Search

STUDY DESIGN.: Cadaveric biomechanical study. OBJECTIVE.: To quantify spinal motion created by transfer methods from supine to prone position in a cadaveric C1-C2 global instability model. SUMMARY OF BACKGROUND DATA.: Patients who have sustained a spinal cord injury remain at high risk for further secondary injury until their spine is adequately stabilized. To date, no study has evaluated the effect of patient transfer methods from supine to prone position in the operating room, on atlantoaxial cervical spine motion. METHODS.: A global instability was surgically created at the C1-C2 level in 4 fresh cadavers. Two transfer protocols were tested on each cadaver. The log-roll technique entailed performing a standard 180 degrees log-roll rotation of the supine patient from a stretcher to the prone position onto the operating room Jackson table (OSI, Union City, CA). The 'Jackson technique' involved sliding the supine patient to the Jackson table, securing them to the table, and then rotating them into a prone position. An electromagnetic tracking device registered motion between the C1 and C2 vertebral segments. Three different head holding devices (Mayfield, Prone view, and blue foam pillow) were also compared for their ability to restrict C1-C2 motion. Six motion parameters were tracked. Repeated measures statistical analysis was performed to evaluate angular and translational motion. RESULTS.: For 6 of 6 measures of angulation and translation, manual log-roll prone positioning generated significantly more C1-C2 motion than the Jackson table turning technique. Out of 6 motion parameters, 5 were statistically significant (P < 0.001-0.005). There was minimal difference in C1-C2 motion generated when comparing all 3 head holding devices. CONCLUSION.: The data demonstrate that manual log-roll technique generated significantly more C1-C2 motion compared to the Jackson table technique. Choice of headrest has a minimal effect on the amount of motion generated during patient transfer, except that the Mayfield device demonstrates a slight trend toward increased C1-C2 motion. [ABSTRACT FROM AUTHOR]

Background: Patients who have sustained a spinal cord injury remain at risk for further neurologic deterioration until the spine is adequately stabilized. To our knowledge, no study has previously addressed the effects of different bed-to-operating room table transfer techniques on thoracolumbar spinal motion in an instability model. We hypothesized that the conventional logroll technique used to transfer patients from a supine position to a prone position on the operating room table has the potential to confer significantly more motion to the unstable thoracolumbar spine than the Jackson technique.Methods: Three-column instability was surgically created at the L1 level in seven cadavers. Two protocols were tested. The manual technique entailed performing a standard logroll of a supine cadaver to a prone position on an operating room Jackson table. The Jackson technique involved sliding the supine cadaver to the Jackson table, securing it to the table, and then rotating it into a prone position. An electromagnetic tracking device measured motion--i.e., angular motion (flexion-extension, lateral bending, and axial rotation) and linear translation (axial, medial-lateral, and anterior-posterior) between T12 and L2.Results: The logroll technique created significantly more motion than the Jackson technique as measured with all six parameters. Manual logroll transfers produced an average of 13.8 degrees to 18.1 degrees of maximum angular displacement and 16.6 to 28.3 mm of maximum linear translation. The Jackson technique resulted in an average of 3.1 degrees to 5.8 degrees of maximum angular displacement (p < 0.001) and 4.0 to 10.0 mm of maximum linear translation (p < 0.05).Conclusions: Compared with the logroll, the Jackson-table transfer method provides superior immobilization of an unstable thoracolumbar spine during transfer of supine cadavers to a prone position on the operating room table.Clinical Relevance: This study addresses in-hospital patient safety. Performing the Jackson turn requires approximately half as many people as required for a manual logroll. This study suggests that the Jackson technique should be considered for supine-to-prone transfer of patients with known or suspected instability of the thoracolumbar spine. [ABSTRACT FROM AUTHOR]

STUDY DESIGN: Nonexperimental. OBJECTIVES: To determine interrater and intrarater agreement for 2 methods of evaluating movement quality during 2 lower extremity functional tasks, and to descriptively compare levels of agreement between the 2 methods. BACKGROUND: Clinicians typically use observational analysis to evaluate movement quality during functional tasks, but the extent of agreement is unknown. METHODS AND MEASURES: Twenty-five uninjured subjects performed 3 trials of unilateral squat and lateral step-down tasks. Three clinicians evaluated the trunk, pelvis, and hips for coronal plane and transverse plane movement deviations. Two rating methods were used: assessment of the entire movement ('overall method') and rating each segment individually ('specific method'). Movement deviation severity was rated using basic clinical guidelines and ratings were repeated from videotape. Percent agreement and weighted kappa coefficients were calculated between rater pairs and rating sessions. Generalized kappa coefficients were calculated across raters. RESULTS: Interrater and intrarater percent agreement were higher using the overall method. Interrater weighted kappa coefficients were similar between rating methods (overall method, 0-0.55; specific method, 0.23-0.53). Intrarater weighted kappa coefficients were higher for the specific method (0.38-0.68) compared to the overall method (0.13-0.50). Generalized kappa coefficients were also higher for specific method compared to the overall method (unilateral squat, 0.19 and 0.01, respectively; lateral step-down, 0.22 and 0.18, respectively) and 95% confidence intervals remained above zero. CONCLUSIONS: Rating movement at body segments appears to result in agreement among raters that is better than chance. Neither rating method produced high agreement, indicating a need to develop more explicit criteria for rating movement deviation severity. [ABSTRACT FROM AUTHOR]

Context: To achieve full spinal immobilization during on-the-field management of an actual or potential spinal injury, rescuers transfer and secure patients to a long spine board. Several techniques can be used to facilitate this patient transfer. Objective: To compare spinal segment motion of cadavers during the execution of the 6-plus-person (6+) lift, iift-and-slide (LS), and logroll (LR) spine-board transfer techniques. Design: Crossover study. Setting: Laboratory. Patients or Other Participants: Eight medical professionals (1 woman, 7 men) with 5 to 32 years of experience were enlisted to help carry out the transfer techniques. In addition, test conditions were performed on 5 fresh cadavers (3 males, 2 females) with a mean age of 86.2 ± 11.4 years. Main Outcomes Measure(s): Three-dimensional angular and linear motions initially were recorded during execution of transfer techniques, initially using cadavers with intact spines and then after C5-C6 spinal segment destabilization. The mean maximal linear displacement and angular motion obtained and calculated from the 3 trials for each test condition were included in the statistical analysis. Results: Flexion-extension angular motion, as well as anteroposterior and distraction-compression linear motion, did not vary between the LR and either the 6+ lift or LS. Compared with the execution of the 6+ lift and LS, the execution of the LR generated significantly more axial rotation (P = .008 and .001, respectively), more lateral flexion (P = .005 and .003, respectively), and more medial-lateral translation (P = .003 and .004, respectively). Conclusions: A small amount of spinal motion is inevitable when executing spine-board transfer techniques; however, the execution of the 6+ lift or LS appears to minimize the extent of motion generated across a globally unstable spinal segment. [ABSTRACT FROM AUTHOR]

The Wilderness Medical Society convened an expert panel in 2018 to develop a set of evidence-based guidelines for the treatment of type 1 and 2 diabetes, as well as the recognition, prevention, and treatment of complications of diabetes in wilderness athletes. We present a review of the classifications, pathophysiology, and evidence-based guidelines for planning and preventive measures, as well as best practice recommendations for both routine and urgent therapeutic management of diabetes and glycemic complications. These recommendations are graded based on the quality of supporting evidence and balance between the benefits and risks or burdens for each recommendation., (Copyright © 2019 Wilderness Medical Society. All rights reserved.)

