Effectiveness of adding a large dose of shoulder strengthening to current nonoperative care for subacromial impingement

Key points

1. 01200 patients with long-standing subacromial impingement were randomised to usual care alone or usual care plus a progressive home elastic-band program designed to at least double the strengthening dose
2. 02SPADI scores improved similarly in both groups by roughly 22 points, well below the 10-point threshold needed to declare the added program superior
3. 03No between-group difference was found for any secondary outcome including shoulder strength, range of motion, pain, or quality of life
4. 04Only 54% of the intervention group and 48% of the control group reached an acceptable symptom state at four months
5. 05Patients in the intervention group spontaneously reduced time on usual-care exercise, suggesting many cannot or will not increase their overall exercise burden

How it was conducted

Design

Pragmatic double-blind randomised controlled superiority trial (SExSI Trial)

Participants

200 adults aged 18-65 with subacromial impingement lasting more than 3 months referred to an orthopaedic outpatient clinic in Denmark

Groups

Control: usual non-surgical care. Intervention: usual care plus home-based progressive elastic-band shoulder strengthening program

Add-on intervention

Three rotator-cuff exercises with elastic band performed to contraction failure, 3 phases over 16 weeks, prescribed time under tension of approximately 12 hours

Primary outcome

Shoulder Pain and Disability Index (SPADI, 0-100) at 4-month follow-up; minimal clinically important difference set at 10 points

Follow-up

5 weeks, 10 weeks, and 4 months

What they found

• Primary outcome SPADI, baseline to 4 months: intervention group improved by -22.1 points (95% CI, -26.6 to -17.6); control group improved by -22.7 points (95% CI, -26.4 to -19.0); between-group mean difference 0.6 points (95% CI, -5.5 to 6.6), P = .8518
• SPADI pain subscale between-group difference: 2.3 points (95% CI, -4.6 to 9.1)
• SPADI function subscale between-group difference: -0.7 points (95% CI, -6.7 to 5.3)
• Abduction strength between-group difference at 4 months: -0.01 Nm/kg (95% CI, -0.04 to 0.02), P = .6280
• External rotation strength between-group difference at 4 months: 0.01 Nm/kg (95% CI, -0.01 to 0.02), P = .2062
• Abduction range of motion between-group difference at 4 months: 3.7 degrees (95% CI, -4.6 to 12.1), P = .3819
• Patient Acceptable Symptom State (PASS) at 4 months: 54% intervention vs 48% control, P = .4127
• Global impression of change (recovered or much improved) at 4 months: 24% intervention vs 27% control, P = .5751
• Actual mean total time under tension completed in the intervention group: 2.9 hours (10,468 seconds) vs prescribed 12 hours
• Intervention group spent on average 35 min/week on usual-care exercise vs 51 min/week in the control group
• Post-hoc analysis adjusting for usual-care exercise time showed no between-group difference: MD 0.2 points (95% CI, -6.0 to 6.3)
• Symptom exacerbations lasting at least 1 week: 49 in intervention group, 47 in control group; no serious adverse events

Limitations

• Actual adherence to the add-on program (mean 2.9 hours) was substantially below the prescribed 12 hours, though the achieved dose was still argued to be clinically meaningful based on prior evidence
• Patients in the intervention group reduced time on usual-care exercise despite instructions not to, potentially diluting the between-group contrast
• Missing primary outcome data at 4 months was 19% overall and higher in the intervention group, although this was likely to bias results in favour of the intervention rather than against it
• The four-month follow-up may be too short to detect longer-term benefits of higher-dose strengthening, though it corresponds to the standard clinical decision point for reassessment

Why it matters

For patients

If you have shoulder impingement and are already doing physiotherapy-guided exercises, doing a large amount of additional home strengthening is unlikely to reduce your pain or disability further, and about half of people still have bothersome symptoms after four months of non-surgical care regardless.

For clinicians

This high-quality RCT shows that simply prescribing more volume of home-based rotator-cuff strengthening on top of usual care does not improve outcomes for subacromial impingement; future efforts should explore patient education, self-management support, and identifying which patients may benefit from second-line interventions including surgery.

For readers

The trial confirms that for a common and stubborn shoulder condition, more exercise is not automatically better, and highlights a significant treatment gap since roughly half of patients remain symptomatic after four months of best available non-surgical care.