with the completely bonded and with the frictionless intera cemented stem to assess the influence of cement creep on faces. With the frictional interface there was residual cement subsidence of the stem, and on the stress and strain in the creep, residual stresses within the cement, and residual subsicement under cyclic load, both in the short and long term.

dence of the stem during the unloaded period; however, the The cement layer was assigned the shear and bulk creep reduction of the stress was at most 13% and the subsidence moduli of Zimmer regular PMMA cement, which were ob-was about 0.46 mm. The much larger subsidence of debonded tained experimentally. The stem-cement interface was stems that is often observed clinically might be attributed to modeled either as (1) completely bonded, (2) completely the factors which were not included in the present model, debonded with friction, or (3) completely debonded such as circumferential bone remodeling.