Morris Campus to Conduct Emergency Training Exercise

University of Minnesota, Morris employees, along with other Stevens County emergency responders, will participate in an emergency training exercise on Thursday, June 29, on campus from 9 a.m. until 2 p.m

A Feasibility Study of Laser-Assisted Titanium Implant Drilling for Periprosthetic Fracture Repair

This body of work studies the feasibility of hand drilling through a titanium implant located in the femur. This is hypothesized to be achievable via laser-assisted drilling with carbide tools. A series of tests were conducted to measure the thrust force and torque with different shaped drill bits under dry- and laser-assisted drilling (using a 200-watt fiber laser), respectively. These drill bits included 2-flute and 3-flute twist drills and a straight flute drill that is clinically available. Successive time under laser exposure was examined. Thermal propagation was examined both experimentally and modeled in Abaqus. Finally, tool wear was examined. When all results are taken in context, the best option for clinical use is the two-flute design. The three-flute design is not practical for use during hand drilling and the straight flute experiences significant tool wear. Further, thermal control will need to be looked at due to a higher heat input from drilling than laser exposure

A Feasibility Study of Laser-Assisted Titanium Implant Drilling for Periprosthetic Fracture Repair

This body of work studies the feasibility of hand drilling through a titanium implant located in the femur. This is hypothesized to be achievable via laser-assisted drilling with carbide tools. A series of tests were conducted to measure the thrust force and torque with different shaped drill bits under dry- and laser-assisted drilling (using a 200-watt fiber laser), respectively. These drill bits included 2-flute and 3-flute twist drills and a straight flute drill that is clinically available. Successive time under laser exposure was examined. Thermal propagation was examined both experimentally and modeled in Abaqus. Finally, tool wear was examined. When all results are taken in context, the best option for clinical use is the two-flute design. The three-flute design is not practical for use during hand drilling and the straight flute experiences significant tool wear. Further, thermal control will need to be looked at due to a higher heat input from drilling than laser exposure

Perceptions of effort and risk assessment

Master of ScienceDepartment of Psychological SciencesMichael E. YoungAlthough risky decision-making tasks present some a priori risk (i.e., base-rate), decision makers often have an opportunity to modify this level of risk through their behaviors. Broadly speaking, risk can be modified by assigning additional resources to an ongoing task or by engaging in specific risk-mitigation strategies before or after the risky decision is made. The modification of risk requires ongoing awareness of task demands, resource constraints, and risk-mitigation strategies that can be used to adapt behavior over time. This thesis explores risk modification that occurs during difficult tasks. Difficult tasks hold greater risks because they fall at the edge of the decision maker’s abilities and are likely to require a greater number of resources to overcome. As resources are engaged they become unavailable for other tasks or strategies to cope with changing task demands. I studied how individuals monitor risks and develop risk mitigation strategies using a videogame task designed to mirror contingencies that would be encountered in the real world. Results from two experiments that involve this task suggest that decision-makers adequately monitor and develop active strategies for dealing with risks. These strategies change over time and vary as a function of task difficulty and experience

Aseptically processed and chemically sterilized BTB allografts for anterior cruciate ligament reconstruction: a prospective randomized study.

PURPOSE: To compare the clinical outcomes of bone-patellar tendon-bone (BTB) allografts processed via a novel sterilization system with the traditional aseptically processed BTB allografts for anterior cruciate ligament (ACL) reconstruction. METHODS: A total of 67 patients undergoing ACL reconstruction at 6 independent investigation sites were randomized into one of two intervention groups, BioCleanse-sterilized or aseptic BTB allografts. Inclusion criteria included an acute, isolated, unilateral ACL tear, and exclusion criteria included prior ACL injury, multi-ligament reconstruction, and signs of degenerative joint disease. Post-op examiners and patients were blinded to graft type. Patients were evaluated at 6, 12, and 24 months. Clinical outcomes were compared using the IKDC, a KT-1000 knee arthrometer, level of effusion, and ranges of motion (ROM). RESULTS: After randomization, 24 patients received aseptic BTB allografts and 43 patients received BioCleanse-sterilized allografts. Significant improvement in IKDC scores (P \u3c 0.0001) as well as KT-1000 results (P \u3c 0.0001) was noted over the 24-month period for both groups. IKDC or KT-1000 results were not significantly different between groups at any time point. Active flexion ROM significantly improved from pre-op to 24-month follow-up (P \u3c 0.0001) with no difference between groups at any time point. Active extension ROM did not differ significantly between the two groups. CONCLUSIONS: These results indicate that the sterilization process, BioCleanse, did not demonstrate a statistical difference in clinical outcomes for the BTB allograft at 2 years. The BioCleanse process may provide surgeons with allografts clinically similar to aseptically processed allograft tissue with the benefit of addressing donor-to-recipient disease. LEVEL OF EVIDENCE: II

