ORCID Profile
0000-0001-9316-6787
Current Organisation
The University of Edinburgh
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Publisher: EasyChair
Date: 2020
DOI: 10.29007/JBV7
Abstract: Dislocation of the bearing occurs in 1 - 6% of Oxford Domed Lateral (ODL) mobile bearing unicompartmental knee replacements (UKRs). Dislocations occur in flexion as the lateral ligaments are lax in this position allowing the knee to distract. Anterior and posterior dislocations are rare: clinically, their dislocation rates are acceptable. Most dislocations tend to occur medially, with the bearing sitting on top of the tibial wall. Using robotics path planning algorithms and a modified Open Motion Planning Library (OMPL) Graphical User Interface (GUI), a dislocation analysis tool was developed to assess the minimum amount of vertical distraction of the femoral component relative to the tibial component required for the mobile bearing to dislocate. In the tool, the Rapidly- exploring Random Trees (RRT) algorithm was applied to the mobile bearing, which enabled autonomous movement of the bearing from a non-dislocated to a dislocated position. Testing increased the relative distance between the femoral component and the tibial component: vertically (2-6 mm) and mediolaterally (0-4 mm) in 0.25 mm increments resulting in a total of 289 configurations. For each configuration, the tool assessed whether mobile bearing dislocation was possible (either medially, laterally, anteriorly or posteriorly). For each mediolateral translation distance, the minimum vertical distraction required for dislocation was recorded. To validate the tool, dislocation results were compared to measurements taken using a custom-built mechanical rig. The minimum amount of distraction required for medial dislocation was similar for the dislocation analysis tool (3.75 to 4.75 mm) as compared to a custom-built mechanical rig (2.5 to 4 mm). The amount of distraction for a medial dislocation was much smaller than that for an anterior or posterior dislocation (6 to 6.25 mm). This explains why medial dislocations are more common. Future work will use this tool to inform implant design, with the aim to reduce the risk of medial dislocation to match that of anterior osterior dislocation, which is clinically acceptable.
Publisher: Elsevier BV
Date: 2021
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2017
DOI: 10.2106/JBJS.RVW.16.00115
Abstract: * Guided growth by tethering part of the growth plate is an established technique for the correction of frontal angular deformities about the knee in children. * A better understanding of the underlying conditions, factors affecting longitudinal growth, and mechanism of response of the growth plate to retardation forces could lead to improvement and expansion of this technique to other sites and indications. * This review article highlights areas of future research and outlines the possible future of guided growth techniques.
Publisher: SAGE Publications
Date: 26-10-2021
DOI: 10.1177/09544119211048558
Abstract: Due to lateral ligament laxity, bearing dislocation occurs in 1%–6% of Oxford Domed Lateral replacements. Most dislocations are medial but they do rarely occur anteriorly or posteriorly. The aim was to decrease the risk of dislocation. For a bearing to dislocate the femoral component has to be distracted from the tibial component. A robotic-path-planning-algorithm was used with a computer model of the implant in different configurations to determine the Vertical Distraction needed for Dislocation (VDD). With current components, VDD anteriorly osteriorly was 5.5 to 6.5 mm and medially was 3.5 to 5.75 mm. A thicker bearing increased VDD medially and decreased VDD anteriorly osteriorly (0.1 mm/1 mm thickness increase). VDD medially increased with the bearing closer to the tibial wall (0.5 mm/1 mm closer), or by increasing the tibial wall height (1 mm/1 mm height increase). VDD anteriorly osteriorly was not influenced by bearing position or wall height. To prevent collision between the femoral and tibial components an increase in wall height must be accompanied by a similar increase in minimum bearing thickness. Increasing the wall height and minimum bearing thickness by 2 mm and ensuring the bearing is 4 mm or less from the wall increased the minimum VDD medially to 5.5 mm. The lower VDD medially than anteriorly osteriorly explains why medial dislocation is more common. If the wall height is increased by 2 mm, the minimum bearing thickness is 5 mm and the surgeon ensured the bearing is 4 mm or less from the wall, the medial dislocation rate should be similar to the anterior osterior dislocation rate, which should be acceptable.
Publisher: British Editorial Society of Bone & Joint Surgery
Date: 08-2020
DOI: 10.1302/0301-620X.102B8.BJJ-2019-1330.R2
Abstract: To report mid- to long-term results of Oxford mobile bearing domed lateral unicompartmental knee arthroplasty (UKA), and determine the effect of potential contraindications on outcome. A total of 325 consecutive domed lateral UKAs undertaken for the recommended indications were included, and their functional and survival outcomes were assessed. The effects of age, weight, activity, and the presence of full-thickness erosions of cartilage in the patellofemoral joint on outcome were evaluated. Median follow-up was seven years (3 to 14), and mean age at surgery was 65 years (39 to 90). Median Oxford Knee Score (OKS) was 43 (interquartile range (IQR) 37 to 47), with 260 (80%) achieving a good or excellent score (OKS 34). Revisions occurred in 34 (10%) 14 (4%) were for dislocation, of which 12 had no recurrence following insertion of a new bearing, and 12 (4%) were revised for medial osteoarthritis (OA). Ten-year survival was 85% (95% confidence interval (CI) 79 to 90, at risk 72). Age, weight, activity, and patellofemoral erosions did not have a significant effect on the clinical outcome or survival. Domed lateral UKA provides a good alternative to total knee arthroplasty (TKA) in the management of lateral compartment OA. Although dislocation is relatively easy to treat successfully, the dislocation rate of 4% is high. It is recommended that the stability of the bearing is assessed intraoperatively. If the bearing can easily be displaced, the fixed rather than the mobile bearing version of the Oxford lateral tibial component should be inserted instead. Younger age, heavier weight, high activity, and patellofemoral erosions did not detrimentally affect outcome, so should not be considered contraindications. Cite this article: Bone Joint J 2020 -B(8):1033–1040.
Publisher: Springer Science and Business Media LLC
Date: 08-02-2022
DOI: 10.1038/S41598-022-05938-W
Abstract: Due to ligament laxity, bearing dislocation occurs in 1–6% of Oxford Domed Lateral (ODL) replacements with most dislocations occurring medially. Dislocations were studied using a previously built mechanical rig, however testing using the rig was inefficient. The aim of this study was to develop a better tool that was more reliable and efficient. An established robotics software package, the Open Motion Planning Library, was modified to accept the ODL components. Using a robotics path planning algorithm, the mobile bearing was allowed to find a way out from between the femoral and tibial components i.e. to dislocate. Testing assessed a range of clinically relevant positions of the femoral component relative to the tibial component. Dislocations were labelled as medial, lateral, anterior or posterior depending on the dislocation direction. The Distraction to Dislocation (DD) measured the minimum vertical distraction of the femoral component from the tibial component for a dislocation to occur. Results were validated against the mechanical rig. Statistical analysis of medial dislocation showed excellent agreement with an intraclass correlation value of 0.993 (95% CI 0.982–0.998). All DDs from the dislocation analysis tool were within 1 mm of the mechanical rig DDs with results sharing a remarkably similar trend. The robotics dislocation analysis tool output DDs which were marginally higher than the manual mechanical rig: 0.50 mm anteriorly, 0.25 mm posteriorly and 0.50 mm laterally. Medially, the computational DD differed on average by 0.09 mm (stand deviation: 0.2026 mm). Our study describes the development and validation of a novel robotics dislocation analysis tool, which allows mobile bearing dislocation risk quantification. The tool may also be used to improve surgical implantation parameters and to assess new implant designs that aim to reduce the medial dislocation risk to an acceptable level.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Irene Yang.