Why are joint injuries slow to heal?

We will start off understanding a sprain. A sprain is basically when you twist lets say your ankle to far and the ligaments are damaged by the excessive twisting of the joint. Ligaments consist of dense regular connective tissue. Dense regular connective tissue is made up of closely packed thick collagenous fibers. Thus when the dense regular connective tissues are damaged it just takes longer for them to heal because they are so densly packed together. Hope this helps! ^_^