12 research outputs found
One-stage Revision ACL reconstruction with hamstring autograft results in satisfactory outcome
No full textObjectives: Revision anterior cruciate ligament (ACL) reconstruction is associated with poorer outcomes and higher rerupture rates when compared to primary ACL reconstruction. There is also a significant heterogeneity in surgical technique, number of stages, and graft options. We report a large single surgeon case series with hamstring autograft as a graft option. Methods: Observational series of revision ACL reconstructions performed by the senior author between 2005 and 2015 was carried out. Chart reviews and clinic follow-ups were performed with the following recorded – re-rupture rate, radiographic grading of osteoarthritis, KT-1000 arthrometer test, IKDC outcome scores and knee range of motion. All patients underwent single bundle four-strand hamstring autograft performed in one stage with use of new tunnels in majority of the cases. Results: 66 patients underwent hamstring autograft one-stage revision ACL reconstruction by Dr Jens Buelow. Chart review was carried out on all patients, and 26 (39%) were followed up in clinic and/or by phone with a mean follow up of 4.7 years. Outcomes included re-rupture rate of 4.5%, reoperation rate of 12%, mean visual analogue scale score of 7.6, mean side-to-side difference of 2.6 mm for KT-1000 arthrometer test, and mean IKDC score of 79. Of the 17 patients with radiographs, 40% had moderate osteoarthritis (grade 2 or 3) at follow-up. Conclusion: Revision ACL reconstruction can result in a satisfactory outcome when performed with a hamstring autograft in one stage. </jats:sec
Hybrid versus double bundle hamstring ACL reconstruction – a review of 626 cases
No full textObjectives: Since 2008, we have offered patients Hybrid ACL (hamstring plus LARS ligament) graft or double bundle hamstring graft. We allow the patients with Hybrid ACL to jog at 2 months and return to sports at 6 months. In comparison we allow the double bundle hamstring group to jog at 4 months and return to sports at 12 months. We considered the hybrid graft, due to its initial stiffness, would allow safe accelerated rehabilitation. Our primary aim was to establish whether Hybrid ACL graft has a higher failure rate compared to double bundle hamstring graft. Our secondary aim was to compare reoperation rates and clinic visit rates between the two groups. Methods: We performed a retrospective study of skeletally mature patients that underwent primary isolated ACL reconstruction by the senior author between 2008 and 2015 comparing double bundle hybrid ACL (DB Hyb), single bundle hybrid ACL (SB Hyb), and double bundle hamstring ACL (DB Ham) graft types. Charts were reviewed to assess reoperation rate, complication rate, re-rupture rate, and number of clinic visits. Graft tensioning positions, remnant sparing percentage, and concurrent meniscal procedures were reviewed as well. Results: 626 patients met the inclusion criteria. DB Hyb group had more males (77%) and a longer mean follow up (5.6 years) than the other two groups. Rerupture rates were 1.2% per year for DB hyb, 0.5% per year for SB Hyb, and 0.8% per year for DB Ham group. DB Hyb group trended towards a higher reoperation rate for arthrofibrosis compared to DB Ham (9.4% vs 4.7%, p-value 0.054). There was no difference in number of clinic visits between the 3 groups. Conclusion: Double bundle hybrid ACL group was associated with higher rates of arthrofibrosis surgery but equivalent rates of failure. </jats:sec
Arthroscopic assessment of patellofemoral tracking predicts patellar instability
No full textObjectives: Surgical management of patellar instability includes proximal realignment procedure such as MPFL reconstruction. The decision to add a distal realignment procedure of tibial tubercle transfer is based on severity of patellar instability judged on either TTTG distance or arthroscopic patellofemoral tracking. We set out to validate our use of arthroscopic patellofemoral tracking for patellar instability management algorithm by analyzing its reproducibility and whether it correlates with patellar instability. Methods: A prospective observational study was carried out at Perth Orthopaedic and Sports Medicine Centre. Patient clinical presentations were divided into three groups - patellofemoral instability, patellofemoral pain, and no patellofemoral symptoms. Standard technique included low flow arthroscopy with single anterolateral viewing portal. Height of the fluid bag and presence of a knee holder was recorded. Knee flexion angle where patella first centrally engages in the trochlear groove was defined as Patellofemoral Congruent Angle (PCA). PCA was estimated by the primary surgeon and the angle was confirmed using a sterile goniometer. A second surgeon, blinded to the initial assessment, then repeated the measurements. Surgeon estimation error, interobserver reliability, and correlation with clinical presentation was analysed. Results: 57 knees were assessed for interobserver reliability. Intra-class correlation was 0.994 between surgeon’s estimate and goniometer reading. Intra-class correlation was 0.992 between the two surgeon’s readings suggesting a very high correlation. 157 patients had their PCA recorded and compared with their diagnosis. Mean PCA was 40 degrees in normal patients, and 118 degrees in patellar instability (p-value <0.001). Conclusion: Arthroscopic assessment of patellofemoral tracking is reproducible and correlates with patellar instability. A cut-off value of 40 degrees is recommended to differentiate normal tracking from abnormal. </jats:sec
Arthroscopic assessment of patellofemoral tracking predicts patellar instability
