Unraveling the Mysteries of the Shoulder

The authors of this review on the shoulder took on a huge project with their research efforts with several goals in mind. First, they wanted to review and revise Codman’s table of shoulder abnormalities. Dr. Codman was the first to compile a list of signs and symptoms for each of over 25 possible conditions affecting the shoulder. Dr. Codman published this table in 1934 and it remains surprisingly accurate today. With the information collected at the Johns Hopkins Medical Center in Baltimore, Maryland, the authors were able to update the table and create a modern version of Codman’s table.

Second, they developed a database back in 1995 with information entered on all of their shoulder patients. The intent was to be able to compare results from before to after surgery. They also hoped to be able to study the data collected and look for patterns of clinical signs and symptoms that might help in diagnosing shoulder problems. They did this by comparing what they found during the preoperative history and exam with their actual findings at the time of the surgery. In this way, they could offer other orthopedic surgeons a summary of how useful are the various tests and measures in use today.

For the database, they collected measurements before, during, and after surgery. Some of the tests included joint range-of-motion, strength, information on general health, and specific provocative shoulder tests. Provocative tests apply load or force to various soft tissue structures of the shoulder to look for signs of damage or injury. Most of these tests are commonly used by orthopedic surgeons, physical therapists, and athletic trainers when assessing shoulder problems.

The reliability and validity of each test was measured for each of seven major conditions affecting the shoulder. The tests included range-of-motion, drop-arm sign, shoulder shrug sign, Neer Impingement sign, Hawkins-Kennedy sign, Speed test, Apprehension tests (anterior and posterior), compression test, lift-off test, painful arc sign, cross-body adduction test, resisted extension test, external rotation lag sign, and Whipple Test. So, you can see it was a very thorough collection of tests used in this field.

The authors provide five tables summarizing their findings for each of these tests. The tests were used with patients who had rotator cuff tears, shoulder arthritis, adhesive capsulitis (frozen shoulder), shoulder instability, labral tears, biceps disease, and arthritis of the acromioclavicular (AC) joint. The acromioclavicular joint is along the front of the shoulder where the clavicle (collar bone) meets the acromion. The acromion is a curved arch of bone over the top of the shoulder coming from the shoulder blade.

Third, they reviewed all the published studies on the shoulder including a wide range of diagnoses such as rotator cuff disease, tendon tears, shoulder instability, bursitis, labral tears, and joint abnormalities. Finally, they included a review of their own experiences examining, diagnosing, and treating complex and challenging shoulder problems. They offer the following observations:

  • The Neer and Hawkins-Kennedy Impingement signs may help diagnose painful tendinosis but by themselves, they do not point to full-thickness rotator cuff tears. Tendinosis refers to chronic (long-term) damage and change in the fibers of the tendon but without active inflammation.
  • Full-thickness rotator cuff tears can be diagnosed when there are three signs present: weak shoulder external rotation, positive drop-arm test, and painful arc of motion. In older adults (60 or older), weak shoulder abduction (moving the arm away from the body) along with a positive impingement sign (either the Neer or the Hawkins-Kennedy test) is 98 per cent positive for a full-thickness tear of the rotator cuff.
  • Acromioclavicular joint abnormalities can contribute to shoulder pain. Look for tenderness over the joint and pain relief when thejoint is injected with a numbing agent.
  • Some tests for shoulder instability are specific enough to truly diagnose an unstable (dislocating) joint. But they aren’t accurate for everyone. For example, the apprehension test (examiner moves shoulder in direction it might dislocate and patient becomes very fearful) is likely to be truly positive 95 per cent of the time — but not for patients with traumatic shoudler instability. There may be enough damage to the soft tissues and joint that they don’t feel pain or a sense that the joint is going to pop out.
  • Some people have shoulder instability in more than one direction. In other words, the joint can dislocate in more than one way. There isn’t one single test for multidirectional instability. Examiners must be careful to differentiate between laxity (looseness of the shoulder) and true instability. It is suspected that laxity is mistaken for instability in many cases.
  • Physicians continue to debate the best way to test for labral tears. The labrum is a fibrous rim of cartilage around the edge of the shoulder socket. It is meant to deepen the fairly shallow socket and help stabilize the head of the humerus in the socket. Some examiners use a bunch of different clinical (provocative) tests, while others suggest arthroscopic examination is the only real way to tell what’s going on with the labrum.

    Pulling together information like this and analyzing data collected over time on many patients may make it possible to create a computer program to help diagnose shoulder problems and thus guide treatment. The hope is that a physician could enter all of the patient’s history, results of physical examination, and results of any imaging studies and the program would run a statistical analysis to find the most likely diagnosis based on the information provided. The authors conclude that the work done so far is just the tip of the iceberg. Many more studies are needed to continue unraveling the mysteries of the complex and challenging conditions affecting the shoulder.