RESUMO
BACKGROUND: To the best of our knowledge, no prior studies have identified any risk factors for subchondral insufficiency fractures of the medial tibial condyle. This study aimed to explain relationships between subchondral insufficiency fractures of the medial tibial condyle and the meniscus status, lower extremity alignment, or osteoporosis. METHODS: This retrospective study included 325 consecutive patients whose chief complaint is knee joint pain and who had visited one institution between April 2016 and March 2021, of which 70 patients (8 men and 62 women) who had suspected subchondral insufficiency fractures of the medial tibial condyle had undergone magnetic resonance imaging and radiographic examination. These patients were divided into two groups based on the results of their magnetic resonance imaging: the insufficiency fracture group included 46 patients who had subchondral insufficiency fractures of the medial tibial condyle and the nonfracture group included 24 patients without fractures. The meniscus injury and medial meniscus extrusion (MME) were evaluated by using magnetic resonance imaging. The Kellgren-Lawrence grade, the femorotibial angle, and the percent mechanical axis (%MA) were evaluated with the use of knee radiographs. T-scores were also measured by using dual-energy X-ray absorptiometry with a bone densitometer. RESULTS: MME were significantly larger and the %MA was significantly smaller in the insufficiency fracture group than that in the nonfracture group. The prevalence of medial meniscus injuries and pathological MME were higher in the insufficiency fracture group than those in the nonfracture group. The prevalence of varus knee and osteoporosis did not vary remarkably different between the two groups. CONCLUSION: The patients who had insufficiency fractures of the medial tibial condyle tended to have medial meniscus extrusion.
RESUMO
We synthesized bis and tris(macrocycle)s in which a two- or three-fold macrocycle was fused and each adopted twisted forms with M- or P-helicity. According to the sense of twisting in each element, diverse conformations can be generated in a molecule. We present two types of conformational preferences. One is the innate preference for a helical form with an identical sense of twisting throughout the entire molecule. The other is the helical-sense preference for a particular sense of twisting. We were interested in the relationship between Kn and (K1)n, where Kn is an equilibrium constant for the conformational interconversion between two helical forms (MM and PP, MMM and PPP) and n is the number of elements, since we considered that the relationship could be a metric to see the interinfluence among these macrocyclic elements in a single molecule. Through VT measurements in 1H NMR and CD spectroscopy, we attempted to quantify the helical-sense preferences induced in the fused macrocycles (n = 2 and 3) to compare Kn and (K1)n.
RESUMO
This study proposes a near virtual-image method for a flat-panel light field display using both lens and aperture arrays. The pixels of the flat-panel display are located between the lens array and its focal plane, which increases the viewing zone. The enlarged virtual images of the pixels are generated, and a single enlarged virtual pixel image is transmitted by each aperture of the aperture array. The aperture array also reduces aberrations of the lens array. Because the apertures within the aperture array are wider than the pitch of the pixels, this produces a higher light efficiency than light field displays with aperture arrays. The effectiveness of the proposed technique was verified using constructed light field displays with only horizontal parallax.
RESUMO
The purpose of this study was to investigate the long-term effects of anterior cruciate ligament (ACL) resection on the morphological and contractile characteristics of rectus femoris (RF) and semimembranosus (SM) muscles in both injured and contralateral hindlimbs in rats. Wistar male rats (8-week old) were used. Rats were divided into two groups; ACL-resected and (sham-operated) control groups. Furthermore, right and left limbs of rats in the ACL-resected group were assigned as ACL-resected and contralateral groups, respectively, at 1 day, 1, 4, and 48 weeks after ACL resection. No ACL-resection-associated changes in the mass of both muscles were observed 1 week after ACL resection. On the other hand, ACL-resection-associated reduction on mean fiber cross-sectional area (fiber CSA) in RF muscle lasted 48 weeks after ACL resection. Furthermore, ACL-resection associated increase in fiber composition of type I fiber in RF muscle in contralateral limbs. In addition, long-term effects of ACL resection were observed in both ACL-resected and contralateral limbs. Evidences from this study suggested that ACL resection may cause to change in the morphological (fiber CSA) and contractile (distribution of fiber types) properties of skeletal muscles around the knee joint in not only injured but also contralateral limb. Rehabilitation for quantitative and qualitative muscle changes by ACL resection may be required a special care for a long-term period.