Objective: Prehospital personnel who lack advanced airway management training must rely on basic techniques when transporting unconscious trauma patients. The supine position is associated with a loss of airway patency when compared to lateral recumbent positions. Thus, an inherent conflict exists between securing an open airway using the recovery position and maintaining spinal immobilization in the supine position. The lateral trauma position is a novel technique that aims to combine airway management with spinal precautions. The objective of this study was to compare the spinal motion allowed by the novel lateral trauma position and the well-established log-roll maneuver., Methods: Using a full-body cadaver model with an induced globally unstable cervical spine (C5-C6) lesion, we investigated the mean range of motion (ROM) produced at the site of the injury in six dimensions by performing the two maneuvers using an electromagnetic tracking device., Results: Compared to the log-roll maneuver, the lateral trauma position caused similar mean ROM in five of the six dimensions. Only medial/lateral linear motion was significantly greater in the lateral trauma position (1.4mm (95% confidence interval [CI] 0.4, 2.4mm))., Conclusions: In this cadaver study, the novel lateral trauma position and the well-established log-roll maneuver resulted in comparable amounts of motion in an unstable cervical spine injury model. We suggest that the lateral trauma position may be considered for unconscious non-intubated trauma patients., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

OBJECTIVE To compare stiffness and resistance to cyclic fatigue of two 3.5-mm locking system plate-rod constructs applied to an experimentally created fracture gap in femurs of canine cadavers. SAMPLE 20 femurs from cadavers of 10 mixed-breed adult dogs. PROCEDURES 1 femur from each cadaver was stabilized with a conical coupling plating system-rod construct, and the contralateral femur was stabilized with a locking compression plate (LCP)-rod construct. An intramedullary Steinmann pin was inserted in each femur. A 40-mm gap then was created; the gap was centered beneath the central portion of each plate. Cyclic axial loading with increasing loads was performed. Specimens that did not fail during cyclic loading were subjected to an acute load to failure. RESULTS During cyclic loading, significantly more LCP constructs failed (6/10), compared with the number of conical coupling plating system constructs that failed (1/10). Mode of failure of the constructs included fracture of the medial or caudal aspect of the cortex of the proximal segment with bending of the plate and pin, bending of the plate and pin without fracture, and screw pullout. Mean stiffness, yield load, and load to failure were not significantly different between the 2 methods of stabilization. CONCLUSIONS AND CLINICAL RELEVANCE Both constructs had similar biomechanical properties, but the conical coupling plating system was less likely to fail than was the LCP system when subjected to cyclic loading. These results should be interpreted with caution because testing was limited to a single loading mode.

Despite the ubiquity of gait assessment in clinic and research, it is unclear how observation impacts gait, particularly in persons with chronic pain and psychological stress. We compared temporal spatial gait patterns in people with and without chronic low back pain (CLBP) when they were aware and unaware of being observed. This was a repeated-measures, deception study in 55 healthy persons (32.0±12.4 yr, 24.2±2.7kg/m 2 ) and persons with CLBP (51.9±17.9 yr, 27.8±4.4kg/m 2 ). Participants performed one condition in which they were unaware of observation (UNW), and three conditions under investigator observation: (1) aware of observation (AWA), (2) investigators watching cadence, (3) investigators watching step length. Participants walked across an 8.4m gait mat, while temporal spatial parameters of gait were collected. The Medical Outcomes Short Form (SF-12), Beck Depression Inventory (BDI), State Trait Anxiety Inventory (STAI), and Oswestry Disability Index (ODI) were completed. Significant condition by group interactions were found for velocity and step length (p<0.05). Main effects of study condition existed for all gait variables except for step width. Main effects of group (healthy, LBP) were significant for all variables except for step width (p<0.05). Regression analyses revealed that after accounting for age, sex, and SF-12 mental component score, BDI scores predict velocity changes during walking from the UNW to AWA conditions. These findings show that people change their gait patterns when being observed. Gait analyses may require additional trials before data can reliably be interpreted and used for clinical decision-making., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Endotracheal intubation is not always an option for unconscious trauma patients. Prehospital personnel are then faced with the dilemma of maintaining an adequate airway without risking deleterious movement of a potentially unstable cervical spine. To address these two concerns various alternatives to the classical recovery position have been developed. This study aims to determine the amount of motion induced by the recovery position, two versions of the HAINES (High Arm IN Endangered Spine) position, and the novel lateral trauma position (LTP)., Method: We surgically created global cervical instability between the C5 and C6 vertebrae in five fresh cadavers. We measured the rotational and translational (linear) range of motion during the different maneuvers using an electromagnetic tracking device and compared the results using a general linear mixed model (GLMM) for regression., Results: In the recovery position, the range of motion for lateral bending was 11.9°. While both HAINES positions caused a similar range of motion, the motion caused by the LTP was 2.6° less (P = 0.037). The linear axial range of motion in the recovery position was 13.0 mm. In comparison, the HAINES 1 and 2 positions showed significantly less motion (-5.8 and -4.6 mm, respectively), while the LTP did not (-4.0 mm, P = 0.067)., Conclusion: Our results indicate that in unconscious trauma patients, the LTP or one of the two HAINES techniques is preferable to the standard recovery position in cases of an unstable cervical spine injury., (© 2016 The Authors. Acta Anaesthesiologica Scandinavica published by John Wiley & Sons Ltd on behalf of Acta Anaesthesiologica Scandinavica Foundation.)

The canine knee is morphologically similar to the human knee and thus dogs have been used in experimental models to study human knee pathology. To date, there is limited data of normal canine 3D knee kinematics during daily activities. The objective of this study was to characterize 3D in-vivo femorotibial kinematics in normal dogs during commonly performed daily activities. Using single-plane fluoroscopy, six normal dogs were imaged performing walk, trot, sit, and stair ascent activities. CT-generated bone models were used for kinematic measurement using a 3D-to-2D model registration technique. Increasing knee flexion angle was typically associated with increasing tibial internal rotation, abduction and anterior translation during all four activities. The precise relationship between flexion angle and these movements varied both within and between activities. Significant differences in axial rotation and coronal angulation were found at the same flexion angle during different phases of the walk and trot. This was also found with anterior tibial translation during the trot only. Normal canine knees accommodate motion in all planes; precise kinematics within this envelope of motion are activity dependent. This data establishes the characteristics of normal 3D femorotibial joint kinematics in dogs that can be used as a comparison for future studies., (© 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Background: Numerous studies have shown that there are better alternatives to log rolling patients with unstable spinal injuries, although this method is still commonly used for placing patients onto a spine board. No previous studies have examined transfer maneuvers involving an injured football player with equipment in place onto a spine board., Purpose: To test 3 different transfer maneuvers of an injured football player onto a spine board to determine which method most effectively minimizes spinal motion in an injured cervical spine model., Study Design: Controlled laboratory study., Methods: Five whole, lightly embalmed cadavers were fitted with shoulder pads and helmets and tested both before and after global instability was surgically created at C5-C6. An electromagnetic motion analysis device was used to assess the amount of angular and linear motion with sensors placed above and below the injured segment during transfer. Spine-boarding techniques evaluated were the log roll, the lift and slide, and the 8-person lift., Results: The 8-person lift technique resulted in the least amount of angular and linear motion for all planes tested as compared with the lift-and-slide and log-roll techniques. This reached statistical significance for lateral bending (P = .031) and medial-lateral translation (P = .030) when compared with the log-roll maneuver. The lift-and-slide technique was significantly more effective at reducing motion than the log roll for axial rotation (P = .029) and lateral bending (P = .006)., Conclusion: The log roll resulted in the most motion at an unstable cervical injury as compared with the other 2 spine-boarding techniques examined. The 8-person lift and lift-and-slide techniques may both be more effective than the log roll at reducing unwanted cervical spine motion when spine boarding an injured football player. Reduction of such motion is critical in the prevention of iatrogenic injury.

