Cementless arthroplasty with a distal femoral shortening for the treatment of Crowe type IV developmental hip dysplasia.

BACKGROUND: Severe developmental dysplasia of the hip is a surgical challenge. The purpose of this study is to describe the cementless arthroplasty with a distal femoral shortening osteotomy for Crowe type IV developmental hip dysplasia and to report the results of this technique. MATERIALS AND METHODS: 12 patients (2 male and 10 female) of Crowe type IV developmental hip dysplasia operated between January 2005 and December 2010 were included in the study. All had undergone cementless arthroplasty with a distal femoral shortening osteotomy. Acetabular cup was placed at the level of the anatomical position in all the hips. The clinical outcomes were assessed and radiographs were reviewed to evaluate treatment effects. RESULTS: The mean followup for the 12 hips was 52 months (range 36-82 months). The mean Harris hip score improved from 41 points (range 28-54) preoperatively to 85 points (range 79-92) at the final followup. The mean length of bone removed was 30 mm (range 25-40 mm). All the osteotomies healed in a mean time of 13 weeks (range 10-16 weeks). There were no neurovascular injuries, pulmonary embolism or no infections. CONCLUSION: Our study suggests that cementless arthroplasty with a distal femoral shortening is a safe and effective procedure for severe developmental dysplasia of the hip.

Polymer-free patterning of graphene at sub-10-nm scale by low-energy repetitive electron beam.

A polymer-free technique for generating nanopatterns on both synthesized and exfoliated graphene sheets is proposed and demonstrated. A low-energy (5-30 keV) scanning electron beam with variable repetition rates is used to etch suspended and unsuspended graphene sheets on designed locations. The patterning mechanisms involve a defect-induced knockout process in the initial etching stage and a heat-induced curling process in a later stage. Rough pattern edges appear due to inevitable stochastic knockout of carbon atoms or graphene structure imperfection and can be smoothed by thermal annealing. By using this technique, the minimum feature sizes achieved are about 5 nm for suspended and 7 nm for unsuspended graphene. This study demonstrates a polymer-free direct nanopatterning approach for graphene.

Combination of a fast cleanup procedure and a DR-CALUX® bioassay for dioxin surveillance in Taiwanese soils.

Our goal was to determine dioxin levels in 800 soil samples collected from Taiwan. An in vitro DR-CALUX® assay was carried out with the help of an automated Soxhlet system and fast cleanup column. The mean dioxin level of 800 soil samples was 36.0 pg-bioanalytical equivalents (BEQs)/g dry weight (d.w.). Soil dioxin-BEQs were higher in northern Taiwan (61.8 pg-BEQ/g d.w.) than in central, southern, and eastern Taiwan (22.2, 24.9, and 7.80 pg-BEQ/g d.w., respectively). Analysis of multiple linear regression models identified four major predictors of dioxin-BEQs including soil sampling location (ß = 0.097, p < 0.001), land use (ß = 0.065, p < 0.001), soil brightness (ß = 0.170, p < 0.001), and soil moisture (ß = 0.051, p = 0.020), with adjusted R2 = 0.947 (p < 0.001) (n = 662). An univariate logistic regression analysis with the cut-off point of 33.4 pg-BEQ/g d.w. showed significant odds ratios (ORs) for soil sampling location (OR = 2.43, p < 0.001), land use (OR = 1.47, p < 0.001), and soil brightness (OR = 2.83, p = 0.009). In conclusion, four variables, including soil sampling location, land use, soil brightness, and soil moisture, may be related to soil-dioxin contamination. Soil samples collected in northern Taiwan, and especially in Bade City, soils near industrial areas, and soils with darker color may contain higher dioxin-BEQ levels.

Pelvic step: the contribution of horizontal pelvis rotation to step length in young healthy adults walking on a treadmill.

