SGEM#121: Internal or External Shoulder Immobilization (It Don’t Matter to Me)

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Date: May 22nd, 2015

Guest Skeptic: Dagny Kane-Haas is a physiotherapist who just completed her Masters degree in Clinical Science in Manipulative Therapy.

Case: 24 year-old man is goofing around on the Memorial Day long weekend at the beach. He falls and dislocates his shoulder for the first time. An examination shows it is an isolated injury and x-rays demonstrate an anterior dislocation of his shoulder without fracture. Procedural sedation is performed with no complications. Post procedure image shows a reduced shoulder joint. You are getting ready to immobilize him and wonder whether it would be best in external or internal rotation.

Background: The shoulder joint has the widest range of motion of any joint in the human body. This makes it very useful and very susceptible to injury. These injuries include dislocation, fracture, rotator cuff tears and neurologic injuries.

The vast majority of shoulder dislocations are anterior. Young active men are at greatest risk for dislocating their shoulder.

Traditional treatment for primary anterior should dislocation has been to immobilize in a sling with the arm positioned in internal rotation and ADDuction. There is a high reoccurrence rate for instabilities especially in the young population.

A disagreement in the literature emerged when Itoi et al. published a couple of studies showing the benefits of external rotation immobilization versus internal immobilization as an alternative to early surgical intervention and possible reduction in recurrent instabilities in young patients.

“Immobilization with the arm in external rotation is effective in reducing the rate of recurrence after initial dislocation of the shoulder.” (Itoi et al J Shoulder Elbow Surg 2003)
“Immobilization in external rotation after an initial shoulder dislocation reduces the risk of recurrence compared with that associated with the conventional method of immobilization in internal rotation. This treatment method appears to be particularly beneficial for patients who are thirty years of age or younger.” (Itoi et al Joint Surg Am 2007)

Liavaag et al. found no reduction in the rate of recurrent instabilities for primary anterior shoulder dislocations, contradicting findings of Itoi et al.

“Immobilization in external rotation does not reduce the rate of recurrence for patients with first-time traumatic anterior shoulder dislocation.” (Livaag et al J Bone and Joint Surg Am 2011)

In 2014 there were two studies looking at the issue of immobilization after primary should dislocation and came to different conclusions.

Clinical Question: What is the best position to immobilize someone after a primary shoulder dislocation?

Reference: Heidari et al. Immobilization in external rotation combined with abduction reduces the risk of recurrence after primary anterior shoulder dislocation. J Shoulder Elbow Surg 2014

Population: Patients age 15 to 55 years-old presenting with primary anterior dislocation of the shoulder
- Excluded: Previous shoulder problems, surgical joint repair, multidirectional instability, needing surgery and associated fractures
External Rotation Brace

Intervention: External rotation (10⁰) with ABduction (15⁰) (AbER)
Comparison: Internal rotation with ADduction (AdIR)
Outcome:
- Primary Outcome: Recurrence rate of dislocation (humeral head completely or partially out of glenoid socket that reduced spontaneously or by manual maneuver)
- Secondary Outcomes: Anterior apprehension test, return to pre-injury sports, non-co operative patients (ie discontinuation rate), and Western Ontario Shoulder Instability Index (WOSI)

Authors’ Conclusions: “Immobilization with the shoulder joint in abduction and external rotation is an effective method to reduce the risk of recurrence after primary anterior shoulder dislocations and should be preferred to the traditional method of immobilization in adduction and internal rotation in clinical practice.”

Quality Checklist for Randomized Clinical Trials:

The study population included or focused on those in the ED. Yes, Patients presenting to a Level 2 trauma center emergency department
The patients were adequately randomized. Yes, 1:1 ratio
The randomization process was concealed. Yes
The patients were analyzed in the groups to which they were randomized. Yes, Intention to treat analysis
The study patients were recruited consecutively (i.e. no selection bias). Yes
The patients in both groups were similar with respect to prognostic factors. Yes
All participants (patients, clinicians, outcome assessors) were unaware of group allocation. No, patients and clinicians would be aware. Unsure if outcome assessors were aware.
All groups were treated equally except for the intervention. Yes
Follow-up was complete (i.e. at least 80% for both groups). Yes (none lost) (that makes me skeptical)
All patient-important outcomes were considered. Yes
The treatment effect was large enough and precise enough to be clinically significant. Yes

Key Results: 102 patients with a mean age of 36 years and 89% men (younger and mostly men, what a surprise)

Significantly less recurrence rate in abduction and external rotation

Primary Outcome: Recurrence Rate by 24 Months:
- 3.9% in AbER vs. 33.3% in AdIR
- Absolute Difference 29.4% or NNT=3
Secondary Outcomes:

This study was powered with the assumption of 30% recurrence rate for the AbER group and 60% in the AdIR group. It was not clear why these numbers were picked to select the sample size. Interestingly, their results demonstrated a much lower rate of recurrence than anticipated with only 4%in the AbER group and 33% in the AdIR group.

