Overview of Randomized Controlled Trials in Primary Total Hip Arthroplasty (34,020 Patients): What Have We Learnt?

To provide an overview of randomized controlled trials (RCTs) in primary total hip arthroplasty summarizing the available high-quality evidence. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA), we searched the Cochrane Central Register of Controlled Trials (2020, Issue 1), Ovid MEDLINE, and Embase. We excluded nonrandomized trials, trials on neck of femur fractures or revision surgery, systematic reviews, and meta-analyses. Trials that met our inclusion criteria were assessed using a binary outcome measure of whether they reported statistically significant findings. These were then classified according to the intervention groups (surgical approach, fixation, and component design use, among others). Three hundred twelve RCTs met the inclusion criteria and were included. The total number of patients in those 312 RCTs was 34,020. Sixty-one RCTs (19.5%) reported significant differences between the intervention and the control groups. The trials were grouped into surgical approach 72, fixation 7, cement 16, femoral stem 46, head sizes 5, cup design 18, polyethylene 25, bearing surfaces 30, metal-on-metal 30, resurfacing 20, navigation 15, robotics 3, surgical technique 12, and closure/drains/postoperative care 13 RCTs. The evidence reviewed indicates that for the vast majority of patients, a standard conventional total hip arthroplasty with a surgical approach familiar to the surgeon using standard well-established components and highly cross-linked polyethylene leads to satisfactory clinical outcomes. This evidence also offers arthroplasty surgeons the flexibility to use the standard and cost-effective techniques and achieve comparable outcomes.