Basic Science

Latest journal articles on bone and joint basic science research from Osteoarthritis and Cartilage, Journal of Orthopaedic Research, Journal of Biomechanics, Connective Tissue Research, Journal of Applied Biomechanics, The Bone & Joint Journal, Journal of Bone and Joint Surgery, Clinical Orthopaedics and Related Research, Acta Orthopaedica, Orthopedic Clinics of North, America, Journal of Orthopaedic Surgery and Research, Orthopedics

Related Articles Changes in the Preferred Transition Speed With Added Mass to the Foot. J Appl Biomech. 2013 Jul 22; Authors: Macleod TD, Hreljac A, Imamura R Abstract This study was conducted to investigate whether adding mass to subjects' feet affects the preferred transition speed (PTS), and to ascertain whether selected swing phase variables (maximum ankle dorsiflexion angular velocity, angular acceleration, joint moment, and joint power) are determinants of the PTS, based upon four previously established criteria. After the PTS of 24 healthy active male subjects was found, using an incremental protocol in loaded (two kg mass added to each shoe) and unloaded (shoes only) conditions, subjects walked at three speeds (60%, 80%, and 100% of PTS) and ran at one speed (100% of PTS) on a motor driven treadmill while relevant data were collected. The PTS of the unloaded condition (2.03 ± 0.12 m·s-1) was significantly greater (p < 0.05) than the PTS of the loaded condition (1.94 ± 0.13 m·s-1). Within both load conditions, all dependent variables increased significantly with walking speed, decreased significantly when gait changed to a run, and were assumed to provide the necessary input to signal a gait transition, fulfilling the requirements of the first three criteria, but only ankle angular velocity reached a critical level prior to the transition, satisfying all four criteria to be considered a determinant of the PTS. PMID: 23878265 [PubMed - as supplied by publisher]Read more... http://www.ncbi.nlm.nih.gov/pubmed/23878265?dopt=Abstract

Related Articles The Effects of Walking Speed on Tibiofemoral Loading Estimated Via Musculoskeletal Modeling. J Appl Biomech. 2013 Jul 22; Authors: Lerner ZF, Haight DJ, Demers MS, Board WJ, Browning RC Abstract Net muscle moments (NMMs) have been used as proxy measures of joint loading, but musculoskeletal models can estimate contact forces within joints. The purpose of this study was to use a musculoskeletal model to estimate tibiofemoral forces and to examine the relationship between NMMs and tibiofemoral forces across walking speeds. We collected kinematic, kinetic, and electromyographic data as ten adult participants walked on a dual-belt force-measuring treadmill at 0.75, 1.25, and 1.50 m·s-1. We scaled a musculoskeletal model to each participant and used OpenSim to calculate the NMMs and muscle forces through inverse dynamics and weighted static optimization, respectively. We determined tibiofemoral forces from the vector sum of intersegmental and muscle forces crossing the knee. Estimated tibiofemoral forces increased with walking speed. Peak early-stance compressive tibiofemoral forces increased 52% as walking speed increased from 0.75 to 1.50 m·s-1, while peak knee extension NMMs increased by 168%. During late stance, peak compressive tibiofemoral forces increased by 18% as speed increased. While compressive loads at the knee did not increase in direct proportion to NMMs, faster walking resulted in greater compressive forces during weight acceptance and increased compressive and anterior/posterior tibiofemoral loading rates in addition to a greater abduction NMM. PMID: 23878264 [PubMed - as supplied by publisher]Read more... http://www.ncbi.nlm.nih.gov/pubmed/23878264?dopt=Abstract

Related Articles Do Qualitative Changes in Inter-limb Coordination Lead to Effectiveness of Aquatic Locomotion Rather than Efficiency? J Appl Biomech. 2013 Jul 22; Authors: Komar J, Sanders RH, Chollet D, Seifert L Abstract This study compared inter-limb coordination and indicators of swim efficiency and effectiveness between expert and recreational breaststroke swimmers. Arm-leg coordination of 8 expert and 10 recreational swimmers at two different paces, slow and sprint, were compared using relative phase between elbow and knee. For each participant, knee and elbow angles were assessed using a 3-D video analysis system with four below and two above cameras. During each phase of the cycle, indicators of swim efficiency (intra-cyclic velocity variations) and effectiveness (horizontal distance, velocity peaks, acceleration peaks) were calculated. Two coordination patterns emerged between expert and recreational swimmers, with significant differences in the relative phase at the beginning of a cycle (-172.4° for experts and -106.6° for recreational swimmers) and the maximum value of relative phase (9.1° for experts and 45.9° for recreational swimmers) (all P<.05). Experts' coordination was associated with higher swim effectiveness (higher acceleration peak: 2.4m.s-2 for experts and 1.6m.s-2 for recreational swimmers) and higher distance covered by the center of mass during each phase of the cycle (all P<.05). This study emphasized how experts coordinate arms and legs to achieve effective behaviour, therefore exhibiting flexibility, mainly in the timing of the glide phase, to adapt to different speed.

Read more ...

