Erdheim-Chester disease involving breast and muscle: Imaging findings

American Journal of Roentgenology16451115-1117AJRO

Blood volume and ejection fraction measurements using CEUS

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Tibial component with and without stem extension in a trabecular metal cone construct

Contains fulltext : 182207.pdf (publisher's version ) (Open Access)PURPOSE: The purpose of this study was to investigate stability and strain distribution of a tibial plateau reconstruction with a trabecular metal cone while the tibial component is implanted with and without a stem, and whether prosthetic stability was influenced by bone mineral density. Trabecular metal cones are designed to fill up major bone defects in total knee arthroplasty. Tibial components can be implanted in combination with a stem, but it is unclear whether this is necessary after reconstruction with a trabecular metal cone. Implanting a stem can give extra stability, but may have negative side effects. METHODS: Tibial revision arthroplasties with trabecular metal cones were performed after reconstruction of a 2B bone defect according to the Anderson Orthopedic Research Institute classification. Components were implanted in seven pairs of cadaveric tibiae; one tibia of each pair was implanted with stem and the other without. All specimens were loaded to one bodyweight alternating between the medial and lateral tibial component. Implant-bone micro-motions, bone strains, bone mineral density and correlations were measured and/or calculated. RESULTS: Tibial components without a stem showed only more varus tilt [difference in median 0.14 degrees (P < 0.05)], but this was not considered clinically relevant. Strain distribution did not differ. Bone mineral density only had an effect on the anterior/posterior tilt [rho: -0.72 (P < 0.01)]. CONCLUSION: Tibial components, with or without a stem, which are implanted after reconstruction of major bone defects using trabecular metal cones produce very similar biomechanical conditions in terms of stability and strain distribution. If in vivo studies confirm that a stem extension is not mandatory, orthopaedic surgeons can decide not to implant a stem. LEVEL OF EVIDENCE: II

Minimally invasive total hip and knee arthroplasty-implications for the elderly patient

Total hip arthroplasty and total knee arthroplasty have proven to be effective surgical procedures for the treatment of hip and knee osteoarthritis. In recent decades, there have been considerable efforts to improve the component designs, modes of fixation, and surgical techniques. Minimally invasive techniques are examples of these developments. Minimally invasive total joint arthroplasty aims at decreasing the surgical incision and minimizing damage to the underlying soft tissue to accelerate postoperative recovery and an earlier return to normal function. The objective here is to report on these recent developments in minimally invasive total joint arthroplasty and their implication for the elderly patient

Reliability and validity of the Dutch version of the foot and ankle outcome score (FAOS)

Background: The Foot and Ankle Outcome Score (FAOS) is a patient-reported questionnaire measuring symptoms and functional limitations of the foot and ankle. Aim is to translate and culturally adapt the Dutch version of the FAOS and to investigate internal consistency, validity, repeatability and responsiveness. Methods: According to the Cross Cultural Adaptation of Self-Report Measures guideline, the FAOS was translated into Dutch. Eighty-nine patients who had undergone an ankle arthroscopy, ankle arthrodesis, ankle ligament reconstruction or hallux valgus correction completed the FAOS, FFI, WOMAC and SF-36 questionnaires and were included in the validity study. Sixty-five of them completed the FAOS a second time to determine repeatability. Responsiveness was analysed in an additional 15 patients who were being treated for foot or ankle problems. Results: Internal consistency of the FAOS is high (Cronbach's alphas varying between 0.90 and 0.96). Repeatability can be considered good, with ICC's ranging from 0.90 to 0.96. Construct validity can be classified as good with moderate-to-high correlations between the FAOS subscales and subscales of the FFI (0.55 to 0.90), WOMAC (0.57 to 0.92) and SF-36 subscales physical functioning, pain, social functioning and role-physical (0.33 to 0.81). Low standard response means were found for responsiveness (0.0 to 0.4). Conclusions: The results of this study show that the Dutch version of the FAOS is a reliable and valid questionnaire to assess symptoms and functional limitations of the foot and ankle

Maximum-likelihood estimation for indicator dilution analysis

Indicator-dilution methods are widely used by many medical imaging techniques and by dye-, lithium-, and thermodilution measurements. The measured indicator dilution curves are typically fitted by a mathematical model to estimate the hemodynamic parameters of interest. This paper presents a new maximum-likelihood algorithm for parameter estimation, where indicator dilution curves are considered as the histogram of underlying transit-time distribution. Apart from a general description of the algorithm, semi-analytical solutions are provided for three well-known indicator dilution models. An adaptation of the algorithm is also introduced to cope with indicator recirculation. In simulations as well as in experimental data obtained by dynamic contrast-enhanced ultrasound imaging, the proposed algorithm shows a superior parameter estimation accuracy over nonlinear least-squares regression. The feasibility of the algorithm for use in vivo is evaluated using dynamic contrastenhanced ultrasound recordings obtained with the purpose of prostate cancer detection. The proposed algorithm shows an improved ability (increase in receiver-operating-characteristic curve area of up to 0.13) with respect to existing methods to differentiate between healthy tissue and cancer