[Optimized polymethyl methacrylate-embedding enables exact section examination of the femur with an uncemented femoral stem].

AIM

Embedding of larger bones, as described in this article, is not possible without marked modifications of the methods followed for small, undecalcified bone specimens. Problems such as turbidity of the PMMA, incomplete hardening of the medullary cavity due to insufficient infiltration and, especially, uncontrolled polymerization with excessive bubbling make analysis of the specimens impossible. Thus, modifications with respect to the infiltration times in the individual solutions, the benzoyl peroxide quantities added and the temperature during the polymerization phase were undertaken.

METHOD

The infiltrations were performed under vacuum. A cooling circulation was created in a standard water bath with a circulator pump to facilitate extraction of the polymerization heat. The use of PMMA blocks as filling material and polymerization inductors was especially important.

RESULTS

There was no turbidity or excessive bubbling of the PMMA in any of the specimens embedded with this method. Analysis of the sections showed a low-bubble medullary cavity with 01 bubble/cm(2). Up to 10 bubbles/cm(2) were observed only in the large cancellous space in the trochanteric region over a length of 56 cm. All bubbles were a maximum of 1.5 mm in size.

CONCLUSION

With the described method it is possible to embed large bones in PMMA.