The double-echo-steady-state (DESS) sequence generates two signal echoes that are characterized by a different contrast behavior. Based on these two contrasts, the underlying T2 can be calculated. For a flip-angle of 90°, the calculated T2 becomes independent of T1, but with very low signal-to-noise ratio. In the present study, the estimation of cartilage T2, based on DESS with a reduced flip-angle, was investigated, with the goal of optimizing SNR, and simultaneously minimizing the error in T2. This approach was validated in phantoms and on volunteers. T2 estimations based on DESS at different flipangles were compared with standard multiecho, spin-echo T2. Furthermore, DESS-T2 estimations were used in a volunteer and in an initial study on patients after cartilage repair of the knee. A flip-angle of 33°was the best compromise for the combination of DESS-T2 mapping and morphological imaging.

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T2 mapping allows visualization of cartilage repair tissue maturation. Global T2 repair tissue values approach that of control sites after more than 1.5 years, similar behavior is seen in the zonal organization.

IntroductionThe increasing prevalence of obesity has led to an increase in total knee arthroplasties (TKAs) being undertaken in patients with a higher body mass index (BMI). TKA in morbidly obese patients can be technically challenging due to numerous anatomical factors and patient co-morbidities. The long-term outcomes in this patient group are unclear. This systematic review aims to compare the long-term revision rates, functional outcomes and complication rates of TKAs in morbidly obese versus non-obese patients.MethodsA search of PubMed, EMBASE and PubMed Central was conducted to identify studies that reported revision rates in a cohort of morbidly obese patients (BMI ≥ 40 kg/m2) that underwent primary TKA, compared to non-obese patients (BMI ≤ 30 kg/m2). Secondary outcomes included Knee Society Objective Scores (KSOS), Knee Society Functional Scores (KSFS), and complication rates between the two groups. The difference in revision rates was assessed using the Chi-squared test. The Wilcoxon signed-rank test was used to compare pre-operative and post-operative functional scores for each group. KSOS and KSFS for morbidly obese and non-obese patients were compared using the Mann–Whitney test. Statistical significance was defined as p ≤ 0.05.ResultsNine studies were included in this review. There were 624 TKAs in morbidly obese patients and 9,449 TKAs in non-obese patients, average BMI values were 45.0 kg/m2 (range 40–66 kg/m2) and 26.5 kg/m2 (range 11–30 kg/m2) respectively. The average follow-up time was 4.8 years (range 0.5–14.1) and 5.2 years (range 0.5–13.2) respectively, with a revision rate of 7% and 2% (p < 0.001) respectively. All functional scores improved after TKA (p < 0.001). Pre- and post-operative KSOS and KSFS were poorer in morbidly obese patients, however, mean improvement in KSOS was the same in both groups and comparable between groups for KSFS (p = 0.78). Overall complication rates,  including infection, were higher in morbidly obese patients.ConclusionsThis review suggests an increased mid to long-term revision rate following primary TKA in morbidly obese patients, however, these patients have a functional recovery which is comparable to non-obese individuals. There is also an increased risk of perioperative complications, such as superficial wound infection. Morbidly obese patients should be fully informed of these issues prior to undergoing primary TKA.

The reported stereophotographic technique may be used as an independent gold standard for validation of the accuracy of quantitative cartilage measurements made using magnetic resonance imaging. The thickness distribution maps show that the thickest articular cartilage occurs over the talar shoulders where osteochondral lesions commonly occur and not in the centre of the talar dome as commonly believed.

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Abstract. This paper presents a general graph-theoretic technique for simultaneously segmenting multiple closed surfaces in volumetric images, which employs a novel graph-construction scheme based on triangulated surface meshes obtained from a topological presegmentation. The method utilizes an efficient graph-cut algorithm that guarantees global optimality of the solution under given cost functions and geometric constraints. The method's applicability to difficult biomedical image analysis problems was demonstrated in a case study of co-segmenting the bone and cartilage surfaces in 3-D magnetic resonance (MR) images of human ankles. The results of our automated segmentation were validated against manual tracings in 55 randomly selected image slices. Highly accurate segmentation results were obtained, with signed surface positioning errors for the bone and cartilage surfaces being 0.02±0.11mm and 0.17 ± 0.12mm, respectively.

Due to the advances in oncological therapy, the life expectancy of patients with malignant tumours and the incidence of pathological fractures have increased over the last decades. Pathological fractures of the long bones are common complications of metastatic disease; however, the outcome of different surgical techniques for the treatment of these fractures has not been clearly defined. The aim of this study was to evaluate differences in patient's survival and postoperative complications after the treatment of pathological fractures of the long bones. Eighty-eight patients with 96 pathological fractures of the long bones were analysed retrospectively. Seventy-five patients with 83 fractures received surgical treatment. The operative treatments used were intramedullary fixation, gliding screws, plate osteosynthesis or arthroplasty. Five patients were still alive at the end of data collection at a median time of 42.5 months, and 16.2% survived 1 year, 7% 2 years and 4% more than 3 years postoperatively. All surgically treated patients had a reduction of local pain and were able to walk after the operation. The overall rate of complications was 8%. Early palliative treatment of pathological fractures of the long bones is indicated in most patients in the advanced stage of metastatic disease. The low complication rate, reduction of local pain and early mobilisation justify the surgical stabilisation of fractures in this cohort of patients.