The joint capsule encases the bones, ligaments, and tendons of the shoulder, allowing mobility of the joint. In a frozen shoulder, the connective tissue of the joint capsule becomes thicker, inflamed, and contracts, leading to increased pain and a limited range of motion. This leads to a positive feedback loop where the patient keeps moving their arm less to avoid pain, decreasing range of motion even more.
There are three stages of a frozen shoulder: freezing, frozen, and thawing. In the “freezing” stage, gradually increasing pain makes motion more difficult for 6 weeks to 9 months. Then in the “frozen” stage, the shoulder remains stiff even though pain may decrease, and it lasts between 4 and 6 months. In the “thawing” stage, pain and stiffness slowly improve between 6 months and 2 years.
Risk Factors and Prevention
Frozen shoulder is most common in adults from 40-60 years old, and affects women more than men. Some other diseases that are correlated with frozen shoulder include diabetes, Parkinson’s, and thyroid disorders.
Another major cause of frozen shoulder is immobilization after surgery. For example, about 10% of patients that have rotator cuff surgery develop frozen shoulders, according to the Mayo Clinic. This presents an opportunity for prevention: continue to exercise the shoulder after surgery or immobilization to maintain its range of motion.
The goal of treatment for frozen shoulder is to decrease pain while increasing range of motion, and this is primarily accomplished nonsurgically. Initial treatments for frozen shoulder include pain medications like aspirin and ibuprofen, as well as physical therapy (to restore ROM). If symptoms, treatments such as steroid injection and hydrodilation may be used. Hydrodilation is the injection of sterile fluidr into the shoulder to stretch and expand the joint capsule in order to improve range of motion. In a steroid injection, cortisone is injected directly into the shoulder joint, which can be helpful for pain in the early stages of frozen shoulder.
A meta analysis from the University of Glasgow found that administering intra-articular (IA) corticosteroid was associated with better outcomes for short term pain, suggesting that it can be helpful within a year of injury.
Though nonsurgical treatments are effective for approximately 90% of patients, surgical treatments can be helpful (Harvard Health Publishing). The goal of frozen shoulder surgery is to stretch and release the joint capsule, and it is done through manipulation, arthroscopy, or a combination of the two. In shoulder manipulation, surgeons force the capsule to move, causing scar tissue to stretch or tear, releasing the tightening of the joint capsule and therefore increasing range of motion of the shoulder. In shoulder arthroscopy, tiny incisions are made to cut through the joint capsule. The recovery for frozen shoulder surgery consists of physical therapy for 6weeks to 3 months to regain ROM.