Background: Medial meniscal extrusion (MME) is an important marker of knee osteoarthritis (KOA) progression. The purposes of this study were: 1) to determine whether there are morphological differences between CT-and MRIderived tibial plateau models; and 2) to determine whether measurement of MME volume and width using an MRIderived tibial model is as accurate as measurements on a CT-derived tibial model. Methods: This was a cross-sectional study that enrolled ten participants with medial KOA (Kellgren-Lawrence grade 1 to 3). Primary outcome was surface difference of the medial tibial plateau between CT-and MRI-derived models. Furthermore, volume and cross-sectional area of the medial tibial plateau were compared between CT-and MRIderived models. Measurements of MME volume and width were compared between CT-and MRI-derived tibial models. Results: Minimal and maximal surface differences of the medial tibial plateau between the CT-and MRI-derived models were − 0.15 [− 0.44, 0.14] mm (mean [95% confidence interval]) and 0.24 [− 0.09, 0.57] mm, respectively. There were no significant differences in volume and cross-sectional area of the medial tibial plateau between CTand MRI-derived tibial models. The MME volumes measured on CT-and MRI-derived models were 942.6 [597.7, 1287.6] mm 3 and 916.2 [557.9, 1274.6] mm 3 , respectively (p = 0.938). The MME widths measured on CT-and MRIderived models were 4.2 [1.9, 6.5] mm and 4.5 [2.2, 6.9] mm, respectively (p = 0.967). Conclusions: CT-and MRI-derived models of the medial tibial plateau did not show significant morphological differences. Both CT-and MRI-derived tibia can be used as a reference to measure MME in early-to-moderate medial KOA.
Background: Total knee arthroplasty (TKA) is commonly performed around the world. Implant designs include fixed-bearing and mobile-bearing. Mobile-bearing design was developed as a rotating platform that allows axial rotation of the insert around the longitudinal axis. This phenomenon may limit full exploitation of the characteristics of the mobile-bearing insert, which may cause wearing and reduce longevity. However, there is limited knowledge on rotational behavior of the polyethylene mobile-bearing insert under weight-bearing conditions. We aimed at determining the rotational motion of each component at full extension and flexed positions during a squatting activity after TKA. Methods: This study was a cross-sectional study (level 4) involving patients with severe knee osteoarthritis scheduled to receive TKA. We examined 13 knees of 11 patients after mobile-bearing TKA (NexGen LPS-Flex, Zimmer Inc.) at 10 weeks and 1 year postoperatively. Four identical metallic beads were embedded into the insert. Wide-base squatting was chosen for analyses. Three-dimensional in vivo poses of the prostheses were created using a 3D-to-2D registration technique. During flexion, rotation of the femoral component relative to the insert (FEM/INS) and tibial component (FEM/TIB) as well as insert rotation relative to the tibial component (INS/TIB) were computed. Repeated measure 2-way ANOVA and post hoc test was used.Results: In the fully extended position, FEM/INS was significantly smaller than INS/TIB both at 10 weeks (− 0.3°vs. 6.3°, p = .013) and 1 year (− 0.8°vs. 4.9°, p = .011), respectively. During the squatting activity, rotation motions of FEM/TIB, FEM/INS, INS/TIB were 5.7°, 5.9°, and 1.8°at 10 weeks and 6.3°, 5.5°, and 1.6°at 1 year, respectively. Rotation motion of FEM/INS was significantly greater than that of INS/TIB at both 10 weeks (p < .001) and 1 year (p < .001). Conclusions:The mobile-bearing insert enhances the compatibility of FEM/INS in extension; the amount of INS/TIB rotation is significantly smaller than that of FEM/INS during a squatting activity. This information will inform surgeons to take caution to perform TKA with a fixed insert in which 6.3°of rotational offset would be added to the rotational alignment at FEM/INS at full extension.
On the chromosomal examination for the sex determination of the hermaphroditic patient, a case with a partial monosomy for the short arm of the chromosome no. 9 (pter --* p22) was found. The present article deals with clinical and cytogenetic studies on this case.Case reports.The propositus was a 8-year-old boy. He was born to a 38-year-old father and a 35-year-old mother as the first child. There was no history of abortion, stillbirth, congenital malformations, and consanguinity in this couple. Clinical examinations revealed that her parents were phenotypically normal showing no evidence for mental deficiency. The birth weight of this patient was 2570 g at 40 weeks of gestation.Remarkable clinical signs of the proband were mental retardation, muscular hypotonia, trigonocephaly, low hair line, hypertelorism, epicanthus, upward slanted and small palpebral fissure, hypersupercilia which nearly jointed with each other supranasally, anteverted nostril and flat nasal bridge, long philtrum, high-arched palate, low set ears, malformed auricle, widely spaced nipples, and hypoplastic genitalia; cryptorchism, small penis, hypespadia, and hypoplastic scrotum. No abnormalities on his hand and feet were observed.Cytological findings. Chromosome slides for the study were prepared from leucocyte cultures established from the propositus and his parents. For differential staining, the G-banding procedures were applied to the slides made by the air-drying procedure. Chromosome counts were made with 25-well-delineated metaphases in each. Karyotypes were analysed in 12 cells each by the conventional and G-banding preparations.The propositus had the karyotype with 46 chromosomes involving a 9p-chromosome. The deleted segment of the 9p chromosome corresponded to the band in 9pter--* 9p22. No other chromosomal abnormalities were noted. His father and mother were chromosomally normal with no slight evidence for the aberration.
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