No full textObjectives: Surgical management of patellar instability includes proximal realignment procedure such as MPFL reconstruction. The decision to add a distal realignment procedure of tibial tubercle transfer is based on severity of patellar instability judged on either TTTG distance or arthroscopic patellofemoral tracking. We set out to validate our use of arthroscopic patellofemoral tracking for patellar instability management algorithm by analyzing its reproducibility and whether it correlates with patellar instability. Methods: A prospective observational study was carried out at Perth Orthopaedic and Sports Medicine Centre. Patient clinical presentations were divided into three groups - patellofemoral instability, patellofemoral pain, and no patellofemoral symptoms. Standard technique included low flow arthroscopy with single anterolateral viewing portal. Height of the fluid bag and presence of a knee holder was recorded. Knee flexion angle where patella first centrally engages in the trochlear groove was defined as Patellofemoral Congruent Angle (PCA). PCA was estimated by the primary surgeon and the angle was confirmed using a sterile goniometer. A second surgeon, blinded to the initial assessment, then repeated the measurements. Surgeon estimation error, interobserver reliability, and correlation with clinical presentation was analysed. Results: 57 knees were assessed for interobserver reliability. Intra-class correlation was 0.994 between surgeon’s estimate and goniometer reading. Intra-class correlation was 0.992 between the two surgeon’s readings suggesting a very high correlation. 157 patients had their PCA recorded and compared with their diagnosis. Mean PCA was 40 degrees in normal patients, and 118 degrees in patellar instability (p-value <0.001). Conclusion: Arthroscopic assessment of patellofemoral tracking is reproducible and correlates with patellar instability. A cut-off value of 40 degrees is recommended to differentiate normal tracking from abnormal. </jats:sec
A two step procedure for testing partial parameter stability in cointegrated regression models
No full textKejriwal and Perron (2010, KP) provided a comprehensive treatment for the problem of testing multiple structural changes in cointegrated regression models. A variety of models were considered depending on whether all regression coefficients are allowed to change (pure structural change) or a subset of the coefficients is held fixed (partial structural change). In this note, we first show that the limit distributions of the test statistics in the latter case are not invariant to changes in the coefficients not being
tested; in fact, they diverge as the sample size increases. To address this issue, we propose a simple two step procedure to test for partial parameter stability. The first entails the application of a joint test of stability for all coefficients as in KP. Upon a rejection, the second conducts a stability test on the subset of coefficients of interest while allowing the other coefficients to change at the estimated breakpoints. Its limit distribution is standard chi-square. The relevant asymptotic theory is provided along with simulations that illustrates the usefulness of the procedure in finite samples.First author draf
Revision Following Cemented and Uncemented Oxford-III Primary Medial Unicompartmental Knee Replacements
No full text
A Collation Tool for Humanists
No full textComparing a set of similar texts, often called collation, gives a scholar insight into the author's thoughts and motives and into the culture of the time period. Multiple editions can be published by an author for a diverse number of reasons such as political pressure or to further character development. Collating a set of editions can help discover the author's motives, but involves methodically comparing text to find minute differences. This task, which is currently done by hand due to unstandardized printing practices in historic novels, is time consuming, and prone to human error due to fatigue. We propose a Virtual Hinman Collator that automates the comparison process and highlights the differences between a set of pages. This is done through an image processing approach that is less susceptible to the issues of optical character recognition on poor quality images. This tool saves the user an immense amount of time which allows more time to focus on analyzing the text and drawing conclusions instead of finding the differences. With this increased productivity, a better understanding of past cultures can be found through recognizing the motivation and thoughts behind the author's works
A Hybrid Filtering Approach of Digital Video Stabilization for UAV Using Kalman and Low Pass Filter
No full textAbstractIn this paper a new video stabilization algorithm for unmanned aerial vehicles (UAV) has been presented which is used to stabilize the video being transmitted from UAV to the ground station. First, the corner points are extracted using Good Features to Track corner detection algorithm and the extracted points are used to compute the optical flow between two consecutive frames. Next, the points detected from optical flow are used to estimate the motion parameters using an affine transform model. Subsequently, a hybrid filter consisting of Kalman and low pass filter is used to smooth the estimated motion parameters and the frames are warped using the smoothed parameters to obtain a stabilized video sequence. The experimental results show that the algorithm can remove the unwanted vibration more effectively than the one that only uses either a Kalman Filter or a low pass filter
On being, subject and truth in the works of Pablo Neruda and Alain Badiou
No full textThe theoretical underpinning of this line of inquiry into the poetry of Pablo Neruda is the mathematico-ontological work of contemporary French philosopher and author of two philosophical magnum opuses, Being and Event and Logics of Worlds (Being and EventII), Alain Badiou. His radical ideas of the ‘object’, the ‘world’ it is contained in, the occurrence of an ‘event’ in the world, and the eventual production of the ‘truth’ as the consequence of the ‘event’ –all of which form the substantial basis of his second book, Logics of Worlds also guides this inquiry. This research aims to map Pablo Neruda’s works onto the mathematical/philosophical framework established by Badiou. After having established the Badiouan idea of an ‘object’., this thesis, instead of treating Neruda’s works as one seamless fabric, would proceed, ‘object’ by ‘object’, as they occur and recur in Neruda’s poetry. Through various proofs in the mathematico-ontological language developed by Badiou in his Logics of Worlds, this inquiry will be a radical new entry into Neruda’s poetry. Alongside, some other texts of a more narrative nature by Alain Badiou on poetry and philosophy would also support the study, by creating more points of intersection between poetry, mathematics, ontology and philosophy. This thesis a purely theoretical/mathematical intervention, hence would progress mainly via 1) a thorough and rigorous reading, analysis and application of related texts –which would include not just the extensive work done by Alain Badiou, but also related philosophers of phenomenology and 2) by creating mathematical proofs at each stage to establish homeo-morphisms between the Nerudian and Badiouan universes. The thesis would aim to apply the rigor and exactitude of mathematics to ascertain and concretize the concepts of Being, Subject and Truth in the combined universe of Alain Badiou and Pablo Neruda
