James A. Johnson

Graham J W King31
Cynthia E Dunning7
George S Athwal7
James R Brownhill6
31Graham J W King
7Cynthia E Dunning
7George S Athwal
6James R Brownhill
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The continuous success of Wikipedia depends upon its capability to recruit and engage new editors, especially those with new knowledge and perspectives. Yet Wikipedia over the years has become a complicated bureaucracy that may be difficult for newcomers to navigate. Mentoring is a practice that has been widely used in offline organizations to help new(More)
Screw displacement axes (SDAs) have been employed to describe joint kinematics in biomechanical studies. Previous reports have investigated the accuracy of SDAs combining various motion analysis techniques and smoothing procedures. To our knowledge, no study has assessed SDA accuracy describing the relative movement between adjacent bodies with an(More)
Previous investigations have implemented screw displacement axes (SDAs) to define the elbow flexion axis for proper positioning of dynamic external fixators and endoprostheses. However, results across studies vary, which may be attributed to forearm position (pronation-supination) during elbow motion, or the mode of loading (active/passive) employed to(More)
There exists a lack of quantitative data in the literature related to the torque produced during axial forearm rotation and the electromyographic (EMG) activity of the muscles involved. Therefore, the purpose of this study was to compare the relative EMG activity of four forearm muscles during resisted forearm rotation. A custom-built device capable of(More)
This in vitro study evaluated the effects of four different muscle-loading ratios on active glenohumeral joint abduction. Eight cadaveric shoulders were tested using a shoulder simulator designed to reproduce unconstrained abduction of the humerus via computer-controlled pneumatic actuation. Forces were applied to cables that were sutured to tendons or(More)
BACKGROUND The anterior bundle of the medial collateral ligament (AMCL) of the elbow has been shown to be the most important valgus stabilizer of the elbow. However, the isometry of this band has not been quantified. HYPOTHESIS Isometric fibers exist within the AMCL, and these fibers are located within its central region. STUDY DESIGN Controlled(More)
This study was conducted to determine the effect of in vitro passive and active loading on humeral head translation during glenohumeral abduction. A shoulder simulator produced unconstrained active abduction of the humerus in 8 specimens. Loading of the supraspinatus, subscapularis, infraspinatus/teres minor, and anterior, middle, and posterior deltoid(More)
BACKGROUND The coracoacromial ligament (CAL) is an important restraint to superior shoulder translation. The effect of CAL release on superior stability following the Latarjet is unknown; therefore, our purpose was to compare the effect of two Latarjet techniques and allograft reconstruction on superior instability. MATERIALS AND METHODS Eight cadaveric(More)
PURPOSE To determine the locations and volumes of bone requiring resection to restore range of motion in patients with osteoarthritis of the elbow, using computational modeling. METHODS A total of 30 patients with primary osteoarthritis of the elbow and restricted range of motion underwent computed tomography. We used the computed tomography data to(More)
This study determined the relationship between the medullary canal axis and the flexion-extension axis of the distal humerus as they relate to implant selection and design for elbow arthroplasty. Computed tomography scans of 40 fresh-frozen cadaveric specimens were analyzed with computer-aided design software. The anterior offset and cubital angle were(More)