Effects of intra-articular administration of autologous bone marrow aspirate on healing of full-thickness meniscal tear: an experimental study on sheep.

Objective: The aim of this study was to evaluate the effects of bone marrow-derived mesenchymal stem cell and bone marrow elements on the healing of meniscal tears.

Methods: This study was performed on twelve, 2-year-old male Tahirova sheep. In each subject, one knee was used for experiment purposes and the other knee was used as a control. After creating a longitudinal full-thickness tear in the red-white zone of the medial meniscus, aspirated autologous bone marrow material was injected into the tear site in the experiment group. The control group received no intervention for secondary healing.

Results: In the macroscopic evaluation of meniscus, a bridging reparation tissue and adhesion were observed between the rims of the tear in the experiment group. There was no statistical difference in collagen fibril formation between the groups (p=0.16). There was significantly more neovascularization in the experiment group than the control group (p=0.003). The cell count was also a significantly higher in the experiment group (p=0.004) and formation of cartilage plaques was more frequent in the experiment group (p=0.016). There was no evidence suggesting intrinsic repair in the meniscus of control group by light and electron microscopy.

Conclusion: An injection of bone marrow into the meniscus tear site improves healing in a meniscal tear model as demonstrated by both light and electron microscopic findings.