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Liang-Ching Tsai, Irving S. Scher and Christopher M. Powers

The purpose of this study is to describe an MRI-based EMG-driven knee model to quantify tibiofemoral compressive and shear forces. Twelve healthy females participated. Subjects underwent 2 phases of data collection: (1) MRI assessment of the lower extremity to quantify muscle volumes and patella tendon orientation and (2) biomechanical evaluation of a drop-jump task. A subject-specific EMG-driven knee model that incorporated lower extremity kinematics, EMG, and muscle volumes and patella tendon orientation estimated from MRI was developed to quantify tibiofemoral shear and compressive forces. A resultant anterior tibial shear force generated from the ground reaction force (GRF) and muscle forces was observed during the first 30% of the stance phase of the drop-jump task. All of the muscle forces and GRF resulted in tibiofemoral compression, with the quadriceps force being the primary contributor. Acquiring subject-specific muscle volumes and patella tendon orientation for use in an EMG-driven knee model may be useful to quantify tibiofemoral forces in persons with altered patella position or muscle atrophy following knee injury or pathology.

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Megan P. Brady and Windee Weiss

clinical diagnostic tests and magnetic resonance imaging (MRI) is debatable. 1 , 3 – 6 Because of the frequency of knee injury, 3 MRI is a common diagnostic tool used for imaging and diagnosis. 5 ACL tears are also diagnosed using clinical diagnostic tests. 1 , 3 – 6 Patient outcomes are dependent on a

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Hans Kainz, Hoa X. Hoang, Chris Stockton, Roslyn R. Boyd, David G. Lloyd and Christopher P. Carty

occasions with at least 1 week between the first and second occasion. On the first occasion participants presented for magnetic resonance imaging (MRI) and 3D motion capture. On the second occasion participants presented for 3D motion capture only. Ethics approval was obtained from the Children’s Health

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Megan P. Brady and Windee Weiss

Clinical Scenario:

Common injuries in high-level and recreational athletes, nonathletes, and the elderly are medial and lateral meniscus tears. Diagnosis of meniscus tears is done with clinical exam, magnetic resonance imaging (MRI), and arthroscopy. The gold standard is arthroscopy, but accuracy of a clinical exam versus MRI diagnosis of meniscus tears is in question. A clinician’s ability to detect a meniscus tear is beneficial to the patient from a timing standpoint. The process of obtaining an MRI and results could be lengthy, but if the meniscus tear is accurately diagnosed clinically, the patient could be suspended from athletics or specific job duties to prevent further injury. In addition, rehabilitation could be initiated immediately, resulting in better outcomes for the patient. The ability to diagnose a meniscus tear clinically could initiate the rehabilitation process much sooner than waiting for MRI testing and results. Beginning the rehabilitation phase earlier may lead to faster postoperative rehabilitation and better patient outcomes. Clinical detection of a meniscus tear will facilitate possible suspension, early treatment, and rehabilitation recommendations, but the MRI will provide more specific information about the injury, including type and location of tear. Thus, surgical decisions such as operative versus nonoperative or meniscectomy versus repair would be based on MRI results.

Focused Clinical Question:

Is a clinical exam as accurate as an MRI scan for diagnosing meniscus tears?

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John M. Mayer, James E. Graves, Todd M. Manini, James L. Nuzzo and Lori L. Ploutz-Snyder

The purpose of this preliminary study was to assess lumbar multifidus, erector spinae, and quadratus lum-borum muscle activity during lifts as measured by changes in transverse relaxation time (T2) from magnetic resonance imaging (MRI). Thirteen healthy adults performed dynamic squat, stoop, and asymmetric stoop lifts at a standard load, with each lift followed by MRI. Increase in T2 for the multifidus and erector spinae was greater for the stoop than squat. No difference in T2 increase was noted between the multifidus and erector spinae for the squat or stoop. Increase in T2 for the contralateral multifidus was less for the asymmetric stoop than stoop. Future research using MRI and other biomechanical techniques is needed to fully characterize lumbar muscle activity during lifts for various populations, settings, postures, and loads.

