The knee is the largest and strongest joint in your body. It is made up of the lower end of the femur (thighbone), the upper end of the tibia (shinbone), and the patella (kneecap). The ends of the bones where they touch are covered with articular cartilage, a smooth slippery substance that protects the bones as you bend and straighten your knee.
In a tibia and fibula X-ray, an X-ray machine sends a beam of radiation through the lower leg, and an image is recorded on a computer or special X-ray film. This image shows the bones (tibia and fibula) and soft tissues of the lower leg.
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An X-ray of the tibia and fibula can help doctors find the cause of pain, tenderness, swelling, or deformity of the lower leg. It can show broken bones. After a broken bone has been set, an X-ray can show if the bones are aligned and if they have healed properly.
Fragility fracture risk in patients with DMD is significantly higher (44), with a fracture prevalence 5-fold higher compared with age-matched healthy young people (48 vs. 9%) with lower limb fractures (femur and tibia) more frequent in DMD. Most of the long-bone fractures in DMD patients are caused by low-energy trauma (i.e., fall from a standing position), an extremely rare condition in healthy young people. Long-bone fractures substantially contribute to functional and postural impairments, accelerating the transition to a wheelchair (45). Moreover, increased fracture risk of 75% (all skeletal sites) after 3 months of full wheelchair use has also been demonstrated (46). Finally, in GC-treated DMD patients, a moderate prevalence of symptomatic VFs (up to 40%) has been reported (47).
Exact pathogenetic mechanisms underneath muscle and bone relationship in LOPD patients are still unknown. These patients have different patterns of muscle involvement, commonly characterized by weakness of paravertebral, hip flexor, and knee extensor muscles that results in poor mechanical load applied to the spine and the proximal femur (59). The clinical phenotype of muscle impairment might explain the site-specific BMD loss (i.e., at LS and/or femoral neck). van den Berg showed a decreased BMD particularly in non-ambulatory and ventilator-dependent patients (54 vs. 15% in ambulant subjects) (58). The authors found a statistically significant positive mild-to-moderate correlation between total body less head (TBLH) BMD and proximal muscle strength of both the upper (r = 0.37) and lower extremities (r = 0.43). Moreover, this study suggested a putative role of prolonged inactivity and immobilization as risk factors for bone loss in these patients (58). These data were confirmed by Khan et al. who analyzed bone microarchitecture using high-resolution peripheral computed tomography (HR-pQCT) at two standard skeletal sites, distal radius and distal tibia (60).
Quantitative cortical micro-architectural endpoints are important for understanding structure-function relations in the context of fracture risk and therapeutic efficacy. This technique study details new image-processing methods to automatically segment and directly quantify cortical density, geometry, and micro-architecture from HR-pQCT images of the distal radius and tibia. An automated segmentation technique was developed to identify the periosteal and endosteal margins of the distal radius and tibia, and detect intra-cortical pore space morphologically consistent with Haversian canals. The reproducibility of direct quantitative cortical bone indices based on this method was assessed in a pooled dataset of 56 subjects with two repeat acquisitions for each site. The in vivo precision error was characterized using root mean square coefficient of variation (RMSCV%) from which, the least significant change (LSC) was calculated. Bland-Altman plots were used to characterize bias in the precision estimates. The reproducibility of cortical density and cross-sectional area measures was high (RMSCV
In situ testing determined the insertion loss ( IL) and absorption coefficients of a candidate absorptive noise barrier (soundwall) to abate railway noise for residents of Anaheim, CA. A 4000 m barrier is proposed south of the tracks, but residential areas to the north have expressed concerns that barrier reflections will increase their noise exposure. To address these concerns, a 3.66 m high by 14.6 m long demonstration barrier was built in the parking lot of Edison Field, Anaheim, as part of a public open house, thereby allowing for acoustical measurements. Insertion loss ( IL) was measured in third-octave bands assuming 1/2-scale construction. The IL for three, scaled railway noise sub-sources (rail/wheel interface, locomotive, and train horn) was measured at six, scaled distances. The highest total, A-weighted IL, after corrections for finite-barrier and point-source speaker effects was 22 dB(A) for rail/wheel noise, 18 dB(A) for locomotive noise, and 20 dB(A) for train horn noise. These results can be compared favourably to IL predictions made using algorithms from the US Federal Rail Administration (FRA) noise assessment guidelines. For the actual barrier installation, shielded residential receivers located south of the project are expected to see their future noise exposures reduced from an unmitigated 78 CNEL to 65 CNEL. Absorption coefficients were measured using time delay spectrometry. At lower frequencies, measured absorption coefficients were notably less than the reverberation room results advertised in the manufacturer's literature, but generally conformed with impedance tube results. At higher frequencies the correspondence between measured absorption coefficients and reverberation room results was much improved. For the actual barrier installation, unshielded residential receivers to the north are expected to experience noise exposure increases of less than 1 dB(A). This factor of increase is consistent with a finding of no impact when assessed 2ff7e9595c
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