Comparison of total ankle replacement and ankle arthrodesis in patients with haemophilia using gait analysis : two case reports

BACKGROUND: Severe hemophilia is an inherited, lifelong bleeding disorder characterized by spontaneous bleeding, which results in painful joint deformities. Currently two surgical treatments are available to treat haemophilia-related ankle joint destruction: ankle arthrodesis and total ankle replacement. The aim of the present study was to compare these two surgical procedures in haemophiliac subjects. CASE PRESENTATION: Kinematic and dynamic parameters were quantified using a three-dimensional gait-analysis system in two similar clinical cases. In Caucasian case 1, ankle arthrodesis was chosen because of a kinematic ankle flexion defect and lack of dynamic power regeneration. The defect in energy absorption was compensated for by the contralateral side. Total ankle replacement in Caucasian case 2 allowed sparing the ipsilateral knee (maximum 0.27 preoperatively vs. 0.71 W/kg postoperatively) and hip joints powers (maximum 0.43 preoperatively vs. 1.25 W/kg postoperatively) because of the small ankle dorsiflexion motion. CONCLUSIONS: Total ankle replacement is recommended for haemophiliac patients who present with a preserved ankle range of motion

High-Density Electromyography Provides New Insights into the Flexion Relaxation Phenomenon in Individuals with Low Back Pain.

Recent research using high-density electromyography (HDEMG) has provided a more precise understanding of the behaviour of the paraspinal muscles in people with low back pain (LBP); but so far, HDEMG has not been used to investigate the flexion relaxation phenomenon (FRP). To evaluate this, HDEMG signals were detected with grids of electrodes (13 × 5) placed bilaterally over the lumbar paraspinal muscles in individuals with and without LBP as they performed repetitions of full trunk flexion. The root mean square of the HDEMG signals was computed to generate the average normalized amplitude; and the spatial FRP onset was determined and expressed as percentage of trunk flexion. Smoothing spline analysis of variance models and the contrast cycle difference approach using the Bayesian interpretation were used to determine statistical inference. All pain-free controls and 64.3% of the individuals with LBP exhibited the FRP. Individuals with LBP and the FRP exhibited a delay of its onset compared to pain-free controls (significant mean difference of 13.3% of trunk flexion).  They also showed reduced normalized amplitude compared to those without the FRP, but still greater than pain-free controls (significant mean difference of 27.4% and 11.6% respectively). This study provides novel insights into changes in lumbar muscle behavior in individuals with LBP

Extracting residues from stone tools for optical analysis: towards an experiment-based protocol

The identification of residues is traditionally based on the distinctive morphologies of the residue fragments by means of light microscopy. Most residue fragments are amorphous, in the sense that they lack distinguishing shapes or easily visible structures under reflected light microscopy. Amorphous residues can only be identified by using transmitted light microscopy, which requires the extraction of residues from the tool’s surface. Residues are usually extracted with a pipette or an ultrasonic bath in combination with distilled water. However, a number of researchers avoid residue extraction because it is unclear whether current extraction techniques are representative for the use-related residue that adheres to a flaked stone tool. In this paper, we aim at resolving these methodological uncertainties by critically evaluating current extraction methodologies. Attention is focused on the variation in residue types, their causes of deposition and their adhesion and on the most successful technique for extracting a range of residue types from the stone tool surface. Based on an experimental reference sample in flint, we argue that a stepwise extraction protocol is most successful in providing rep- resentative residue extractions and in preventing damage, destruction or loss of residue.Evohaf