Objective To assess the efficacy of arthroscopic subacromial decompression (ASD) by comparing it with diagnostic arthroscopy, a placebo surgical intervention, and with a non-operative alternative, exercise therapy, in a more pragmatic setting.
Design Multicentre, three group, randomised, double blind, sham controlled trial.
Setting Orthopaedic departments at three public hospitals in Finland.
Participants 210 patients with symptoms consistent with shoulder impingement syndrome, enrolled from 1 February 2005 with two year follow-up completed by 25 June 2015.
Interventions ASD, diagnostic arthroscopy (placebo control), and exercise therapy.
Main outcome measures Shoulder pain at rest and on arm activity (visual analogue scale (VAS) from 0 to 100, with 0 denoting no pain), at 24 months. The threshold for minimal clinically important difference was set at 15.
Results In the primary intention to treat analysis (ASD versus diagnostic arthroscopy), no clinically relevant between group differences were seen in the two primary outcomes at 24 months (mean change for ASD 36.0 at rest and 55.4 on activity; for diagnostic arthroscopy 31.4 at rest and 47.5 on activity). The observed mean difference between groups (ASD minus diagnostic arthroscopy) in pain VAS were −4.6 (95% confidence interval −11.3 to 2.1) points (P=0.18) at rest and −9.0 (−18.1 to 0.2) points (P=0.054) on arm activity. No between group differences were seen between the ASD and diagnostic arthroscopy groups in the secondary outcomes or adverse events. In the secondary comparison (ASD versus exercise therapy), statistically significant differences were found in favour of ASD in the two primary outcomes at 24 months in both VAS at rest (−7.5, −14.0 to −1.0, points; P=0.023) and VAS on arm activity (−12.0, −20.9 to −3.2, points; P=0.008), but the mean differences between groups did not exceed the pre-specified minimal clinically important difference. Of note, this ASD versus exercise therapy comparison is not only confounded by lack of blinding but also likely to be biased in favour of ASD owing to the selective removal of patients with likely poor outcome from the ASD group, without comparable exclusions from the exercise therapy group.
Conclusions In this controlled trial involving patients with a shoulder impingement syndrome, arthroscopic subacromial decompression provided no benefit over diagnostic arthroscopy at 24 months.
Trial registration Clinicaltrials.gov NCT00428870.

中文翻译：

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肩峰下减压与诊断性关节镜检查对肩膀的撞击：随机，安慰剂手术控制的临床试验

目的通过比较关节镜下肩峰下减压（ASD）与诊断性关节镜，安慰剂外科手术干预以及非手术替代运动疗法在更实际的情况下进行评估，以评估其有效性。
设计多中心，三组，随机，双盲，假对照试验。在芬兰的三所公立医院
设置骨科。
参与者210例具有与肩部撞击综合征相符的症状的患者，于2005年2月1日入选，并于2015年6月25日完成了为期两年的随访。
干预措施包括自闭症，诊断性关节镜检查（安慰剂对照）和运动疗法。
主要观察指标在24个月时，肩膀休息和手臂活动时的肩膀疼痛（视觉模拟评分（VAS）从0到100，其中0表示没有疼痛）。最小临床重要差异的阈值设置为15。
结果在进行治疗分析的主要目的（ASD与诊断性关节镜检查）中，在24个月的两个主要结局中均未观察到组间差异的临床相关性（静止时ASD为36.0，活动时为55.4；诊断性关节镜在静止时为31.4，而在活动时为31.4。 47.5）。疼痛VAS的两组之间的平均差异（ASD减去诊断性关节镜检查）为静止时为-4.6（95％置信区间-11.3至2.1）点（P = 0.18）和-9.0（-18.1至0.2）点（P = 0.054） ）进行手臂活动。在继发结局或不良事件中，ASD组和诊断性关节镜检查组之间未发现组间差异。在二级比较（ASD与运动疗法）中，在两个静息期VAS的24个月时，两个主要结局均发现ASD具有统计学意义的显着差异（-7.5，-14）。0至-1.0，点；P = 0.023）和手臂活动的VAS（-12.0，-20.9至-3.2，点； P = 0.008），但各组之间的平均差异未超过预先规定的最小临床重要差异。值得注意的是，这种ASD与运动疗法的比较不仅因缺乏盲目性而混淆，而且由于有选择地将ASD组可能有不良预后的患者从患者中剔除而没有可比性排除在运动疗法之外，而且有可能偏向于ASD团体。
结论在这项涉及肩部撞击综合征患者的对照试验中，在24个月时，关节镜下肩峰下减压比诊断性关节镜检查无益处。
试用注册Clinicaltrials.gov NCT00428870。