It looked to me that as his body was forced into Aldridge's, the latter's elbow was forced into the back of Hayward's hand, with his palm facing his own abdomen or chest. As the bodies hit hard, a bunch of force was imparted into the hand from the single point of that elbow. It didn't look like what the internet says that a boxer's fracture is.I'd be very surprised. Boxer's fracture is usually 5th metacarpal (occasionally also in combination with 4th as well) that occurs when punching something hard with closed fist. It's at a specific location and has a specific angulation, hard to imagine Hayward did that just awkwardly running into a screen.
Probably more like the 2nd Xray down on the left, not the top X-ray on the left.
http://pathologies.lexmedicus.com.au/pathologies/metacarpal-fractures