The musculoskeletal system has an innate ability to regenerate itself following injury. However, there are numerous clinical complications where tissue level damage exceeds the body’s natural healing ability such as high energy trauma, infection and disease. In these situations, the ability to regenerate is compromised, leading to a reduction in the structural and functional capability of the tissue. Surgeons and researchers have begun exploring the use of scaffolds/grafts to augment healing, with the aim of providing temporary mechanical support to the tissue, while enhancing the body’s innate regenerative capacity.
Our group has developed a comprehensive in vitro evaluation system for biomaterial scaffolds, covering immunogenicity and host cell growth, differentiation and matrix production. This is followed by pre-clinical in vivo evaluations, overseen and carried out by orthopaedic surgeons. The scaffolds are provided to us by academic and commercial researchers and are designed to enhance the regenerative capacity of large bony defects and difficult to heal tendon-bone injuries. We have evaluated both natural and synthetic materials designed for use as stand-alone scaffolds, or as delivery systems for growth factors targeted to the tissue of interest.
Over the past 6yrs we have had scaffolds that looked promising from a cytocompatability point of view, but failed the immunogenicity testing. Similarly, we have had scaffolds that have passed the in vitro testing stage, only to disappoint with in vivo evaluation. The scaffolds that have given the best results have often been the simplest in terms of structure and capability to deliver growth factors.
Despite the growing biomaterial/scaffold market, and the readiness of clinicians to take on new technologies, to date nothing has proven to be as effective as autologous tissue grafting. Thus, more work is needed to create scaffolds that mimic the in vivo environment, both in structure and biochemical cues.