Good mid- to long-term THA outcomes with a modified cementless rectangular biconical stem design.

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Materials science

Background:

• Second- and third-generation cementless Zweymüller stems are known for good long-term total hip arthroplasty (THA) outcomes.
• The PPF cementless proximal press-fit femoral stem is a design variation based on the Zweymüller stem.

Purpose of the Study:

• To evaluate the performance of the PPF cementless proximal press-fit femoral stem.
• Assess survivorship, clinical function, and radiographic outcomes of this implant in THA.

Main Methods:

• Retrospective analysis of 250 patients (303 hips) undergoing THA between 1998 and 2011.
• Mean follow-up of 10.9 years, including radiographic examination and clinical assessment (Forgotten Joint Score, VAS pain score).
• Kaplan-Meier analysis was used for survivorship calculation.

Main Results:

• Mid- to long-term stem survival rates of 99.1% at 10 years and 95.6% at 15 years.
• Excellent functional outcomes with median Forgotten Joint Score of 91 and median VAS pain score of 0.
• Radiolucent lines observed in 43.1% of hips, with varying grades of ossification and some cases of osteolysis.

Conclusions:

• The cementless proximal press-fit femoral stem demonstrates good mid- to long-term survival and functional results in THA.
• This implant design is considered equivalent in performance to second- and third-generation Zweymüller stems.