I had major mva December last year. 5 fractures to parts of my pelvis, fractured occipital condyle, other fractures of ribs, ankle, closed head injury, etc.

MRI says Multilevel facet arthrosis advanced on the left side at L5/S1 where there is mild marrow oedema followed by arthrosis on the right at L5/S1 and bilaterally at L4/5. is this caused by old age (I am now 61) or by the mva