Constrained acetabular liners cemented into cages during total hip revision arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering

Background:

• Acetabular bone loss and hip instability present significant challenges in revision total hip arthroplasty.
• Existing treatments may not adequately address severe bone defects and instability, necessitating advanced reconstructive techniques.

Purpose of the Study:

• To evaluate the clinical and radiographic outcomes of revision total hip arthroplasty using cemented constrained acetabular liners in conjunction with protrusio cages.
• To assess the efficacy and failure rates of this combined approach in patients with substantial acetabular bone loss and hip instability.

Main Methods:

• A retrospective study involving 16 patients undergoing revision total hip arthroplasty with constrained acetabular liners cemented into cages.
• Clinical outcomes were assessed using the Harris hip score, and radiographic data were collected for evaluation.
• Follow-up averaged 28 months, with 13 patients available for final assessment.

Main Results:

• The average preoperative Harris hip score was 27, improving to 62 postoperatively.
• Despite functional improvement, the overall radiographic failure rate was 23% at the latest follow-up.
• Poor acetabular bone stock and altered biomechanical stresses from constrained implants likely contributed to the observed failures.

Conclusions:

• The use of cemented constrained acetabular liners with protrusio cages in revision total hip arthroplasty for severe acetabular bone loss and instability yields modest functional gains but carries a significant risk of radiographic failure.
• This technique should be considered a bailout or salvage procedure rather than a primary reconstructive option.
• Further research is needed to optimize implant design and surgical techniques for managing complex acetabular defects in revision hip surgery.