Functional Changes in Articular Cartilage After Meniscal Allograft Transplantation: A Quantitative Histochemical Evaluation in Rabbits

Purpose: To evaluate quantitatively functional changes in articular cartilage after immediate and delayed meniscus transplantation in rabbits. Type of Study: Experimental study. Methods: Thirty rabbits were divided into 5 groups: groups A and C were subjected to meniscectomy only, groups B and D underwent meniscal transplantation immediately after meniscectomy, and group E had delayed transplantation 6 weeks after meniscectomy. Six nonoperated knees served as controls. Functional changes in articular cartilage were examined at 6 weeks (groups A, B) and 1 year (groups C, D, E, controls) after surgery by measuring proteoglycan content of the extracellular matrix as a measure of its quality and lactate dehydrogenase (LDH) activity in chondrocytes as a measure of their vitality. Results: At 6-week and 1-year follow-up, no significant differences were found between the immediate transplant group and postmeniscectomy group. The delayed transplant group showed a significantly decreased proteoglycan content compared with the postmeniscectomy group. No significant differences in cellular LDH activity were found between the immediate transplant group and postmeniscectomy group at 6 weeks and 1 year. However, the delayed transplant group showed a significant decrease in LDH activity compared with the postmeniscectomy group. Conclusions: Immediate meniscal transplantation in rabbits did not significantly reduce degenerative changes of articular cartilage in comparison with meniscectomy on a short-term and long-term basis, whereas delayed transplantation led to more degenerative changes than meniscectomy. Clinical Relevance: Before meniscus transplantation can be considered as an alternative to meniscectomy in clinical practice, it has to be determined whether this procedure has any protective effect on articular cartilage on the long term.