Characterization of Malalignment between Atrial and Ventricular Septa in Overriding/Straddling Tricuspid and Mitral Valves

Objective:Overriding/straddling of an atrioventricular valve is a consequence of atrial-ventricular septal malalignment.We sought to characterize the malalignment by analogizing it to a flap-door and using structured approach.Methods:The echocardiograms and magnetic resonance images of 35 patients with overriding/straddling tricuspid or mitral valve were evaluated to assess the following modifiers;the malaligned part of the septum,the reference structure,and the mechanism,direction and severity of malalignment.Results:The pathology included classic overriding tricuspid valve in 15,classic overriding mitral valve in 12,and overriding tricuspid valve with left juxtaposition of atrial appendages in 8.In classic overriding tricuspid valve,the ventricular septum was hinged to the anterior interventricular groove and its insertion to the posterior interventricular groove was displaced toward the right ventricle.The VSD primarily involved the inlet but also extended toward the anterior interventricular groove.In classic overriding mitral valve,the ventricular septum was hinged to the posterior interventricular groove and crux cordis.Its insertion to the anterior interventricular groove was displaced toward the left ventricle.The VSD primarily involved the anterior part but also extended toward the inlet.Overriding tricuspid valve with left juxtaposition of atrial appendages had a mild degree of malalignment with displacement/rotation of the atrioventricular junction.Evenly spaced short-axis images were most helpful in characterizing the pathology.Conclusions:Overriding/straddling atrioventricular valves can be easily understood by analogizing the atrial-ventricular septal malalignment to a flap-door and describing the pathology in a structured manner.Contrary to what has previously been known,the VSD is not limited to the inlet or outlet part of the ventricular septum.

Eight-year trajectories of malalignment progression in symptomatic knee osteoarthritis

Background: Although various therapies have been developed to treat malalignment in osteoarthritic knees, the pattern of malalignment progression is still unclear. This study aimed to identify homogeneous subgroups with distinct trajectories of malalignment progression in subjects with symptomatic knee osteoarthritis (KOA) and to determine corresponding risk factors.Methods: Eight-year follow-up (from 2004 to 2012) data on 1252 participants with symptomatic KOA from the Osteoarthritis Initiative were included. Varus/valgus angle progression was characterized by group-based trajectory models. Time-varying covariates were introduced into the model to investigate how they affected trajectories. Multinomial logistic regression for trajectory group membership was applied to ascertain risk factors.Results: Five subgroups were identified. Participants in the varus worsening trajectory (n = 166) or valgus worsening trajectory (n = 118) proceeded to worsen malalignment over time. The neutral trajectory (n = 378), varus stable trajectory (n = 328), and valgus stable trajectory (n = 262) maintained close to the initial varus/valgus angle over 8 years. Higher baseline Kellgren and Lawrence grade (odds ratio [OR] = 4.35,P < 0.001 for varus;OR= 3.85,P < 0.001 for valgus) and "severe" baseline malalignment (OR = 13.57,P < 0.001 for varus;OR = 23.04,P < 0.001 for valgus) were risk factors for worsening trajectories. The cutoff point of the baseline varus/valgus angle to discriminate between stable or worsening trajectory was -4.5° for varus and 3.6° for valgus.Conclusions: This study identified the malalignment progression pattern - minor malalignment (-4.5° to +3.6°) tends to remain stable, while major baseline malalignment is likely to progress. This provides a reference for therapy to prevent malalignment from deteriorating and emphasizes the necessity of determining the trigger factors for malalignment onset.

Waders(Scolopacidae)surviving despite malaligned leg fractures in the wild:kinematics of bipedal locomotion

Background: Bone fracture frequencies and survival rates are essential parameters in skeleton evolution, but information on the functional consequences of naturally healed fractures is scarce. No leg bone fracture healing in the wild has been reported so far from long-legged Charadriiformes(waders), which depend on bipedal locomotion for feeding.Methods: We documented a healed but malaligned tarsometatarsus fracture in a wild Willet(Tringa [Catoptrophorus]semipalmata), and a malaligned tibiotarsus fracture in a Curlew(Numenius arquata) skeleton from a museum collection. Functional consequences of the malalignments were evaluated by kinematic analyses of videos(Willet) and in silico 3D modeling(Curlew).Results: The Willet's left tarsometatarsus exhibited an angular malalignment of 70°, resulting in a limping gait that was less pronounced at high than at low walking speed. The bird seemed unable to club the toes of the left foot together, apparently a secondary effect of the deformity. The Curlew's tibiotarsus showed an angular and an axial malalignment, causing the foot to rotate outwards when the intertarsal joint was flexed. Despite the severe effects of their injuries, the birds had survived at least long enough for the fractures to heal completely.Conclusions: Somewhat unexpectedly, leg fractures are not necessarily fatal in long-legged waders, even if deformities occur in the healing process. Bipedal locomotion on vegetated grounds must have been impeded due to the bone malalignments in both analyzed cases. The birds probably alleviated the impact of their handicaps by shifting a larger proportion of their activities to vegetation-free habitats.