The acromio-clavicular joint ("AC joint ") is where the clavicle ("the "collar bone")is connected to the scapula (the "shoulder blade"). Ligaments form a strong connection between these bones. During activity and motion, there is some rotation that occurs between these bones, particularly when raising the arm overhead.
Just like any other joint in the body, damage to the AC joint can result in pain as a result of inflammation and overload of the damaged joint. Such damage results in arthritis. Arthritis can be a result of prior injury, inflammatory diseases (such as rheumatoid arthritis, gout and many other diseases) or as a result of osteoarthrosis which may or may not have a clear cause in any given patient. Severe repetitive overuse and excess loads may cause AC joint degeneration too. This is particularly common in weightlifters. When any of these problems happen the joint causes pain and limits activity.
AC joint problems are diagnosed by careful evaluation of your symptoms and by x-ray evaluation. In some cases, MRI scan or bone scan may be suggested and show the problem even more clearly. AC joint problems can exist along with other shoulder problems and it is not rare to need to treat the AC joint as one component of complete and effective treatment.
Treatment of AC Arthritis
In the early stages, avoiding painful activities, rest, and anti-inflammatory medications may control symptoms adequately. Injection of a locally acting steroid and local anesthetic is often the next step. This puts the medicine right where it needs to work and often provides excellent relief of the pain. Another advantage of injection is that during the first minutes and hours after the injection, the numbing medicine part of the injection provides a good test of whether or not the pain is coming from the area of the injection. IF the pain is relieved soon after the injection then the source of shoulder pain is well localized. Just how long the injection will last is hard to predict. It often lasts several months or more. If there is a good result from injection lasting for a number of months, sometimes injection can be repeated with relief again. However, if symptoms continue to come back, surgery may be necessary.
What does the surgery do and how long is the recovery?
Surgery for AC joint arthritis involves "AC joint resection" which means removing a portion of the end of the clavicle (less than 1 cm usually) in order to clean out the damaged cartilage and to prevent the bones from rubbing together and causing pain. This type of surgery can be done either arthroscopically through several small incisions or through a standard "open" incision. Most of the time I do this surgery arthroscopically but there are certain situations in which open surgery is best. The long term results of either approach are very good. The arthroscopic approach does allow, on average, faster recovery and has a cosmetic advantage as well. Risks of surgery include standard risks of anesthesia complications, infection, continued pain and the need for further surgery among other potential complications. However, good results are expected in 80-90% of cases. Surgery is generally done as an outpatient, unless associated medical problems make admission necessary.
We will see you 2-3 days after surgery to change your bandage and check your motion. Sutures are removed about 7-10 days after surgery. You may have a shoulder brace for as little as 7-10 days and if there are no other surgical repairs being done at the same time you may be allowed to be out of the sling as soon as you are comfortable. Full recovery from AC joint resection surgery generally occurs about 3 months after surgery but can be longer depending on your desired activity level. The assistance of a professional physical therapist may be suggested in your post-operative recovery depending on your rate of progress.