The effect of femoral offset modification on gait after total hip arthroplasty

Background and purpose

A decrease of 15% in femoral offset (FO) has been reported to generate a weakness of the abductor muscle, but this has not been directly linked to an alteration of gait. Our hypothesis was that this 15% decrease in FO may also generate a clinically detectable alteration in the gait.

Patients and methods

We performed a prospective comparative study on 28 patients who underwent total hip arthroplasty (THA) for unilateral primary osteoarthritis. The 3D hip anatomy was analyzed preoperatively and postoperatively. 3 groups were defined according to the alteration in FO following surgery: a minimum decrease of 15% (9 patients), restored (14), and a minimum increase of 15% (5). A gait analysis was performed at 1-year follow-up using an ambulatory device. Each limb was compared to the contralateral healthy limb.

Results

In contrast to the “restored” group and the “increased” group, in the “decreased” group there was a statistically significant asymmetry between sides, with reduced range of motion and a lower maximal swing speed on the operated side.

Interpretation

A decrease in FO of 15% or more after THA leads to an alteration in the gait. We recommend 3-D preoperative planning because the FO may be underestimated by up to 20% on radiographs and it may therefore not be restored, with clinical consequences.The femoral offset (FO) and limb length have to be restored during total hip arthroplasty (THA) in order to improve the functional outcomes and to reduce the risk of limping, dislocation (McGrory et al. 1995, Downing et al. 2001, Bourne and Rorabeck 2002, Asayama et al. 2005, Kiyama et al. 2010), and edge loading (Sariali et al. 2010). The restoration of the FO also appears to be crucial to improve the long-term survival rates of THA. Sakalkale et al. (2001) reported that restoration of the FO reduces the wear in THA.With respect to the functional outcomes of THA, a decrease of 15% in FO has been reported to generate weakness of the abductor muscle (Asayama et al. 2005), but this has not been directly linked to an alteration of gait. Indeed, this threshold was defined under laboratory conditions using a CYBEX machine, which does not correspond to realistic activities of daily living. Our hypothesis was that a 15% decrease in the FO may also generate a clinically detectable alteration of gait.Many devices are available for analysis of gait, but most of them are constraining and cannot be used without laboratory conditions (Lamontagne et al. 2011). Some authors have proposed the use of devices for ambulatory gait analysis that can be used for long distances and under realistic daily living conditions (Aminian et al. 2004). For example, the Physilog device (Aminian et al. 2004) has been validated as an evaluation tool for the clinical assessment of patients before and after THA.We analyzed the consequences of an alteration in FO after THA for gait under realistic walking conditions.     

Limited plastic potential of the left ventral premotor cortex in speech articulation: Evidence From intraoperative awake mapping in glioma patients

Objectives: Despite previous lesional and functional neuroimaging studies, the actual role of the left ventral premotor cortex (vPMC), i.e., the lateral part of the precentral gyrus, is still poorly known. Experimental design:We report a series of eight patients with a glioma involving the left vPMC, who underwent awake surgery with intraoperative cortical and subcortical language mapping. The function of the vPMC, its subcortical connections, and its reorganization potential are investigated in the light of surgical findings and language outcome after resection. Principal observations: Electrostimulation of both the vPMC and subcortical white matter tract underneath the vPMC, that is, the anterior segment of the lateral part of the superior longitudinal fascicle (SLF), induced speech production disturbances with anarthria in all cases. Moreover, although some degrees of redistribution of the vPMC have been found in four patients, allowing its partial resection with no permanent speech disorders, this area was nonetheless still detected more medially in the precentral gyrus in the eight patients, despite its invasion by the glioma. Moreover, a direct connection of the vPMC with the SLF was preserved in all cases. Conclusions: Our original data suggest that the vPMC plays a crucial role in the speech production network and that its plastic potential is limited. We propose that this limitation is due to an anatomical constraint, namely the necessity for the left vPMC to remain connected to the lateral SLF. Beyond fundamental implications, such knowledge may have clinical applications, especially in surgery for tumors involving this cortico‐subcortical circuit. Hum Brain Mapp 35:1587–1596, 2014. © 2013 Wiley Periodicals, Inc.     

The effect of delivering the chemokine SDF-1α in a matrix-bound manner on myogenesis

Several chemokines are important in muscle myogenesis and in the recruitment of muscle precursors during muscle regeneration. Among these, the SDF-1α chemokine (CXCL12) is a potent chemoattractant known to be involved in muscle repair. SDF-1α was loaded in polyelectrolyte multilayer films made of poly(l-lysine) and hyaluronan to be delivered locally to myoblast cells in a matrix-bound manner. The adsorbed amounts of SDF-1α were tuned over a large range from 100 ng/cm² to 5 μg/cm², depending on the initial concentration of SDF-1α in solution, its pH, and on the film crosslinking extent. Matrix-bound SDF-1α induced a striking increase in myoblast spreading, which was revealed when it was delivered from weakly crosslinked films. It also significantly enhanced cell migration in a dose-dependent manner, which again depended on its presentation by the biopolymeric film. The low-crosslinked film was the most efficient in boosting cell migration. Furthermore, matrix-bound SDF-1α also increased the expression of myogenic markers but the fusion index decreased in a dose-dependent manner with the adsorbed amount of SDF-1α. At high adsorbed amounts of SDF-1α, a large number of Troponin T-positive cells had only one nucleus. Overall, this work reveals the importance of the presentation mode of SDF-1α to emphasize its effect on myogenic processes. These films may be further used to provide insight into the role of SDF-1α presented by a biomaterial in physiological or pathological processes.     

