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.
Arthritis of the shoulder joint could be osteoarthritis affecting the bone or peri-arthritis affecting the soft tissues of the shoulder. Osteoarthritis is more commonly observed of the two and is caused by deterioration of the cartilage which is responsible for the smooth functioning of the shoulder joint. Generally the wearing off of the cartilage causes friction in the joint on movement resulting in inflammation, pain, swelling and stiffness. But, there are also types of shoulder arthritis which are caused by non-inflammatory loss of cartilage from injury, surgery complications or as a condition related to rotator cuff loss. Stiffness experienced by shoulder arthritis patients is caused by the loss of normal concave shape of the glenoid socket and convex shape of the humeral head.
Rotator Cuff Injury
The rotator cuff is a group of muscles and tendons which are responsible for holding your gleno-humeral joint in place. A rotator cuff injury may include any type of irritation or damage the rotator cuff group of tendons and muscles. The four tendons that are a part of the rotator cuff generally sustain injuries with the muscles rarely being injured. Repetitive motions are a major cause of rotator cuff injury and so they are mostly observed in individuals who repeatedly perform overhead motions in their profession such as baseball players, basketball players, carpenters and painters. As compared to the other two, rotator cuff causes direct damage to the tendons in the form of partial or complete tear. A shoulder cuff injury may cause minor pain in its initial phases before developing into a severe injury. A major difference between rotator cuff injury and arthritis is that rotator cuff injury is generally caused to one arm while arthritis normally occurs in both the joints.
Pain or no pain, if you have trouble moving your shoulder joint, it is sign enough to see your physiotherapist.