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This thesis summarises the history of the distal tibial pilon fracture and explores it with newly available techniques. It describes in detail exactly what a pilon fracture is and attempts to identify the mechanisms by which it occurs.

Aim and methodology: Ankle injuries account for 8% of all minor injuries attending emergency departments in the United Kingdom and the Ottawa ankle rules were introduced to assess the need for x-ray in the early 1990s (Stiell et al 1992). Although the rules are said to have reduced the number of ankle x-rays requested the frequency of fractures in the population still receiving x-rays is only 15% nationally. This study aims to assess whether the tuning fork can increase the diagnostic accuracy of the Ottawa ankle rules when used on twisting ankle injuries by multiple operators in multiple emergency care settings. A mixed methods study conducted in two phases was undertaken. Phase one consisted of a diagnostic test study using the Ottawa ankle rules in conjunction with the tuning fork test on patients already screened as being Ottawa positive to the ‘malleolar’ zone and requiring an x-ray of their ankle. Patients aged 12 years or over who had sustained an ankle injury by a twisting mechanism were eligible to take part. Patient age, gender, ethnicity, and previous history of injury or presence of distracting injuries, degree of swelling, and role of operator were all considered potential variables for an accurate tuning fork test, and these were analyzed individually and in a multiple logistical regression model to assess for predictor variables of a correct tuning fork test. Phase two of the study included a series of focus group discussions to explore participant and clinician experiences of the tuning fork test. Data was analyzed using thematic analysis. Results Data was collected for 2-years and 1313 patients were included in the final analysis. 56% of the study participants were male. Mean age was 34 years (range 12-91). 98% were of white ethnic origin. 210 (16%) were diagnosed with fractures, of which 38 were deemed to be not clinically significant. The tuning fork had a diagnostic accuracy of 56% (95% CI 53-58), NPV 96% (95% CI 94-97), sensitivity 84% (95% CI 78-89) and specificity 51% (95% CI 48-54). X-rays could have been reduced by 47% but this was at the expense of missing 29 ‘clinically significant’ fractures. However, seven of these were managed as soft tissue injuries and in nine the initial assessment of tenderness did not match the site of the fracture. A total of 113 clinicians (nurses & doctors) were involved in performing the tuning fork test independently. Patient age (adjusted OR 1.021, p. <0.001) and role of the operator (adjusted OR 1.595, p. 0.003 for nurse) were the only predictors of an accurate test. Ten patients and ten clinicians attended the focus group discussions in phase two of the study. Patients and clinicians appeared to accept the tuning fork as a method for assessment provided adequate explanation was given. Patients claimed the tuning fork test was not painful but had a similar sensation to that of a ‘Tens’ machine. There were differences in opinion between the two groups as to whether the tuning fork was accurate or not and clinicians held the perception that patients expect an x-ray when they present with an ankle injury, whereas patients disagreed with this. Patients were fully aware of the dangers of x-rays and stated that a reduction in x-rays was one of the main potential benefits of the study. Conclusions This is the largest study to investigate the accuracy of the tuning fork to detect fractures, not only in the size of the study population but the number of clinicians involved. It is also the first to report inconclusive Ottawa ankle rule and tuning fork test results. It is unlikely that the lower sensitivity will be accepted by patients and clinicians. Further research to assess inter-operator reliability is recommended before implementing the tuning fork test into clinical practice.