Objective: To examine whether runners recovering from a lower body musculoskeletal injury have different metabolic, cardiopulmonary, and gait responses compared with healthy runners., Design: Cross-sectional study., Setting: Research laboratory at an academic institution., Methods: Healthy runners (n = 50) were compared with runners who were recently injured but had returned to running (n = 50). Both groups were participating in similar cross-training modalities such as swimming, weight training, biking, and yoga. Running gait was analyzed on a treadmill using 3-dimensional motion capture, and metabolic and cardiopulmonary measures were captured simultaneously with a portable metabolic analyzer., Main Outcome Measures: Rate of oxygen consumption, heart rate, ventilation, carbohydrate and fat oxidation values, gait temporospatial parameters and range of motion measures (ROM) in the sagittal plane, energy expenditure, and vertical displacement of the body's center of gravity (COG)., Results: The self-selected running speed was different between the injured and healthy runners (9.7 ± 1.1 km/h and 10.6 ± 1.1 km/h, respectively; P = .038). No significant group differences were noted in any metabolic or cardiopulmonary variable while running at the self-selected or standard speed (13.6 km/h). The vertical displacement of the COG was less in the injured group (8.4 ± 1.4 cm and 8.9 ± 1.4, respectively; P = .044). ROM about the right ankle in the sagittal plane at the self-selected running speed during the gait cycle was less in the injured runners compared with the healthy runners (P < .05)., Conclusions: Runners with a recent lower body injury who have returned to running have similar cardiopulmonary and metabolic responses to running as healthy runners at the self-selected and standard speeds; this finding may be due in part to participation in cross-training modes that preserve cardiopulmonary and metabolic adaptations. Injured runners may conserve motion by minimizing COG displacement and ankle joint ROM during a gait cycle., (Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Study Objective: To compare the amount of segmental vertebral motion produced with the lateral recovery position and the HAINES technique when performed on cadavers with destabilized cervical spines., Methods: The cervical spines of 10 cadavers were surgically destabilized at the C5-C6 vertebral segment. Sensors from an electromagnetic tracking device were affixed to the vertebrae in question to monitor the amount of anterior/posterior, medial/lateral, and distraction/compression linear motion produced during the application of the two study techniques., Results: The statistical analysis of linear motion data did not reveal any significant differences between the two recovery positions., Conclusion: At this time, no single version of the recovery position can be endorsed for the spine-injured trauma patient. More research is needed to fully ascertain the safety of commonly used recovery positions.

Background: The purposes of this study were to compare the oxygen cost, metabolic parameters and temporalspatial variables between barefoot and shod running in trained mid-forefoot runners., Methods: Experienced runners (N.=21; 30±10.9 years; 16 men) performed two separate 20 minute treadmill running bouts at ~77% of estimated maximal heart rate. Rate of oxygen consumption (VO2), energy cost, fuel use and heart rate (HR) were collected continuously using a portable gas analyzer. Three-dimensional motion capture was used to measure temporalspatial parameters., Results: Participants ran at a mean self-selected speed of 3.1±0.3 m/s for both conditions, at intensities corresponding to mean HR values of 146 bpm (shod) and 144 bpm (barefoot). Steady State VO2 was not different between the shod and barefoot conditions (39.4± 4.7 mL/kg*min vs. 40±5.2 mL/kg*min, respectively). The total energy expended in the shod and barefoot conditions was 974±134 kJ and 979±142 kJ. The average non-protein respiratory exchange ratios, proportions and amount of fat and carbohydrate used were not different between conditions. Cadence was 2.5% higher and center of gravity vertical displacement was 0.5 cm less for the barefoot condition (P<0.05)., Conclusion: In trained mid-forefoot runners experienced with barefoot running, there are not significant metabolic differences between shod and barefoot running conditions. Barefoot running increases cadence and decreases foot contact time and vertical displacement. Experienced participants were likely able to titrate kinematics to standardize energy output and fuel use for a given running distance and speed irrespective of shoe wear.

Purpose: This pilot study tested whether FiberWire provides similar protection to steel wire against repair displacement in patella fractures., Methods: Thirteen cadaver knees were cyclically loaded with 10 cycles (0-90° flexion) and fracture displacement was recorded. Fixation methods were also tested in load to failure (>3 mm displacement)., Results: There was no difference between wire types in fracture displacement (1.4 mm ± 0.33 mm vs 1.2 mm ± 0.34 mm, respectively; p = 0.418) or in the load to failure (714.7 N ± 110.9 N vs 744.5 N ± 92.8 N, respectively; p = 0.360)., Conclusion: FiberWire provides similar protection to steel wire against repair displacement after fixation of patellar fractures.

Objective: To compare accuracy of a noninvasive single-plane fluoroscopic technique with radiostereometric analysis (RSA) for determining 3-D femorotibial poses in a canine cadaver with normal stifle joints., Sample: Right pelvic limb from a 25-kg adult mixed-breed dog., Procedures: A CT scan of the limb was obtained before and after metal beads were implanted into the right femur and tibia. Orthogonal fluoroscopic images of the right stifle joint were acquired to simulate a biplanar fluoroscopic acquisition setup. Images were obtained at 5 flexion angles from 110° to 150° to simulate a gait cycle; 5 cycles were completed. Joint poses were calculated from the biplanar images by use of RSA with CT-derived beaded bone models and compared with measurements obtained by use of CT-derived nonbeaded bone models matched to single-plane, lateral-view fluoroscopic images. Single-plane measurements were performed by 2 observers and repeated 3 times by the primary observer., Results: Mean absolute differences between the single-plane fluoroscopic analysis and RSA measurements were 0.60, 1.28, and 0.64 mm for craniocaudal, proximodistal, and mediolateral translations, respectively, and 0.63°, 1.49°, and 1.58° for flexion-extension, abduction-adduction, and internal-external rotations, respectively. Intra- and interobserver repeatability was strong with maximum mean translational and rotational SDs of 0.52 mm and 1.36°, respectively., Conclusions and Clinical Relevance: Results suggested that single-plane fluoroscopic analysis performed by use of CT-derived bone models is a valid, noninvasive technique for accurately measuring 3-D femorotibial poses in dogs.

Objective: To compare the effects of 4 months of isolated lumbar resistance exercise and total body resistance exercise on walking performance in obese, older adults with chronic low back pain. A secondary analysis examined whether responsiveness to training modulated walking improvement., Design: Randomized, controlled trial., Setting: Research laboratory affiliated with tertiary care facility., Methods and Intervention: Participants (N = 49; 60-85 years) were randomized into a 4-month resistance exercise intervention (TOTRX), lumbar extensor exercise intervention (LEXT), or a control group (CON)., Main Outcome Measurements: Walking performance, maximal low back strength and leg strength, and average resting and low back pain severity score (from an 11-point numerical pain rating scale; NRSpain) were collected at baseline and month 4., Results: The TOTRX and LEXT improved lumbar extensor strength relative to CON, and the TOTRX (P < .05). NRSpain scores at month 4 were lowest in the TOTRX group compared with the LEXT and CON groups, respectively (2.0 ± 1.7 points vs 3.7 ± 2.6 points and 4.6 ± 2.4 points; P < .006). A total of 53% and 67% of participants in the TOTRX and LEXT groups were responders who made lumbar extensor strength gains that achieved ≥20% greater than baseline values. Although the TOTRX demonstrated the greatest improvement in walking endurance among the intervention groups, this did not reach significance (10.1 ± 12.2% improvement in TOTRX vs 7.4 ± 30.0% LEXT and -1.7 ± 17.4% CON; P = .11). Gait speed increased most in the TOTRX (9.0 ± 13.5%) compared with the LEXT and CON groups (P < .05). The change in lumbar extensor strength explained 10.6% of the variance of the regression model for the change in walking endurance (P = .024)., Conclusions: The use of LEXT and TOTRX produced similar modest improvements in patients' walking endurance. Lumbar extensor strength gain compared with leg strength gain is a moderate but important contributor to walking endurance in obese older adults with chronic low back pain. Responders to resistance exercise programs (event those with only lumbar extension exercise) who make at least a 20% improvement in strength can expect better improvement in walking endurance than those who do not achieve this strength improvement., (Copyright © 2014 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Androgen administration protects against musculoskeletal deficits in models of sex-steroid deficiency and injury/disuse. It remains unknown, however, whether testosterone prevents bone loss accompanying spinal cord injury (SCI), a condition that results in a near universal occurrence of osteoporosis. Our primary purpose was to determine whether testosterone-enanthate (TE) attenuates hindlimb bone loss in a rodent moderate/severe contusion SCI model. Forty (n=10/group), 14 week old male Sprague-Dawley rats were randomized to receive: (1) Sham surgery (T9 laminectomy), (2) moderate/severe (250 kdyne) SCI, (3) SCI+Low-dose TE (2.0 mg/week), or (4) SCI+High-dose TE (7.0 mg/week). Twenty-one days post-injury, SCI animals exhibited a 77-85% reduction in hindlimb cancellous bone volume at the distal femur (measured via μCT) and proximal tibia (measured via histomorphometry), characterized by a >70% reduction in trabecular number, 13-27% reduction in trabecular thickness, and increased trabecular separation. A 57% reduction in cancellous volumetric bone mineral density (vBMD) at the distal femur and a 20% reduction in vBMD at the femoral neck were also observed. TE dose dependently prevented hindlimb bone loss after SCI, with high-dose TE fully preserving cancellous bone structural characteristics and vBMD at all skeletal sites examined. Animals receiving SCI also exhibited a 35% reduction in hindlimb weight bearing (triceps surae) muscle mass and a 22% reduction in sublesional non-weight bearing (levator ani/bulbocavernosus [LABC]) muscle mass, and reduced prostate mass. Both TE doses fully preserved LABC mass, while only high-dose TE ameliorated hindlimb muscle losses. TE also dose dependently increased prostate mass. Our findings provide the first evidence indicating that high-dose TE fully prevents hindlimb cancellous bone loss and concomitantly ameliorates muscle loss after SCI, while low-dose TE produces much less profound musculoskeletal benefit. Testosterone-induced prostate enlargement, however, represents a potential barrier to the clinical implementation of high-dose TE as a means of preserving musculoskeletal tissue after SCI.

