All of the following are hallmarks of RTC arthropathy, except:

The hallmark features of rotator cuff (RTC) arthropathy include various observable changes in imaging studies that reflect the pathology associated with rotator cuff injuries.

In the case of increased acromio-humeral distance, this finding is not characteristic of RTC arthropathy; rather, it may suggest that there is no significant rotator cuff tear or that the humeral head is positioned normally relative to the acromion. In RTC arthropathy, one would generally expect to see a decreased acromio-humeral distance, indicating superior migration of the humeral head due to insufficient rotator cuff function.

On the other hand, severe rotator cuff muscle atrophy evident on CT or MRI is a significant finding in RTC arthropathy as it indicates chronic rotator cuff injury or dysfunction. Humeral head elevation on X-ray reflects the compensatory changes in shoulder mechanics when the rotator cuff is unable to stabilize the humeral head appropriately. Intact axillary nerve conduction on EMG or nerve conduction study suggests the nerve is functioning properly, which is important for muscle function around the shoulder, but does not align with the pathology associated with RTC arthropathy that involves rotator cuff dysfunction.

Collectively, these characteristics emphasize the