Randelli 2011.

Methods	Randomised controlled trial: participants were randomised utilising block procedure. Participants had final follow‐up at 24 months Trial conducted: Department of Scienze Medico Chirurgiche, University of Milano, IRCCS Policlinico San Donato, Milano, Italy; recruitment: from April 2007‐January 2008
Participants	Participants: 53 undergoing arthroscopic repair of rotator cuff tears Inclusion criteria: a complete rotator cuff tear confirmed intraoperatively; agreed to wear a dedicated brace for 4 weeks postoperatively; had a preoperative platelet count > 150,000; minimum preoperative haemoglobin of 11.0 g/dL; no infectious diseases or diseases that may have limited follow‐up; BMI < 33 Exclusion criteria: previous rotator cuff repair; active infection; osteomyelitis or sepsis, or distant infections; osteomalacia or other metabolic bone disorders; unco‐operative or had disorders that made them incapable of following directions, or who were unwilling to return for follow‐up examinations; vascular insufficiency, muscular atrophy, or neuromuscular diseases of the affected arm; cigarette smokers; had received steroid injection(s) in the affected shoulder Age: PRT group mean (range): 61.6 years (8.3) No PRT mean (range): 59.5 years (10.7) Gender: PRT group (number of men:women): 8:19 No PRT (number of men:women): 13:13 Sports activity: not available
Interventions	Participants were submitted to arthroscopic rotator cuff repair (single row repair, absorbable anchors) by a single surgeon. Acromioplasty was performed in all cases PRT (number of participants = 26): single, intraoperative injection. 54 mL blood mixed with 6 mL citrate as an anticoagulant. The product was centrifuged for 15 minutes at 3200 rpm. PRP was separated and centrifuged (2 minutes) to increase fibrinogen concentration and mixed with PRP. A final 6 mL PRP was applied through the arthroscopic portals PRT preparation: kit: GPS II, Biomet Biologics (Warsaw, IN) Quantification of platelet concentrates after preparation: not reported No PRT (number of participants = 27): no platelet‐rich therapy controls Co‐interventions: same rehabilitation protocol
Outcomes	Constant score SST UCLA score VAS Strength in external rotation Rate of retear
Other quality issues	Sample size: the authors calculated the sample size Validation of PRT: the exact composition of the PRP was unknown
Notes	Authors had 8 follow‐up losses (4 in each group). Pain was measured in short intervals in the early postoperative period
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation	Low risk	A block randomised procedure was used to generate a randomisation list
Allocation concealment	Low risk	Used sequentially‐numbered, opaque and sealed envelopes
Blinding All outcomes	Low risk	The participants and outcome assessors were blinded to the treatment
Incomplete outcome data addressed All outcomes	Low risk	Missing outcome data were balanced in numbers across intervention groups
Free of selective reporting	Unclear risk	The study protocol is not available but all expected outcomes were assessed
Free of other bias	Low risk	The study appears to be free of other sources of bias