It's a common and well-known consequence of hip replacements.

This paper from 2015 describes a similar case (quickly identified via X-ray by the deformation of the metal structure)

    "It has been well established in the literature that revision of a fractured ceramic total hip replacement with metallic components can result in metallosis. Several authors have reported symptomatic cobalt toxicity after revision of a failed ceramic head component to a metal-on-polyethylene articulation"

https://pmc.ncbi.nlm.nih.gov/articles/PMC4958112/