Acetabular reconstruction with a threaded prosthesis for failed total hip arthroplasty.

Area of Science:

• Orthopedic Surgery
• Biomaterials Engineering

Background:

• Revision hip arthroplasty addresses failed primary hip replacements.
• Cemented arthroplasties can fail, necessitating revision with specialized components.
• Acetabular bone stock quality is critical for implant success.

Purpose of the Study:

• To evaluate the short-term efficacy and failure modes of the MEC-Ring threaded acetabular component in revision hip arthroplasty.
• To identify factors associated with MEC-Ring component failure.

Main Methods:

• A cohort of 35 patients undergoing revision hip arthroplasty with the MEC-Ring component was studied.
• Follow-up ranged from two to four years (mean 2.5 years).
• Radiographic assessment included supine oblique roentgenograms to evaluate the component-bone interface, focusing on radiolucencies and migration. Patient-reported pain scores were also collected.

Main Results:

• A high revision rate of 44% was observed within the short follow-up period.
• Patients with poor acetabular bone stock and bone grafting experienced significantly higher failure rates.
• Radiographic analysis revealed 86% of patients had radiolucencies, with 67% being progressive. Progressive radiolucencies or component migration correlated with increased failure.
• Progressive radiolucencies were also linked to worse pain scores in non-failed cases.

Conclusions:

• The MEC-Ring threaded acetabular component demonstrates a high failure rate in revision hip arthroplasty.
• Its use is not recommended, especially in patients with compromised acetabular bone stock.
• Poor bone quality and radiographic signs of loosening are critical indicators of potential component failure.