Related Articles Kinetics of Badminton Lunges in Four Directions. J Appl Biomech. 2013 Jul 22; Authors: Hong Y, Wang SJ, Lam WK, Cheung JT Abstract The lunge is the most fundamental skill in badminton competitions. Fifteen university-level male badminton players performed lunge maneuvers in four directions, namely, right-forward, left-forward, right-backward, and left-backward, while wearing two different brands of badminton shoes. The test compared the kinetics of badminton shoes in performing typical lunge maneuvers. A force plate and an insole measurement system measured the ground reaction forces and plantar pressures. These measurements were compared across all lunge maneuvers. The left-forward lunge generated significantly higher first vertical impact force (2.34 ± 0.52 BW) than that of the right-backward (2.06 ± 0.60 BW) and left-backward lunges (1.78 ± 0.44 BW); higher second vertical impact force (2.44 ± 0.51 BW) than that of the left-backward lunge (2.07 ± 0.38 BW); and higher maximum anterior-posterior shear force (1.48 ± 0.36 BW) than that of the left-backward lunge (1.18 ± 0.38 BW). Compared with other lunge directions, the left-forward lunge showed higher mean maximum vertical impact anterior-posterior shear forces and their respective maximum loading rates, and the plantar pressure at the total foot and heel regions. Therefore, the left-forward lunge is a critical maneuver for badminton biomechanics and related footwear research because of the high loading magnitude generated during heel impact. PMID: 23878207 [PubMed - as supplied by publisher]Read more... http://www.ncbi.nlm.nih.gov/pubmed/23878207?dopt=Abstract

Related Articles Frontal Plane Knee and Hip Kinematics During Sit-to-Stand and Proximal Lower Extremity Strength in Persons with Patellofemoral Osteoarthritis: A Pilot Study. J Appl Biomech. 2013 Jul 22; Authors: Hoglund LT, Hillstrom HJ, Barr-Gillespie AE, Lockard MA, Barbe MF, Song J Abstract

Read more ...

Related Articles A Kinetic and Kinematic Analysis of the Effect of Stochastic Resonance Electrical Stimulation and Knee Sleeve During Gait in Osteoarthritis of the Knee. J Appl Biomech. 2013 Jul 22; Authors: Collins A, Blackburn T, Olcott C, Jordan JM, Yu B, Weinhold P Abstract

Read more ...

Related Articles Intrarater Test-Retest Reliability of Static and Dynamic Stability Indexes Measurement Using the Biodex® Balance System During Unilateral Stance. J Appl Biomech. 2013 Jul 20; Authors: Arifin N, Abu Osman NA, Wan Abas WA Abstract The measurements of postural balance often involve measurement error which affects the analysis and interpretation of the outcomes. In most of the existing clinical rehabilitation research, the ability to produce reliable measures is a prerequisite for an accurate assessment of an intervention after a period of time. Although clinical balance assessment has been performed in previous study, none has determined the intrarater test-retest reliability of static and dynamic stability indexes during dominant single stance. In this study, one rater examined twenty healthy university students (Female= 12, Male= 8) in two sessions separated by seven days intervals. Three stability indexes which are Overall stability index (OSI), anterior/ posterior stability index (APSI), and medial/ lateral stability index (MLSI) in static and dynamic conditions were measured during single dominant stance. Intraclass correlation coefficient (ICC), standard error measurement (SEM) and 95% confidence interval (95% CI) were calculated. Test-retest ICC for OSI, APSI, and MLSI were 0.85, 0.78, and 0.84 during static condition while 0.77, 0.77, and 0.65 during dynamic condition, respectively. We concluded that the postural stability assessment using Biodex balance system (BSS) demonstrates 'good to excellent' test-retest reliability over a one-week time interval. PMID: 23878204 [PubMed - as supplied by publisher]Read more... http://www.ncbi.nlm.nih.gov/pubmed/23878204?dopt=Abstract

Related Articles Connexin 43 is a potential regulator in fluid shear stress-induced signal transduction in osteocytes. J Orthop Res. 2013 Jul 22; Authors: Li X, Liu C, Li P, Li S, Zhao Z, Chen Y, Huo B, Zhang D Abstract

Read more ...

Related Articles Implant-associated localized osteitis in murine femur fracture by biofilm forming Staphylococcus aureus: A novel experimental model. J Orthop Res. 2013 Jul 22; Authors: Windolf CD, Meng W, Lögters TT, Mackenzie CR, Windolf J, Flohé S Abstract

Read more ...

Related Articles Hyperbaric oxygen therapy suppresses osteoclast formation and bone resorption. J Orthop Res. 2013 Jul 22; Authors: Hadi HA, Smerdon GR, Fox SW Abstract The cellular and molecular mechanism through which hyperbaric oxygen therapy (HBO) improves osteonecrosis (ON) is unclear. The present study therefore examined the effect of HBO, pressure and hyperoxia on RANKL-induced osteoclast formation in RAW 264.7 cells and human peripheral blood monocytes (PBMC). Daily exposure to HBO (2.4 ATA, 97% O2 , 90 min), hyperbaric pressure (2.4 ATA, 8.8% O2 , 90 min) or normobaric hyperoxia (1 ATA, 95% O2 , 90 min) significantly decreased RANKL-induced osteoclast formation and bone resorption in normoxic conditions. HBO had a more pronounced anti-osteoclastic effect than hyperoxia or pressure alone and also directly inhibited osteoclast formation and resorption in hypoxic conditions a hallmark of many osteolytic skeletal disorders. The suppressive action of HBO was at least in part mediated through a reduction in RANK, NFATc1, and Dc-STAMP expression and inhibition of hypoxia-induced HIF-1α mRNA and protein expression. This data provides mechanistic evidence supporting the use of HBO as an adjunctive therapy to prevent osteoclast formation and bone loss associated with low oxygen partial pressure. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. PMID: 23878004 [PubMed - as supplied by publisher]Read more... http://www.ncbi.nlm.nih.gov/pubmed/23878004?dopt=Abstract