title: The CSAW Study (Can Shoulder Arthroscopy Work?) - a placebo-controlled surgical intervention trial assessing the clinical and cost effectiveness of arthroscopic subacromial decompression for shoulder pain: study protocol for a randomised controlled trial.
abstract: BACKGROUND
  Arthroscopic subacromial decompression (ASAD) is a commonly performed surgical intervention for shoulder pain. The rationale is that removal of a bony acromial spur relieves symptoms by decompressing rotator cuff tendons passing through the subacromial space. However, the efficacy of this procedure is uncertain. The objective of this trial was to compare the efficacy and cost-effectiveness of ASAD in patients with subacromial pain using appropriate control groups, including placebo intervention.
  
  
  METHODS
  The trial is a three-group, parallel design, pragmatic, randomised controlled study. The intervention content for each group (ASAD, active monitoring with specialist reassessment (AMSR) and investigational shoulder arthroscopy only (AO)) enables assessment of (1) the efficacy of the surgery against no surgery; (2) the need for a specific component of the surgery-namely, removal of the bony spur; and (3) quantification of the placebo effect. Concealed allocation was performed using a 1:1:1 randomisation ratio and using age, sex, baseline Oxford Shoulder Score (OSS) and centre as minimisation criteria. The primary outcome measure is the OSS at 6 months post randomisation. A total of 300 patients recruited over 24 months from a minimum of 14 UK shoulder units over 24 months were required to detect a difference of 4.5 points on the OSS (standard deviation, 9) with 90% power and to allow for 15% loss to follow-up. Secondary outcomes include cost-effectiveness, pain, complications and patient satisfaction. A substantial qualitative research component is included. The primary analysis will be conducted on the modified intention-to-treat analysis. Sensitivity analysis will be used to assess the robustness of the results with regard to the underlying assumptions about missing data using multiple imputation.
  
  
  CONCLUSIONS
  This trial uses an innovative design to account for the known placebo effects of surgery, but it also will delineate the mechanism for any benefit from surgery. The investigational AO group is considered a placebo intervention (not sham surgery), as it includes all components of subacromial decompression except the critical surgical element. Some discussion is also dedicated to the challenges of conducting placebo surgery trials.
  
  
  BACKGROUND
  UK Clinical Research Network UKCRN12104. Registered 22 May 2012. International Standard Randomised Controlled Trial ISRCTN33864128 . Registered 22 June 2012. ClinicalTrials.gov NCT01623011 . Registered 15 June 2012.
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Botnar Research Centre, University of Oxford, Headington, Oxford, OX3 7LD, UK. david.beard@ndorms.ox.ac.uk.
authors.forename: David
authors.initials: D
authors.lastname: Beard
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Botnar Research Centre, University of Oxford, Headington, Oxford, OX3 7LD, UK. jonathan.rees@ndorms.ox.ac.uk.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Rees
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Botnar Research Centre, University of Oxford, Headington, Oxford, OX3 7LD, UK. ines.rombach@ndorms.ox.ac.uk.
authors.forename: Ines
authors.initials: I
authors.lastname: Rombach
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Botnar Research Centre, University of Oxford, Headington, Oxford, OX3 7LD, UK. cushla.cooper@ndorms.ox.ac.uk.
authors.forename: Cushla
authors.initials: C
authors.lastname: Cooper
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Botnar Research Centre, University of Oxford, Headington, Oxford, OX3 7LD, UK. jonathan.cook@ndorms.ox.ac.uk.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Cook
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Botnar Research Centre, University of Oxford, Headington, Oxford, OX3 7LD, UK. naomi.merritt@ndorms.ox.ac.uk.
authors.forename: Naomi
authors.initials: N
authors.lastname: Merritt
authors.affiliation: Nuffield Department of Population Health, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford, OX3 7LF, UK. alastair.gray@dph.ox.ac.uk.
authors.forename: Alastair
authors.initials: A
authors.lastname: Gray
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Botnar Research Centre, University of Oxford, Headington, Oxford, OX3 7LD, UK. steve.gwilym@ndorms.ox.ac.uk.
authors.forename: Stephen
authors.initials: S
authors.lastname: Gwilym
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Botnar Research Centre, University of Oxford, Headington, Oxford, OX3 7LD, UK. andrew.judge@ndorms.ox.ac.uk.
authors.forename: Andrew
authors.initials: A
authors.lastname: Judge
authors.affiliation: Institute for Science and Ethics, University of Oxford, Suite 8, Littlegate House, 16/17 St Ebbe's Street, Oxford, OX1 1PT, UK. julian.savulescu@philosophy.ox.ac.uk.
authors.forename: Julian
authors.initials: J
authors.lastname: Savulescu
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Botnar Research Centre, University of Oxford, Headington, Oxford, OX3 7LD, UK. jane.moser@ndorms.ox.ac.uk.
authors.forename: Jane
authors.initials: J
authors.lastname: Moser
authors.affiliation: School of Social and Community Medicine, University of Bristol, Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. jenny.donovan@bristol.ac.uk.
authors.forename: Jenny
authors.initials: J
authors.lastname: Donovan
authors.affiliation: School of Social and Community Medicine, University of Bristol, Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. marcus.jepson@bristol.ac.uk.
authors.forename: Marcus
authors.initials: M
authors.lastname: Jepson
authors.affiliation: School of Social and Community Medicine, University of Bristol, Canynge Hall, 39 Whatley Road, Bristol, BS8 2PS, UK. marcus.jepson@bristol.ac.uk.
authors.forename: Caroline
authors.initials: C
authors.lastname: Wilson
authors.affiliation: Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Headley Way, Headington, Oxford, OX3 9DU, UK. irene@fmrib.ox.ac.uk.
authors.forename: Irene
authors.initials: I
authors.lastname: Tracey
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Botnar Research Centre, University of Oxford, Headington, Oxford, OX3 7LD, UK. karolina.wartolowska@ndorms.ox.ac.uk.
authors.forename: Karolina
authors.initials: K
authors.lastname: Wartolowska
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Botnar Research Centre, University of Oxford, Headington, Oxford, OX3 7LD, UK. benjamin.dean@ndorms.ox.ac.uk.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Dean
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Botnar Research Centre, University of Oxford, Headington, Oxford, OX3 7LD, UK. andrew.carr@ndorms.ox.ac.uk.
authors.forename: Andrew
authors.initials: A
authors.lastname: Carr
mesh_terms: D000174:Acromion / Q000503:physiopathology / Q000601:surgery*; D001182:Arthroscopy / Q000009:adverse effects / Q000191:economics* / Q000379:methods; D002985:Clinical Protocols; D003362:Cost-Benefit Analysis; D019299:Decompression, Surgical / Q000009:adverse effects / Q000191:economics* / Q000379:methods; D005260:Female; D017048:Health Care Costs; D006801:Humans; D057194:Intention to Treat Analysis; D008297:Male; D054850:Osteophyte / Q000175:diagnosis / Q000191:economics* / Q000503:physiopathology / Q000601:surgery*; D010147:Pain Measurement; D017060:Patient Satisfaction; D011183:Postoperative Complications / Q000191:economics; D011237:Predictive Value of Tests; D012107:Research Design; D018401:Sample Size; D020069:Shoulder Pain / Q000175:diagnosis / Q000191:economics* / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D006113:United Kingdom