Master of Science in Engineering, Youngstown State University, 2019, Department of Mechanical, Industrial and Manufacturing Engineering

It is estimated that about 18 out of 100,000 people rupture their Achilles tendon every year. A review of 4000 Achilles tendon ruptures found that 75% were related to sports activities. Currently, the methods for fixing Achilles tendon ruptures are in need of improvement. Due to the prevalence of Achilles tendon injuries in sports and the fact that tendons have poor wound healing, there has been an abundance of studies on treatments for Achilles tendon injuries. Many different techniques and therapies using biologics have been researched. One area, however, that has not been well researched is the addition of a combination of mesenchymal stromal cells and platelet-rich plasma as a treatment method for wound healing enhancement. There is also a lack of studies comparing different treatment methods as they progress through time. This study chose the following treatment methods: collagen (CoTa); collagen and platelet-rich plasma (PRP); collagen and mesenchymal stromal cells (MSC); and collagen, platelet-rich plasma, and mesenchymal stromal cells (CPM) to follow through two recovery times: 1 week and 2 weeks. Lewis rats were chosen and a full transection of the right Achilles tendon was performed 6 mm proximal to the calcaneal bone. At 1 or 2 weeks both Achilles tendons of the rats were extracted and tensile tests were performed. Maximum force, engineering stress, strain, modulus of elasticity, total strain energy, and elastic strain energy were determined. Differences in the treatment groups at 1 week recovery were notable, no differences were found between the treatment groups at 2 week recovery, however differences could be seen when compared to the left virgin tissue controls. Computational modeling led to preliminary finite element models for each treatment group. Validation for each model was achieved by comparison with experimental data. Further development of the finite element analysis would allow for a more accurate model and allow for better comparisons betwe (open full item for complete abstract)

Committee: Hazel Marie PhD (Advisor); Diana Fagan PhD (Committee Member); Virgil Solomon PhD (Committee Member); Jason Walker PhD (Committee Member) Subjects: Biomechanics; Biomedical Engineering; Biomedical Research

Master of Science, The Ohio State University, 2009, Veterinary Clinical Sciences

The tibial plateau leveling osteotomy (TPLO) was introduced in 1993 as an innovative surgical procedure to treat stifle instability secondary to rupture of the cranial cruciate ligament (CCL) (Slocum 1993). The TPLO procedure eliminates cranial tibial thrust by converting this force into a compressive joint reaction force without restoring the passive constraint of the cranial cruciate ligament, resulting in a stable stifle during the stance phase of the gait cycle (Slocum 1993, Sahar 2006). The osteotomy created is stabilized by one of a variety of custom designed TPLO plates all of which vary in design characteristics, material and biomechanical properties. Large and giant breed dogs have been shown to have a predisposition to develop rupture of the cranial cruciate ligament at a young age and biomechanical data regarding the performance of TPLO implants in these breeds is lacking (Duval 1999, Whitehair 1993). The objective of this study was to compare the axial stiffness of TPLO constructs stabilized with a single Synthes® broad TPLO plate (TPLO-broad) or a Slocum TPLO plate and a limited contact dynamic compression plate (LC-DCP) (TPLO-double). Synthetic bone models were randomly assigned to one of two groups. All models underwent a standard TPLO and were stabilized with either a Synthes® Broad TPLO plate or a Slocum TPLO plate and a LC-DCP. A gap was maintained at the osteotomy during plate application. Constructs were testes in axial compression and axial displacement and loads were recorded. Construct stiffness was calculated from load-displacement curves and comparisons of mean stiffness were performed. The mean construct stiffness for the TPLO-broad constructs was not significantly different from that of the TPLO-double constructs. The minimum effective number of implants should be used clinically to achieve stability when performing a TPLO. Implant stiffness is a key contributor to the stability of an osteotomy and is integral to osteotomy healing.

