Tibial stress fractures are common in runners. However, it is unclear what factors are associated with tibial stress fractures. This study aimed to investigate 1) magnitudes of bone contact forces occurring while running 2) whether or not repeated application of running loads is sufficient to explain tibial stress fractures and 3) whether or not muscle fatigue alters the potential of tibial stress fractures. Tibial stress fractures were predicted through an estimation of the minimum number of cycles to failure (Nfail) using an integrated experimental and mathematical modeling approach. Short running trials within a speed range of 3.5-4 m/s of ten male runners were evaluated with a coupled force plate and 3 dimensional motion analysis system. The collected data were used to estimate joint reaction forces (JRF) and joint moments. Using these JRF and muscle forces predicted from optimization, 2-D bone contact forces at the distal end of the tibia were determined. Next, tibial stresses were estimated by applying these bone contact forces to a tibial model, which were then used to predict the Nfail. All procedures were repeated after plantarflexors fatigued from prolonged running. This study found that peaks of compressive and posterior shear forces occurred during mid stance, and these peaks equaled 8.91 ± 1.14 BW and -0.53 ± 0.16 BW, respectively. These bone contact forces led to a backward bending of the tibia during most of the stance phase and resulted in the maximum stresses of - 43.4 ± 10.3 MPa on the posterior face of the tibia. These maximum stresses predicted the group mean of Nfail as being 5.28*10⁶ cycles. However, 2.5% to 56% of population of runners have a chance of getting tibial stress fractures within 1 million cycles of a repeated foot impact. Within the context of muscle force and stress estimation procedures used in this study, Nfail appeared to increase after fatigue, not decrease as we hypothesized. / Graduation date: 2005

The purpose of this study was to evaluate the burden of care (BOC) of two presurgical infant orthopedic (PSIO) protocols used for complete unilateral cleft lip and palate (CUCLP), and to compare aesthetic outcomes with centres not utilizing PSIO. Four samples were collected. Two from the same centre that underwent either traditional infant orthopedics (TIO) or nasoalveolar molding (NAM) and two from centres not employing PSIO. BOC data were collected for the PSIO groups and photos at age 5 were collected for ratings of nasolabial aesthetics. The BOC of NAM was found to be significantly greater than IO for number of visits (9.9 vs. 6.6, (p<0.001)) and days wearing the appliance (127 vs. 112, (p<0.05)). Significant differences in aesthetic ratings were noted amongst the three centres but not between the NAM and TIO groups. Overall, an increased burden of NAM over TIO was detected, without an observable aesthetic improvement.

The purpose of this study was to evaluate the burden of care (BOC) of two presurgical infant orthopedic (PSIO) protocols used for complete unilateral cleft lip and palate (CUCLP), and to compare aesthetic outcomes with centres not utilizing PSIO. Four samples were collected. Two from the same centre that underwent either traditional infant orthopedics (TIO) or nasoalveolar molding (NAM) and two from centres not employing PSIO. BOC data were collected for the PSIO groups and photos at age 5 were collected for ratings of nasolabial aesthetics. The BOC of NAM was found to be significantly greater than IO for number of visits (9.9 vs. 6.6, (p<0.001)) and days wearing the appliance (127 vs. 112, (p<0.05)). Significant differences in aesthetic ratings were noted amongst the three centres but not between the NAM and TIO groups. Overall, an increased burden of NAM over TIO was detected, without an observable aesthetic improvement.

Thesis (M.S.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 35-41).

