SGEM#74: Broken Arms (Diagnosing Rotator Cuff Disease)

http://thesgem.com/2014/05/sgem74-broken-arms-diagnosing-rotator-cuff-disease/

Podcast Link: SGEM74

Date:  May 1st, 2014 

Guest Skeptic: Physiotherapist Dagny Kane-Haas. Dagny is a currently studying for her Masters degree in Clinical Science in Manipulative Therapy.

Case Scenario: A 54 year old man presents with increasing pain in his right shoulder.

Question: Does this patient with shoulder pain have rotator cuff disease?

Background: Shoulder pain is the third most common MSK reason for seeking medical attention. There are 4.5 million visits per year in the USA. Rotator cuff disease is the most common cause. It can have a big impact on quality of life especially if it is the dominant arm. Majority of these conditions are treated medically with only few requiring surgery.

Anatomy of the rotator cuff beyond just remembering the SITS nemonic.

• Supraspinatus – ABducts the arm (suprascapular nerve -C5)
• Infraspinatus – Externally rotates the arm (suprascapular nerve C5-6)
• Teres Minor – Externally rotates the arm and some ADduction (Axillary nerve -C5)
• Subscapularis – Some ADdcution and internally rotates the arm (upper an lower subscapular nerve C5-6)

Patients with rotator cuff disease can present with pain, loss of function, decrease range of motion, weakness, stiffness, crepitus and difficulty sleeping.

Treatment is often rest, ice and non-steroidal anti-inflammatories. Physical therapy can play a significant role in treatment but can take three months.

Article: Hermans J et al. Does This Patient With Shoulder Pain Have Rotator Cuff Disease? The Rational Clinical Examination Systematic Review. JAMA. 2013;310(8):837-847

• Population: Five studies with a total of 432 patients and 442 shoulders. Not ED based but patients referred to an Orthopaedic, Sports Medicine or Rheumatology Clinic.
• Intervention: Pain provocation test, Strength test, and Composite test
• Comparison: Operating room, ultrasound or MRI
• Outcome: Partial or full tear of rotator cuff
• Excluded Studies: Rheumatoid arthritis, fibromyalgia, shoulder instability, labral lesions, fractures, adhesive capsulitis, tumors, complex regional pain syndrome and disorders from strokes.
• Included Studies: Description of history, physical or clinical tests Detailing of sensitivity and specificity Use of a reference standard with diagnostic criteria pre-specified Presentation of original data or available Language of one of the authors (Danish, Dutch, English, French, German, Norwegian, Spanish, Swedish)

Authors Conclusion: “Because specialists performed all the clinical maneuvers for RCD in each of the included studies with no finding evaluated in more than 3 studies, the generalizability of the results to a non-referred population is unknown. A positive painful arc test result and a positive external rotation resistance test result were the most accurate findings for detecting RCD, whereas the presence of a positive lag test (external or internal rotation) result was most accurate for diagnosis of a full-thickness rotator cuff tear.”

Diagnostic Study Quality Check List:

1. The diagnostic question is clinically relevant with an established criterion standard. Yes
2. The search for studies was detailed and exhaustive. Yes
3. The methodological quality of primary studies were assessed for common forms of diagnostic research bias. Yes
4. The assessments of studies were reproducible. Yes
5. There was low heterogeneity for estimates of sensitivity or specificity. Unsure
6. The summary diagnostic accuracy is sufficiently precise to improve upon existing clinical decision making models. NO

Key Results: Five studies were included in this JAMA review with between 30-203 shoulders in each study. Prevalence of RCD was from 33% to 81%.

Painful Arc Test: The patient holds arm straight out at the side of their body. Examiner brings the patient’s shoulder into full ABduction. The study is positive if patient has pain between 60-120 decrease. This indicates subacromial or rotator cuff disorder.

• +LR 3.7 (95% CI, 1.9-7.0)
• -LR 0.36 (95% CI, 0.23-0.54).

The Hawkins test or Neer test had little value.

External Rotation Lag Test: Elbow bent 90 degrees with hand out front. Examiner passively rotates the patient’s arm to full external rotation. Positive test is when patient is unable to maintain a position of full external rotation.

