Gait, function and quadriceps strength after intraarticular hyaluronan injections in patients with symptomatic knee osteoarthritis

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenIntroduction: Knee OA is a common cause of decline in function and is generally associated with joint malalignment and laxity, joint space narrowing, quadriceps weakness, as well as sclerosis and attrition of subchondral bone. Intraarticular (IA) injections of Hyaluronic Acid (HA) are indicated to palliate symptoms and improve function in patients with knee OA. Primary outcome measures in studies on the efficacy of this treatment are largely self reports of pain and function. The purpose of the study was to investigate the effects of HA injections on knee function and sagittal plane kinematics in patients with knee OA. Materials and Methods: Thirteen subjects with symptomatic knee OA and scheduled for 5, weekly, IA injections of HA were recruited. Each subject was tested for baseline data. Posttreatment testing sessions were conducted within 3 weeks of finishing the series of HA and again five months after treatment. Kinematic data were collected at 120 Hz using an eight camera motion analysis system (VICON, Oxford Metrics). Subjects walked along a 10 m walkway at self-selected pace. Ten walking trials were collected and averaged. Knee function was assessed with a knee specific questionnaire (Knee Outcome Survey (KOS)), goniometric range of motion (ROM) measures, a six minute walk (6MW) and a timed stair climbing task. Quadriceps strength was evaluated isometrically at 90° with a KinCom dynamometer (Chattanooga Group, Inc., Chattanooga, TN) and expressed as a ratio of the force output of the involved vs. uninvolved side (Quadriceps Index (QI)). Repeated measures analysis of variance (ANOVA) with pairwise comparisons, multivariate analysis, linear regression analysis and paired t-tests were used to analyze the data. Alpha was set at 0.05. Results: Multivariate analysis of knee flexion angles was used at two stages of weight acceptance; initial contact (IC) and peak knee flexion (PKF) between involved (INV) and uninvolved (UNINV) knees across the three testing times. The analysis showed an interaction between stage of weight acceptance and side (F=18.716; p=0.001). There were significant interlimb differences in knee excursion during weight acceptance (flexion angle from IC to PKF) for the first (5.3°; p=0.005), second (5.2°; p=0.001) and third (5.2°; p=0.001) testing times; the affected knee demonstrating less movement. Excursions of the INV and the UNINV knees did not change across testing times. Multivariate analysis of goniometric total knee ROM between the INV and UNINV knee across testing times showed an interaction by side (F=29.996; p<0.001) but not for testing time. The INV knee’s ROM was on average 8° less than that of the UNINV at the first testing session (p=0.003), 5.2° less at the second (p<0.001) and 7.2° less at the third testing session (p=0.001). Knee ROM of either knee did not change across testing times. Larger knee flexion ROM at baseline predicted greater improvement on KOS scores on the first post-treatment testing session (r2=.540; p=0.004). Larger knee flexion ROM at the first post-treatment predicted greater improvements on KOS scores at the later testing session (r2=.398; p=0.021). Significant within-subjects effects of testing times on KOS scores were found(F=4.65; p=0.02),on 6MW distance (F=12.010; p<0.001) and QI (F=5.903; p=0.013). Discussion: Subjects demonstrated significantly improved function after a series of intra-articular hyaluronan injections as evaluated with the KOS and functional testing. Kinematic interlimb differences were unchanged across testing times despite these improvements. Goniometric measures of total knee range of motion confirmed interlimb differences in available joint ROM. Although subjects demonstrated ample functional ROM, this was not utilized during weight acceptance. The truncated knee flexion may impede the shock absorbing mechanism of the knee and impact the progression of knee OA. While improvements in self reported scores were not maintained at the 5 month evaluation, walking distance continued to improve over time. This indicates that functional improvements persisted despite concurrently increasing symptoms

Image of the Energy Gap Anisotropy in the Vibrational Spectum of a High Temperature Superconductor

We present a new method of determining the anisotropy of the gap function in layered high-Tc superconductors. Careful inelastic neutron scattering measurements at low temperature of the phonon dispersion curves in the (100) direction in La_(1.85)Sr_(.15)CuO_4 would determine whether the gap is predominately s-wave or d-wave. We also propose an experiment to determine the gap at each point on a quasi-two-dimensional Fermi surface.Comment: 12 pages + 2 figures (included