[Truncated abstract] Renewed interest in the fixation of fractures using plates has been stimulated by an improved understanding of the biology of fracture healing and a drive towards minimally invasive surgery. This has led to a change in the way we use plates nowadays and the way in which we build the bone-plate construct, as well as the development of new implants better suited to these techniques. As a result of this, we have now the potential to safely expand the indications for plate fixation especially in the management of fractures in osteopenic bone. This thesis provides scientific evidence allowing for better formulation of the optimum way to use the modern plating systems in the clinical setting. Biological fracture repair with conventional plates, in terms of a less rigid construct to enhance fracture healing, is becoming increasingly popular. By omitting screws the construct becomes more flexible with a risk of fixation failure. It was the aim of the first paper to investigate in an experimental model the construct strength of different conventional plate lengths and number / position of the screws, and if an oblique screw at the plate end could increase the fixation strength. Our data suggest that the plate length is the most important factor in withstanding forces in cantilever bending. Longer plates with an equal number of screws require greater peak loads to failure than short plates with more screws. Furthermore, an oblique screw at the plate end produces an increased strength of fixation in all different test setups. However, the difference is more significant in shorter plates and in constructs with no screw omission adjacent to the fracture site. ... Following cyclic loading, however, locking plates can better retain fracture reduction compared to compression plates. On the other hand, under torsional load the compression plate appears to be biomechanical superior to the locking system. In supracondylar comminuted femur fractures, combining the two principles results in less plastic deformation, and a higher load to failure compared to their single application. The last two papers examine the behaviour of locking plates in osteopenic bone. In cadaveric intra-articular calcaneal fractures, the locking plate showed a significantly lower irreversible deformation during cyclic loading and a significantly higher load to failure. In dorsal and volar fixed angle distal radius constructs in a cadaveric model, all constructs showed adequate stability with minimal deformation on fatigue testing under physiological conditions in good bone quality. In osteoporotic bone, however, dorsal fixed angle constructs are stiffer and stronger than volar constructs. The addition of a styloid plate to a volar plate does not significantly improve stability.

Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2007. / Includes bibliographical references.

Thesis (Ph. D.)--University of Western Australia, 2007.

Inaug.-Diss. - Erlangen.

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INTRODUCTION: Women’s gymnastics has the highest injury incidence rates for NCAA female college athletes. Gymnastics maneuvers may require support and transfer of the entire body weight from the feet to the hands. Such motions cause excessive loading and stress across joint surfaces which on occasion can exceed the mechanical strength of upper limb joints and supportive musculoskeletal structures, resulting in injuries ranging from acute fractures to chronic overuse injuries like osteochondritis dissecans. Recent technological advances have only now made it possible to analyze the complex and simultaneous motions in multiple planes required for evaluation of even the most basic gymnastic maneuvers like the round-off back handspring (ROBHS). OBJECTIVES: There is a paucity of data characterizing upper extremity injury causation and biomechanical risk factors in the small number of gymnastics studies conducted. The first hand contact for any gymnastics skill has never been quantitatively assessed. Therefore, the primary objective of this study is to perform a detailed 3D biomechanical characterization of the round-off back handspring (ROBHS) first hand contact and evaluate any potential correlations to upper extremity injury determinants. METHODS: A 3D motion capture camera and force plate system captured the relative positon of reflective markers affixed to 62 anatomical positions on subjects during performance of an ROBHS. A virtual model of each subject was constructed using Nexus C-motion software. Programming with Visual3D and MATLAB software was used to calculate desired force, kinematic and kinetic variables such as joint torques and angles. Past medical history questionnaires were administered, and clinical range of motion and strength measures were assessed. RESULTS: Compared with other factors analyzed, hand contact order appeared to have the highest degree of influence on upper extremity biomechanics at both the time of initial contact and throughout the entire movement sequence. The second contact limb was correlated with a larger average ground contact force, whereas while the first contact limb was related to a shorter time to peak force development and larger magnitude rotational kinematic variables, especially at the elbow—the primary site of upper extremity injury. For the first hand contact, torque development at the elbow and shoulder appeared to be related, and wrist and shoulder variables were presumably related to ground reaction force (GRF) development. The proposed literature elbow injury mechanism may need some adjustment to reflect the impact of elbow flexion angle on GRF and elbow valgus torque, key variables tied to chronic elbow joint capsule overload injuries. CONCLUSIONS: The novel information provided by this study can be used to guide future recommendations for the prevention of upper extremity injury in gymnastics training and competition. Improved understanding of associated force, kinetic, and kinematic biomechanical variables like joint torque could have implications for movement specific body positioning with the potential for extrapolation to gymnastics moves with similar loading patterns. Possible protective technique interventions based on study findings include increasing second hand elbow flexion during the round-off phase of motion or minimizing the time between hand contacts.