Transverse plane pelvis rotations during walking may be regarded as the "first determinant of gait". This would assume that pelvis rotations increase step length, and thereby reduce the vertical movements of the centre of mass-"the pelvic step". We analysed the pelvic step using 20 healthy young male subjects, walking on a treadmill at 1-5 km/h, with normal or big steps. Step length, pelvis rotation amplitude, leg-pelvis relative phase, and the contribution of pelvis rotation to step length were calculated. When speed increased in normal walking, pelvis rotation changed from more out-of-phase to in-phase with the upper leg. Consequently, the contribution of pelvis rotation to step length was negative at lower speeds, switching to positive at 3 km/h. With big steps, leg and pelvis were more in-phase, and the contribution of pelvis rotation to step length was always positive, and relatively large. Still, the overall contribution of pelvis rotations to step length was small, less than 3%. Regression analysis revealed that leg-pelvis relative phase predicted about 60% of the variance of this contribution. The results of the present study suggest that, during normal slow walking, pelvis rotations increase, rather than decrease, the vertical movements of the centre of mass. With large steps, this does not happen, because leg and pelvis are in-phase at all speeds. Finally, it has been suggested that patients with hip flexion limitation may use larger pelvis rotations to increase step length. This, however, may only work as long as the pelvis rotates in-phase with the leg.

Effects of experimentally increased trunk stiffness on thorax and pelvis rotations during walking.

Patients with non-specific low back pain, or a similar disorder, may stiffen their trunk, which probably alters their walking coordination. To study the direct effects of increasing trunk stiffness, we experimentally increased trunk stiffness during walking, and compared the results with what is known from the literature about gait coordination with, e.g., low back pain. Healthy subjects walked on a treadmill at 3 speeds (0.5, 1.0 and 1.5m/s), in three conditions (normal, while contracting their abdominal muscles, or wearing an orthopedic brace that limits trunk motions). Kinematics of the legs, thorax and pelvis were recorded, and relative Fourier phases and amplitudes of segment motions were calculated. Increasing trunk stiffness led to a lower thorax-pelvis relative phase, with both a decrease in thorax-leg relative phase, and an increase in pelvis-leg relative phase, as well as reduced rotational amplitude of thorax relative to pelvis. While lower thorax-pelvis relative phase was also found in patients with low back pain, higher pelvis-leg relative phase has never been reported in patients with low back pain or related disorders. These results suggest that increasing trunk stiffness in healthy subjects causes short-term gait coordination changes which are different from those seen in patients with back pain.

[Comparison of three methods of internal fixations for intertrochanteric femoral fractures in elderly patients].

OBJECTIVE: To compare the clinical effects of three methods of internal fixations in treating intertrochanteric fractures in elderly patients. METHODS: From 2004 to 2008, the clinical data of 112 patients with intertrochanteric fractures were retrospectively analyzed. There were 63 males and 49 females, aged from 60 to 80 years with an average of 66.2 years. The patients were treated respectively with dynamic hip screws (DHS group, 40 cases), anatomic plate (anatomic plate group, 36 cases) and proximal femoral intramedullary nails (PFN group, 36 cases). The data of each group were collected for statistical analysis on the following aspects: operative time, blood loss volume, clinical healing time of fracture, postoperative complications, and hip functional score of Harris. RESULTS: All these patients were followed up from 20 to 24 months with an average of 22.6 months. There was no significant difference in operative time, blood loss volume among three groups; there was significant difference in clinical healing time of fracture, Harris score and postoperative complications among three groups (P < 0.05). In the healing time, the PFN group was significantly less than that of other groups (P = 0.001), but there was no differences between DHS group and anatomic plate group. In the Harris score, the PFN group was significantly higher than that of other groups (P = 0.001), but there was no differences between DHS group and anatomic plate group. In the aspect of postoperation complication, there was 2 cases of coxa vara, 1 case of internal fixation loosening and 1 case of deep venous thrombosis in the DHS group; there were 2 cases of deep venous thrombosis in the PFN group; there were 2 cases of coxa vara and 1 case of internal fixation loosening in the anatomic plate group (P = 0.001). CONCLUSION: In the treatment of intertronchanteric fractures, proximal femoral intramedullary nail may be the best choice, which can decrease healing time as well as complications postoperatively.