It is a common misconception amongst patients suffering from frozen shoulder, arthritis or rotator cuff tear that all of them are the same because of similar signs and symptoms. Yes, they all have shoulder pain and limited range of motion as common ground but the causes are very different. Shoulder stiffness is felt in all the three diseases but medically, all of them are recognised as separate diseases.
Our shoulder consists of a gleno-humeral (ball and socket) joint which has the head of our upper arm bone (humerus) fit perfectly into the socket of the shoulder blade (scapula). The stiffness associated with frozen shoulder is caused by formation of scar tissue in the joint leaving no room for the ball and socket joint to function. Now, the difference between frozen shoulder and the other two conditions is that the ball and socket joint generally remains unharmed. Shoulder motion is hampered because of the tightness in the joint capsule but the joint surfaces remain intact. Frozen shoulder is completely treatable, unlike arthritis which can only be contained. A frozen shoulder is diagnosed when an individual has had no history of shoulder injuries or surgeries whatsoever and still the shoulder has limited range of motion.