Implantation of a Novel Cryopreserved Viable Osteochondral Allograft for Articular Cartilage Repair in the Knee

Restoration and repair of articular cartilage injuries remain a challenge for orthopaedic surgeons. The standard first-line treatment of articular cartilage lesions is marrow stimulation; however, this procedure can often result in the generation of fibrous repair cartilage rather than the biomechanically superior hyaline cartilage. Marrow stimulation is also often limited to smaller lesions, less than 2 cm2. Larger lesions may require implantation of a fresh osteochondal allograft, though a short shelf life, size-matched donor requirements, potential challenges of bone healing, limited availability, and the relatively high price limit the wide use of this therapeutic approach. We present a straightforward, single-stage surgical technique of a novel reparative and restorative approach for articular cartilage repair with the implantation of a cryopreserved viable osteochondral allograft (CVOCA). The CVOCA contains full-thickness articular cartilage and a thin layer of subchondral bone, and maintains the intact native cartilage architecture with viable chondrocytes, growth factors, and extracellular matrix proteins to promote articular cartilage repair. We report the results of a retrospective case series of three patients who presented with articular cartilage lesions more than 2 cm2 and were treated with the CVOCA using the presented surgical technique. Patients were followed up to 2 years after implantation of the CVOCA and all three patients had satisfactory outcomes without adverse events. Controlled randomized studies are suggested for evaluation of CVOCA efficacy, safety, and long-term outcomes

Mechanical Stimulation Increases Knee Meniscus Gene RNA-level Expression in Adipose-derived Stromal Cells

Background: Efforts have been made to engineer knee meniscus tissue for injury repair, yet most attempts have been unsuccessful. Creating a cell source that resembles the complex, heterogeneous phenotype of the meniscus cell remains difficult. Stem cell differentiation has been investigated, mainly using bone marrow mesenchymal cells and biochemical means for differentiation, resulting in no solution. Mechanical stimulation has been investigated to an extent with no conclusion. Here, we explore the potential for and effectiveness of mechanical stimulation to induce the meniscal phenotype in adipose-derived stromal cells. Methods: Human adipose-derived stromal cells were chosen for their fibrogenic nature and conduciveness for chondrogenesis. Biochemical and mechanical stimulation were investigated. Biochemical stimulation included fibrogenic and chondrogenic media. For mechanical stimulation, a custom-built device was used to apply constant, cyclical, uniaxial strain for up to 6 hours. Strain and frequency varied. Results: Under biochemical stimulation, both fibrogenic (collagen I, versican) and chondrogenic (collagen II, Sox9, aggrecan) genes were expressed by cells exposed to either fibrogenic or chondrogenic biochemical factors. Mechanical strain was found to preferentially promote fibrogenesis over chondrogenesis, confirming that tensile strain is an effective fibrogenic cue. Three hours at 10% strain and 1 Hz in chondrogenic media resulted in the highest expression of fibrochondrogenic genes. Although mechanical stimulation did not seem to affect protein level expression, biochemical means did affect protein level presence of collagen fibers. Conclusion: Mechanical stimulation can be a useful differentiation tool for mechanoresponsive cell types as long as biochemical factors are also integrated

Use of controlled low dose gamma irradiation to sterilize allograft tendons for ACL reconstruction: biomechanical and clinical perspective

As reviewed here, numerous biomechanical and clinical studies support the use of controlled, low temperature irradiation of allograft tendons, to provide both excellent clinical results and medical-device grade sterile allografts with minimal risk of disease transmission