Aseptic Failure Rates in Revision Total Knee Arthroplasty Using Structural Allografts Versus Porous Metal Cones for...

Management of significant bone loss in revision total knee arthroplasty (rTKA) poses unique challenges. This systematic review and meta-analysis evaluates the effectiveness of structural allografts and porous metal cones for Anderson Orthopaedic Research Institute (AORI) Grade 2 and 3 defects, focusing on their re-revision rates due to aseptic loosening. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, databases including MEDLINE, EMBASE, and CINAHL were searched up to June 2023. We included original clinical studies (January 2000-June 2023) assessing structural allografts or porous metal cones in rTKA for AORI 2 or 3 defects. Data from 52 studies (2,568 cases) were analyzed using a random-effects model to calculate pooled re-revision rates due to aseptic loosening. Subgroup analyses were conducted among the metal cones studies to explore heterogeneity sources. The pooled incidence of re-revision due to aseptic loosening was significantly lower for porous metal cones at 0.71% (95% CI: 0.33%-1.51%) compared to 2.81% (95% CI: 1.11%-6.92%) for allografts. Subgroup analysis indicated that re-revision rates for metal cones remained consistently low across varying follow-up durations, affirming their sustained effectiveness. Variability in re-revision rates by study size suggested higher incidences in larger studies, possibly reflecting the complexity of cases or differences in clinical practices. Temporal trend analysis highlighted an increasing preference for metal cones since 2012. Porous metal cones demonstrate superior mid-term durability with significantly lower re-revision rates compared to structural allografts for severe metaphyseal bone defects. Long-term functional outcomes and patient-specific recommendations are necessary to further validate these findings.