• +LR, 7.2 (95% CI, 1.7-31)
• -LR 0.57 (95% CI, 0.35-0.92) 

Internal Rotation Lag Test: The hand is behind back with elbow flexed 90 degrees. The arm is lifted off the back by examiner and patient is asked to maintain position. Positive test is when patient is unable to maintain the position.

• +LR, 5.6 (95% CI, 2.6-12)
• -LR 0.4 (95% CI, 0.00-0.58)

Drop Arm Test: Patient holds their arm straight out to the side at shoulder level. They are asked to lower the arm slowly from this ABducted position. The test is positive if the patient immediately drops the arm and complains of pain.

• +LR, 3.3 (95% CI, 1.0-11)
• -LR 0.83 (95% CI, 0.70-0.97)

JAMA made a video of the paper: Does This Patient With Shoulder Pain Have Rotator Cuff Disease? The Rational Clinical Examination Systematic Review. Click HERE to watch the five minute video.

Comments: The most common cause of shoulder pain is rotator cuff disease (RCD). This study tries to shed some light on the physical examination techniques/tests that can help identify who has RCD.

While this is an important question the external validity to the emergency department is limited. None of the five studies included in the review were from the ED. All of the patients were seen in out-patient clinics (orthopedics, rheumatology or sports medicine).

This creates verification bias (work-up or referral bias) and probably accounts for the high prevalence of RCD (33%-81%) compared to the general population estimates of (2.8%-15%). This type of bias tends to overestimate the sensitivity and under-estimate the specificity.

The painful arc test was the best of all the pain provocation tests (+LR3.7). Best among strength testing was the external rotation lag test (+LR 7.2) and the internal rotation lag test (+LR 5.6) for full thickness tears. The best performing test to rule-out RCD was a normal internal rotation lag test (-LR 0.04).

These are physical examination techniques which can be learned and done easily in the emergency department to assess and diagnose RCD. Because of the verification bias in the available studies we are not sure how accurate these test would be in the emergency department.

Dagny suggests reading a paper by Park et al. Diagnostic accuracy of clinical tests for the different degrees of subacromial impingement syndrome. J Bone Joint Surg Am. 2005 Jul;87(7):1446-55. This study looked at the sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of eight different tests for making the diagnosis of rotator cuff disease.

Bottom Line: Take an x-ray if you are concerned about bone injury or involvement. Conduct an examination you are confident in performing. Treat the patients pain. Arrange for appropriate follow-up.

Clinical Application: This study will not change my clinical practice. I will get an x-ray if concerned about bone injury or involvement. Conduct my typical shoulder examination without the specialized tests. Provide appropriate pain medication. Arrange for imaging studies depending on my clinical concern and resources (US vs. MRI). Suggest follow-up with primary care physician or specialist depending on local practice patterns.

You can also consider referring these types of patients to your friendly neighbourhood physiotherapist. Remember that it can take three months to treat rotator cuff pathology with this treatment modality.

What do I tell my patient? It appears your may have a rotator cuff disease. Rest your arm, apply ice and take some NSAIDs for the pain. Follow-up with your primary care doctor in the next week or so. If it is still sore they may suggest getting an US here or sending you to the city for an MRI. Your doctor may suggest seeing a physiotherapist if it is not improving quickly.

Keener Kontest: Last weeks winner was Liju Philip a PGY4 from Long Island Jewish Medical Center. They knew three conditions which could require intravenous medication to lower blood pressure:

• Pre-Eclampsia
• Aortic Dissection
• Acute Cardiogenic Pulmonary Edema

If you want to play the Keener Kontest this week then listen to the podcast for the question. Email me your answer at TheSGEM@gmail.com with “keener” in the subject line. The first person to correctly answer the question will receive a cool skeptical prize.

A special shout out to the North York Emergency Medicine Update 2014 (EMUpdate) conference held in Toronto last week. It was one of the best EM meetings I have every attended. Great speakers, great venue, great educational value and great group who organized the conference. Thank you so much for inviting me speak on social media, evidence based medicine and medical myths.

Remember to be skeptical of anything you learn,