Committee: Jonathan Dyce MRCVS (Advisor); Michael Kowaleski DVM (Committee Member); Matthew Allen MRCVS (Committee Member); Bianca Hettlich DVM (Committee Member) Subjects: Veterinary Services

Doctor of Philosophy, Case Western Reserve University, 2012, Pathology

The most important factor contributing to short-term and long-term success of cementless total joint arthroplasties is osseointegration. Osseointegration is the process by which a direct structural and functional connection between living bone and the surface of an implant is made. Surface contaminants may remain on orthopaedic implants after sterilization procedures and impair osseointegration. For example, specific lots of hip replacement Sulzer Inter-OPTM acetabular shells that were associated with impaired osseointegration and early failure rates were found to be contaminated with both bacterial debris and machine oil residues. However, few osseointegration studies have focused on surface contaminants and their effect on implant integration is unknown. Therefore, we developed a novel murine model that provides quantitative and reproducible measurements of osseointegration to study the effect of surface contaminants. We found that a rigorous cleaning procedure significantly enhances osseointegration compared to implants that were autoclaved. The most likely interpretation of these results is that surface contaminants on the autoclaved implants inhibit osseointegration. Using our murine model, we also found that Gram-negative bacterial derived LPS or machine oil residues on implants inhibit osseointegration. Ultrapure LPS adherent to titanium alloy discs had no detectable effect on early stages of MC3T3-E1 osteogenesis in vitro such as attachment, spreading or growth but inhibited later stages of osteogenic differentiation and mineralization. In contrast, machine oil on titanium alloy discs inhibited osteoblast attachment, spreading, growth, differentiation and mineralization in vitro. These results demonstrate that both adherent LPS and machine oil can significantly impair osseointegration through direct effects on osteoblasts; however, they do so by inhibiting distinct steps in the process. The presence of both LPS and machine oil could lead to synergistic impai (open full item for complete abstract)

Committee: Edward Greenfield PhD (Advisor); James Anderson MD, PhD (Committee Chair); Nicholas Ziats PhD (Committee Member); Eben Alsberg PhD (Committee Member); Clive Hamlin PhD (Committee Member); Christopher Hernandez PhD (Committee Member) Subjects: Biomedical Research

Master of Science in Engineering, University of Akron, 2006, Biomedical Engineering

Autogenous bone graft (ABG) is considered the evaluation standard for cranial defect reconstruction material. A variety of bone substitutes have been used as alternative materials for this procedure, each having its own advantages and disadvantages. Carbonated calcium phosphate (CCPP), a biomaterial form of hydroxyapatite (HA), has been increasingly used for cranial reconstructions. For defects of certain size and shape, CCPP is used with a titanium mesh for structural stability. At the present time there have been no published studies in the literature comparing the biomechanical and histological properties of these cranial bone reconstruction structures over time. In this study two different reconstruction structures were compared to autogenous bone grafts with respect to time. Reconstruction structure A (RCA) used a slow setting CCPP, whereas reconstruction structure B (RCB) used a fast setting CCPP. Unilateral or bilateral cranial defect reconstructions were conducted on sheep with full thickness defect sizes of 1.5 × 3.0 cm. A total of 24 sheep were divided into eight groups with post surgical periods of 0, 6 and 12 months. The skulls' biomechanical properties were evaluated using a free weight drop test protocol. In addition, intact parietal bone was also evaluated at 12 months as a control. Peak acceleration, peak force transmission and time to peak acceleration parameters obtained from the drop weight test were used for analysis. Immediately post-surgery there were no significant differences in any biomechanical characteristics of the experimental groups. At 12 months, the autogenous bone graft (ABG) reconstructions had a significantly superior impact characteristic compared to reconstructions of slow setting CCPP with titanium mesh scaffold and reconstructions of fast setting CCPP with titanium mesh scaffold (p<0.05). At 12 months ABG was not significantly different from the intact bone (p>0.05).

Committee: Glen Njus (Advisor) Subjects: