Abstract:
Introduction: Orthopaedic surgery improves patient outcomes through musculoskeletal repair. Generally repairs are successful, however some areas, such as rotator cuff repair, anterior cruciate ligament (ACL) reconstruction and spinal fusion, can be complicated by failure of bone and/or tendon healing. Rotator cuff tears are a common cause of pain and functional impairment. Repairs of large rotator cuff tears have variable success rates, with re-tear rates post-arthroscopic repair reported to be as high as 69%. Tears of the ACL are the most common ligamentous injury of the knee. Younger patient age has recently been highlighted as a risk factor for ACL re-ruptures post-reconstruction. In spinal fusion surgery, non-union remains a problem, with up to 50% non-union reported. Simple, safe and cost effective alternatives, such as locally harvested bone, are required. Aim: To assess the efficacy of selected tendon and bone graft materials to improve outcomes in orthopaedic surgery. Three studies are presented here to attempt to achieve this overall aim: 1. To assess the efficacy of a novel biomaterial scaffold, ovine forestomach extracellular matrix (OFM) and growth factor, lactoferrin, in augmenting rotator cuff repair. 2. To identify biological causes for the increased failure rate of hamstrings autografts used for ACL reconstruction in younger patients. 3. To assess the efficacy of locally harvested bone dust as an autograft for spinal fusion. Methods: Using an in vivo rat model, the effects of OFM and lactoferrin on rotator cuff healing were assessed. The biological profile of hamstrings tendons, collected from human surgeries, was assessed through histological, biomechanical and gene expression analysis of young versus old patients. The osteoinductive properties of bone dust was assessed in vitro. Findings: Rotator cuff augmentation with OFM and lactoferrin improved histological healing but had no biomechanical benefit. Hamstrings autografts from younger patients trended towards increased elasticity and stiffness and increased expression of tendon genes. Bone dust significantly increased osteoblast proliferation, differentiation and collagen production. Conclusions: Rotator cuff augmentation and locally harvested bone dust for spinal fusion may increase the surgeon’s armoury and improve patient outcomes. Identifying reasons for hamstrings autograft failure in young patients highlights another area for potential augmentation/improvement.