The Masquelet technique is a two-staged surgical procedure with initial segmental bone resection and temporary placement of an antibiotic polymethylmethacrylate (PMMA) cement spacer into the defect site. This spacer induces the formation of a synovia-like membrane. In the second stage of the surgery, this membrane is opened, the PMMA cement spacer is removed and subsequently, the membrane cavity is filled with cancellous bone as well as growth factors.
The aim of the current study was to define an optimal time interval for the second stage of the surgery by histological and cellular characterization of Masquelet membranes and cell biology (bioactivity) as well as correlation to the duration of PMMA spacers in the surgical site.
Membranes of 65 patients were harvested during the routine surgical removal of PMMA spacers at the second stage of a knee total endoprosthesis. This procedure of temporary implantation of a PMMA spacer was comparable to the two-stage Masquelet technique.
While in the Masquelet technique the membrane has to be preserved at the second stage, the total removal of the membrane has been done during the surgical debridement of the knee total endoprosthesis change. This membrane was then available without restriction for further cell biological characterization.
Histological analyses showed that the structure of the membrane was two- or three-layered and changed during the course of time. To analyze the biological activity of the various Masquelet membranes, MSC were co-cultured with removed membranes.
The results clearly show that the bioactivity of the membranes did not significantly change over time and that the biological efficiency did not decrease even in elderly membranes. Similar results were obtained by microarray analysis of membrane lysates. The comparison of protein patterns from membranes of different age showed that the protein expression pattern were almost identical to single variations at various time points. Furthermore, high number of mesenchymal stem cells could be detected by immunohistochemical analysis within all samples. For the localization of the MSC in the different membranes, a double staining with the surface markers CD105/CD73 or CD90/CD73 was performed.
In addition, cells could be isolated from all membranes, which expressed the MSC surface markers CD73 and CD105 on their surfaces and which expressed a pluripotent differentiation potential. Thus, the isolated membrane cells fulfilled the characteristics of mesenchymal stem cell driven bioactivity.
The results show that the biological efficiency does not decrease even in elderly membranes. This study thus provides new findings on surgery using the Masquelet technique, which directly impacts future considerations regarding the time point of the second operation.
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rehabilitationDescription, key words: