Final answer:
The recommended diameter Half Pin for usage in the humerus historically followed the rule of thumb of 5 diameters side-to-side and 7-8 diameters deep, but newer recommendations suggest up to 8 diameters side-to-side and 15 diameters deep for improved stability.
Step-by-step explanation:
The selection of a Half Pin diameter for use in the humerus is based on biomechanical considerations to provide adequate stability and support for the bone while minimizing the risk of complications. In the past, a common rule of thumb was to use a Half Pin with a diameter that allows for at least 5 diameters of space from side-to-side and 7 to 8 diameters deep within the humerus. However, newer studies and practice have suggested using larger dimensions – up to 8 diameters side-to-side and 15 diameters deep – to ensure better fixation and stability.