negative camber in the rear tires

What would you check first when the rear tires at the bottom lean out and the tops inward. My thought is to replace struts with new adjustable struts with lock-ins.

appreciate opinions,
Russell

Strut rods and the yoke shafts at the differential. Strut rod bushings gone bad should be pretty obvious, yoke end play is .050" maximum. Worn yoke shafts will cause the wheel to tip in because the half shaft moves closer to the differential.