Summary of findings for the main comparison. Subacromial decompression compared to placebo surgery.
| Subacromial decompression compared to placebo surgery for people with impingement syndrome without full‐thickness rotator cuff tears | ||||||
| Patient or population: people with impingement syndrome without full‐thickness rotator cuff tears Setting: hospitals in Finland and UK Intervention: subacromial decompression Comparison: placebo surgery (diagnostic arthroscopy) | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with placebo surgery | Risk with subacromial decompression | |||||
| Paina (scale from 0‐10, 0 is no pain) Follow‐up: 1 year | The mean pain was 2.9 pointsb | The mean pain was 0.26 points better (0.84 better to 0.33 worse) | ‐ | 284 (2 RCTs) | ⊕⊕⊕⊕ High | Absolute difference 3% better (8% better to 3% worse); relative difference 4% better (12% better to 5% worse)c |
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Functional outcome (Constant score from 0‐100, 100 is best) Follow‐up: 1 year |
The mean functional outcome was 69b | MD 2.76 higher (1.36 lower to 6.87 higher) | 274 (2 RCTs) | ⊕⊕⊕⊕ High | Absolute difference 3% better (7% better to 1% worse); relative difference 9% better (22% better to 4% worse)c | |
| Global assessment of treatment success | 655 per 1000 | 708 per 1000 (610 to 832) | RR 1.08 (0.93 to 1.27) | 290 (2 RCTs) | ⊕⊕⊕⊝ Moderated | Absolute difference 5% more reported success (5% fewer to 16% more); relative difference 8% more reported success (7% fewer to 27% more) |
| Health‐related quality of life (scale from −0.59 to 1, 1 is perfect health) Follow‐up: 1 year | The mean health‐related quality of life was 0.73b | MD 0.03 lower (0.11 lower to 0.06 higher) | 285 (2 RCTs) | ⊕⊕⊕⊕ High | SMD 0.09 worse (0.39 worse to 0.21 better) Absolute difference 2% worse (7% worse to 4% better); relative difference 5% worse (20% worse to 11% better)c |
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| Adverse events | 37 per 1000 | 34 per 1000 (11 to 98) | RR 0.91 (0.31 to 2.65) | 406 (2 RCTs)d | ⊕⊕⊕⊝ Moderatee | Absolute difference of 1% fewer events with surgery (4% fewer to 3% more); relative difference 9% fewer events with surgery (69% fewer to 165% more) |
| Serious adverse events | No events | No events | No estimate | 331 (2 RCTs) | ⊕⊕⊕⊝ Moderatef | Although precise estimates are unknown, serious adverse event rates in observational studies are reported as less than 1%g |
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; MD: mean difference; RR: risk ratio; SMD: standardised mean difference | ||||||
| GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. | ||||||
aPain measured with numeric rating scale (NRS) or visual analogue scale (VAS). bMedian value in placebo groups after one‐year follow‐up. cRelative changes calculated relative to baseline in control group (i.e. absolute change (mean difference) divided by mean at baseline in the placebo group from Paavola 2018 (values were: 7.23 points on 0 to 10‐point VAS pain; 31.7 points on 0 to 100‐point Constant score) and Beard 2018 (0.55 points on EQ‐5D quality‐of‐life scale). Absolute change calculated as mean difference divided by scale of the instrument, expressed as percentage.
dPooled both placebo and non‐operative (exercise or no treatment) comparisons from randomised controlled trials in the analysis of adverse events eDowngraded due to imprecision (due to low event rates, or 95% confidence intervals that included both benefits and harms) in the randomised trials.
fDowngraded due to indirectness as arthroscopic procedures other than subacromial decompression were included in the surgery registry observational data gSerious adverse events as reported in observational studies, 7 per 1000 (95% CI 6 to 8 per 1000) include: deep infection; pulmonary embolism; uncontrolled bleeding; myocardial infection; acute renal failure; ventilation more than 48 hours; cerebral vascular incident; septic shock; cardiac arrest; wound dehiscence; deep venous thrombosis; pneumonia; bleeding requiring transfusion; nerve injury; death; organ space infection.