Objective: To compare biomechanical properties of (1) 4.5 mm cortical screws and Fitz Fenestrated Tubular Transcondylar (F2T2) screws; (2) normal humeri and humeri with an intracondylar osteotomy; and (3) humeri with an intracondylar osteotomy stabilized with either a 4.5 mm cortical screw or a F2T2 screw., Study Design: Cadaveric biomechanical assessment., Sample Population: 4.5 mm cortical screws (n = 10), 5.85 mm F2T2 screws (n = 10), and paired dog humeri (n = 40)., Methods: Cortical and F2T2 screws were loaded to failure in 3-point bending. Ten pairs of humeri with or without an intracondylar osteotomy were axially loaded to failure. Ten additional pairs of humeri with an intracondylar osteotomy were alternately stabilized with a positional cortical or F2T2 screw and axially loaded to failure., Results: Mean stiffness, yield load, and failure load was significantly greater (P < .001) for the F2T2 screws compared with cortical screws as well as for intact humeri compared with humeri with an intracondylar osteotomy (P < .001). There were no significant differences in mean stiffness (P = .59), yield load (P = .31), or failure load (P = .24) between humeri with stabilized intracondylar osteotomy., Conclusion: Isolated F2T2 screws have superior mechanical properties to 4.5 mm cortical screws when loaded in 3-point bending. Intracondylar osteotomy adversely affected humeral mechanical integrity. Osteotomized humeri stabilized by either screw had comparable mechanical properties.

Background: Transection of the canine cranial cruciate ligament (CCL) is a well-established osteoarthritis (OA) model. The effect of CCL loss on contact pressure and joint alignment has not been quantified for stifle loading in standing. The purposes of the study were to measure femorotibial contact areas and stresses and joint alignment following transection of the CCL in an ex vivo model. We hypothesized that transection of the CCL would lead to abnormal kinematics, as well as alterations in contact mechanics of the femorotibial joint., Methodology/principal Findings: Eight canine hindlimbs were tested in a servo-hydraulic materials testing machine using a custom made femoral jig. Contact area and pressure measurements, and femorotibial rotations and translations were measured in the normal and the CCL-deficient stifle in both standing and deep flexion angles. We found that at standing angle, transection of the CCL caused cranial translation and internal rotation of the tibia with a concurrent caudal shift of the contact area, an increase in peak pressure and a decrease in contact area. These changes were not noted in deep flexion. At standing, loss of CCL caused a redistribution of the joint pressure, with the caudal region of the compartment being overloaded and the rest of the joint being underloaded., Conclusion: In the Pond-Nuki model alterations in joint alignment are correlated with shifting of the contact points to infrequently loaded areas of the tibial plateau. The results of this study suggest that this cadaveric Pond-Nuki model simulates the biomechanical changes previously reported in the in-vivo Pond-Nuki model.

The purpose of this study was to determine whether the pull-through force of soft-tissue allografts increases over time after being hydrated with saline-soaked sponges. Eighteen aseptic soft-tissue, fresh-frozen anterior tibialis allograft specimens were thawed and sized using standard sizing guides. After sizing, initial pull-through force was measured using an Instron Model 5865 machine. Grafts were randomized to soak in saline sponges for 20, 40, or 60 min. After soaking, pull-through force was again assessed. Pre- and post-soaking pull-through forces were compared using a paired t test. The effect of time on pull-through force was evaluated using an ANOVA and Tukey post hoc test. Two allografts had initial pull-through forces outside the inclusion criteria and were excluded. The average pull-through force for the remaining 16 allografts pre-soaking was 43.0 N and post-soaking was 81.7 N, for an increase of 90 % (P < 0.001). Longer hydration time in the saline soaked sponges was not correlated with higher pull-through force (P = 0.724). Pull-through force post-hydration was not related to the allograft diameter (P = 0.641). Post-hydration, 33 % of grafts that had soaked for 20 min and 40 % of grafts that had soaked for 40 or 60 min required greater than 100 N pull-through force. Our data supports the hypothesis that soft-tissue allografts swell as a result of being stored in saline-soaked sponges, resulting in greater pull-through forces during graft passage. Surgeons should bear in mind that allografts swell when stored in saline-soaked gauze and should size their tunnels accordingly.

Background This study created an anatomic reconstruction of the distal oblique bundle (DOB) of the interosseous membrane to determine its effect on distal radioulnar joint (DRUJ) instability and compare this technique with distal radioulnar ligament (DRUL) reconstruction. Questions/Purposes We hypothesized that this reconstruction would provide equivalent stability to DRUL reconstruction and that combining the two techniques would enhance stability. Methods Six cadaveric upper limbs were affixed to a custom frame. The volar/dorsal translation of the radius relative to the ulna was measured in 60° pronation, neutral, and 60° supination. Translation was sequentially measured with the DRUJ intact, with sectioned DRULs and triangular fibrocartilaginous complex (TFCC), and with sectioned DOBs. Reconstructions were performed on the DRULs, on the DOB tensioned in both neutral and supination, and employing both techniques. Results The DOB reconstruction, tensioned both in the neutral position and in 60° supination, was more stable than the partial and complete instability in 6/6 specimens in pronation and the neutral position and in 5/6 specimens in supination. The DOB reconstruction and the DOB reconstruction tensioned in supination were more stable than the DRUL reconstruction in 4/6 patients. Combining the two techniques did not further reduce translation. Conclusions The DOB reconstruction is capable of improving stability in the unstable DRUJ.

Context: Two methods have been proposed to transfer an individual in the prone position to a spine board. Researchers do not know which method provides the best immobilization., Objective: To determine if motion produced in the unstable cervical spine differs between 2 prone logrolling techniques and to evaluate the effect of equipment on the motion produced during prone logrolling., Design: Crossover study., Setting: Laboratory., Patients or Other Participants: Tests were performed on 5 fresh cadavers (3 men, 2 women; age = 83 ± 8 years, mass = 61.2 ± 14.1 kg)., Main Outcome Measure(s): Three-dimensional motions were recorded during 2 prone logroll protocols (pull, push) in cadavers with an unstable cervical spine. Three equipment conditions were evaluated: football shoulder pads and helmet, rigid cervical collar, and no equipment. The mean range of motion was calculated for each test condition., Results: The pull technique produced 16% more motion than the push technique in the lateral-bending angulation direction (F1,4 = 19.922, P = .01, η(2) = 0.833). Whereas the collar-only condition and, to a lesser extent, the football-shoulder-pads-and-helmet condition demonstrated trends toward providing more stability than the no-equipment condition, we found no differences among equipment conditions. We noted an interaction between technique and equipment, with the pull maneuver performed without equipment producing more anteroposterior motion than the push maneuver in any of the equipment conditions., Conclusions: We saw a slight difference in the motion measured during the 2 prone logrolling techniques tested, with less lateral-bending and anteroposterior motion produced with the logroll push than the pull technique. Therefore, we recommend adopting the push technique as the preferred spine-boarding maneuver when a patient is found in the prone position. Researchers should continue to seek improved methods for performing prone spine-board transfers to further decrease the motion produced in the unstable spine.

