Treatment of osteoarthritis by implantation of Mg- and WE43-cylinders : a preclinical study on bone and cartilage changes and their influence on pain sensation in rabbits

With its main features of cartilage degeneration, subchondral bone sclerosis and osteophyte formation, osteoarthritis
represents a multifactorial disease with no effective treatment options. As biomechanical shift in the
trabecular network may be a driver for further cartilage degeneration, bone enhancement could possibly delay
OA progression. Magnesium is known to be osteoconductive and already showed positive effects in OA models.
We aimed to use magnesium cylinders to enhance subchondral bone quality, condition of cartilage and pain
sensation compared to sole drilling in vivo. After eight weeks of implantation in rabbits, significant increase in
subchondral bone volume and trabecular thickness with constant bone mineral density was found indicating
favored biomechanics. As representative for pain, a higher number of CD271+ vessels were present in control
samples without magnesium. However, this result could not be confirmed by sensitive, objective lameness
evaluation using a pressure sensing mat and no positive effect could be shown on either cartilage degeneration
evaluated by OARSI score nor the presence of regenerative cells in CD271-stained samples. The presented results
show a relevant impact of implanted magnesium on key structures in OA pain with missing clinical relevance
regarding pain. Further studies with shifted focus should examine additional structures as joint capsule or osteophytes.