Radiographic failure patterns of polished cemented stems.

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Materials science in implants

Background:

• Femoral component design in total hip arthroplasty (THA) has evolved to enhance implant longevity.
• Surface finish and geometry are key factors influencing cemented femoral stem performance.
• Previous studies indicated potential issues with rough femoral stems.

Purpose of the Study:

• To evaluate the failure rates and radiographic failure patterns of four distinct polished femoral stem geometries.
• To determine if design modifications in polished stems over a decade improved clinical outcomes.
• To compare the performance of polished stems to historical data on rough stems.

Main Methods:

• Retrospective review of 1031 THAs performed between 1993 and 2003.
• Analysis of aseptic loosening rates and failure patterns in polished femoral stems with 4-microinch surface roughness but varying geometries.
• Minimum 2-year follow-up for all patients.

Main Results:

• Seven stems (0.6%) required revision for aseptic loosening by 2005, all originating at the cement-bone interface.
• Average time from loosening onset to revision was 3.3 years.
• No significant differences in loosening rates or radiographic failure patterns were observed among the four stem geometries. Bone damage was minimal and manageable.

Conclusions:

• Polished femoral stems, irrespective of geometric variations, demonstrate a low incidence of aseptic loosening in THA.
• The design evolution of polished stems did not yield a discernible improvement in failure rates or patterns compared to earlier designs.
• These findings suggest that polished femoral stems offer a favorable outcome with less bone damage than previously reported for rough stems.