An ultrasonic nondestructive evaluation (NDE) technique has been developed to characterize the superficial layer of articular cartilage. The technique utilizes the unique properties of surface waves to detect changes in mechanical properties of the surface layer of the test sample. Experiments were performed first on poly(vinyl alcohol) (PVA) hydrogels, a material used to model articular cartilage, to examine repeatability and the ability of wave propagation parameters to reflect changes in material properties. Dynamic shear and compression tests were performed on 20% and 25% PVA by weight hydrogels to examine the difference in material properties. Ultrasonic NDE tests with longitudinal, shear and surface waves were performed on the hydrogels. Wave speeds in the 20% and 25% hydrogels were compared. Results showed that ultrasonic NDE with surface waves was repeatable and the technique was able to detect material property changes in hydrogels. Ultrasonic NDE tests with surface waves were then performed on healthy and damaged bovine articular cartilage. Wave speeds in the healthy cartilage were compared to speeds in enzymatically digested cartilage. Results showed that ultrasonic NDE with surface waves was repeatable and the technique was able to detect material property changes in the superficial layer of articular cartilage. Findings suggest that the technique has potential to be a tool in diagnosing diseases involving cartilage degeneration, such as osteoarthritis.

Year 2019, football, rugby, netball and skiing had most occurring ACL injuries, listed by United Kingdom National Ligament Report (NLR). The standard procedure treatment of complete laceration of the ACL, is performed by tissue autograft implantation designed from a patellar tendon, for replacement of damaged tissue using orthopaedic surgery. The aim of this thesis is to design and fabricate an ACL graft, attempting to mimic the natural ACL, for the purpose of tissue reconstruction. The desired graft analogues exhibited properties imitating native connective tissue, reducing pain through drug delivery with great biocompatibility and enhance suture mechanical strength. Various biomaterials were implemented into this study, utilising strategies; polymer solution fabrication, electrospinning, hydrogel synthesis, mechanical braiding and graft assembly to fabricate an ACL graft. The polymeric material poly (E- caprolactone) (PCL) was researched, utilising its ability to fabricate scaffolds. Results showed, three analogue ACL grafts (Braided PCL-BP, Braided PCL + Hydrogel-BPH & Braided PCL + Sutures-BPS) created utilising the properties of braiding, hydrogels and sutures, ultimately improving the versatility of electrospinning for tissue engineering and reconstruction. Graft analogues were tested and compared against patellar tendons producing similar tensile properties. Poly vinyl alcohol (PVA) hydrogels successfully held ibuprofen, revealing drug delivery characteristics, polyester threads improved mechanical properties of electrospun grafts and dry degradation showed that PCL did not lose significant mass over two months. Conclusion, tensile strength of patella tendon was 395x, 790x & 56x of analogue grafts (BP, BPH & BPS) respectively, having potential for improvement of tensile parameters for ligament reconstruction.