Flight Calibration Services (Germany)

The disturbing effects of scattering objects such as wind turbines (WTs) and other buildings on the flight navigation aid Doppler very high frequency omnidirectional radio range (DVOR) have been addressed in previous publications. Nevertheless, a practically feasible possibility to precisely and consistently predict the DVOR bearing deviation before the buildings’ construction is still missing. In this contribution, a method based on numerical simulations is presented which allows calculating the DVOR receiver's antenna voltage in the time domain for dynamically disturbed environments. Separating its frequency modulated and amplitude modulated content, the indicated DVOR bearing is calculated subsequently by determining the corresponding phase difference. Finally, the calculation results are validated by in situ measurements of DVOR signal disturbances in the environment of eight WTs.

Open-wedge valgus high tibial osteotomy is a well-established procedure in the management of medial osteoarthritis of the knee. In recent years, improved osteotomy and fixation methods have led to an increased use of this technique. The aim of this study was to identify predictive parameters for the clinical outcome after valgus high tibial osteotomy. A multicentre case series involving retrospective capture of baseline data and prospective outcome assessment of patients with knee OA who underwent an osteotomy using Tomofix(®) plate was conducted. Functional outcome was assessed using Oxford 12-item Knee Score. Before surgery, the majority of patients had grade III (52%) and grade IV (33%) lesions according to Outerbridge classification. Three hundred and eighty-six of 533 eligible patients were interviewed for follow-up after an average of 3.6 years. The mean Oxford Knee Score was 43 points. Six per cent experienced at least one local postoperative complication. There was a tendency towards lower score results in patients with a higher preoperative degree of the medial cartilage lesion. No correlation between patient age and the Oxford Knee Score was observed. Being male, being operated by an experienced surgeon, having no intake of pain medication at follow-up and having no postoperative complication are positive predictors of the Oxford Knee Score up to 5 years after surgery. This study reveals favourable midterm results after valgus high tibial osteotomy in varus osteoarthritis, even in older patients with high degree of cartilage damage. II.