We also had some concerns with blinding. While the patient and clinicians were not blinded to the intervention, it was unclear whether the outcome assessors were aware of group allocation.

A lack of blinding may have impacted the primary and secondary outcomes. Patents had a telephone interview at 24 months and filled out a WOSI score at 33 months.

Recall bias could have been introduced and patients may have experience a placebo effect on the subjective WOSI assessment knowing they were in the intervention group.

The discontinuation or non-cooperation was higher in the AbER group (20%) vs. the AdIR group (6%). This was thought to be due to the unpleasant effect on activities of daily living with an external immobilized upper limb. It made it difficult to sleep, walk through doorways and not hit people in a crowded environment.

However, the increased discontinuation rate in the AbER group would have favored the control by potentially increasing the reoccurrence rate for the AbER group.

Then there were no patients lost to follow up for their primary outcome at 24 months. This was different that Itoi 2007 who had 20% loss and Liavaag 2011 who had 2% lost to follow-up. While this could be true, 100% follow-up always make us a bit more skeptical.

They did have a few patients lost to follow up at their secondary outcome follow-up WOSI score at 33 months (3 from intervention and 2 from the control group).

Comment on Authors’ Conclusion Compared to SGEM Conclusion: These results from a single centre seem too good to be true.

Dr. Daniel Whelan

Special Guest: Dr. Daniel Whalen is an orthopedic surgeon practicing at St. Michaels’ Hospital in Toronto. He did medical school at Memorial University, residency at the University Toronto and then did a number of fellowships in sports medicine, arthroscopy, shoulder surgery and trauma. This was followed by a Masters Degree in Clinical Epidemiology with his primary interest being joint instability.

Reference: Whelan et al. External rotation immobilization for primary shoulder dislocation: a randomized controlled trial. Clin Orthop Relat Res 2014

Population: Adults younger than 35 with primary anterior shoulder dislocation
- Inclusion: Skeletally mature patients under age of 35; sustained a primary anterior shoulder dislocation defined by radiographs documenting dissociation of the humerus anterior to the glenoid or injury by abduction, ER with sudden pain and deformity requiring manipulative reduction.
- Exclusion: History of previous shoulder instabilities, associated significant fractures or proximal humerus (except Hill-Sachs lesion or small Bankart Lesion), or unwilling/unable to participate.
Intervention: External rotation brace.
External Rotation Brace: External rotation brace.

Comparison: Internal rotation sling.
Outcome:
- Primary Outcome: Recurrent instability defined by a documented episode of anterior shoulder dislocation with xray evidence requiring manipulative reduction in hospital or healthcare setting or multiple episodes of shoulder subluxation which was disabling enough to seek surgical stabilization. An Orthopaedic Surgeon was mandatory in the case of recurrent subluxations before categorized as having an adverse event.
- Secondary Outcomes: Clinical assessment, compliance and disease-specific quality of life questionnaires – Western Ontario Shoulder Instability Index (WOSI) and American Shoulder and Elbow Surgeons form (ASES).

Authors’ Conclusions: “Despite previous published findings, our results show immobilization in external rotation did not confer a significant benefit versus sling immobilization in the prevention of recurrent instability after primary anterior shoulder dislocation.”

Quality Checklist for Randomized Clinical Trials:

