Jónsson and Mjöberg 2015.

Study characteristics
Methods	Single‐centre RCT
Participants	Country of study: Sweden Sample size: 20 participants with 20 fractures Age: mean 49 years (range 24 to 77) Sex: 9 males (45%) and 11 females Fracture type: closed tibial plateau fracture with split depression (Schatzker II; n=14) or pure depression (Schatzker III; n=6) fracture Injury severity: not reported Inclusion criteria: a split depression (Schatzker II) or pure depression (Schatzker III) fracture; at least 5 mm depression of the articular surface and surgery undertaken within 7 days of injury. Exclusion criteria: open fracture, concomitant injuries, chronic disease affecting healing or joint function, and insufficient understanding of spoken and written Swedish.
Interventions	Surgical procedure: a standard surgical technique was used in each case. The depressed, comminuted articular fragments were elevated en masse from below, either through the fracture itself (Schatzker II) or through a window made beneath the plateau (Schatzker III). The metaphyseal void was then tightly packed with either (Group 1: n = 11) titanium granules mixed with 2 mL saline per 5 mL of granules to facilitate injection, or (Group 2: n = 9) bone graft, with the aim of supporting the elevated articular fragment. Tantalum bone markers were inserted into the largest osteochondral fragment and into the intact tibial metaphysis with the intention of later radiostereometric measurements of the redepression (which failed for technical reasons). Each fracture was stabilised with a laterally placed non‐locking condylar buttress plate. Postoperatively, all operated knees were immobilised in plaster for 6 weeks and non‐weight‐bearing for 12 weeks. Technique 1 (n = 11): bone defect filled with porous titanium granules measuring 1.0 mm to 1.4 mm in diameter Technique 2 (n = 9): bone defect filled with bone graft from the iliac crest.
Outcomes	Follow‐up: 1, 3, and 6 weeks and 3, 6, and 12 months. Primary outcome measure: recurrent depression of the articular surface measured using non‐weight‐bearing (Week 1 and Week 3) and non‐weight‐bearing radiographs (Month 3, 6, and 12). This was measured using the intact adjacent surface as reference on an AP projection angled 15° caudally (tibial‐plateau view) using the standard digital ruler provided in the software of the Sectra IDS7 system. The frontal view was calibrated using the uppermost 4.5‐mm screw in the distal plate as a reference. All measurements were repeated 5 times with several days in between. Only those images which could be repeated at least twice were used. Recurrent depression at follow‐up was relative to any residual depression measured on the immediate postoperative X‐ray. Secondary outcome measures: operating time, knee pain measured using VAS, and the functional outcome measured using the Lysholm Knee Score.
Notes	A priori power calculation defined that a minimum of 10 participants would be required per trial arm. The planned sample size was 24 (12 per arm) to account for loss to follow‐up. The trial was halted after the 18th participant had been followed‐up for 12 months. At this point, 20 participants had been recruited. Interim analysis indicated recurrent depression of the articular surface of between 2 mm and 5 mm in 4 of the 8 participants treated with autografting, but none in the titanium granule group. This was deemed significant. Source of funding: "The porous titanium granules were supplied by Tigran Technologies AB, Malmö, Sweden" (Page 840).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was performed: "Randomisation was by sealed and serially‐numbered envelopes which were opened shortly before the start of the surgical procedure" (Page 837).
Allocation concealment (selection bias)	Low risk	Allocation was concealed: "Randomisation was by sealed and serially‐numbered envelopes which were opened shortly before the start of the surgical procedure" (Page 837). No mention made on who performed this.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding of participants or personnel was not mentioned. Whilst blinding for personnel may have been challenging given the nature of this surgical intervention, the participants may have been blinded to group allocation given they were anaesthetised during the "intervention delivery phase".
Blinding of outcome assessment (detection bias) All outcomes	High risk	Outcome assessment blinding was not mentioned. This may have been challenging for intraoperative outcomes and radiographic assessment but may have been possible for self‐completed Lysholm Knee Score and VAS pain assessment.
Incomplete outcome data (attrition bias) All outcomes	High risk	4 participants (20%) not included in outcome data. This included 1 participant in the control group who was lost to follow‐up at 12 months; and 3 participants whose follow‐up radiographs were excluded because the image quality was poor (Page 838). It was not reported which group these 3 participants were allocated to.
Selective reporting (reporting bias)	Unclear risk	All outcomes outlined in methods section were reported in results section. No published protocol or trial registration available.
Other bias	Low risk	Limited evidence of baseline characteristic imbalance for key characteristics between intervention and control groups. No other source of bias detected.