Aseptic necrosis of the femoral head (AVN) leads to destruction of the affected hip joint, predominantly in younger patients. Advanced core decompression (ACD) is a new technique that may allow better removal of the necrotic tissue by using a new percutaneous expandable reamer. A further modification is the refilling of the drill hole and the defect with an injectable, hard-setting, composite calcium sulphate (CaSO₄)-calcium phosphate (CaPO₄) bone graft substitute. Compression tests were performed on seven pairs of femoral cadaver bones. One femur of each pair was treated with ACD, while the opposite side remained untreated. Clinically, the postoperative outcome of 27 hips in 23 patients was performed by physical examination 6 weeks after ACD and at average follow-up of 9.69 months, and compared with the preoperative results. MRI was used to assess the removal of the necrotic tissue, any possible progression of AVN and evaluation of collapse. In the biomechanical analysis, the applied maximum compression force that caused the fracture did not significantly differ from the untreated opposite side. The overall results of postoperative physical examinations were significantly better than preoperatively. Five hips (18.5%) were converted to a total hip replacement. The follow-up MRIs of the other patients showed no progression of the necrotic area. The first follow-up results of ACD have been encouraging for the early stages of aseptic necrosis of the femoral head. In our opinion, an assured advantage is the high stability of the femoral neck after ACD, which allows quick rehabilitation.

There is still controversy as to whether minimally invasive total hip arthroplasty enhances the postoperative outcome. The aim of this study was to compare the outcome of patients who underwent total hip replacement through an anterolateral minimally invasive (MIS) or a conventional lateral approach (CON). We performed a randomized, prospective study of 75 patients with primary hip arthritis, who underwent hip replacement through the MIS (n=36) or CON (n=39) approach. The Western Ontario and McMaster Universities Osteoarthritis Index and Harris Hip score (HHS) were evaluated at frequent intervals during the early postoperative follow-up period and then after 3.5 years. Pain sensations were recorded. Serological and radiological analyses were performed. In the MIS group the patients had smaller skin incisions and there was a significantly lower rate of patients with a positive Trendelenburg sign after six weeks postoperatively. After six weeks the HHS was 6.85 points higher in the MIS group (P=0.045). But calculating the mean difference between the baseline and the six weeks HHS we evaluated no significant differences. Blood loss was greater and the duration of surgery was longer in the MIS group. The other parameters, especially after the twelfth week, did not differ significantly. Radiographs showed the inclination of the acetabular component to be significantly higher in the MIS group, but on average it was within the same permitted tolerance range as in the CON group. Both approaches are adequate for hip replacement. Given the data, there appears to be no significant long term advantage to the MIS approach, as described in this study.

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IntroductionPeople with cirrhosis of the liver are predisposed to developing oral lesions. The occurrence and type of lesion depend on the degree of liver function impairment and its type, and on the severity and duration of systemic diseases. In children, the age at which the early symptoms of liver disease are experienced is also of great importance.AimTo assess the prevalence of oral pathological lesions in children and adolescents with cirrhosis of the liver, and their correlation with the degree of liver function impairment.Material and methodsClinical and laboratory results of liver function tests (Model of End-Stage Liver Disease/Score of Paediatric End-Stage Liver Disease, Child-Pugh score) were assessed in 35 patients with cirrhosis of the liver. The average age of the patients was 10.7 ±4.74 years. All patients also had their oral cavities examined (mucosa, gingiva – GI, hygiene – PLI, teeth – dmft/dmfs and DMFt/DMFs, DDE Index and Candida spp. presence) and this was then correlated to the degree of liver function impairment.ResultsAccording to the Child-Pugh scale, 16 patients were class A and 19 were class B/C. Jaundice during the first 3 years of life occurred in 9 patients. Mucosal lesions were found in 26 out of 35 patients (74%), including 10 out of 16 (63%) in Child-Pugh group A, and 16 out of 19 (84%) in group B/C (NS – non significant). Oral candidiasis occurred more often in class B/C than in class A (47.4% vs. 12.5%; p < 0.05). The GI index (Gingival Index) and PLI index (Dental Plaque Index) did not differ between the groups (A vs. B/C) but correlated in the whole group (R = 0.58) as well as in subgroups A (R = 0.65) and B/C (R = 0.59). Dmft/dmfs and DMFt/DMFs indexes did not differ between groups A and B/C, and neither did the DMFt/DMFs in patients with/without enamel defects.ConclusionsOral mucosal lesions are commonly found in children with cirrhosis of the liver. Advanced liver disease promotes oral candidiasis. Severity of gingivitis correlates with the presence of dental plaque.

Earwig wings are highly foldable structures that lack internal muscles. The behaviour and shape changes of the wings during flight are yet unknown. We assume that they meet a great structural challenge to control the occurring deformations and prevent the wing from collapsing. At the folding structures especially, the wing could easily yield to the pressure. Detailed microscopy studies reveal adaptions in the structure and material which are not relevant for folding purposes. The wing is parted into two structurally different areas with, for example, a different trend or stiffness of the wing veins. The storage of stiff or more flexible material shows critical areas which undergo great changes or stress during flight. We verified this with high-speed video recordings. These reveal the extent of the occurring deformations and their locations, and support our assumptions. The video recordings reveal a dynamical change of a concave flexion line. In the static unfolded state, this flexion line blocks a folding line, so that the wing stays unfolded. However, during flight it extends and blocks a second critical folding line and prevents the wing from collapsing. With these results, more insight in passive wing control, especially within high foldable structures, is gained.