Modular revision strategy with bispherical augments in severe acetabular deficiency reconstruction

Area of Science:

• Orthopedic Surgery
• Arthroplasty
• Biomaterials

Background:

• Reconstructing severe acetabular deficiency during total hip arthroplasty (THA) revisions presents significant surgical challenges.
• Restoring the hip center of rotation (HCOR) and addressing bone loss are critical for successful outcomes.
• Novel bispherical augments (BA) have been developed to manage acetabular bone defects.

Purpose of the Study:

• To compare the clinical and radiographic outcomes of bispherical augments (BA) versus porous tantalum augments (TA) in revision THA for severe acetabular deficiency.
• To evaluate the efficacy of BA in restoring the hip center of rotation (HCOR) and correcting leg length discrepancy (LLD).

Main Methods:

• A comparative study involving 25 patients receiving BA and 22 patients receiving TA for revision THA between July 2017 and December 2018.
• Clinical outcomes assessed via Harris hip scores, with radiographic evaluation including HCOR and LLD correction.
• Follow-up averaged 2.9 years, with 25 hips in the BA group and 20 hips in the TA group available for final analysis.

Main Results:

• No significant differences were observed in Harris hip scores, HCOR, or LLD correction between the BA and TA groups.
• Bispherical augments were predominantly placed in acetabular zone II, while tantalum augments favored zone I (P=0.010).
• The BA group required more screws for fixation (mean 2.1 vs. 1.3, P=0.000), with no evidence of implant loosening or migration in either group. One dislocation occurred in the BA group, managed successfully with closed reduction.

Conclusions:

• Bispherical augments demonstrate comparable clinical and radiological outcomes to tantalum augments in revision THA with severe acetabular deficiency.
• Bispherical augments represent a reliable alternative surgical technique for complex acetabular reconstruction.
• Further research may explore long-term outcomes and optimal placement strategies for bispherical augments.