Ockert 2010.

Study characteristics
Methods	Method of randomisation: used closed envelopes Assessor blinding: unknown Loss to follow‐up (2010 publication): 10 participants excluded from analysis following randomisation; 6 with polytrauma, 2 with neurologic deficiency and 2 (1 versus 1) who were converted to shoulder arthroplasty intraoperatively. There was no mention of group allocation at randomisation or evaluation in the paper ‐ these (8 versus 2) were notified after contact with the lead trial investigator. Loss to follow‐up (2014 publication): not stated
Participants	Ludwig‐Maximilians University, Munich, Germany Period of study recruitment: August 2006 to July 2008 (extended to February 2010 for 2014 publication) 2010 publication: 76 participants, aged over 18 years, with displaced proximal humeral fractures with displacement > 1 cm and angulation of fragments > 45 degrees (Neer criteria) Exclusion criteria: poly‐traumatised patients, neurologic deficit or intraoperative conversion to shoulder arthroplasty. (Paper noted there were no open or pathological fractures.) Of 66: 48 female, 18 male; mean age 68 years, range 29 to 92 years 2014 publication: 124 participants with displaced proximal humeral fractures with displacement > 1 cm and angulation of fragments > 45 degrees (Neer criteria) Exclusion criteria: open or pathological fractures, poly‐traumatised patients, primary nerve palsy (given as examples) 89 female, 35 male; mean age 71 years, range not given
Interventions	1. Polyaxial angular stable plate fixation using a Non‐Contact Bridging – Proximal Humerus (NCB‐PH) plate (Zimmer GmbH). Polyaxial plating allows a range of 0‐ to 15‐degree angle off‐centre. After insertion, a threaded screw cap locks the axis of the screw. 2. Monoaxial angular stable plate fixation with a PHILOS plate (Synthes GmbH). Monoaxial locking plate technique is characterised by fixed divergent and convergent screw orientation due to threaded screw holes. A deltopectoral approach was used for open reduction and internal fixation of all fractures. All participants received prophylactic intravenous antibiotic immediately before surgery. "The postoperative rehabilitation protocol included immediate passive‐ and active‐assisted range of motion (ROM) up to 60‐degree angle of abduction and elevation without forced external rotation for 6 weeks. Full ROM with active exercises was started 6 weeks after operation.” (2010 publication) Assigned: 39/37 (2010 publication); 58/66 (2014 publication but post‐randomisation exclusions may have occurred) Completed: 29/37; 58/66 (2014 publication)
Outcomes	2010 publication: Length of follow‐up: 6 months (X‐rays 1 day, 6 weeks, 3 months and 6 months) Secondary varus displacement (> 10 degrees) Delayed union (due to osteonecrosis) Intra‐articular screw cut out Reoperation: revision surgery and early hardware removal Infection (none) Neurovascular injuries (none) 2014 publication: Length of follow‐up: 12 months (X‐rays 1 day, 6 weeks, and 3, 6 and 12 months) Revision surgery (reasons given: secondary varus displacement, subacromial impingement, intra‐articular screw cut out, infection) Screw position in different region of the humeral head
Funding and conflict of interest statements	There was no statement on funding. A conflict of interest statement in one article stated: "None".
Notes	Request for information sent to Dr Ockert on 2 June 2012. Repeated on 8 June 2012, in email to Peter Biberthaler regarding identification and further information on ongoing trial referred to in conference abstract (Biberthaler 2009) ‐ it seems highly likely that the ongoing trial was this trial. However, this was not clear from email from Ben Ockert on 18 June 2012; this also provided details of the method of randomisation, the numbers allocated and analysed in each group. The 2014 publication of this trial (Ockert 2014) reported on an additional 48 participants, reflecting an extended period of trial recruitment, and a longer follow‐up. Only the revision surgery data from Ockert 2014 were used in this review.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"[C]onsecutive patients ... were prospectively randomized". No description of sequence generation
Allocation concealment (selection bias)	Unclear risk	"[C]onsecutive patients ... were prospectively randomized". Contact from trialist revealed they "used closed envelope technique for randomization". (Exclusion criteria appeared to be applied post‐randomisation.) 2014 publication: "Randomization was performed by closed envelope technique."
Blinding (performance bias and detection bias) Functional outcomes, pain, clinical outcomes, complications	High risk	No mention of blinding. Radiographic assessment performed by two trained radiologists twice in separate sessions 8 weeks apart. Consensus decision for osteonecrosis and implant‐related failure. Criteria for healing stated
Blinding (performance bias and detection bias) Death, reoperation	Unclear risk	No mention of blinding, but unlikely to affect this
Incomplete outcome data (attrition bias) Functional outcomes, pain, clinical outcomes, complications	High risk	"Follow‐up rate was 71% of all radiographs taken 1 day, 6 weeks, 3 months, and 6 months after surgery." Numbers of participants allocated or assessed by intervention group provided after personal communication. Post‐randomisation exclusions (10/76 = 13%) were imbalanced (8 versus 2) and other loss to follow‐up not accounted for. 2014 publication: concerns about post‐randomisation exclusions continue for this publication
Incomplete outcome data (attrition bias) Death, reoperation	Unclear risk	As above. Paper described cases of revision surgery and early removal of metalwork; however, group allocation not given. Information provided subsequently
Selective reporting (reporting bias)	High risk	No protocol available. The extension of the recruitment, incomplete results and lack of full listing of exclusion criteria are of concern in the Ockert 2014 publication.
Balance in baseline characteristics?	Unclear risk	"The fracture types were equally distributed in both study groups." However, this applied to 66 participants. Does not state how many participants in each group or compare demographics Age and gender were comparable in the two groups in the Ockert 2014 publication. There was no mention of fracture type.
Free from performance bias?	Low risk	Six experienced surgeons performed the surgery: "In advance of this study, all surgeons were trained in the respective monoaxial and polyaxial locking plate system”. Same antibiotic regimen and postop management