Plasma chemistry reference values in the gyr falcon (Falco rusticolus)

Blood samples were collected from 102 clinically healthy gyr falcons (Falco rusticolus) over a time period of approximately 3 years as part of routine examination procedures. Standard blood chemistry analyses were carried out to establish normal reference values for the species. Plasma chemistry analyses included alkaline phosphatase (ALP), amylase, blood urea nitrogen, bile acids, calcium, cholesterol, creatinine, creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), glucose, phosphate, iron, total protein, total bilirubin, and uric acid. Reference intervals were determined using a quantile approach with 90 % confidence intervals of the limits. Juveniles and adults differ in ALT, creatinine, AST, glucose, LDH, and uric acid. Sexes differ in ALP, CK, AST, and phosphorus. This study provides valuable information on the plasma biochemistry values for gyr falcons that may help in the medical management of this endangered and commonly used falconry species.     

Rare bioparticle detection via deep metric learning

Recent deep neural networks have shown superb performance in analyzing bioimages for disease diagnosis and bioparticle classification. Conventional deep neural networks use simple classifiers such as SoftMax to obtain highly accurate results. However, they have limitations in many practical applications that require both low false alarm rate and high recovery rate, e.g., rare bioparticle detection, in which the representative image data is hard to collect, the training data is imbalanced, and the input images in inference time could be different from the training images. Deep metric learning offers a better generatability by using distance information to model the similarity of the images and learning function maps from image pixels to a latent space, playing a vital role in rare object detection. In this paper, we propose a robust model based on a deep metric neural network for rare bioparticle (Cryptosporidium or Giardia) detection in drinking water. Experimental results showed that the deep metric neural network achieved a high accuracy of 99.86% in classification, 98.89% in precision rate, 99.16% in recall rate and zero false alarm rate. The reported model empowers imaging flow cytometry with capabilities of biomedical diagnosis, environmental monitoring, and other biosensing applications.

Conventional deep neural networks use simple classifiers to obtain highly accurate results. However, they have limitations in practical applications. This study demonstrates a robust deep metric neural network model for rare bioparticle detection.     

Severe infantile isolated exocrine pancreatic insufficiency caused by the complete functional loss of the SPINK1 gene

Exocrine pancreatic insufficiency (EPI) is rare in children, with most if not all cases occurring as part of syndromic conditions such as cystic fibrosis and Shwachman–Diamond syndrome. Here we report two cases, both presenting with severe EPI around 5 months of age. Characterized by diffuse pancreatic lipomatosis, they otherwise exhibited no remarkable deficiencies in other organs. Novel non‐identical homozygous variants (a deletion removing the entire SPINK1 gene and an insertion of a full‐length inverted Alu element into the 3′‐untranslated region of the SPINK1 gene) resulting in the complete functional loss of the SPINK1 gene (encoding pancreatic secretory trypsin inhibitor) were identified in each patient. Having correlated our findings with current knowledge of SPINK1's role in exocrine pancreas pathophysiology, we propose that complete and partial functional losses of the SPINK1 gene are associated with quite distinct phenotypes, the former causing a new pediatric disease entity of severe infantile isolated EPI.     

Ammonium accumulation and chemokine decrease in culture media of Gcdh−/− 3D reaggregated brain cell cultures

Glutaric Aciduria type I (GA-I) is caused by mutations in the GCDH gene. Its deficiency results in accumulation of the key metabolites glutaric acid (GA) and 3-hydroxyglutaric acid (3-OHGA) in body tissues and fluids. Present knowledge on the neuropathogenesis of GA-I suggests that GA and 3-OHGA have toxic properties on the developing brain.We analyzed morphological and biochemical features of 3D brain cell aggregates issued from Gcdh^?/? mice at two different developmental stages, day-in-vitro (DIV) 8 and 14, corresponding to the neonatal period and early childhood. We also induced a metabolic stress by exposing the aggregates to 10 mM l-lysine (Lys).Significant amounts of GA and 3-OHGA were detected in Gcdh^?/? aggregates and their culture media. Ammonium was significantly increased in culture media of Gcdh^?/? aggregates at the early developmental stage. Concentrations of GA, 3-OHGA and ammonium increased significantly after exposure to Lys. Gcdh^?/? aggregates manifested morphological alterations of all brain cell types at DIV 8 while at DIV 14 they were only visible after exposure to Lys. Several chemokine levels were significantly decreased in culture media of Gcdh^?/? aggregates at DIV 14 and after exposure to Lys at DIV 8.This new in vitro model for brain damage in GA-I mimics well in vivo conditions. As seen previously in WT aggregates exposed to 3-OHGA, we confirmed a significant ammonium production by immature Gcdh^?/? brain cells. We described for the first time a decrease of chemokines in Gcdh^?/? culture media which might contribute to brain cell injury in GA-I.