Orthopaedic Basic Science Journal Scan

Related Articles

OARSI recommended performance-based tests to assess physical function in osteoarthritis of the hip or knee: Authors' reply.

Osteoarthritis Cartilage. 2013 Jul 21;

Authors: Dobson F, Bennell K, Hinman R, Roos E, Abbott H, Stratford P, Davis A, Buchbinder R, Snyder-Mackler L, Hansen P, Thumboo J, Henrotin Y

PMID: 23883594 [PubMed - as supplied by publisher]

Read more... http://www.ncbi.nlm.nih.gov/pubmed/23883594?dopt=Abstract

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Performance-based tests to assess physical function in osteoarthritis of the hip or knee: Comment and proposal.

Osteoarthritis Cartilage. 2013 Jul 21;

Authors: Dekker J

PMID: 23883593 [PubMed - as supplied by publisher]

Read more... http://www.ncbi.nlm.nih.gov/pubmed/23883593?dopt=Abstract

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CXCR4 antagonism attenuates load-induced periosteal bone formation in mice.

J Orthop Res. 2013 Jul 23;

Authors: Leucht P, Temiyasathit S, Russell A, Arguello JF, Jacobs CR, Helms JA, Castillo AB

Abstract

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Geometric mouse variation: Implications to the axial ulnar loading protocol and animal specific calibration.

J Biomech. 2013 Jul 20;

Authors: Wagner DW, Chan S, Castillo AB, Beaupre GS

Abstract

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Linear center-of-mass dynamics emerge from non-linear leg-spring properties in human hopping.

J Biomech. 2013 Jul 20;

Authors: Riese S, Seyfarth A, Grimmer S

Abstract
Given the almost linear relationship between ground-reaction force and leg length, bouncy gaits are commonly described using spring-mass models with constant leg-spring parameters. In biological systems, however, spring-like properties of limbs may change over time. Therefore, it was investigated how much variation of leg-spring parameters is present during vertical human hopping. In order to do so, rest-length and stiffness profiles were estimated from ground-reaction forces and center-of-mass dynamics measured in human hopping. Trials included five hopping frequencies ranging from 1.2 to 3.6Hz. Results show that, even though stiffness and rest length vary during stance, for most frequencies the center-of-mass dynamics still resemble those of a linear spring-mass hopper. Rest-length and stiffness profiles differ for slow and fast hopping. Furthermore, at 1.2Hz two distinct control schemes were observed.

PMID: 23880438 [PubMed - as supplied by publisher]

Read more... http://www.ncbi.nlm.nih.gov/pubmed/23880438?dopt=Abstract

Relationship Between Tibial Acceleration and Proximal Anterior Tibia Shear Force Across Increasing Jump Distance.

J Appl Biomech. 2013 Jul 22;

Authors: Sell TC, Akins JS, Opp AR, Lephart SM

Abstract
Proximal anterior tibia shear force is a direct loading mechanism of the anterior cruciate ligament (ACL) and is a contributor to ACL strain during injury. Measurement of this force during competition may provide insight into risk factors for ACL injury. Accelerometers may be capable of measuring tibial acceleration during competition. The purpose of this study was to examine the relationship between acceleration measured by a tibia-mounted accelerometer and proximal anterior tibia shear force as measured through inverse dynamics and peak posterior ground reaction forces during two leg stop-jump tasks. Nineteen healthy, male subjects performed stop-jump tasks across increasing jump distances. Correlation coefficients were calculated to determine if a relationship exists between accelerometer data and proximal anterior tibia shear force and peak posterior ground reaction force. An analysis of variance was performed to compare these variables across jump distance. Significant correlations were observed between accelerometer data and peak posterior ground reaction force, but none between accelerometer data and proximal anterior tibia shear force. All variables except peak proximal anterior tibia shear force increased significantly as jump distance increased. Overall, results of this study provide initial, positive support for the use of accelerometers as a useful tool for future injury prevention research.

Leg Dominance May Not be a Predictor of Asymmetry in Peak Joint Moments and Ground Reaction Forces During Sit to Stand Movements.

J Appl Biomech. 2013 Jul 22;

Authors: Schofield J, Parent E, Lewicke J, Carey JP, El-Rich M, Adeeb S

Abstract
Sit-to-stand transfer is a common prerequisite for many daily tasks. Literature, often assumes symmetric behavior across the left and right side. Although this assumption of bilateral symmetry is prominent, few studies have validated this supposition. This pilot study uniquely quantifies peak joint moments and ground reaction forces (GRFs), using a Euclidian Norm approach, to evaluate bilateral symmetry and its relation to lower limb motor-dominance during sit to stand in ten (10) healthy males. Peak joint moments and GRFs were determined using a motion capture system, and inverse dynamics. This analysis included joint moment contributions from all three body planes (sagittal, coronal, and axial) as well as vertical and shearing GRFs. A paired, one-tailed t-test was utilized, suggesting asymmetrical joint moment development in all three lower extremity joints as well as ground reaction forces (P<.05). Furthermore, using an unpaired two-tailed t-test, asymmetry developed during these movements does not appear to be predictable by participants' lower limb motor-dominance (P<.025). Consequently, when evaluating sit-to-stand it is suggested the effects of asymmetry be considered in the interpretation of data. The absence of a relationship between dominance and asymmetry prevents the suggestion that one side can be tested to infer behavior of the contralateral.

A Biomechanical Review of the Techniques Used to Estimate or Measure Resistive Forces in Swimming.

J Appl Biomech. 2013 Jul 22;

Authors: Sacilotto G BD, Ball N, Mason BR

Abstract
Resistive or drag forces encountered during free swimming greatly influence the swim performance of elite competitive swimmers. The benefits in understanding the factors which affect the drag encountered will enhance performance within the sport. However, the current techniques used to experimentally measure or estimate drag values are questioned for their consistency, therefore limiting investigations in these factors. This paper aims to further understand how the resistive forces in swimming are measured and calculated. All techniques outlined demonstrate both strengths and weaknesses in the overall assessment of free swimming. By reviewing all techniques in this area the reader should be able to select which one is best depending on what researchers want to gain from the testing.

PMID: 23878267 [PubMed - as supplied by publisher]

Read more... http://www.ncbi.nlm.nih.gov/pubmed/23878267?dopt=Abstract

Comparison of Stance Phase Knee Joint Angles and Moments Using Two Different Surface Marker Representations of the Proximal Shank in Walkers and Runners.

J Appl Biomech. 2013 Jul 22;

Authors: Petit DJ, Willson JD, Barrios JA

Abstract
Efforts to compare different surface marker configurations in 3-dimensional motion analysis are warranted as more complex and custom marker sets become more common. At the knee, different markers can been used to represent the proximal shank. Often, two anatomical markers are placed over the femoral condyles, with their midpoint defining both the distal thigh and proximal shank segment ends. However, two additional markers placed over the tibial plateaus have been used to define the proximal shank end. For this experiment, simultaneous data for both proximal shank configurations were independently collected at two separate laboratories by different investigators, with one lab capturing a walking population and the other a running population. Common discrete knee joint variables were then compared between marker sets in each population. Using the augmented marker set, peak knee flexion after weight acceptance was less (1.2-1.7°, p<0.02) and peak knee adduction was greater (0.7-1.4°, p<0.001) in both data sets. Similarly, the calculated peak knee flexion moment was less by 15-20% and internal rotation moment was greater by 11-18% (p<0.001). These results suggest that the calculation of knee joint mechanics are influenced by the proximal shank's segment endpoint definition, independent of dynamic task, investigator, laboratory environment, and population in this study.