Efficacy and Safety of Acetabular Cup without Screw Fixation in Total Hip Arthroplasty: A Systematic Review and Meta-Analysis

Abstract

Background and Objectives: Adequate initial fixation of the uncemented acetabular component in total hip arthroplasty is necessary to achieve long-term survival. Although screw fixation contributes to improved cup stability, there is currently no consensus on the use of this method. This study aimed to assess the existing randomized controlled trials (RCTs) on the efficacy and safety of cup fixation in total hip arthroplasty without screws. Materials and Methods: We searched the EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials, World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov databases to identify RCTs published before February 2022. Primary outcomes were reoperation, cup migration, and Harris Hip Score. Secondary outcomes were the presence of a radiolucent line in the acetabular region, translation and rotation movement, and polyethylene wear. We conducted meta-analyses using the random-effects models. The revised Cochrane risk-of-bias tool was used to assess the risk of bias for outcomes of interest; the Grading of Recommendations, Assessment, Development, and Evaluation approach was used to summarize the body of evidence. Results: We included six reports from four studies. Total hip arthroplasty without screw fixation to the acetabular cup had little to no effect on reoperation (pooled relative risk, 0.98; 95% confidence interval, 0.14–6.68; I2 = 0%), cup migration (pooled relative risk, 1.72; 95% confidence interval, 0.29–10.33; I2 = 1%), Harris Hip Score (mean difference, 1.19; 95% confidence interval, −1.31–3.70; I2 = 0%), radiolucent line (pooled relative risk, 5.91; 95% confidence interval, 0.32–109.35), translation and rotation of all axes, and polyethylene wear (mean difference, 0.01; 95% confidence interval, −0.01–0.04; I2 = 0%), with very low certainty of evidence on all measures. Conclusions: The efficacy of acetabular cups without screw fixation in total hip arthroplasty remains uncertain, suggesting the need for prudent clinical application. Further large-scale, well-designed studies with low risk of bias are required.

The Validation of Two-Dimensional and Three-Dimensional Radiographic Measurements of Host Bone Coverage in Total Hip Arthroplasty for Hip Dysplasia: A Comparison with Intra-Operative Measurements

“…Second, several studies have already reported satisfactory results with the use of the pressfit fixation of a cementless hemispherical cup. However, despite the ongoing controversy regarding the effectiveness of additional screw fixation in many studies reported in the literature [31,32], we believe that it can be helpful in augmenting the stability of cups in cases of hip dysplasia. Screws are not commonly used for acetabular cups during the performance of THA in a normal acetabulum.…”

“…Finally, conducting additional studies will be needed for an examination of intra-operative measurements of host bone coverage. Several principles must be followed for the achievement of a stable cup fixation in patients with hip dysplasia [29][30][31]. First, ensuring the sufficient contact of the acetabular cup and medial host bone through adequate medialization with a 1 mm or 2 mm press-fit fixation of the hemispherical acetabular cup is important in order to overcome the challenge posed by the shallow cotyloid fossa and small acetabulum of patients with hip dysplasia.…”