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Sunday, June 30, 2013

Rotator Cuff Tear: Understanding This Common Occurrence in Personal Injury

Rotator Cuff Tear:  Understanding This Common Occurrence in Personal Injury

Dr. Alan Himmel

Anyone who has ever treated or represented a person with a rotator cuff tear, is fully aware of the troublesome nature of this injury.

But, what do we really know about this traumatic condition?

First, a little anatomy:  The rotator cuff is group of four muscles.  They are the Supraspinatus, Infraspinatus, Teres minor, and Subscapularus.  For purposes of remembering these muscles, just think "SITS."  This is an easy mnemonic, which any student of anatomy should remember.  The names of these muscles, like a lot of structures in the body, often tell a little bit about where they are located within the body.  For example, "supra"-spinatus is located superior to the "spine" of the scapula.  The "infra"-spinatus is located inferior to the "spine" of the scapula.  The "sub"-scapularus is located behind or deep to the scapula.

These muscles, like all skeletal muscles have a function, and they are to move bones by pulling on them, and also help give support to the bony structures of the body. Skeletal muscles must connect to bones in order to be able to pull on them, and they are connected by way of tendons.  The tendon on a muscle is what actually connects the muscle to the bone.  Unlike muscle which can contract and stretch, tendons do not have this ability.  They are simply there to connect the two structures together.  They are generally in-elastic and are very strong.

Notice the white colored tissue?  These are the tendons of the SITS muscles, and these tendons are connecting to the head of the humerus.  They will cause movement as well as to help to stabilize the joint and hold it in place.

The SITS muscles control very specific actions of the shoulder. And, the supraspinatus muscle is of most interest, because its the most commonly injured of the SITS muscles. The supraspinatus controls the action such as raising the arm out to the side (abduction) and turning the arm backward (external rotation). Because of this motion, one can easily see the stress it would be under, by a baseball pitcher, for example.
Abduction and external rotation of shoulder

So, where is the injury?  Where is the "tear?"

Most commonly, the rotator cuff injury is to the supraspinatus tendon.  Again, this tendon connects the supraspinatus (which sits above the spine of the scapula) and connects to the head of the humerus.  And more specifically, its the far end or distal end of the tendon, very close to the humoral head.   There is a small area that is known as the "critical zone" which is an area within the actual tendon that is much less rich in blood supply. This area of hypovascularization is a weak spot on the tendon because it is not supplied by rich blood, to the same extent as other parts of the tendon and muscle are.  It is thought that this is the reason most of the tears occur in that area.

What else can cause a traumatic tear of the supraspinatus besides a sports injury?  Falling on an out stretched arm can cause a tear.(1)  Sometimes when the person falls, the collarbone is fractured or the gleno-humeral joint (shoulder socket) is dislocated at the same time as the tear, although it is not necessary to have a fracture at the same time as the tear.  I have had a few patients over the years who have experienced a fall which resulted in a torn supraspinatus tendon.  In fact, in my personal experience the damage to the tendon is more common in falls than in sports related, or repetitive motion activities.  

The impairment and  treatment are almost always the same.  Usually the patient presents with pain, weakness, los of motion, and swelling in the shoulder.  They tell me they cannot take a gallon of milk out of the refrigerator with the affected shoulder.  Treatment consists of anti inflammatory modalities including icing.  Non steroidal anti-inflammatory medication is suggested.  Strengthening exercises are started.  

The MRI is the diagnostic type that is best suited to definitively diagnose the tear, since the injury is soft tissue in nature.(2)  X-ray very often turns up nothing unless there is a fracture of the humeral head where the tendon attaches, the collar bone is broken, or there is a dislocation.  

Clinical correlation is important.  When did the patient first start feeling the pain?  How was the shoulder prior to the fall?  Did the patient have his arm outstretched at the time of the fall?  All good questions and part of the patient history.

I always suggest the least invasive and safest treatment options for my patients first, but sometimes if strengthening and rehabbing the torn tendon fails, the next step is that the patient tries cortisone injections and unfortunately, surgery may become part of their future.

How this injury will affect the patient in the future is important to document.  The shoulder is never exactly the same as before the tear.  There is always some degree of pain and loss of range of motion.  Frequent exacerbations due to use of the shoulder are common.  Is the patient dominant handed on the side of the injury?  If so, the impairment will be more significant.  Will the injury have any impact on the future income of the patient?  Sometimes this is yet to be determined.

My contact information is:

1.   2013 Feb;29(2):366-76. doi: 10.1016/j.arthro.2012.06.024. Epub 2013 Jan 3.An evidenced-based examination of the epidemiology and outcomes of traumatic rotator cuff tears.
Sports Medicine Program, Rush University Medical Center, Chicago, Illinois 60612, USA.

2.   2012 Dec;20(3):361-4.
Non-contrast magnetic resonance imaging for diagnosing shoulder injuries.
Arnold HOrthopaedisch - Unfallchirurgische Praxisklinik, Orrthopaedisches Zentrum Fichtelgebirge, Rehau, Germany.

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