Artikel
Validierung eines Robotersystems zur Erforschung passiver gleno-humeraler Kinematik
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Veröffentlicht: | 2. Oktober 2012 |
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Gliederung
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Objective: The glenohumeral (GH) joint has the greatest range of motion in the human body but little intrinsic stability, thereby increasing its susceptibility to excessive translations and injury. Current models used to study shoulder kinematics are limited because they isolate the GH joint, implement dynamic motion patterns with low reproducibility, and track motions discontinuously or with limited accuracy. To overcome these limitations, we have designed a novel system in which the entire shoulder girdle is studied using highly reproducible trajectories created by a robotic actuator to control a full cadaveric torso.
Methods: High-speed cameras track bone markers and calibrated anatomical scapular landmarks for continuous registration of the center of the GH joint. In this study, we valuated the system`s capacity to capture reproducibly GH translations in intact and pathologic shoulder conditions. We subjected a left and a right shoulder of two anthropometrically different cadaveric torsos to three sequential trials of humeral elevation prior to and after the implementation and restoration of scapular winging as well as a full thickness supraspinatus tear.
Results and conclusions: The system was consistently capable of detecting differences in GH translations as small as 0.5 mm between the intact, altered, and restored shoulder presentations. For each condition, three trials were performed. The registration of GH translations was highly reproducible with intraclass correlation coefficients (ICC) of 0.77 to 0.99 (P<0.001) and standard deviations (SD) of 0.16 mm to 0.64 mm. These data illustrate the systems high validity in describing GH kinematics.
With this system we will be able to study complex shoulder joint kinematics using a whole torso and thus no impairing the adjacent joints.