Simplify the following text for a Grade 13 native English-speaking person.
Original: Radiological examination of his bones showed `` age-conditioned or strain-induced degeneration '' in these areas , including osteochondrosis and slight spondylosis in the lumbar spine and wear-and-tear degeneration in the knee and especially the ankle joints .
Simplified: X-ray examination of his bones showed `` age-conditioned or strain-induced degeneration '' in these areas .