Two-year follow-up of bone mineral density changes in the knee after meniscal allograft transplantation: Results of an explorative study.

BACKGROUND: The potential chondroprotective effect of meniscal allograft transplantation (MAT) is unclear. Subchondral bone mineral density (BMD) and subchondral bone remodeling play important roles in osteoarthritis development. Evaluation of subchondral BMD after MAT might give more insight into the potential chondroprotective effect. The purpose of this study was to determine early BMD changes in the knee after MAT.

METHODS: Twenty-six consecutive patients underwent MAT during 2010-2013. The BMD was measured using dual-energy x-ray absorptiometry (DXA) scan preoperatively, and six months, one and two years postoperatively. Bone mineral density was measured in six regions of interest (ROIs) in the tibia and femur (medial, central, lateral) in both treated and healthy contralateral knees.

RESULTS: The BMD levels of MAT knees did not significantly change during two years of follow-up in almost all ROIs. Bone mineral density was significant higher in nearly all ROIs in MAT knees at almost all follow-ups compared to healthy contralateral knees. In the healthy contralateral knees, BMD slightly, but not statistically, decreased in the first postoperative year, where it normalized to baseline values at two-year follow-up. The BMD levels in all ROIs did not significantly differ between the patients with or without chondropathy at baseline and two-year follow-up.

CONCLUSION: Based on the findings, MAT did not show a significant influence on BMD in the first two postoperative years. Longer follow-up is necessary to prove the potential chondroprotective effect of MAT using BMD measurements.