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The challenge of recruiting patients into a placebo-controlled surgical trial

Kristoffer B Hare12*, L Stefan Lohmander13 and Ewa M Roos1

Author Affiliations

1 Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark

2 Department of Orthopedics, Slagelse Hospital, Ingemannsvej 18, 4200 Slagelse, Region Zealand, Denmark

3 Department of Orthopedics, Clinical Sciences Lund, University of Lund, Paradisgatan 2, 221 00 Lund, Sweden

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Trials 2014, 15:167  doi:10.1186/1745-6215-15-167

Published: 13 May 2014



Randomized placebo-controlled trials represent the gold standard in evaluating healthcare interventions but are rarely performed within orthopedics. Ethical concerns or well-known challenges in recruiting patients for surgical trials in general have been expressed and adding a placebo component only adds to this complexity. The purpose of this study was to report the challenges of recruiting patients into an orthopedic placebo-controlled surgical trial, to determine the number of patients needed to be screened and allocated in order to include one participant into the trial, and to identify reasons associated with participation in a placebo-controlled randomized surgical trial.


Data were extracted from an ongoing placebo-controlled randomized controlled trial (RCT) on meniscectomy versus placebo surgery. We calculated the number of patients needed to be screened in order to include the required number of participants into the RCT. Participating patients were asked about their rationale for joining the study and which type of information was most useful for deciding upon participation.


A total of 476 patients entered the screening group, of which 190 patients fulfilled the inclusion and exclusion criteria. 102 patients declined to participate in the study due to various reasons and 46 were later excluded (no meniscus lesion on the magnetic resonance imaging scan or withdrawn consent). A total of 40 patients were finally included in the RCT. To include one patient into the RCT, 11.9 individuals needed to be screened. A total of 69% of participating patients considered the oral information to be the most important and the most common reason for participating was the contribution to research (90%).


Patients are willing to participate in an orthopedic placebo-controlled surgical trial. Oral information given by the surgeon to the patient and the contribution to research are important aspects to enhance patient recruitment.

Trial registration NCT01264991, registered 21 December 2010.

Feasibility; Placebo; Surgery; Recruitment; Trial