How is the Rotator Cuff injured?
The majority of injuries to the rotator cuff are “wear and tear” type of injuries to the soft tissue of the socket. Most patients cannot remember a specific event where the pain and problem began. Most commonly, the pain is at a low level at first and barely gets in the way of normal activities. Patients seek help when the pain gets in the way of sleep, sports, or daily activities.
How do you know there is an injury?
Shoulder pain is the most common symptom in rotator cuff injuries. Pain that interrupts sleep is also very common. Pain can range from a dull ache at rest to a sharp pain with activities that elevate the arm. It can radiate to the neck, front, back, and side of the shoulder. It often radiates down the outside of the arm as well. Although we don’t yet fully understand the pain mechanisms in the shoulder, the bursa appears to be a major source of pain signals.
Pinching and pain with elevation of the arm:
Pain and pinching or catching when you elevate your arm above the shoulder can be signs of impingement. (See chapter 1, figure 1-5b.) This can vary from a low level ache to a forceful sharp pain.
Weakness and motion loss:
Weakness while elevating the arm is the second most common symptom reported. Some patients with very large tears cannot elevate their arm at all. Loss of ability to elevate the arm can also be related to stiffness in the shoulder, sometimes known as frozen shoulder.
Abrasion and Partial Tearing:
When pinching of the tendon has been present long enough, injury will start to occur. This is similar to a door rubbing on carpet and wearing it down. The tendon injury can be from direct rubbing or from tension when the cuff is pinched. Direct contact can injure the tendon on the bursal side of the tendon. It can also stop the normal movement of the tendon on the superficial layers and result in increased tension on the deep side of the tendon.
Pain generated from an injury of the shoulder can send signals to the muscles of the shoulder to limit activity. During an examination, this can test like a rotator cuff tear. When the injury heals or is treated the muscle no longer receives the signal of an injury and returns to full activity. This is common with impingement and bursal inflammation. It is also common after surgery.
Nerve dysfunction is perhaps the most complicated problem in shoulder injuries. The nerves around the shoulder and those that come from the neck can be involved with a shoulder injury. Sometimes they are simply irritated and inflamed. Sometimes they have been pinched by the muscle spasm. Occasionally, they have been stretched or torn.
It can be a challenge to determine whether shoulder injury is the cause of neck and nerve pain, or if neck and nerve injury are the cause of shoulder pain. Large rotator cuff tears are associated with nerve injury to the suprascapular nerve. This can affect the recovery after surgery. Nerve injuries to the suprascapular nerve can mimic a large rotator cuff tear.
There are three common systemic disorders that can pose as challenges to treatment.
1) Diseases of the soft tissue such as rheumatoid arthritis can predispose the rotator cuff to tear and complicate surgical repair.
2) Diabetes can predispose a patient for sustained inflammation.
3) The microvascular disease associated with diabetes can weaken the tendons of the rotator cuff.
These three secondary injuries require the expertise of your doctor to assess and treat.