Objective: To (1) compare the effect of cyclic loading on craniocaudal tibial translation in cranial cruciate ligament (CrCL)-deficient stifles after extracapsular stabilization, and (2) evaluate the effect of peak force during cyclic loading on the rate of development of craniocaudal laxity., Study Design: Biomechanical cadaveric study., Sample Population: Cadaveric pelvic limbs (n = 24 pairs) from skeletally mature dogs., Methods: Twenty-four pairs of stifles were randomly assigned to 4 stabilization groups: nylon leader lateral circumfabellar-tibial suture (NLS); FiberTape lateral circumfabellar-tibial suture (FTLS); TightRope (TR); or bone anchor (BA). Contralateral limbs were cyclically loaded to produce cranial tibial translation at peak forces of either 80 or 160 N. Craniocaudal displacement of the tibia was measured with a mechanical testing machine during cyclic loading with the CrCL intact, after CrCL transection, and after extracapsular stabilization. The number of cycles each construct underwent before reaching 200% and 300% of the mean craniocaudal displacement present during cyclic loading of the CrCL-intact stifles was calculated. Number of cycles among treatment groups was compared with a Kruskal-Wallis test. P < .05 was considered significant., Results: Mean ± SD translation before and after CrCL transection were 3.9 ± 0.6 and 14.6 ± 1.7 mm, respectively. TR constructs resisted significantly more cycles than NLS constructs before reaching 7.8 mm (200%) and 11.7 mm (300%) of translation when loaded to 80 N. No other differences between constructs were significant at a peak load of 80 N. All constructs reached 7.8 and 11.7 mm of translation in fewer cycles when loaded to 160 N than at 80 N., Conclusions: TR constructs were most resistant to elongation during cyclic loading. Doubling the peak force during cyclic loading significantly decreased the number of cycles constructs withstood, supporting recommendations for restricting postoperative activity after extracapsular stabilization of the CrCL-deficient stifle., (© Copyright 2013 by The American College of Veterinary Surgeons.)

Objective: This study examined the changes in synovial fluid levels of cytokines, oxidative stress and viscosity six months after intraarticular hyaluronic acid (HA) treatment in adults and elderly adults with knee osteoarthritis (OA)., Design: This was a prospective, repeated-measures study design in which patients with knee OA were administered 1% sodium hyaluronate. Patients (N=28) were stratified by age (adults, 50-64 years and elderly adults, ≥65 years). Ambulatory knee pain values and self-reported physical activity were collected at baseline and month six., Materials and Methods: Knee synovial fluid aspirates were collected at baseline and at six months. Fluid samples were analyzed for pro-inflammatory cytokines (interleukins 1β, 6,8,12, tumor necrosis factor-α, monocyte chemotactic protein), anti-inflammatory cytokines (interleukins 4, 10 13), oxidative stress (4-hydroxynonenal) and viscosity at two different physiological shear speeds 2.5Hz and 5Hz., Results: HA improved ambulatory knee pain in adults and elderly groups by month six, but adults reported less knee pain-related interference with participation in exercise than elderly adults. A greater reduction in TNF-α occurred in adults compared to elderly adults (-95.8% ± 7.1% vs 19.2% ± 83.8%, respectively; p=.044). Fluid tended to improve at both shear speeds in adults compared to the elderly adults. The reduction in pain severity correlated with the change in IL-1β levels by month six (r= -.566; p=.044)., Conclusion: Reduction of knee pain might be due to improvements in synovial fluid viscosity and inflammation. Cartilage preservation may be dependent on how cytokine, oxidative stress profiles and viscosity change over time.

One major concern regarding soft tissue allograft use in surgical procedures is the risk of disease transmission. Current techniques of tissue sterilization, such as irradiation have been shown to adversely affect the mechanical properties of soft tissues. Grafts processed using Biocleanse processing (a proprietary technique developed by Regeneration Technologies to sterilize human tissues) will have better biomechanical characteristics than tissues that have been irradiated. Fifteen pairs of cadaveric Achilles tendon allografts were obtained and separated into three groups of 10 each. Three treatment groups were: Biocleanse, Irradiated, and Control (untreated). Each specimen was tested to determine the biomechanical properties of the tissue. Specimens were cyclically preloaded and then loaded to failure in tension. During testing, load, displacement, and optical strain data were captured. Following testing, the cross sectional area of the tendons was determined. Tendons in the control group were found to have a higher extrinsic stiffness (slope of the load-deformation curve, p = .005), have a higher ultimate stress (force/cross sectional area, p = .006) and higher ultimate failure load (p = .003) than irradiated grafts. Biocleanse grafts were also found to be stiffer than irradiated grafts (p = .014) yet were not found to be statistically different from either irradiated or non-irradiated grafts in terms of load to failure. Biocleanse processing seems to be a viable alternative to irradiation for Achilles tendon allografts sterilization in terms of their biomechanical properties.

Background: As prehospital emergency rescuers prepare cervical spine-injured adult patients for immobilization and transport to hospital, it is essential that patients be placed in a favorable position. Previously, it was recommended that patients with cervical spine injuries be immobilized in a slightly flexed position using pads placed beneath the head. However, it is unknown how neck flexion created with pad placement affects the unstable spine., Objective: To determine the effects of three different head positions on the alignment of unstable vertebral segments., Methods: Five cadavers with a complete segmental instability at the C5 and C6 level were included in the study. The head was either placed directly on the ground (or spine board) or on foam pads. Three conditions were tested: no pad; pads 2.84 cm thick; and pads 4.26 cm thick. Pads were positioned beneath the head to determine their effect on spinal alignment. Anterior-posterior translation, flexion-extension motion, and axial displacement across the unstable segment were compared between conditions., Results: Although statistical tests failed to identify any significant differences between pad conditions, some meaningful results were noted. In general, the "no pad" condition aligned the spine in a position that best replicated the intact spine., Conclusions: Because the goal of emergency rescuers is to conserve whatever physiologic or structural integrity of the spinal cord and spinal column that remains, the outcome of this study suggests that this goal may be best achieved using the "no pad" condition. However, it is recommended that more research be conducted to confirm these preliminary findings., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Introduction: Spinal stenosis is defined as neurogenic claudication due to narrowing of the spinal canal lumen diameter. As the disease progresses, ambulation and gait may be impaired. Self-report measures are routinely used in the clinical setting to capture data related to lumbar pain symptoms, function and perceived disability. The associations between self-report measures and objective measures of physical function in patients with lumbar spinal stenosis are not well characterized. The purpose of this study was to determine the correlation between self-reported assessments of function with objective biomechanical measures of function., Methods: 25 subjects were enrolled in this study. Subjects completed self-report questionnaires and biomechanical assessments of gait analysis, lumbar 3D ROM and lumbar proprioception. Correlations were determined between self-report measures and biomechanical data., Results: The Oswestry Disability Index (ODI) was strongly correlated with stride length and gait velocity and weakly correlated with base of support. ODI was also weakly correlated with left lateral bending proprioception but not right lateral bending. The SF12 was not significantly correlated with any of the biomechanical measurements. Pain scores were weakly correlated with velocity, and base of support, and had no correlation any of the other biomechanical measures., Discussion: There is a strong correlation between gait parameters and functional disability as measured with the ODI. Quantified gait analysis can be a useful tool to evaluate patients with lumbar spinal stenosis and to assess the outcomes of treatments on this group of patients., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: The effects of advanced airway management on cervical spine alignment in patients with upper cervical spine instability are uncertain., Methods: To examine the potential for mechanical disruption during endotracheal intubation in cadavers with unstable cervical spines, we performed a prospective observational cohort study with 3 cadaver subjects. We created an unstable, type II odontoid fracture with global ligamentous instability at C1-2 in lightly embalmed cadavers, followed by repetitive intubations with 4 different airway devices (Airtraq laryngoscope, Lightwand, intubating laryngeal mask airway [LMA], and Macintosh laryngoscope) while manual in-line stabilization was applied. Motion analysis data were collected using an electromagnetic device to assess the degree of angular movement in 3 axes (flexion-extension, axial rotation, and lateral bending) during the intubation trials with each device. Intubation was performed by either an emergency medical technician or attending anesthesiologist., Results: Overall, 153 intubations were recorded with the 4 devices. The Lightwand technique resulted in significantly less flexion-extension and axial rotation at C1-2 than with the intubating LMA (mean difference in flexion-extension 3.2° [95% confidence interval {CI}, 0.9°-5.5°], P = 0.003; mean difference in axial rotation 1.6° [95% CI, 0.3°-2.8°], P = 0.01) and Macintosh laryngoscope (mean difference in flexion-extension 3.1° [95% CI, 0.8°-5.4°], P = 0.005; mean difference in axial rotation 1.4° [95% CI 0.1°-2.6°], P = 0.03)., Conclusions: In cadavers with instability at C1-2, the Lightwand technique produced less motion than the Macintosh and intubating LMA.

