A comparison of the shrinkage of commercial bone cements when mixed under vacuum

Abstract

The outcome of a cemented hip arthroplasty is partly dependent on the type of cement which is used. The production of an interface gap between the stem and the cement mantle as a result of shrinkage of the cement, may be a factor involved. Palacos R, Palacos LV (both with gentamicin), CMW 1, CMW 2, CMW Endurance (CMWE) and Simplex were prepared under vacuum and allowed to cure overnight in similar cylinders. The next day this volume was determined by the displacement of water. Shrinkage varied between 3.82% and 7.08% with CMWE having the lowest and Palacos LV the highest. This could be a factor to consider when choosing a cement for a shape-closed stem.

Radius Fracture Repair Using Volumetrically Expanding Polyurethane Bone Cement

“…This expansion is in contrast to the small contraction of the PMMA cement during cure. 16 An additional factor in the elevated strength might relate to a potential modulus-related reduction in stress concentrations in specimens fixed with PBC versus PMMA. Future material-specific finite element modeling might provide insight into this hypothesis.…”

“…Moreover, PMMA volumetrically contracts during curing, increasing the likelihood for gap formation at the interface of cement to trabecular bone. 16 Similarly, a severe material property mismatch between cancellous bone (modulus generally in the 50 -500 MPa range 17 ) and rigid PMMA (modulus of approximately 2500 -3000 MPa 18 ) increases the potential for stress shielding, bone resorption, and fracture at the cement-bone interface. Polymethylmethacrylate fails to integrate with host bone, lacking the porosity requisite for bone ingrowth into the material.…”

In vitro comparison of Refobacin-Palacos R with Refobacin Bone Cement and Palacos R + G

“…The statistical differences found in our study must be considered irrelevant, as much higher shrinkage values are commonly found. If they had been vacuum-mixed, thus reducing the porosity of the cement, we would have expected up to 7% shrinkage (Kwong and Power 2006).…”

Bonding of a Silorane‐Based Composite System to Bone

“…[14] Silorane-based composite has the advantage of low shrinkage (0.79%) compared with several commercial PMMA cements (3.82-7.08%). [15] The results of bond strength tests usually have a wide variation. Researchers often present data using mean value and standard deviation.…”