Gumina 2012.

Methods	Randomised controlled trial: allocation concealment derived from randomisation (sealed envelopes). Participants were followed for a mean of 13 months Trial conducted: Orthopaedic Clinic, University of Rome 'Sapienza', Rome, Italy; recruitment: from June‐December 2009
Participants	Participants: 80 undergoing arthroscopic repair of rotator cuff tears Included participants: reparable large full‐thickness posterosuperior rotator cuff tears Excluded participants: partial‐thickness tear; small or massive full‐thickness tear; traumatic tear; biceps instability; labral pathology amenable to surgical treatment; os acromiale; degenerative arthritis of the glenohumeral joint; autoimmune or rheumatologic disease; previous surgery in the same shoulder and Workers' compensation claims Age: PRT group mean (SD): 60 years (4.4) No PRT mean (SD): 63 years (5.9) Gender: PRT group (number of men:women): 20:19 No PRT (number of men:women): 21:16 Sports activity: not available
Interventions	All participants underwent arthroscopic rotator cuff repair PRT (number of participants = 40): single, intraoperative intervention (platelet‐leukocyte membrane), 10 mL blood was centrifuged for 10 minutes at 120 x g. The product was added to gluconate and batroxobin, for 20‐30 minutes (product is a platelet‐leukocyte membrane) PRT preparation: kit: RegenKit, Regen Lab, Le Mont‐Sur‐Lausanne, Switzerland) Quantification of platelet concentrates after preparation: white blood cells (7 x 103/mm3), platelet (> 400 x 103/mm3), 1.7 times greater than the normal level in whole blood. No PRT (number of participants = 40): no platelet‐rich therapy controls Co‐interventions: same rehabilitation protocol for both groups
Outcomes	Constant scores Simple Shoulder Test MRI (repair integrity): Sugaya classification
Other quality issues	Sample size: a priori power calculations not available Validation of PRT: quantification reported
Notes	In the intervention group, 1 membrane was used for each repair anchor 4 follow‐up losses (1 in the PRT group), reasons not known The authors provided the study protocol/trial registration details, ID: ISRCTN93082180
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation	Unclear risk	Randomisation reporting was unclear
Allocation concealment	High risk	The envelope was opened 3 days prior to surgery rather than during surgery
Blinding All outcomes	Unclear risk	The study was probably not blinded
Incomplete outcome data addressed All outcomes	Low risk	Missing outcome data were balanced in numbers across intervention groups
Free of selective reporting	Low risk	The study protocol was available and all of the study’s prespecified (primary and secondary) outcomes that are of interest in the review have been reported in the prespecified way
Free of other bias	Low risk	The study appears to be free of other sources of bias