Background: There are several factors that can affect the fatigue life of a bone plate, including the mechanical properties of the plate and the complexity of the fracture. The position of the screws can influence construct stiffness, plate strain and cyclic fatigue of the implants. Studies have not investigated these variables in implants utilized for long bone fracture fixation in dogs and cats. The purpose of the present study was to evaluate the effect of plate working length on construct stiffness, gap motion and resistance to cyclic fatigue of dog femora with a simulated fracture gap stabilized using a 12-hole 2.4 mm locking compression plates (LCP). Femora were plated with 12-hole 2.4 mm LCP using 2 screws per fracture segment (long working length group) or with 12-hole 2.4 mm LCP using 5 screws per fracture segment (a short working length group)., Results: Construct stiffness did not differ significantly between stabilization techniques. Implant failure did not occur in any of the plated femora during cycling. Mean ± SD yield load at failure in the short plate working length group was significantly higher than in the long plate working length group., Conclusion: In a femoral fracture gap model stabilized with a 2.4 mm LCP applied in contact with the bone, plate working length had no effect on stiffness, gap motion and resistance to fatigue. The short plate working length constructs failed at higher loads; however, yield loads for both the short and long plate working length constructs were within physiologic range.

Objective: This study determined whether kinesiophobia levels were different among older adults with chronic low back pain (LBP) and varying body mass index and whether kinesiophobia predicted perceived disability or walking endurance., Design: This study was a secondary analysis from a larger interventional study. Older adults with obesity with LBP (N = 55; 60-85 yrs) were participants in this study. Data were stratified on the basis of body mass index: overweight (25-29.9 kg/m), obese (30-34.9 kg/m), and severely obese (35 kg/m). The participants completed a battery of surveys (the modified Tampa Scale of Kinesiophobia [TSK-11], the Fear-Avoidance Beliefs Questionnaire, the Pain Catastrophizing Scale, and the perceived disability measures of the Oswestry Disability Index and the Roland Morris Disability Questionnaire). Walking endurance time was captured using a symptom-limited graded walking treadmill test. The peak LBP ratings were captured during the walk test., Results: Walking endurance times did not differ by body mass index group, but the peak LBP ratings were higher in the moderately and severely obese groups compared with the overweight group (3.0 and 3.1 vs. 2.1 points; P < 0.05). There was no difference in the kinesiophobia scores (the TSK-11, the Pain Catastrophizing Scale, and the Fear-Avoidance Beliefs Questionnaire work and activity subscores) or the perceived disability scores (the Oswestry Disability Index and the Roland Morris Disability Questionnaire). However, adjusted regression analyses revealed that the TSK-11 scores contributed 10%-21% of the variance of the models pain with walking and perceived disability caused by back pain. Kinesiophobia was not a significant contributor to the variance of the regression model for walking endurance., Conclusions: In the older population with obesity with LBP, the TSK-11 might be a quick and simple measure to identify patients at risk for poor self-perception of functional ability. The TSK and the Oswestry Disability Index may be quick useful measures to assess initial perceptions before rehabilitation. Kinesiophobia may be a good therapeutic target to address to help affected older adults with obesity fully engage in therapies for LBP.

Objective: This study determined whether mobility and functional pain were different among older men and women with chronic low-back pain and varying body mass index levels., Design: This was a comparative, descriptive study of older adults with obesity with low-back pain (N = 55; 60-85 yrs). The participants were stratified on the basis of body mass index: overweight (25-29.9 kg/m), obese (30-34.9 kg/m), and severely obese (35 kg/m). The participants completed a functional test battery (walking endurance, chair rise, stair climb, 7-day activity monitoring, and gait parameters) and pain ratings with activity ("functional pain")., Results: The functional pain scores during walking and stair climb were highest in the severely obese group compared with the overweight group (P < 0.05), but the functional test scores were not found to be significantly different by body mass index. Gait base of support was 36% greater and single/double support times were 3.1%-6.1% greater in the severely obese group compared with the overweight group (P < 0.05). The women had slower chair rise and stair climb times and had slower walking velocity than did the men. Daily step numbers were lowest in the severely obese group compared with the obese and overweight groups (2971 vs. 3511 and 4421 steps per day; P < 0.05) but were not different by sex. Normalized lumbar extensor, abdominal curl, and leg press strength values were lowest in the severely obese group, and the women had 18%-34% lower strength values than did the men for all three exercises (P < 0.05). Lumbar strength was associated with stair climb, chair rise, and walking endurance times. Body mass index was an independent predictor of walking endurance time but not of steps taken per day., Conclusions: In this study, the persons with obesity reported higher functional pain values during walking and stair climb and had lower lumbar strength compared with the overweight participants. Rehabilitation strategies that include lumbar extensor strengthening may help improve functional mobility and walking duration, both of which can help with weight management in older adults with obesity with chronic low-back pain.

Objective: To compare the effect of hyaluronic acid (HA) intra-articular knee injections on pain and functional outcomes in persons with knee osteoarthritis (OA) over 6 months, and to determine whether or not changes in functional pain are related to improvements in quality of life., Design: A prospective cohort study., Setting: A research laboratory in an academic medical center., Participants: Patients with knee OA (N = 53) who were receiving medical care for OA., Interventions: Intra-articular knee injections of HA (3 injections, each separated by 1 week) and a comparative noninjection group., Main Outcome Measurements: Functional pain and outcomes assessments during chair rise, stair climbing, and a 6-minute walking test (by using 0-10 point numerical pain ratings during each test); gait parameters; Medical Outcomes Short Form-36 (SF-36) scores and subscores; the Western Ontario McMaster University Osteoarthritis Index (WOMAC)., Results: Six months after HA, the completion times for the chair rise and stair climb tasks, and the distance covered during the 6-minute walk were not different between the groups. However, functional pain ratings during stair climbing decreased in the HA-treated group (P = .05). Six-month changes in gait velocity, cadence, stride length, step length, and the percentage of the gait cycle spent in single support were all higher after HA injection at month 6 (all P < .05). Significant group-by-time interactions existed for total WOMAC scores. SF-36 Vitality subscores improved by 13%, and Role Physical scores were higher in patients treated with HA injection compared with participants in the noninjection group (P < .05). Regression analyses revealed that changes in the functional pain measures did not correspond with SF-36 scores., Conclusions: HA is associated with lower functional pain severity, with minimal impact on functional test scores. We interpreted this finding to represent an increase in the quality of the movement and functional activity. The change in functional pain did not correspond to changes in SF-36 quality-of-life scores., (Copyright © 2013 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Context: Excessive spinal motion generated during multiple bed transfers of patients with unstable spine injuries may contribute to neurological deterioration., Objective: To evaluate spinal motion in a cadaveric model of global spinal instability during hospital bed transfers using several commonly used techniques., Design/participants: A motion analysis and evaluation of hospital bed transfer techniques in a cadaveric model of C5-C6 and T12-L2 global spinal instability. Setting/outcome measures: Global instability at C5-C6 and T12-L2 was created. The motion in three planes was measured in both the cervical and lumbar spine during each bed transfer via electromagnetic motion detection devices. Comparisons between transfers performed using an air-assisted lateral transfer device, manual transfer, a rolling board, and a sliding board were made based on the maximum range of motion observed., Results: Significantly less lateral bending at C5-C6 was observed in air-assisted device transfers when compared with the two other boards. Air-assisted device transfers produced significantly less axial rotation at T12-L2 than the rolling board, and manual transfers produced significantly less thoracolumbar rotation than both the rolling and sliding boards. No other significant differences were observed in cervical or lumbar motion. Motion versus time plots indicated that the log roll maneuvers performed during rolling board and sliding board transfers contributed most of the observed motion., Conclusions: Each transfer technique produced substantial motion. Transfer techniques that do not include the logroll maneuver can significantly decrease some components of cervical and lumbar motion. Thus, some spinal motion can be reduced through selection of transfer technique.

