photograph by Rui G. Santos | Dreamstime
Ask Dr. Kevin Coates what he likes best about working on the human shoulder and he doesn’t hesitate. “I like all of it,” says the orthopedic surgeon and sports medicine specialist who joined Memphis Orthopaedic Group in August. “The complexity of it, the things that can go wrong — they offer a challenge, and I like that.”
In at least one way the shoulder joint resembles the hip joint; each is a ball within a socket. The shoulder joint’s parts are the humeral head, or ball of the arm, and the glenoid, or socket, of the shoulder blade. But unlike the hip, which has bony constraints that help keep it stable, says Coates, the shoulder’s bones are held in place by muscles, tendons, and ligaments. A crucial part of the shoulder is the rotator cuff, a series of four tendons that stabilize the shoulder joint while it’s moving. “It holds that ball right where it’s supposed to be, so you have good kinematics, or shoulder motion, in a lot of directions and can put your hands where you can use them,” says Coates. “Basically, with the shoulder joint, you trade stability for increased motion.”
Naturally, with such a flexible joint, injuries are bound to occur. The most common, says Coates, is rotator cuff tendonitis, or shoulder impingement. “That’s where you have inflammation of tissue between the shoulder joint and the acromion, or the bony point of your shoulder. This can be caused by a weak rotator cuff muscle allowing the humeral head — or ball part of the shoulder joint — to contact the acromion. Or it can be a misshapen acromion, which can poke downward and decrease that space between the humeral head and pinch the rotator cuff tissue.”
The most common treatments for this affliction are anti-inflammatory drugs, such as ibuprofen or Aleve, followed by physical therapy. “So first you calm that inflammation and then start restrengthening those muscles and tendons and correct the motion of the humeral head,” says Coates. “That way you can break the cycle.” If that approach doesn’t work, Coates suggests a steroid injection between the cuff and the top of the shoulder. “That also calms the inflammation and makes it easier to do rehab.”
Sometimes, despite these therapies, the cuff will remain painful, even when a tear in the rotator cuff doesn’t appear in an MRI. In that case, Coates will look at the whole shoulder area to ensure he’s not missing anything. “Then we’ll go into the subacromial space and clean out the bursa,” he says. “These are fluid-filled sacs between skin and bone that can get inflamed. We can shave off some of the bone of the surface of the acromion to keep it from pushing against the bursa, and that can help.”
If a tear is discovered, treatment depends on its size. With a full-thickness tear, which means the tendon is completely off the bone, Coates is inclined to do surgery especially if the patient is young. “The natural history of such a tear is that it just gets bigger,” he explains. “And later, if a shoulder replacement is needed, the rotator cuff becomes a very important structure in that procedure. So the larger the tear, the more you want to fix it right away.”
“The larger the tear in the rotator cuff, the more you want to fix it right away.”
As for partial-thickness tears, the most common is the articular surface type that usually responds to rehab and doesn’t require surgery. “With these you have the joint surface underneath, with no bursal tissue to irritate. The other type of partial tear is the bursal-sided tear, which is more painful and more often requires surgery.”
For some patients the time comes for a full shoulder replacement. “The main indication for this procedure,” says Coates, “is limitation of motion accompanied by pain.” The symptoms are usually caused by arthritis, which wears away the cartilage at the ends of the bones.
In shoulder replacement, the patient may need only the humeral head — or arm part — of the joint replaced, or he may need a new glenoid, or socket, as well. “In order to do a total, you need an intact and functioning rotator cuff because it provides stability,” says Coates. “If it’s torn and can’t be repaired, you’re not a candidate for total shoulder replacement.”
However, an alternative to the standard total replacement is basically reversing the placement of the artificial joints. “You take the ball part and put it on the glenoid, or essentially make the socket at the top of the humerus. It allows function and does not require the rotator cuff to be intact.” What is required, adds Coates, is a functioning deltoid muscle, which is on the upper side of the arm. “Without a good deltoid you can’t have a reverse.” If the muscle is dysfunctional, the surgeon will try to relieve pain, if not restore function. “We can resect — or cut the end off the bones,” says Coates. “At least with that resection, where you take pieces out, we do relieve pain.”
Major advancements have been seen in materials and techniques used in shoulder surgery. One product Coates specifically likes is an anchor. “When you repair a tendon back down to the bone, the way you pass the suture through the tendon has really improved through the use of an anchor,” he says. “It’s shaped like a screw with a recessed eyelet in the back. The screw goes down into the bone and the eyelet is recessed in the screw below the bone’s level. The suture then goes through the tendon and pulls it down to bone to help it heal.”
Recovery from surgery depends on the type done. “With rotator cuff surgery, it depends on how big the tear was and the quality of tissue during surgery. I like to tell people they’ll be in a sling for six weeks.” says Coates. The strengthening aspect can take six to eight months or even up to a year. “We don’t want to try to strengthen a muscle that’s not able to function through a full range of motion and run the risk of damaging it again.” In shoulder replacement, which involves the rotator cuff’s front tendon, “you need that to heal before you have much motion,” says Coates.
No matter how complex and challenging shoulder repair can be, Coates keeps his eye on this goal: Giving the patient a pain-free and functional shoulder. “When we can accomplish this, it’s very satisfying.”