FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

COLD WEATHER NOT RESPONSIBLE FOR READER'S FROZEN SHOULDER

Question: I've recently had manipulation under anesthetic for a frozen shoulder that didn't respond to physical therapy and medications. Now I'm recovering and wondering what caused my frozen shoulder. I sure don't want it to come back.

Answer: The shoulder joint is a complicated structure. The upper arm bone, the humerus, is connected to the shoulder bone, the scapula, with a ball-and-socket type of joint. The shoulder's version of this joint style allows for great range of movement at the expense of some stability. In other words, the socket --called the glenoid cavity is so shallow that the relatively large ball called the head of the humerus won't stay in its proper place without constant support from the shoulder muscles and ligaments.

Injury to the shoulder may focus on the bones, the supporting ligaments, the muscles or any of several other less conspicuous parts. In "frozen shoulder" the damage is to the parts that support the bones, primarily the ligaments and joint capsule, not to the bones themselves. This type of soft tissue injury does not occur because of exposure to very low temperatures, despite what the name of the condition implies. The name comes from the lack of motion in the joint: It's frozen and won't move!

A single memorable accident such as the time you caught yourself from falling three stories to your death by grabbing the roof gutter may proceed a frozen shoulder. More commonly, frozen shoulder follows repeated lesser injuries or strains: as an example, the sore shoulders you experienced after carrying those many bundles of new shingles onto the roof. (Next time, hire professional roofers!)

The body reacts to injury whether repeated minor ones or a single major episode by producing inflammation. This reaction brings extra circulation, nutrients and other things necessary for healing to the damaged area. The swelling which accompanies inflammation produces pain, and it is particularly painful when the injured part or parts are moved. The normal reaction to pain is to hold the part still a generally wise response. But in some situations, this lack of motion leads to, or at least contributes to, the onset of frozen shoulder.

The bones that meet at the shoulder joint are enclosed and surrounded by the "joint capsule," a tough, fibrous supporting structure with a smooth inner surface. The numerous muscles and ligaments that support and move the shoulder normally slide over the joint capsule when the arm moves. Inflammation resulting from injury can cause the joint capsule to form scars attaching it to neighboring tissues. Arm movement then stretches and pulls on these parts in an unnatural way resulting in decreased motion and shoulder pain. This is frozen shoulder, also called "adhesive capsulitis" in doctor jargon.

In your case, medication and physical therapy were unable to restore normal motion, so your doctor forcefully tore loose these adhesions by manipulating your arm actually moving it through its normal range of motion while you were under the anesthetic. This manipulation can't be done while you are awake. The pain would cause you to tighten the shoulder muscles sufficiently to injure them before the scarring adhesions of the joint capsule could be broken.

The best way to keep from having a frozen shoulder again is to follow your doctor's advice do those exercises to maintain the full shoulder "range of motion"! It is also important to avoid heavy strains to the shoulder until it is totally healed and to take any anti-inflammatory medication that was prescribed.

Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.