Monoflanged Custom-Made Acetabular Components Promote Biomechanical Restoration of Severe Acetabular Bone Defects by Metallic Defect Reconstruction

Background: Custom-made acetabular components (CMAC) are one established method to address severe acetabular bone defects. Monoflanged CMAC may represent an advantageous alternative to establish triflanged CMAC as they promote better primary stability through metallic defect reconstruction and thus anatomic restoration of the center of rotation (COR).

Methods: Fifty-eight consecutive (21 triflanged and 37 monoflanged) CMAC were evaluated for overall survival, reasons for revision, radiological restoration of COR, and clinical outcome parameters.

Results: There were no significant differences between both design types regarding overall survival, revision rates, Harris Hip Score, or visual analog scale (pain) score at latest follow-up (mean, 56.3 ± 28.7 months). Triflanged CMAC showed a significant lateralization (P ≤ .001) and cranialization (P = .003) of the COR compared to the contralateral side. Monoflanged CMAC restored the anatomic COR. Reasons for revision surgery and explantation were periprosthetic joint infection (n = 12) and aseptic loosening (n = 2) without significant differences between both groups.

Conclusion: Monoflanged CMAC demonstrate similar clinical outcome parameters and survival rates as triflanged CMAC but superior biomechanical features and represent therefore a solid alternative treatment option and implant design.