I also experienced hair loss after each joint replacement surgery. Now after 3 joint replacement surgeries hair loss was never discussed. But this is the first place I have seen it . I read an article somewhere about how surgery is a physical trauma and stress puts severe physical and emotional stress on our body, triggering a sharp spike in cortisol and other stress hormones. And that high cortisol pushes a large number of active hair follicles prematurely into a resting phase. None of my hair has grown back , not my eyebrows . My hair is still falling out at 77 yo & almost bald in the front. I have learned techniques to cover the thinning areas and wear my hair up most of the time.