Objective: To evaluate the effect of proximal ulnar rotational osteotomy (PURO) on the contact mechanics and 3-dimensional (3D) alignment of cadaveric normal dog elbows., Study Design: Ex vivo biomechanical study., Animals: Unpaired thoracic limbs from 12 dogs (mean ± SD weight, 26 ± 4 kg)., Methods: PURO consisted of a transverse osteotomy with 30° external rotation of the proximal segment. With the limb under 200 N axial load, contact area (CA), mean contact pressure (CP) and peak contact pressure (PCP) were measured using digital pressure sensors in the medial and lateral compartments and 3D static elbow poses were obtained, before and after PURO. Each specimen was tested at 115°, 135°, and 155° elbow flexion, with the antebrachium in neutral rotation, in 28° supination, and in 16° pronation. Repeated measures ANOVAs with post-hoc Bonferroni (P ≤ .05) were performed., Results: PURO caused significant changes, mostly at 135° elbow flexion and neutral antebrachial rotation, characterized by decreased CP (10%) and PCP (10%) in the medial compartment, and increased CP (27%) and PCP (23%) in the lateral compartment. The apex of the medial coronoid process translated 3.4 mm caudally, 1.7 mm abaxially, and rotated 1.8° externally relative to the radial head. Humeroradial varus angulation reduced by 6.7°., Conclusions: In limited poses, PURO displaces the medial coronoid process caudally and abaxially and shifts contact pressures towards the lateral elbow compartment by decreasing varus angulation., (© Copyright 2012 by The American College of Veterinary Surgeons.)

Objective: To determine mechanical properties of various prosthetic materials secured to cadaveric canine femurs via various methods and to compare results with those for isolated loops of prosthetic material., Sample: 80 femurs obtained from cadavers of skeletally mature large-breed dogs., Procedures: 10 femoral constructs in each of 8 groups (single circumfabellar loop of polyethylene cord, double loop of polyethylene tape secured via a bone anchor [BAPT], single or double circumfabellar loops of nylon leader material [CNL] or polyethylene tape [CPT], or single or double loops of polyethylene tape secured via a toggle placed through a bone tunnel [BTPT]) and 10 isolated loops of prosthetic material in each corresponding configuration were tested. Stress relaxation, creep, elongation, load at 3 mm of displacement, stiffness, and peak load at failure were determined., Results: 5 single CNL constructs failed before completion of testing. Double CNL and single circumfabellar polyethylene cord constructs had the lowest loads at 3 mm of displacement. Single and double CPT constructs had the highest stiffness. Double BTPT and CPT constructs had the highest peak loads at failure. Double BTPT, double CPT, and BAPT constructs were mechanically superior on the basis of lower creep and stress relaxation and higher stiffness and load at 3 mm of displacement versus other constructs. Stiffness of femoral constructs was 28% to 69% that of corresponding isolated prosthetic loops., Conclusions and Clinical Relevance: Double BTPT, double CPT, and BAPT constructs were mechanically superior to other constucts. Mechanical properties and methods of anchorage and securing of free ends of prostheses contributed to mechanical properties of constructs.

Objective: To evaluate the effects of antebrachial rotation at 3 elbow flexion angles on contact mechanics and 3-dimensional (3D) alignment of normal dog elbows., Study Design: Ex vivo biomechanical study., Animals: Unpaired thoracic limbs from 18 dogs (mean ± SD weight, 27 ± 4 kg)., Methods: With the limb under 200 N axial load, digital pressure sensors measured contact area (CA), mean contact pressure (MCP), peak contact pressure (PCP), and PCP location in the medial and lateral elbow compartments, and 3D static poses of the elbow were obtained. Each specimen was tested at 115°, 135°, and 155° elbow flexion, with the antebrachium in a neutral position, in 28° supination, and in 16° pronation. Repeated measure ANOVAs with post-hoc Bonferroni (P ≤ .0167) were performed., Results: Both pronation and supination decreased CA by 16% and 8% and increased PCP by 5% and 10% in the medial and lateral compartments, respectively. PCP location moved 2.3 mm (1.8-3.2 mm) closer to the apex of the medial coronoid process in pronation and 2.0 mm (1.8-2.2 mm) farther away in supination. The radial head and medial coronoid process rotated 5.4° and 1.9° internally during pronation and 7.2° and 1.2° externally during supination., Conclusions: Contact mechanics and 3D alignment of normal dog elbows varied significantly at different elbow poses., (© 2012 by The American College of Veterinary Surgeons.)

Testosterone enanthate (TE) administration attenuates bone loss in orchiectomized (ORX) rats. However, testosterone administration may increase risk for prostate/lower urinary tract related adverse events and polycythemia in humans. Trenbolone enanthate (TREN) is a synthetic testosterone analogue that preserves bone mineral density (BMD) and results in less prostate enlargement than testosterone in young ORX rodents. The purpose of this experiment was to determine if intramuscular TREN administration attenuates bone loss and maintains bone strength, without increasing prostate mass or hemoglobin concentrations in skeletally mature ORX rodents. Forty, 10 month old male F344/Brown Norway rats were randomized into SHAM, ORX, ORX+TE (7.0mg/week), and ORX+TREN (1.0mg/week) groups. Following surgery, animals recovered for 1 week and then received weekly: vehicle, TE, or TREN intramuscularly for 5 weeks. ORX reduced total and trabecular (t) BMD at the distal femoral metaphysis compared with SHAMs, while both TREN and TE completely prevented these reductions. TREN treatment also increased femoral neck strength by 28% compared with ORX animals (p<0.05), while TE did not alter femoral neck strength. In addition, TE nearly doubled prostate mass, compared with SHAMs (p<0.05). Conversely, TREN induced a non-significant 20% reduction in prostate mass compared with SHAMs, ultimately producing a prostate mass that was 64% below that found in ORX+TE animals (p<0.01). Hemoglobin concentrations and levator ani/bulbocavernosus (LABC) muscle mass were elevated in ORX+TE and ORX+TREN animals to a similar degree above both SHAM and ORX conditions (p<0.01). In skeletally mature rodents, both high-dose TE and low-dose TREN completely prevented the ORX-induced loss of tBMD at the distal femoral metaphysis and increased LABC mass. TREN also augmented femoral neck strength and maintained prostate mass at SHAM levels. These findings indicate that TREN may be an advantageous agent for future clinical trials evaluating agents capable of preventing bone loss resulting from androgen deficiency., (Published by Elsevier Inc.)

Osteoarthritis (OA) is the most frequent cause of disability in the United States, with the medial compartment of the knee being most commonly affected. The initiation and progression of knee OA is influenced by many factors, including kinematics. In response to loading during weight-bearing activity, cartilage in healthy knees demonstrates spatial adaptations in morphology and mechanical properties. These adaptations allow certain regions of the cartilage to respond to loading; other regions are less well suited to accommodate loading. Alterations in normal knee kinematics shift loading from cartilage regions adapted for loading to regions less well suited for loading, which leads to the initiation and progression of degenerative processes consistent with knee OA. Kinematic variables that are associated with the development, progression, and severity of knee OA are the adduction moment and tibiofemoral rotation. Because of its strong correlation with disease progression and pain, the peak adduction moment during gait has been identified as a target for treatment design. Gait modification offers a noninvasive option for seeking significant reductions. Gait modification has the potential to reduce pain and slow the progression of medial compartment knee OA., (Copyright © 2012 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Background: Joint pain is a common musculoskeletal complaint of morbidly obese patients that can result in gait abnormalities, perceived mobility limitations, and declining quality of life (QOL). It is not yet known whether weight loss 3 months after bariatric surgery can induce favorable changes in joint pain, gait, perceived mobility, and QOL. Our objectives were to examine whether participants who had undergone bariatric surgery (n = 25; laparoscopic Roux-en-Y gastric bypass or laparoscopic adjustable gastric banding) demonstrate improvements in joint pain, gait (speed, stride/step length, width of base of support, toe angles, single/double support, swing and stance time, functional ambulatory profile), mobility, and QOL by 3 months compared with nonsurgical controls (n = 20). The setting was an orthopedics laboratory at a university hospital in the United States., Methods: The present study was a prospective, comparative study. Numeric pain scales (indicating the presence and severity of pain), mobility-related surveys, and the Medical Outcomes Study short-form 36-item questionnaire (SF-36) were completed, and gait and walking speed were assessed at baseline and at month 3., Results: The bariatric group lost an average of 21.6 ± 7.7 kg. Significant differences existed between the 2 groups at month 3 in step length, heel to heel base of support, and the percentage of time spent in single and double support during the gait cycle (all P <.05). The severity of low back pain and knee pain decreased by 54% and 34%, respectively, with no changes in the control group (P = .05). The walking speed increased by 15% in the bariatric group (108-123 cm/s; P <.05) but not in the control group. Compared with the control group, fewer bariatric patients perceived limitations with walking and stair climbing by month 3. The bariatric group had a 4.8-cm increase in step length, 2.6% increase in single support time during the gait cycle, and 2.5-cm reduction in the base of support (all P <.05). The SF-36 physical component scores increased 11.8 points in the bariatric group compared with the control group, which showed no improvement by month 3 (P <.0001)., Conclusions: Improvements in some, but not all, gait parameters, walking speed, and QOL and of perceived functional limitations occur by 3 months after a bariatric procedure., (Copyright © 2012 American Society for Metabolic and Bariatric Surgery. Published by Elsevier Inc. All rights reserved.)

