To demonstrate the role of an antibiotic containing bone substitute, native bone active proteins and muscle transforming into bone.
Recurrent osteomyelitis was eradicated and filled with a gentamycin eluting bone substitute (Cerament™l G) consisting of sulphate and apatite phases and covered by a muscle flap. C2C12 muscle cells were seeded on the bone substitute in-vitro and their phenotype was studied. Another muscle cell line L6 was seeded with osteoblast conditioned medium containing bone active proteins and specific markers were studied for bone differentiation.
A chronic, longstanding, fistulating osteomyelitis was operated with radical eradication and filling of the cavity with gentamycin eluting bone substitute. At one year, the patient had no leg pain and a healed wound. Significant bone was also seen in the overlaying muscle, at one month post-op disappearing after 6-months. Local delivery of gentamycin had a protective effect on bone formation. C2C12 cells seeded on the gentamycin eluting bone substitute depicted no difference in proliferation when compared to plain bone substitute and expressed 4 folds higher Alkaline phosphatase (ALP) compared to controls. C2C12 cells expressed proteins and genes coding for collagen type 1 (Col 1), osteocalcin (OCN), osteopontin (OPN) and bonesialoprotein (BSP). L6 cells cultured with osteoblast conditioned medium remained uninucleated and expressed osteoblastic proteins like Col 1, OCN, OPN and BSP.
Bone substitute with gentamycin leads to differentiation of mesenchymal cells into bone in-vitro. Native bone active proteins from an osteoblast culture can induce differentiation of muscle cells in-vitro. Clinical observations with rapid bone formed in the bone substitute and in some cases in the muscle are a consequence of both leakage of bone active proteins and also from osteoprogenitor cells coming from the overlaying muscle interacting with the osteoinductive bone substitute.
