Healthy adults with a Magnetic resonance imaging (MRI) was performed in standing and bending forward to 30, 45 and 60°, with markers on the skin at L1, L3, L5 and S1. Lumbar spine shape was characterised using statistical shape modelling and participants grouped into Purpose and Background:
Methods:
Spinal stability is associated with low back pain and affects the spines ability to support loads. Stability can be achieved if the applied force follows the curvature of the spine, passing close to the vertebral centroids. Previously we showed that calculated muscle forces required for stability in an idealised model increased with increasing and more evenly distributed lumbar curvatures. The purpose of this study was to calculate the muscle forces required for stability in standing in a group of healthy adults. Positional MRI was used to acquire sagittal images of the lumbar spine in a standing posture in 30 healthy adults. Sacral inclination was measured and active shape modelling used to characterise lumbar spine shape. A two-dimensional model of the lumbar spine was constructed using vertebral centroid positions and a simplified representation of the lumbar extensor muscles. The muscle forces required at each level to produce a follower load were calculated using a force polygon.Background and Aim
Methods
Low birth weight is related to decreased lumbar spine vertebral canal size and bone mineral content later in life, suggesting that antenatal factors affect spine development. The purpose of this study was to explore associations between antenatal factors and lumbar spine morphology in childhood. Antenatal data and supine MR images of the lumbar spine were available for 161 children. Shape modelling, using principle components analysis, was performed on mid-sagittal images to quantify different modes of variation in lumbar spine shape. Previously collected measures of spine canal dimensions were analysed.Purpose and Background
Methods
Low back pain is highly prevalent, particularly in manual occupations. We previously showed that the lumbar spine has an intrinsic shape, identifiable in lying, sitting and standing postures, that affects the spine's response to load. Its effects on motion are unknown. Here we investigate whether intrinsic spinal shape is detectable throughout a greater range of postures and its effect on how healthy adults lift a weighted box. The lumbar spine was imaged using a positional MRI with participants (n=30) in 6 postures ranging from extension to full flexion. Active shape modelling was used to identify and quantify ‘modes’ of variation in lumbar spine shape. 3D motion capture analysed participants' motion while lifting a box (6–15 kg, self-selected).Background and Aim
Methods
Spondylolysis (SL) of the lower lumbar spine is frequently associated with spina bifida occulta (SBO). There has not been any study that has demonstrated biomechanical or genetic predispositions to explain the coexistence of these two pathologies. To test the hypothesis that fatigue failure limits will be exceeded in the case of a bifid arch, but not in the intact case, when the segment is subjected to complex loading corresponding to normal sporting activities.Background
Purpose
Lumbar spondylolysis is a fatigue fracture of the pars interarticularis and correlates with Spina Bifida Oculta (SBO) in 67%. Load is normally transferred across the arch in axial rotation. Bifid arch results in increased strain across the isthmus of the loaded inferior articular process.Introduction
Hpothesis
We identified a series of 128 patients who had unilateral open reconstruction of the anterior cruciate ligament (ACL) by a single surgeon between 1993 and 2000. In all, 79 patients were reviewed clinically and radiologically eight to 15 years after surgery. Assessment included measurement of the Lysholm and Tegner scores, the ACL quality-of-life score and the Short Form-12 score, as well as the International Knee Documentation Committee clinical assessment, measurement of laxity by the KT-1000 arthrometer, a single-leg hop test and standardised radiography of both knees using the uninjured knee as a control. Of the injured knees, 46 (57%) had definite radiological evidence of osteoarthritis (Kellgren-Lawrence grade 2 or 3), with a mean difference between the injured and non-injured knees of 1.2 grades. The median ACL quality-of-life score was 80 (interquartile range (IQR) 60 to 90), the Lysholm score 84 (IQR 74 to 95), the Short Form-12 physical component score 54 (IQR 49 to 56) and the mean Hop Index 0.94 (0.52 to 1.52). In total 58 patients were graded as normal, 20 as nearly normal and one as abnormal on the KT-1000 assessment and pivot-shift testing. Taking the worst-case scenario of assuming all non-attenders (n = 48), two septic failures and one identified unstable knee found at review to be failures, the failure rate was 40%. Only two of the patients reviewed stated that they would not have similar surgery again. Open reconstruction of the ACL gives good, durable functional results, but with a high rate of radiologically evident osteoarthritis.
