Rotator Cuff Tears
The shoulder is one of the most mobile joints in the body. To provide this level of motion, the shoulder is constructed of a ball and cup configuration that allows motion in almost any direction. The shape and size of the bones is similar to a basketball (ball) and dinner plate (cup). The rotator cuff keeps the ball positioned correctly or centered on the plate (especially necessary because the plate or cup is situated vertically in the shoulder). The rotator cuff consists of four tendons; there is one tendon in the front of the shoulder, two in the back of the shoulder, and one on top of the shoulder. When these tendons are exposed to too much force, they can tear. The most commonly injured tendon is the supraspinatus, the one that crosses over the top of the joint.
Rotator cuff injury can vary from a slight stretch of the tendon (mild sprain) to a full tear. Tears can also vary in size, from partial tearing of one tendon to complete tears of several tendons. The ends of the tendons may be pulled well away (retracted) from their attachment site on the humerus (bone of the upper arm). It is generally believed by most orthopedic surgeons that full-thickness tears will not heal on their own. In recent studies looking at patients under 60 with full-thickness tears, about 49% of tears got bigger, 43% stayed the same, and 8% decreased in size over 2-3 years. A MRI scan is often used to determine whether a tear is present and may be able to distinguish between a partial tear and a full-thickness tear (especially if dye is injected into the shoulder before the scan).
Left photo: Rotator cuff tendon tear, viewed arthroscopically. Right photo: Tear arthroscopically repaired.
Partial rotator cuff tears generally cause discomfort at the side of the shoulder and into the upper arm. Nighttime pain is common, especially laying on the affected shoulder. Reaching above the head or behind the body or back is often uncomfortable as well. Strength is rarely affected except by pain and range of motion of the shoulder is typically good. Partial tears are usually initially treated with physical therapy. If the pain persists, an arthroscopic trimming (debridement) is considered. Larger partial tears, i.e. those that affect more than ½ of the fibers of the tendon in any one area, are often repaired as if they were fully torn.
Full-thickness tears rarely heal (although they frequently become less painful with time). This usually results in weakness of the arm, although patients may compensate over time and have fairly good range of motion. Over time, the tears often progress in size and may evolve into a “massive” rotator cuff tears. The end-result of a massive tear is migration of the ball up out of the cup, resulting in arthritis. The arthritis, once it has progressed to constant pain, may need to be treated with shoulder replacement surgery.
To repair a full-thickness rotator cuff tear, arthroscopy is often recommended. During arthroscopic rotator cuff repair, a miniature camera is inserted into the joint and the tear is assessed. Typically, the repair is performed using four incisions, one in the front, one in the back, and two on the side of the shoulder. The rotator cuff is typically reattached to the bone it tore from with suture anchors which are essentially like drywall screws with stitches attached to them. The anchors are placed into the bone the tendon tore from and the stitches are used to sew the tendon back to the bone. The stitches then serve as spot-welds for the tendon, holding it in place while the fibers of the tendon grow into and reattach to the bone. Once the fibers grow back to the bone, the stitches are no longer necessary.
Physical therapy after a rotator cuff repair generally last about four months, although continued healing for a year or so does occur. Some variability will occur between patients based on tear size, type of repair, and the presence of disease processes like diabetes. Therapy after a repair will vary a bit from patient to patient, but generally follows four stages: protection phase (limited or gentle therapy), passive motion phase (the shoulder is moved without using the muscles attached to the shoulder), active motion phase (using the muscles attached to the shoulder), and strengthening phase. The timeframe for this process may extend from three to five months.
December 23, 2009
William Silver, MD
Triangle Orthopedic Associates
Raleigh, NC
See the following for more information on rotator cuff tears and repairs:
American Association of Orthopaedic Surgeons - Rotator Cuff Injuries (opens in new window)
Arthroscopy Association of North America - Rotator Cuff Injuries (opens in new window)