The Role of Stem Shape and Geometry in Revision and Complication Risk Following Primary Total Hip Arthroplasty: A...

Primary THA may be performed with femoral stems that differ in shape and geometry. The purpose of this meta-analysis was to evaluate the revision and complication risks of the following stem designs: (1) anatomic; (2) single-wedge; (3) single-taper; and (4) taper wedge.

A comprehensive search of four electronic databases (PubMed, CINAHL Plus, EMBASE, and SCOPUS) was performed for all articles pertaining to this topic from January 2015 to January 2025. A total of 18 studies were selected for inclusion. There were: (1) 12,969 anatomic; (2) 17,115 single-taper; (3) 19,326 single-wedge; and (4) 1,965 taper wedge stems.

The revision rate was highest within the anatomic stem cohort (3.9%; 95% confidence interval [CI], 3.6 to 4.2), with lower rates being found in single-taper (relative risk [RR], 0.38; 95% CI, 0.34 to 0.43; P = 0.0001), single-wedge (RR, 0.31; 95% CI, 0.27 to 0.35; P = 0.0001), and taper wedged stems (RR, 0.52; 95% CI, 0.4 to 0.68; P = 0.0001). Periprosthetic joint infection risk was 0.22% (95% CI, 0.15 to 0.31) within anatomic stems and was higher in single-taper (RR, 2.12; 95% CI, 1.5 to 2.98; P = 0.0002) and taper wedge cohorts (RR, 2.52; 95% CI, 1.27 to 5.01; P = 0.004). Aseptic loosening rate with anatomic stems was 0.65% (95% CI, 0.52 to 0.79), and the single wedge was lower (RR, 0.72; 95% CI, 0.56 to 0.92; P = 0.014). The risk of instability in anatomic stems was 0.44% (95% CI, 0.33 to 0.56) with a much lower rate in single-taper (RR, 0.7; 95% CI, 0.51 to 0.94; P = 0.025) and single-wedge stems (RR, 0.15; 95% CI, 0.09 to 0.25; P = 0.0001). Periprosthetic fracture incidence in anatomic stems was 1.4% (95% CI, 1.2 to 1.6). The rates were much lower in single-taper (RR, 0.74; 95% CI, 0.63 to 0.87; P = 0.001) and single-wedge cohorts (RR, 0.21; 95% CI, 0.16 to 0.27; P = 0.0001).

Anatomic stems had a higher risk of revision, instability, and fracture. The risk of periprosthetic joint infection was highest in taper wedge stems. Future research should focus on comparative studies that further investigate any potential increased risk of certain complications following primary THA based on various construct designs. Revision risk was highest in the anatomic stem cohort.