Patch augmentation surgery for rotator cuff repair: the PARCS mixed-methods feasibility study.BACKGROUND
 A rotator cuff tear is a common, disabling shoulder problem.  Symptoms may include pain, weakness, lack of shoulder mobility and sleep disturbance.  There is a need to improve the outcome of rotator cuff surgery, and the use of patch augmentation (on-lay or bridging) to provide support to the healing process and improve patient outcomes holds promise.  Patches have been made using different materials (e.g. human/animal skin or tissue and synthetic materials) and processes (e.g. woven or mesh).


 OBJECTIVES
 The aim of the Patch Augmented Rotator Cuff Surgery (PARCS) feasibility study was to determine the design of a definitive randomised controlled trial assessing the clinical effectiveness and cost-effectiveness of a patch to augment surgical repair of the rotator cuff that is both acceptable to stakeholders and feasible.


 A mixed-methods feasibility study of a randomised controlled trial.


 DATA SOURCES
 MEDLINE, EMBASE and the Cochrane Library databases were searched between April 2006 and August 2018.


 The project involved six stages: a systematic review of clinical evidence, a survey of the British Elbow and Shoulder Society's surgical membership, a survey of surgeon triallists, focus groups and interviews with stakeholders, a two-round Delphi study administered via online questionnaires and a 2-day consensus meeting.  The various stakeholders (including patients, surgeons and industry representatives) were involved in stages 2-6.


 The systematic review comprised 52 studies; only 15 were comparative and, of these, 11 were observational (search conducted in August 2018).  These studies were typically small (median number of participants 26, range 5-152 participants).  There was some evidence to support the use of patches, although most comparative studies were at a serious risk of bias.  Little to no published clinical evidence was available for a number of patches in clinical use.  The membership survey of British Elbow and Shoulder surgeons [105 (21%) responses received] identified a variety of patches in use.  Twenty-four surgeons (77%) completed the triallist survey relating to trial design.  Four focus groups were conducted, involving 24 stakeholders.  Differing views were held on a number of aspects of trial design, including the appropriate patient population (e.g. patient age) to participate.  Agreement on the key research questions and the outline of two potential randomised controlled trials were achieved through the Delphi study [29 (67%)] and the consensus meeting that 22 participants attended.


 The main limitation was that the findings were influenced by the participants, who are not necessarily representative of the views of the relevant stakeholder groups.


 CONCLUSION
 The need for further clinical studies was clear, particularly given the range and number of different patches available.


 Randomised comparisons of on-lay patch use for completed rotator cuff repairs and bridging patch use for partial rotator cuff repairs were identified as areas for further research.  The value of an observational study to assess safety concerns of patch use was also highlighted.  These elements are included in the trial designs proposed in this study.


 The systematic review is registered as PROSPERO CRD42017057908.


 This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol.  See the NIHR Journals Library website for further project information.
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