Rotator Cuff Tear
Rotator Cuff Tear web based movie
The rotator cuff is critical to normal, healthy shoulder function, as it plays a vital role in stabilizing the shoulder joint during arm motion. Tears of the rotator cuff are some of the most frequent injuries treated by orthopaedic surgeons, and these tears typically occur in patients older than 45-50 years of age. “Partial-thickness” or incomplete, tears of the rotator cuff can initially be treated non-operatively with rest, anti-inflammatories, cortisone injections, and physical therapy. “Full-thickness” or completes tears are usually recommended for surgery as these tears lack the ability to heal without surgical repair.
The rotator cuff is composed of four muscles and their attached tendons. The muscles all originate on the shoulder blade and attach to the upper arm bone (or “humerus”) via tendons. The shoulder is a “ball & socket” joint. The upper part of the humerus forms a ball shape and this fits into a small cup or socket (called the “glenoid”) on the outside of the shoulder blade. The ball is much larger than the socket and therefore very unconstrained which allows us to move our shoulders over a wide range. The four tendons of the rotator cuff weave together and form a three-sided sleeve or “cuff” of tendon that surrounds the ball and stabilizes it in the socket. The critical function of the rotator cuff provides the shoulder with a stable point of rotation and allows larger muscles around the shoulder to raise the arm overhead, to the side and behind the back around this fixed point.
Rotator cuff tears may occur after a traumatic injury to the arm, such as a fall or shoulder dislocation. More commonly, however, they occur as attritional injuries due to the tendons “wearing out” over time, which can cause tearing. As we age, blood flow to the tendons lessens and leads to degeneration and weakening of the tissue over time. Stress on the tendons with use of the arm causes fibers of the tendon to rupture, and overtime these tiny ruptures can amount to a full tendon detachment, even without a specific injury to the shoulder. This is why these tears occur more commonly in an older age group. In addition, bone spurs may develop in the areas around the rotator cuff that can rub against the tendon and cause mechanical tearing.
Tears may be “partial-thickness” or “full-thickness.” Partial-thickness tears are incomplete and usually result from general wear-and-tear. Partial tears can be thought of like an old shoelace that has fraying but remains intact. The rotator cuff is 1.5-2.5 centimeters thick in some areas so significant fraying and partial-tearing of the rotator cuff may be present before a full tear occurs. Full-thickness tears are a complete detachment of a portion of the rotator cuff from the upper part of the humerus bone.
Recent research on rotator cuff tearing has given surgeons insight on the fate of untreated full-thickness tears. What we now know is that full tears do not heal if left untreated. The reason for this is that once the tendon detaches completely from the bone it is continually pulled away from the bone and its normal attachment site by the action of the rotator cuff muscles. This is similar to a retractable tape measure used in carpentry. Because of the continual pull of the rotator cuff muscles, full-thickness tears tend to grow larger over time and involve more of the rotator cuff tendons as more stress is placed on the adjacent tendons.
Symptoms of rotator cuff tears generally involve pain with use of the arm. The pain is usually felt on the side of the shoulder and may radiate down the side of the arm to the elbow and into the hand. Painful catching or grinding sensations may occur. Sleep is generally affected as the pain is felt when rolling onto the involved arm. Weakness of the shoulder may be present either due to pain when trying to lift objects, or if the tear is extensive and disrupts normal shoulder function.
Diagnosis is made by a history of the patient’s symptoms and a physical examination of shoulder function. X-rays are evaluated to look for bone spurs or limitation of the space occupied by the rotator cuff by the overlying acromion bone of the shoulder blade. A MRI scan is needed to determine whether a tear is present as tendons cannot be seen on Xrays. MRI is also useful for detecting other injuries in and around the shoulder that may also require treatment. If a patient is unable to have and MRI scan, then an Ultrasound study may be performed instead, though ultrasound images generally do not reveal the same level of detail as a MRI image.
Treatment of rotator cuff tears depends on several factors including the type of tear (partial versus full-thickness), the cause of the tear (sudden injury versus gradual wear-and-tear) and the overall health and activity level of the patient. Full-thickness tears are usually recommended for surgery, particularly if the tear resulted from a sudden injury. Surgical repair is the only treatment that will lead to healing of the torn tendon back to its normal attachment point on the humerus bone and restore normal rotator cuff function. Surgery is particularly indicated for active patients who want to return to activities requiring high-level shoulder function.
In patients with partial-thickness or attritional tears due to wear-and-tear, an initial non-operative treatment approach is usually recommended. This treatment approach involves rest, anti-inflammatory medicine, physical therapy exercises and possibly a cortisone injection. If this initial treatment fails, surgery may be considered.
For more information, visit http://orthoinfo.aaos.org/topic.cfm?topic=A00406.