Arthrodesis is usually offered to patients in whom a two stage exchange arthroplasty has already failed or is likely to fail because of local factors (such as soft tissue damage, bone loss or poor perfusion), or because of systemic conditions which categorise the patient as a C-host (e.g. immune deficiency, diabetes and malnutrition). In other words arthrodesis is selected for patients with the worst prognosis. I use an intramedullary nail extending from trochanter to just above the ankle which is locked distally only. The nail is curved with an arc of a 2 meter radius. This conforms to the shape of the femur and when passed through to the straight tibia it ends against the posterior cortex of the distal tibia where the bone is thickest. It creates an angle of between 9° and 11° of flexion at the knee. The nail is bent into 5° of valgus at the point where the femur and tibia meet. This allows the two bones to coapt, dynamise and unite. The procedure is performed in two stages. At the first every effort is made to eradicate the infection by debridement and appropriate local and systemic antibiotics. The nail is inserted at the second procedure and again every effort is made to deal with infection. If infection persists one can easily remove the nail when the knee has fused, and repeat the attempt to eradicate the infection in better circumstances. I have devised a scoring system in order to evaluate the eradication of infection based on clinical grounds, laboratory investigations and radiological examination. This allows for the fact that cure of an infection is not based on any one parameterIntroduction
Method
Fifteen percent of the primary total knee arthroplasties (TKA) fails within 20 years. Among the main causes for revision surgery are instability and patellofemoral pain. Currently, the diagnostic pathway requires various diagnostic techniques to reveal the original cause for the failed knee prosthesis and is therefore time consuming and inefficient. Accordingly, there is a growing demand for a diagnostic tool that is able to simultaneously visualize soft tissue structures, bone and TKA. Magnetic resonance imaging (MRI) is capable of visualising all the structures in the knee although a trade- off needs to be made between metal artefact reducing capacities and image quality. Low-field MRI (0.25T) results in less metal artefacts and a lower image quality compared with high-field MRI (1.5T). The aim of this study is to develop a MRI imaging guide to image the problematic TKA and to evaluate this guide by comparing low-field and high-field MRI on a case study. Based on literature and current differential diagnostic pathways a guide to diagnose patellofemoral pain, instability, malposition and signs of infection or fracture with MRI was developed. Therefore, methods as Insall Salvati, patellar tilt angle and visibility of fluid and soft tissues were chosen. Visibility was scored on a VAS scale from 0 to 100mm (0mm zero visibility, 100mm excellent visibility). Subsequently, this guide is used to analyse MRI scans made of a volunteer (female, 61 years, right knee) with primary TKA (Biomet, Zimmer) in sagittal, coronal and transversal direction with a FSE PD metal artefact reducing (MAR) sequence (TE/TR 12/1030ms, slice thickness 4.0mm, FOV 260×260×120mm3, matrix size 224×216) on low-field MRI (Esaote G-scan Brio, 0.25T) and with a FSE T1-weighted high bandwidth MAR sequence (TE/TR 6/500ms, slice thickness 3.0mm, FOV 195×195×100mm3, matrix size 320×224) on high-field MRI (Avanto 1.5T, Siemens). Scans were analysed three times by one observer and the intra observer reliability was calculated with a two-way random effects model intra class correlation coefficient (ICC).Introduction
Method
External fixator knee arthrodesis is a salvage procedure mainly used in cases of end-stage infected total knee replacement (iTKR). A stable fixation combined with bone-ends compression is basic to achieve knee fusion in such a scenario but providing enough stability can be challenging in the presence of severe bone loss after multiple previous procedures. Compared with monoplanar configuration, a biplanar frame achieves improved coronal stiffness, while providing the advantages of good access to the wound and allowance of early ambulation. Our primary hypothesis stated that a biplanar frame would achieve higher and quicker fusion rate than a monolateral configuration. We conducted a retrospective cohort study examining patients managed with biplanar external fixator knee fusion due to non-revisable iTKR between 2014 and 2018. We compared this group of patients with a historical cohort-control patient who had been previously published by our unit in 2013, since we switched from a monoplanar to a biplanar configuration for the management of this kind of complex end-stage iTKR. Primary end-points were fusion rate, time to achieve bone fusion and infection eradication rate. Limb-length discrepancy, pain level, patient satisfaction, and health-related quality of life were also evaluated.Aim
Method
