Discs and cartilage serve to absorb shock and keep the bones from rubbing against one another. If the ligaments become torn or over-stretched the joint becomes unstable and resultant friction causes the discs or cartilage to become worn down causing a loss of height. The disc and cartilage may also become worn away by repeated motion. This loss of height causes further ligament laxity and thus more instability. The friction of the joint is a stress.
Bones respond to stress by making more bone.
This results in bone spurring which is the body's attempt to splint or stabilize the unstable joint. Degenerative disease is merely the body's attempt to stabilize joints as the tendons and ligaments have not been able to heal because of lack of blood supply. If a patient has considerable degenerative arthritis , the loss of disc or cartilage height causes a laxity of the supporting ligaments. This causes joint instability. Reconstruction has been shown to be effective in these conditions, causing the lax ligaments to become strengthened, thus stabilizing the joint and allowing for increased function and endurance.