[Filling of osteochondral donor site defects. Experimental study with tricalcium phosphate cement and BMP-2].

Aim: Osteochondral grafting procedures have developed into one of the preferred methods of treatment for focal osteochondral lesions, although the management of the donor site remains problematic. In this animal study, an attempt at sealing the donor site with a fully-resorbable tricalcium phosphate bone cement was evaluated.
Method: Autologous osteochondral transplantation of the medial and lateral condyle was performed on the ovine knee using a standard operative protocol. The ensuing defect was filled with the original beta-TCP cement laterally, while medially the cement was augmented with 50 micro g BMP-2. Two groups, consisting of 10 sheep each, were evaluated after three and 6 months, respectively.
Results: The clinical evaluation of the specimens revealed an improved reconstruction of the joint surface following the application of the augmented biomaterial. Macroscopically, the superficial border of the original donor site could easily be outlined at both time periods in both groups. Solid osteointegration of the bone cement could be documented radiographically as early as three months following implantation.
Conclusion: The beta-TCP bone cement represents a promising resorbable filler for osteochondral defects. The augmentation with BMP-2 seems to expedite the remodelling process and improve the surface reconstruction.