An intramedullary nail is a trauma treatment device used for fracture fixation of long bones. These devices are subject to failure, including lag screw cut-out and failure at the lag screw insertion hole from high stress concentrations in that region. Clinical developments for such devices are frequently based on a trial and error method, which often results in failure before improvement. However, the finite element method can be used for the development of trauma treatment devices, and their interaction with bone, by providing a large data set at a relatively low cost. Also, parameters can be changed to assess the relative benefits of one device to another. A novel finite element model has been developed that can be used for the analysis of intramedullary nails inserted into long bones. A commercially available finite element package, ANSYS, has been used to implement the modelling strategy. The finite element modelling technique has been applied to fractures of the proximal femur, but the model is generic, and can be developed to deal with any form of intramedullary device where contact between the bone and implant is important. The finite element strategy can be used in pre-clinical trials to test a new device, or for the design optimisation of existing devices. The finite element model consists of the device surrounded by a thin layer of bone, which forms a 'base' model component that is re-usable. This 'base' component can be mathematically connected to any long bone model, forming an integrated implant and bone construct. The construct can be used to assess which device is best suited to a particular fracture, for example. Contact elements have been used to allow stresses to develop as contact is achieved within the implant and bone construct. Pre-assignment of contact points is not required. Verification of the finite element model is achieved by comparison to available data from experiments carried out on constructs of bone and device that use intramedullary femoral nails. In this thesis the finite element model has been applied to two areas of proximal femoral nailing. The finite element model is used to analyse the distal end of a Gamma nail, and shows that analyses that do not consider contact may not lead to accurate predictions of stresses. The model has been developed for using configurations with one and two distal locking screws. The most distal locking screw is more critical under axial loading, and the more proximal screw is more important for bending loads. The use of 'softer' screws distributes the load more evenly between them. The finite element model has been used to investigate the mechanical environment of a fracture callus for a femoral neck fracture, and a subtrochanteric fracture. The use of one and two lag screws, fracture gap size and material properties of the nail have been investigated for a stiffening callus. Results show that the use of two lag screws for a neck fracture provides a more rigid support at the early stages of fracture healing, and minimises stress-shielding once the callus has healed. For subtrochanteric fractures there is a critical point at which the fracture callus is able to carry any load. A Titanium nail significantly reduces the peak stress at the lag screw insertion hole, and titanium lag screws share the load more evenly between them. Each two-lag-screw configuration used transfers a similar load into the fracture callus. A configuration using a larger lag screw above a smaller has a significantly higher stress at the upper lag screw insertion hole. Critically, the load shared between two lag screws changes as the fracture callus stiffens and an assessment should be made at different stages of fracture healing to optimise the use of a device.

Η παρούσα διατριβή αποσκοπεί στη διερεύνηση της βέλτιστης μεθόδου θεραπείας για τα ασταθή κατάγματα κάτω πέρατος κερκίδας. Προς τούτο, μετά από μια σύντομη εισαγωγή, στο γενικό της μέρος η διατριβή παρουσιάζει στοιχεία ανατομικής και κινηματικής της πηχεοκαρπικής και της κάτω κερκιδοωλενικής. Στη συνέχεια γίνεται αναφορά στα κατάγματα του κάτω πέρατος της κερκίδος, τα προβλήματα που προκύπτουν κατά τη θεραπεία τους και το ρόλο των κυκλοτερών συστημάτων εξωτερικής οστεοσύνθεσης (Ilizarov). Στο ειδικό μέρος της διατριβής παρουσιάζεται η κλινική μελέτη που έγινε στην Ορθοπαιδική Κλινική του Πανεπιστημίου Πατρών και αφορούσε σε ασθενείς με κατάγματα κάτω πέρατος κερκίδος που αντιμετωπίστηκαν με κυκλοτερές σύστημα εξωτερικής οστεοσύνθεσης. / Unstable distal radius fractures remain a challenge for the treating orthopaedic surgeon. We present a retrospective follow-up study (mean follow-up 12.5 months) of 20 patients with 21 unstable distal radius fractures that were reduced in a closed manner and stabilized with a nonbridging Ilizarov external fixator. Subsequent insertion of olive wires for interfragmentary compression was performed in cases with intra-articular fractures. According to the overall evaluation proposed by Gartland and Werley scoring system 12 wrists were classified as excellent, 6 as good, 2 as fair and 1 as poor. Grade II pin-tract infection in distal fracture fragment was detected in 3 wires from a total of 78 (3.8%) and in 4 half pins out of a total of 9 (44.4%). Pronation was the most frequently impaired movement. This was restricted in 4 patients (19%) in whom a radioulnar transfixing wire was applied. Symptoms of irritation of superficial sensory branch of the radial nerve occurred in 3 patients with an olive wire applied in a closed manner in the distal fragment. Ilizarov method yields functional results comparable to that of other methods whilst it avoids wrist immobilization, open reduction and reoperation for implant removal. The method is associated with a low rate of major complication and satisfactory functional outcome.