Her left look appears to have 'sunken'. We believe this happened as a result of aggression from another cow, and sadly this cow was propelled forwards into a gate edge, which consequently knocked her hook bone out of place.
She became very slightly lame on her left side and walked slower around a week - we gave her painkillers to ease the pain and made sure that she was kept indoors overnight while she was recovering.
This happened around 3 months ago and to this day she is still part of the milking herd. She does not require any more attention than any other cow and is eating, milking and bulling normally.
If you have a cow with a knocked off hook, do not expect the worst. Usually, if they can get up, they will be able to recover normally. As always, be patient, give attentive care and do not rush any procedures (i.e. milking, moving) with them. If you can, pull them out of the large waiting line for milking to stop them from getting pushed over.
It is questionable whether she will be able to calve again, because the hook bone (tuber coxae) is part of the pelvic structure and hence the birth canal may be obstructed.