Can skeletal morphology change in adults?
Bone never stops changing.
Your bones are constantly being broken down and reformed on a microscopic level. Your bones are done growing at a certain point but they continue to be reshaped. Remember bone exists to supply calcium (and to a lesser extent phosphorus), to your muscles, Your body needs to break down the surface of the bones for this calcium.*  So bone is dissolved and redeposited constantly, this regulated mineral levels but also allows the bone to slowly reshape itself.
Bone will slowly reshape itself to resist any stress it experiences, for instance if you build muscle the attachment point for the muscle will become more rugged to strengthen the attachment. A runner's leg bones will get thicker and denser to resist the greater stresses. Joint surfaces can even reshape with repetitive motion.
*bone originally evolved as armor but this has been lost in modern vertebrates. Vertebrate muscle requires calcium to function, Vertebrates have lost the armor but not the need for a calcium store, and have repurposed into a structural support. Vertebrates without structural bone need to have massive calcium levels in their body tissue instead.
for continued reading there is a whole series of books by R. Mcneill Alexander that cover bones in fascinating detail.