Conventional Humeral Retroversion Measurements Using Computed Tomography Slices or Ultrasound Images Are Not Correlated With the 3-Dimensional Humeral Retroversion Angle.

Background: Humeral retroversion angles determined by previous techniques are varied and/or biased by morphologic variations of the proximal and distal humerus, and their validity should be revisited. To overcome the limitations of previous studies associated with 2-dimensional (2D) images and the reference axes, a 3-dimensional (3D) measurement of humeral retroversion is required. However, comparisons of 2D imaging methods with the 3D computed tomography (CT) measurement as a reference standard have not been heretofore performed.

Scapular Kinematics During Late Cocking of a Simulated Throwing Activity in Baseball Players With Shoulder Injury: A Cross-Sectional Study Using a 3D-to-2D Registration Technique.

Context: Abnormal scapular kinematics during throwing motion in baseball players with shoulder disorders has not yet been clarified, although altered scapular position has been suggested to be associated with shoulder disorder.

Objective: To determine if the shoulders of baseball players with throwing disorders demonstrate abnormal scapular kinematics during the simulated arm-cocking phase of throwing activity.

Design: Cross-sectional study.

Reliability and validity in measurement of true humeral retroversion by a three-dimensional cylinder fitting method.

Hypothesis And Background: Humeral retroversion is defined as the orientation of the humeral head relative to the distal humerus. Because none of the previous methods used to measure humeral retroversion strictly follow this definition, values obtained by these techniques vary and may be biased by morphologic variations of the humerus. The purpose of this study was 2-fold: to validate a method to define the axis of the distal humerus with a virtual cylinder and to establish the reliability of 3-dimensional (3D) measurement of humeral retroversion by this cylinder fitting method.

The effects of a semi-rigid brace or taping on talocrural and subtalar kinematics in chronic ankle instability.

Background: A semi-rigid brace or taping is often used to prevent giving-ways in the joint with chronic ankle instability (CAI). However, it remains unknown whether the application of a semi-rigid brace or taping modifies abnormal kinematics in CAI joints. The objective of this study was to determine if the application of a semi-rigid brace or taping of the ankle normalizes abnormal weight-bearing kinematics in CAI joints during ankle internal rotation in plantar flexion.

In vivo kinematics of the talocrural and subtalar joints during weightbearing ankle rotation in chronic ankle instability.

Background: Chronic ankle instability (CAI) results in abnormal ankle kinematics, but there exists limited quantitative data characterizing these alterations. This study was undertaken to investigate kinematic alterations of the talocrural and subtalar joints in CAI.

Methods: A total of 14 male patients with unilateral CAI (mean age = 21.