The study population included or focused on those in the ED. Yes/No. “Patients were recruited from emergency departments and outpatient orthopaedic and primary care clinics at three university centers. Patients were assessed within 7 days of injury by the site study coordinator for eligibility.” So they were not strictly patients from the ED
The patients were adequately randomized. Yes, patients were assigned by computer-generated, permuted block algorithm
The randomization process was concealed. Yes, sealed opaque, sequentially numbered envelopes opened only after inclusion criteria were met
The patients were analyzed in the groups to which they were randomized. Yes, Intention to treat basis.
The study patients were recruited consecutively (i.e. no selection bias). No
The patients in both groups were similar with respect to prognostic factors. Yes, patient demographics and prognostics very similar at baseline.
All participants (patients, clinicians, outcome assessors) were unaware of group allocation.
- No, Patients were aware.
- Unsure, We tried to keep the physiotherapist blinded to the group assignment.
- Yes, outcome assessors were blinded.
All groups were treated equally except for the intervention. Yes, all received a standardized 16-week physical therapy program.
Follow-up was complete (i.e. at least 80% for both groups). Yes, loss of 17% to follow-up (10 out of 60). Equal loss in both groups.
All patient-important outcomes were considered. Yes, recurrence rate and two valid and reliable self-reported patient assessment scores (WOSI and ASES).
The treatment effect was large enough and precise enough to be clinically significant. No

Key Results: There were a total of 60 patients randomized in this study with 31 in the external rotation and 29 in the internal rotation immobilization group. Mean patient age was 23 years with 92% (55/60) men.

No Superiority with External Rotation

Primary Outcome: Rate of Recurrent Instability
- 37% (10/27) ER vs. 40% (10/25) IR
Secondary Outcomes:
- No difference in WOSI between the two different immobilization strategies.
- There was a small statistical difference in ASES but we are not sure of the clinical significance.

Recruitment/Blinding:
- These were not consecutive patients but could that have introduced some selection bias?
- You recruited not just ED patients but also Ortho clinic and primary care do you think that introduced referral bias?
- Blinding (patients knew if their arm was sticking out but and you tried to hide this from physio. Do you think the study could have been unblinded to the treating clinician (physiotherapist) and would that impact the primary outcome of recurrence or secondary outcome of patient subjective scoring?
WOSI and WOSI vs. ASES:
- WOSI was reported as a percent in your study but an absolute number in the Heidari study. How do we compare these two numbers?
- Why do you think there was a difference between WOSI and ASES
Statistical Stuff:
- You had less recurrence than expected a priori leaving you with an underpowered study.
- Why did you decide to use means +/- standard deviation (SD) with p values rather than giving means with a 95% confidence interval (CI) and calculate a number needed to treat (NNT) to prevent one recurrence?
Why did you find no superiority to external rotation when Itoi and Heidari did find benefit?
- Was it the age of patients (yours was younger)?
- Do you think different populations/cultures (Japan/Iran) vs. Canadian/Norway played a role?
- Itoi Included patients with fractures but your study specifically excluded fractures
- How about the different external rotation immobilization devices/braces. They were not the same, could that have had an impact on the results?
- Heidari had more abduction and more external rotation than your study. Would that explain the different findings between the two studies?
Large Randomized Control Trial or Systematic Review:
- So there are conflicting results in the literature on what is the best position to immobilize a patient after a primary anterior shoulder dislocation. Do we just need a much bigger study or would a systematic review help sort this out?

Comment on Authors’ Conclusion Compared to SGEM Conclusion: We agree with the authors’ conclusions that there is “no benefit” demonstrated with external rotation vs. internal rotation immobilization with the disclaimer that it was underpowered due to the lower than expected recurrence rate.

SGEM Bottom Line: We do not know what is the best position for primary anterior shoulder dislocations to be immobilized.

Case Resolution: The patient is placed in a standard internal rotation immobilization sling. He is provided with specific instruction to wear the sling for 3-4 weeks and then return for re-assessment. He will then be started on a course of physiotherapy to restore range of motion, strength and function.

Clinically Application: This clinical situation makes an excellent opportunity for shared decision-making. This means collaborating with the patient about the two reasonable options. Provide information about the traditional internal rotation vs. the external rotation immobilization. Reassure the patient there is no right or wrong answer and what ever they decide will be fine.

What do I tell my patient? We have put your shoulder back in the joint. There is a high chance it can pop out again. You need to have it immobilized for the next month and then start physiotherapy. Traditionally we have put people in a sling. Some research suggests having your arm sticking out to the side could be better. Other researchers has said the opposite. The new way may turn out to be better but it is big device and can be awkward. What do you want to do?

Keener Kontest: Last weeks winner was Oliver Welner. Oliver is an EM Pharmacist from Kitchener. He knew erythromycin was originally isolated from a soil sample. The bacteria name is Streptomyces erythreus.

Listen to the podcast for this weeks keener question. If you know the answer send an email to TheSGEM@gmail.com with “keener” in the subject line. The first correct response will win a cool skeptical prize.