Physiotherapy Research Unit, Nuffield Orthopaedics Centre NHS Trust, Oxford and Primary Care Clinical Sciences, University of Birmingham, Birmingham, UK.
Clin Rehabil. 2011 Mar;25(3):264-74. doi: 10.1177/0269215510380824. Epub 2010 Oct 22.
(1) To develop trial protocols which promote the achievement of blind outcome assessment. (2) To report outcome assessor beliefs regarding group allocation at follow-up assessments. (3) To document and describe instances of unblinding occurring during the trial to assist and inform rehabilitation researchers and clinicians.
Prospective longitudinal observational study.
An NHS Hospital Trust specializing in orthopaedic surgery.
One hundred and seven patients participating in a prospective pragmatic randomized controlled trial investigating physiotherapy rehabilitation following total knee arthroplasty, plus three outcome assessors.
A protocol was developed using available research and designed to minimize instances of unblinding during a physiotherapy rehabilitation trial. Administrative, office, patient and research staff procedures were included.
Trial questionnaires measured blind outcome assessment responses at 3 and 12 months post surgery. The outcome assessor kept a field diary recording the events surrounding instances of unblinding. Data underwent descriptive and content analysis.
Blind outcome assessment was believed successful for n = 74 (81.32%) assessments at 3-month follow-up, and n = 83 (91.21%) at 12 months. Forty instances (n = 28 participants) of unblinding were described in the field diary. While the main cause of unblinding was participants telling the outcome assessor, in 12.5% of events the assessor drew the wrong conclusion regarding group allocation. Not all unblinding events were remembered at subsequent assessments, even in this relatively small trial.
Blind outcome assessment was considered achievable in this trial. Specific trial protocols enabled blinding beliefs to be reported and instances of unblinding to be described.
（1）制定试验方案以促进盲法结局评估的实现。（2）报告结局评估者在随访评估时对分组的信念。（3）记录和描述试验中发生的破盲实例，以帮助和告知康复研究人员和临床医生。
前瞻性纵向观察性研究。
一家专门从事矫形外科手术的英国国民保健制度医院信托。
107 名参与前瞻性实用随机对照试验的患者，该试验调查全膝关节置换术后物理治疗康复，外加 3 名结局评估者。
使用现有研究制定了一项方案，旨在最大限度地减少物理治疗康复试验中的破盲实例。包括行政、办公室、患者和研究人员的程序。
试验问卷在术后 3 个月和 12 个月时测量盲法结局评估的反应。结局评估者记录了破盲事件周围的事件，并保持了一份现场日记。数据进行了描述性和内容分析。
在 3 个月随访时，74 项（81.32%）评估被认为盲法结局评估成功，在 12 个月时，83 项（91.21%）评估被认为盲法结局评估成功。现场日记中描述了 40 次（n=28 名参与者）破盲事件。虽然破盲的主要原因是参与者告知结局评估者，但在 12.5%的事件中，评估者对分组的结论有误。即使在这个相对较小的试验中，并非所有的破盲事件都能在随后的评估中被记住。
在这项试验中，盲法结局评估被认为是可行的。具体的试验方案使盲法信念得以报告，破盲实例得以描述。