Specificity of muscle action after anterior cruciate ligament injury

Abstract Neuromuscular control is believed to be a critical factor in dynamic knee stability. The purpose of this study was to evaluate voluntary muscle control in anterior cruciate ligament deficient (ACL-D) and uninjured people. Twenty athletes of similar age participated in this study. Subjects performed a target-matching protocol that required them to produce isometric moments about the knee with fine control in flexion, extension, varus, and valgus (i.e., loads were generated in the plane perpendicular to the long axis of the shank). Electromyographic data were collected from 10 muscles that span the knee. A specificity index was calculated for each muscle to describe how fine-tuned (specific) its muscle activity pattern was with respect to its principal direction of action in the load plane. Diminished specificity of muscle action was observed in 8 of 10 muscles in the ACL-D subjectsÕ involved knees when compared with the activity patterns from their uninvolved knees and those from the uninjured subjectsÕ knees. The vastus lateralis muscle was especially affected. Increased and more global co-contraction was also observed in the ACL-D limbs. The alterations in muscle firing patterns observed in this study are consistent with diminished neuromuscular control

Magnetism and Structural Distortion in the La0.7Sr0.3MnO3 Metallic Ferromagnet

Neutron scattering studies on a single crystal of the highly-correlated electron system, La1-xSrxMnO3 with x~0.3, have been carried out elucidating both the spin and lattice dynamics of this metallic ferromagnet. We report a large measured value of the spin wave stiffness constant, which directly shows that the electron transfer energy of the d band is large. The spin dynamics, including magnetic critical scattering, demonstrate that this material behaves similar to other typical metallic ferromagnets such as Fe or Ni. The crystal structure is rhombohedral, as previously reported, for all temperatures studied (below ~425K). We have observed new superlattice peaks which show that the primary rhombohedral lattice distortion arises from oxygen octahedra rotations resulting in an R-3c structure. The superlattice reflection intensities which are very sensitive to structural changes are independent of temperature demonstrating that there is no primary lattice distortion anomaly at the magnetic transition temperature, Tc = 378.1 K, however there is a lattice contraction.Comment: Submitted to Phys. Rev. B. (03Aug95) Uuencoded gz-compressed .tar file of Postscript text (12 pages) and 6 figures. Also available by WWW from http://insti.physics.sunysb.edu/~mmartin/ under my list of publications or by e-mail reques

Clinical predictors of elective total joint replacement in persons with end-stage knee osteoarthritis

Abstract Background Arthritis is a leading cause of disability in the United States. Total knee arthroplasty (TKA) has become the gold standard to manage the pain and disability associated with knee osteoarthritis (OA). Although more than 400 000 primary TKA surgeries are performed each year in the United States, not all individuals with knee OA elect to undergo the procedure. No clear consensus exists on criteria to determine who should undergo TKA. The purpose of this study was to determine which clinical factors will predict the decision to undergo TKA in individuals with end-stage knee OA. Knowledge of these factors will aid in clinical decision making for the timing of TKA. Methods Functional data from one hundred twenty persons with end-stage knee OA were obtained through a database. All of the individuals complained of knee pain during daily activities and had radiographic evidence of OA. Functional and clinical tests, collectively referred to as the Delaware Osteoarthritis Profile, were completed by a physical therapist. This profile consisted of measuring height, weight, quadriceps strength and active knee range of motion, while functional mobility was assessed using the Timed Up and Go (TUG) test and the Stair Climbing Task (SCT). Self-perceived functional ability was measured using the activities of daily living subscale of the Knee Outcome Survey (KOS-ADLS). A logistic regression model was used to identify variables predictive of TKA use. Results Forty subjects (33%) underwent TKA within two years of evaluation. These subjects were significantly older and had significantly slower TUG and SCT times (p 2 = 0.403). Conclusions Younger patients with full knee ROM who have a higher self-perception of function are less likely to undergo TKA. Physicians and clinicians should be aware that potentially modifiable factors, such as knee ROM can be addressed to potentially postpone the need for TKA.</p

Biogenesis of a novel compartment for autophagosome-mediated unconventional protein secretion

A novel membrane structure called CUPS is assembled during the secretion of unconventional cargo such as Acb1