A Resurfacing-Regenerative Approach to Repair Osteochondral Defects

Osteochondral defects (OCDs), areas of localized joint damage to articular cartilage and underlying subchondral bone, often lead to pain, loss of joint function, and osteoarthritis. Clinical repair is focused on biological grafting procedures but are innately limited by graft availability and donor site morbidity. We have developed a bioprosthetic implant, combining articular cartilage resurfacing and osseous tissue regeneration, as a new method for OCD repair. These implants – “cartilage-capped, regenerative osteochondral plugs (CC-ROPs)” - combine a multi-network hydrogel (cartilage cap) and osseous scaffold (base). The cartilage cap is prepared from a multi-network, electrostatic hydrogel that gives rise to articular cartilage-like mechanical, hydration, and tribological properties. The osseous scaffold base is prepared from a semi-interpenetrating polymer network (semi-IPN) of poly(ε-caprolactone)-diacrylate (PCL-DA) and poly(L-lactic acid) (PLLA). The scaffold is intrinsically osteoinductive and has a trabecular bone-like modulus as well as robust degradation rates to facilitate bone ingrowth. Formed as cylindrical plugs, CC-ROPs may be implanted into OCDs using existing grafting techniques and be fabricated in a range of sizes. <i>In vitro</i> and <i>in vivo</i> performance of the cartilage cap, osseous scaffold, and CC-ROP device demonstrate encouraging results towards development of an alternative OCD treatment.