Section 1: The dataset

    DIAMETER OF THE HUMERAL HEAD WAS BASED ON:
The following are studies, thoughts and ideas. Nothing is validated or peer reviewed. A think tank for discussion and entertainment. Predicted dimensions or sizes or images and drawings are not intended to use or treat. 

section 2: estimation of FLEX/PERFORM humeral stem size based on MINOR humeral head diameter and thickness lateral humeral cortex shaft

FLEX

Enter Messieh tuberosity distance from the preoperative CT scan (mm):


AND enter the cortical wall thickness of humeral canal from the preoperative CT scan (mm):



The 75% DFR estimated size is :

entertainment purposes only. Not validated. each physician must use their judgement. All rights reserved

PERFORM
SECTION 3: BONE QUALITY
Enter the thickness of the lateral wall humeral cortex (mm); not validated; entertainment purposes only; not intended to diagnose
The T-Score is:
The cortical thickness of the proximal humeral diaphysis predicts bone mineral density of the proximal humerus
​June 2003
The Bone & Joint Journal 85(4):611-7
We found clinically useful threshold values for the deltoid tuberosity index less than 1.4 and for the Tingart measurement less than 5 mm for determination of low bone quality of the proximal humerus.
Deltoid Tuberosity Index: A Simple Radiographic Tool to Assess Local Bone Quality in Proximal Humerus FracturesChristian Spross, MD, Nicola Kaestle, MD, Emanuel Benninger, MD, Jürgen Fornaro, MD, Johannes Erhardt, MD, Vilijam Zdravkovic, MD, and Bernhard Jost, Prof, MD
SECTION 3: Messieh humeral retroversion measurement angle technique
The elbow transepicondylar axis may not be required
​Data in progress; Not yet validated;
 The mean humeral retroversion is 31.42° ± 12.10° using CT methods; the method using the bicipital groove center showed lower concordance, whereas the method using the posterior margin of the bicipital groove demonstrated higher concordance
Not validated

SECtion 4: mathematical description of the humeral head diameter

Observations of the shoulder joint, combined with a well controlled CT scan dataset, were the primary source of data enabling the derivation of the anatomy of the proximal humerus. This is a key step to achieve balance with reverse shoulder replacements . The major/ minor diameters of the humeral head is normally 1.1 and follows Keplers law for planetary orbits. (Not validated)
SECTION 5:  POSTERIOR HUMERAL SUBLUXATION BASED ON GLENOID VERSION

SECTION 6: Eccentricity of PROXIMAL HUMERUS
Picture

​The eccentricity of an ellipse can be defined as ratio between foci (2ea) to the major axis 2a  
http://hyperphysics.phy-astr.gsu.edu/hbase/kepler.html#c4​
Picture
Minor axis 44
Major axis 48


eccentricty= .4 (range = .47-5)
not validated
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