The relevance of neutral arm positioning for true ap-view X-ray to provide true projection of the humeral head shaft angle
| Autor: | Michael Blauth, P. Mayrhofer, Clemens Hengg, Markus Wambacher, Franz Kralinger, Simon A. Euler |
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| Rok vydání: | 2015 |
| Předmět: |
Orthotic Devices
Sling (implant) Proximal humerus Rotation Oblique projection Models Biological Patient Positioning 03 medical and health sciences 0302 clinical medicine Humans Medicine Orthopedics and Sports Medicine Orthodontics 030222 orthopedics biology Shoulder Fracture business.industry 030229 sport sciences General Medicine Anatomy biology.organism_classification Orthotic device Radiography body regions Valgus True projection Humeral Head Shoulder Fractures Diagnostic assessment Surgery business |
| Zdroj: | Archives of Orthopaedic and Trauma Surgery. 136:213-221 |
| ISSN: | 1434-3916 0936-8051 |
| Popis: | Textbooks commonly recommend using the true anterior–posterior (ap)-view with the patient’s arm in a sling and therefore in internal rotation (IR) for radiologic diagnostic assessment of the proximal humerus after trauma. However, IR or external rotation (ER) may affect the projection of the head shaft angle (HSA) and therefore bias the diagnostic conclusion significantly. We hypothesized that neutral rotation (NR) of the arm is mandatory for true ap-view to provide true projection of the HSA. A simplified geometrical model of the proximal humerus was used to examine the influence of different arm positions and angulations of the central ray in relation to the projection of the HSA. Both ER and IR misleadingly suggested an increased valgus angle. Simulating the true ap-view with the central ray in cranio-caudal direction, IR changed the projection of the HSA substantially. In conclusion, standard fixation of the patient’s arm in a shoulder sling in IR for true ap-view may result in an oblique projection, potentially leading to incorrect surgical implications. To prevent misdiagnosed valgus or varus angulation, NR of the arm should be obeyed when performing true ap-view X-ray. We, therefore, highly recommend to overcome the traditionally arm position, ensuring the true amount of dislocation to assure correct surgical implications and comparable follow-up examinations. |
| Databáze: | OpenAIRE |
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