Evaluation of Injuries and Boot Design in Ice Figure Skating and Imaging Modalities for Preoperative Planning in Total Knee Arthroplasty

Ice figure skating is a popular recreational and competitive sport where artistry and athleticism find their best mix, with an increasing participation to the sport in recent years. As in many other sports, injuries in ice figure skating are common. However, several studies reported an alarming increase of figure skaters suffering from injuries in the past 25 years, and suspected that the majority of these injuries are the consequence of the increased demand for technical difficulties in the programs, like triple and quadruple jumps. This increased demand has brought to an increased time spent on training activity which accentuated the problems derived by the use of the ice figure skate. To overcome the limitations of the present skate design, it is important to understand the main issues related to its use. Thus, the first aim of this Ph.D. research was to collect data about the prevalence of injuries in ice figure skaters and to understand which factors related to the athlete or the skate itself correlate with a specific type of injury. Our results suggested that the heel represents a major area of concern for the high prevalence of calcaneal bursitis and calluses in proximity of the Achilles tendon, suggesting that improvements on the boot heel cup design should take priority. The choice of the appropriate boot stiffness should take into account skaters’ weight in addition to the skating level, and boot retailers should be better educated to sell the appropriate boot size and stiffness to the skaters. The increased technical difficulties in the sport has also brought to an increase in the skating boot stiffness to protect the ankle from the most difficult jump landings. However, the increased boot stiffness prevent the skater’s foot and ankle from attenuating the impact developed in jump landings. This impact has been suggested to be responsible of the many overuse injuries that affect thousands of skaters every year. Hence, the second aim of this Ph.D. research was to test the effect of two design variables of the skating boot in reducing the landing impact. Our results showed that the use of a 1mm thickness viscoelastic insert, weather used as an insole or a sole under the boot, and a 6 mm reduction in the boot heel height do not appear to affect kinetic variables during jump landings. However, further investigation are needed to test the effectiveness of changes in boot heel height and viscoelastic inserts without the intra- and inter-subjects variability in jump landings, for example by using a mechanical testing device that can simulated the toe to heel landing of the athletes’ skate. This thesis investigates also a secondary topic, the evaluation of the errors in the preoperative planning for kinematically-aligned total knee arthroplasty when developed with three-dimensional bone models obtained from magnetic resonance imaging (MRI) and computed tomography (CT). Since the morphology of three-dimensional bone models obtained from MRI and CT is inaccurate to certain degree, then the preoperative planning may be inaccurate because based on a bony anatomy which differs from the one of the actual patient. Hence, my doctoral research focused on the development of a methodology to analyze the error in the preoperative planning caused by errors in the morphology of the bone models obtained with MRI and CT. First, our results suggested that a gold standard bone model can be obtained with a laser scanner system with a repeatability error below 70 μm and used as a reference to compare MRI and CT bone models. Secondly, this study shows that the marker-based methodology developed is promising to evaluate the difference in the bone models and thepreoperative plans for kinematically-aligned TKA. The identification of the location of the fiducial markers can be achieved with repeatability errors below 0.25 mm, but the error in the registration of the bone models was too high for the scope of this study. Further improvement includes evaluating the use of the hard probe to scan the markers for the gold standard model, increasing the size of the fiducial marker, and decreasing the slice thickness for the imageacquisition of the marker with the MRI.