Object: The proper prehospital and inpatient management of patients with unstable spinal injuries is critical for prevention of secondary neurological compromise. The authors sought to analyze the amount of motion generated in the unstable thoracolumbar spine during various maneuvers and transfers that a trauma patient would typically be subjected to prior to definitive fixation., Methods: Five fresh cadavers with surgically created unstable L-1 burst fractures were tested. The amount of angular motion between the T-12 and L-2 vertebral segments was measured using a 3D electromagnetic motion analysis device. A complete sequence of maneuvers and transfers was then performed that a patient would be expected to go through from the time of injury until surgical fixation. These maneuvers and transfers included spine board placement and removal, bed transfers, lateral therapy, and turning the patient prone onto the operating table. During each of these, the authors performed what they believed to be the most commonly used versus the best techniques for preventing undesirable motion at the injury level., Results: When placing a spine board there was more motion in all 3 planes with the log-roll technique, and this difference reached statistical significance for axial rotation (p = 0.018) and lateral bending (p = 0.003). Using logrolling for spine board removal resulted in increased motion again, and this was statistically significant for flexion-extension (p = 0.014). During the bed transfer and lateral therapy, the log-roll technique resulted in more motion in all 3 planes (p ≤ 0.05). When turning the cadavers prone for surgery there was statistically more angular motion in each plane for manually turning the patient versus the Jackson table turn (p ≤ 0.01). The total motion was decreased by almost 50% in each plane when using an alternative to the log-roll techniques during the complete sequence (p ≤ 0.007)., Conclusions: Although it is unknown how much motion in the unstable spine is necessary to cause secondary neurological injury, the accepted tenet is to minimize motion as much as possible. This study has demonstrated the angular motion incurred by the unstable thoracolumbar spine as experienced by the typical trauma patient from the field to positioning in the operating room using the best and most commonly used techniques. As previously reported, using the log-roll technique consistently results in unwanted motion at the injured spinal segment.

Introduction: Obesity rates continue to rise and more total hip arthroplasty procedures are being performed in progressively younger, obese patients. Hence, maintenance of long term physical function will become very important for quality of life, functional independence and hip prosthesis survival. Presently, there are no reviews of the long term efficacy of total hip arthroplasty on physical function. This review: 1) synopsized available data regarding obesity effects on long term functional outcomes after total hip arthroplasty, and 2) suggested future directions for research., Methods: A literature search was conducted from 1965 to January of 2011 for studies that evaluated long term functional outcomes at one year or longer after THA in obese (body mass index values ≥ 30 kg/m2) and non-obese patients (body mass index <30 kg/m2)., Results: Five retrospective studies and 18 prospective studies were identified as those that assessed physical function before surgery out to ≥ one year after total hip arthroplasty. Study sample sizes ranged from 108-18,968 and followed patients from one to twenty years. Total hip arthroplasty confers significant pain reduction and improvement in quality of life irrespective of body mass index. Functional improvement occurred after total hip arthroplasty among all studies, but obese patients generally did not attain the same level of physical function by the follow-up time point., Discussion: Uncontrolled obesity after total hip arthroplasty is related to worsening of comorbidities and excessive health care costs over the long term. Aggressive and sustainable rehabilitation strategies that include physical exercise, psychosocial components and behavior modification may be highly useful in maximizing and maintaining weight loss after total hip arthroplasty.

Background: Currently, up to 25% of patients with spinal cord injuries may experience neurologic deterioration during the initial management of their injuries. Therefore, more effective procedures need to be established for the transportation and care of these to reduce the risk of secondary neurologic damage. Here, we present more acceptable methods to minimize motion in the unstable spine during the management of patients with traumatic spine injuries., Methods: This review summarizes more than a decade of research aimed at evaluating different methods of caring for patients with spine trauma., Results: The most commonly utilized technique to transport spinal cord injured patients, the log rolling maneuver, produced more motion than placing a patient on a spine board, removing a spine board, performing continuous lateral therapy, and positioning a patient prone for surgery. Alternative maneuvers that produced less motion included the straddle lift and slide, 6 + lift and slide, scoop stretcher, mechanical kinetic therapy, mechanical transfers, and the use of the operating table to rotate the patient to the prone position for surgical stabilization., Conclusions: The log roll maneuver should be removed from the trauma response guidelines for patients with suspected spine injuries, as it creates significantly more motion in the unstable spine than the readily available alternatives. The only exception is the patient who is found prone, in which case the patient should then be log rolled directly on to the spine board utilizing a push technique.

Purpose. We have observed worsening thumb pain following carpal tunnel release (CTR) in some patients. Our purpose was to determine the effect of open CTR on thumb carpometacarpal (CMC) biomechanics. Methods. Five fresh-frozen cadaver arms with intact soft tissues were used. Each specimen was secured to a jig which fixed the forearm at 45° supination, and the wrist at 20° dorsiflexion, with thumb pointing up. The thumb was axially loaded with a force of 130 N. We measured 3D translation and rotation of the trapezium, radius, and first metacarpal, before and after open CTR. Motion between radius and first metacarpal, radius and trapezium, and first metacarpal and trapezium during loading was calculated using rigid body mechanics. Overall stiffness of each specimen was determined. Results. Total construct stiffness following CTR was reduced in all specimens but not significantly. No significant changes were found in adduction, pronation, or dorsiflexion of the trapezium with respect to radius after open CTR. Motion between radius and first metacarpal, between radius and trapezium, or between first metacarpal and trapezium after open CTR was not decreased significantly. Conclusion. From this data, we cannot determine if releasing the transverse carpal ligament alters kinematics of the CMC joint.

Introduction: Previous research has found that the log roll (LR) technique produces significant motion in the spinal column while transferring a supine patient onto a spine board. The purpose of this project was to determine whether log rolling a patient with an unstable spine from prone to supine with a pulling motion provides better thoracolumbar immobilization compared to log rolling with a push technique., Methods: A global instability was surgically created at the L1 level in five cadavers. Two spine-boarding protocols were tested (LR Push and LR Pull). Both techniques entailed performing a 180° LR rotation of the prone patient from the ground to the supine position on the spine board. An electromagnetic tracking device registered motion between the T12 and L2 vertebral segments. Six motion parameters were tracked. Repeated-measures statistical analysis was performed to evaluate angular and translational motion., Results: Less motion was produced during the LR Push compared to the LR Pull for all six motion parameters. The difference was statistically significant for three of the six parameters (flexion-extension, axial translation, and anterior-posterior (A-P) translation)., Conclusions: Both the LR Push and LR Pull generated significant motion in the thoracolumbar spine during the prone to supine LR. The LR Push technique produced statistically less motion than the LR Pull, and should be considered when a prone patient with a suspected thoracolumbar injury needs to be transferred to a long spine board. More research is needed to identify techniques to further reduce the motion in the unstable spine during prone to supine LR.