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Igor Setuain, Mikel Izquierdo, Fernando Idoate, Eder Bikandi, Esteban M. Gorostiaga, Per Aagaard, Eduardo L. Cadore and Jesús Alfaro-Adrián

Context:

The muscular function restoration related to the type of physical rehabilitation followed after anterior cruciate ligament reconstruction (ACLR) using autologous hamstring tendon graft in terms of strength and cross-sectional area (CSA) remain controversial.

Objective:

To analyze the CSA and force output of quadriceps and hamstring muscles in subjects following either an Objective Criteria-Based Rehabilitation (OCBR) algorithm or the usual care (UCR) for ACL rehabilitation in Spain, before and 1 year after undergoing an ACLR.

Design:

Longitudinal clinical double-blinded randomized controlled trial.

Setting:

Sports-medicine research center.

Patients:

40 recreational athletes (30 male, 10 female [24 ± 6.9 y, 176.55 ± 6.6 cm, 73.58 ± 12.3 kg]).

Intervention:

Both groups conducted differentiated rehabilitation procedures after ACLR. Those belonging to OCBR group were guided in their recovery according to the current evidence-based principles. UCR group followed the national conventional approach for ACL rehabilitation.

Main Outcome Measures:

Concentric isokinetic knee joint flexor-extension torque assessments at 180°/s and Magnetic Resonance Imaging (MRI) evaluations were performed before and 12 months after ACLR. Anatomical muscle CSA (mm2) was assessed, in Quadriceps, Biceps femoris, Semitendinous, Semimembranosus, and Gracilis muscles at 50% and 70% femur length.

Results:

Reduced muscle CSA was observed in both treatment groups for Semitendinosus and Gracilis 1 year after ACLR. At 1-year follow-up, subjects allocated to the OCBR demonstrated greater knee flexor and extensor peak torque values in their reconstructed limbs in comparison with patients treated by UCR.

Conclusions:

Objective atrophy of Semitendinosus and Gracilis muscles related to surgical ACLR was found to persist in both rehabilitation groups. However, OCBR after ACLR lead to substantial gains on maximal knee flexor strength and ensured more symmetrical anterior-posterior laxity levels at the knee joint.

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Grant E. Norte, Katherine R. Knaus, Chris Kuenze, Geoffrey G. Handsfield, Craig H. Meyer, Silvia S. Blemker and Joseph M. Hart

also prohibit the use of force-based measurement techniques, such as isometric knee extension torque and muscle activation, or confound the accuracy of strength estimates during early phases of recovery. Magnetic resonance imaging (MRI)-based volumetric assessment of skeletal muscle, on the other hand

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John W. Chow, Warren G. Darling and James C. Ehrhardt

The purpose of this study was to determine the coordinates of the origin and insertion, muscle volumes, lengths, lines of action, and effective moment arm of the quadriceps muscles in vivo using magnetic resonance imaging (MRI) and radiography for a pilot study involving musculoskeletal modeling. Two magnetic resonance scans were performed, and axial images were obtained for the left thigh of a female subject in the anatomical position to measure muscle volume, coordinates of the origin and insertion, and muscle belly length at the anatomical position of each quadriceps muscle. Six knee radiographs were used to determine the effective moment arm of the quadriceps force at different knee flexion angles. A combination of MRI and radiography data was used to compute the muscle lengths at different knee flexion angles. The coordinates of the vastus lateralis, muscle volumes of individual quadriceps muscles, and effective moment arms were clearly different from the corresponding values from cadaver data reported in the literature. These comparisons demonstrate the advantages of using personalized muscle parameters instead of those collected from cadavers and dry-bone specimens.

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Marion Kellermann, Christoph Lutter and Thilo Hotfiel

relative immobilization of 5 days after injury was performed, according to the athlete’s pain level and ability to walk. Magnetic resonance imaging (MRI), which was performed to evaluate the injury’s severity as gold standard, revealed a grade III muscle injury of the semimembranosus muscle with muscle

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Thomas Cattagni, Vincent Gremeaux and Romuald Lepers

-associated differences in triceps surae muscle composition and strength—an MRI-based cross-sectional comparison of contractile, adipose and connective tissue . BMC Musculoskelet Disord . 2014 ; 15 ( 1 ): 209 . doi: 10.1186/1471-2474-15-209 21. Kanis JA , McCloskey EV , Johansson H , Oden A , Melton LJ