Biermann 2020.

Study characteristics
Methods	Method of randomisation: computer‐generated randomisation sequence; closed envelopes Assessor blinding: blinded Loss to follow‐up at 12 months: 10/72 (1 lost to follow‐up; 3 died; 6 excluded as biceps tenodesis performed)
Participants	University Hospital, Munich, Germany Period of study recruitment: January 2016 to April 2018 72 participants with displaced (> 1 cm or > 45 degrees angulation) intracapsular proximal humeral fractures. Age 18+ years. Written informed consent. Exclusion criteria: previous fracture of the proximal humerus, other injuries to the same proximal humerus requiring surgery, polytrauma, concomitant nerve injury, known rotator cuff tear, alcoholism or drug use, non‐statutory independent person, dementia, non‐command of written or spoken German language, open fracture, medical conditions that precluded surgery Post‐randomisation exclusion: biceps tenodesis performed due to concomitant injury of the long head of the biceps tendon (dislocation, instability, subluxation, and/or tear): this occurred in 3 participants of each group Of 62: 41 female, 21 male; mean age 65 years, range not given
Interventions	Surgery was within 5 days of fracture. Used deltopectoral approach with the patient placed in the beach chair position. General anaesthesia. Open reduction and internal fixation with a locking (PHILOS) plate placed 5 mm lateral to the bicipital groove and 5 mm inferior to the most lateral insertion of the supraspinatus tendon. Full‐thickness rotator cuff tears were treated if present. Tuberosity sutures used in all cases. Two locking screws were placed in the inferior third of the humeral head (calcar screws). 1. Additional glenohumeral joint lavage. A 1.8 x 43 mm paracentesis needle was placed in the anterior glenohumeral joint space in between the humeral head and the glenoid rim superior to the palpated subscapularis tendon and inferior to the supraspinatus tendon. A 50‐mL syringe filled with sterile Ringer solution was connected via a luer lock adapter; the fluid was gently infused inside the capsule and then aspirated. After aspiration, the humerus was abducted and rotated in order to mobilise clotted hematoma. A newly filled syringe was used for every flushing process. This procedure was repeated until no remnant of the hemarthrosis was detected, followed by the aspiration of residual fluid only. During movements of the arm, the tip of the needle was pulled back just enough to remain inside the capsule in order to prevent damage to the glenohumeral cartilage. 2. No additional glenohumeral joint lavage Sling for postoperative comfort and pain management during the first week. Passive‐ and active‐assisted abduction and elevation until 90o  from the first day after surgery. Assistive rotation was allowed up to 20o postoperatively, progressing to 40o "after 6 weeks". After 6 weeks, no further restrictions. Rehabilitation was monitored and followed 2 to 3 times a week until 6 months from surgery. Assigned: 36/36 Completed (1 year): 31/31
Outcomes	Length of follow‐up: 1 year; also assessed at 6 weeks and 3 & 6 months Constant score Shoulder range of motion Complications: total, screw penetration (0), plate malposition (0), avascular necrosis, secondary displacement, adhesive capsulitis Mortality
Funding and conflict of interest statements	There was no statement on direct funding of the trial. The authors declared that they and their families had no commercial conflict of interests.
Notes	Previously ongoing Date of first enrolment: 31 January 2019 Dr Ben Ockert Ludwig‐Maximilians‐Universität München Nußbaumstr. 20, 80336 Munich, Germany E‐mail: ben.ockert at med.uni‐muenchen.de
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomization was accomplished by an external operating system ‘‘randoulette’’ from the Institute of Biometry and Epidemiology of our institution."
Allocation concealment (selection bias)	Unclear risk	"Randomization was concealed by the use of a closed envelope technique, which was opened by the surgeon just before performing the operation" No mention of the envelopes being opaque or sequentially numbered.
Blinding (performance bias and detection bias) Functional outcomes, pain, clinical outcomes, complications	Low risk	"Randomization was ... kept blinded to the patient and the staff assessing the clinical follow‐up for the whole study period."
Blinding (performance bias and detection bias) Death, reoperation	Low risk	"Randomization was ... kept blinded to the patient and the staff assessing the clinical follow‐up for the whole study period."
Incomplete outcome data (attrition bias) Functional outcomes, pain, clinical outcomes, complications	Unclear risk	Participant flow diagram provided. Losses, including post‐randomisation exclusions based on intraoperative findings, were the same in each group: 5/36 (14%).
Incomplete outcome data (attrition bias) Death, reoperation	Low risk	Participant flow diagram provided. Losses, including post‐randomisation exclusions based on intraoperative findings, were the same in each group: 5/36 (14%).
Selective reporting (reporting bias)	High risk	Retrospective trial registration. Incomplete definition of study inclusion in trial report. No patient‐reported outcome measures (PROMs).
Balance in baseline characteristics?	Unclear risk	Baseline characteristics provided only for those in the analyses. No major imbalances in these but distribution of surgically‐treated rotator cuff tears not reported.
Free from performance bias?	Low risk	Surgery was by 3 experienced senior trauma surgeons who used the same operating procedures in both groups. There was a common rehabilitation protocol in both groups.