Creaney 2011.

Methods	Randomised controlled trial: randomisation held in sealed envelopes. Not clear how the allocation sequence was generated. Participants followed for 6 months. Participants were blinded to the procedure. Assessors were independent Trial conducted: no details available; recruitment: no details available
Participants	Participants: 150 with elbow tendinopathy Included participants: adults with elbow tendinopathy (< 6 months' duration) that had failed to respond to physical therapy exercises Exluded participants: previous injection therapies (e.g. Corticoid) Age: PRT group mean (range):53 years (not available) No PRT mean (range): 48 years (not available) Gender: PRT group (number of men:women): 46:34 No PRT (number of men:women): 45:25 Sports activity: not available
Interventions	All participants underwent 2 injections (at 0 and 1 month) with previous local anaesthesia (2 mL bupivacaine). Injections performed by ultrasound guidance by an musculoskeletal radiologist PRT (number of participants = 80): 8.5 mL blood sample, tube with citrate anticoagulant PRT preparation: no kit. Preparation: 15 minutes of centrifugation, 1.5 mL platelet‐rich plasma siphoned from buffy coat layer Quantification of platelet concentrates after preparation: 10 random samples of blood demonstrated a 2.8‐fold (CI 2.3‐3.5) elevation from baseline for the platelet concentration No PRT (number of participants = 70): autologous blood injections ‐ details not reported Co‐interventions: same rehabilitation protocol for both groups
Outcomes	PRTEE
Other quality issues	Sample size: powered for PRTEE Validation of PRT: quantification reported
Notes	Participants who did not improve with the proposed intervention (failure) had the option to undergo surgical treatment. This study was included using an inclusion criterion that differed from the published protocol: autologous whole blood was considered as a control intervention
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation	Unclear risk	Not reported
Allocation concealment	Low risk	Used sequentially‐numbered, opaque and sealed envelopes
Blinding All outcomes	Low risk	Participants and outcomes assessors were blinded
Incomplete outcome data addressed All outcomes	High risk	Missing outcome data were balanced in numbers across intervention groups. In addition, intention‐to‐treat analyses were performed. However, the data available for PTREE did not include 7 versus 12 participants who had subsequent surgery
Free of selective reporting	High risk	The study protocol is not available and the authors evaluated only 1 primary outcome (PRTEE). In addition, the clinical follow‐up period was short for participants who underwent elbow tendinopathy treatment
Free of other bias	Low risk	Participants were permitted to receive other treatments. However, authors performed analysis as intention‐to‐treat