SURFACE FINISH AFFECTS THE CLINICAL AND RADIOGRAPHIC PERFORMANCE OF A MODERN, CEMENTED FEMORAL STEM FOR TOTAL HIP ARTHROPLASTY.

Abstract

The role of surface finish on the survivorship of cemented stems is controversial. The purpose of this study is to prospectively evaluate the mid-term clinical and radiographic performance of a cohort of patients who underwent total hip replacement with two identical cemented femoral stems differing only in surface finish (VerSys, Zimmer, Warsaw, IN).

64 total hip replacements with a rough stem (Ra: 70–100 micro inches) and 138 total hip replacements with a satin finish stem (Ra: 20–25 micro inches) were followed clinically and radio graphically for 4 to 7 years. All surgeries were performed by one surgeon, during a period of 1 year, utilizing the same surgical approach and technique, ace tabular cup, cement type and cementing technique. The groups had similar demographics, diagnosis, preoperative clinical score, cement mantle quality, alignment, and length of follow up.

The preoperative and postoperative Hospital for Special Surgery Hip Score at last follow up of the patients with a successful operation was not significantly different among the two groups. Five hips in the rough group and none in the satin group developed aseptic loosening and required revision (p=0.0009). The femoral bone-cement interface revealed progressive radiolucent lines or osteolysis in 8 out of 64 rough stems and in 3 out of 138 satin stems (p=0.01). There were progressive radiolucenciesor osteolysis in 44 out of possible 448 Gruen zones in the rough surface group and in 8 out of possible 966 Gruen zones in the satin finish group(p< 0.001).

A rough, textured stem is more likely to fail at intermediate follow-up than a satin surface stem. We recommend that the surface of cemented stems should be satin or polished, with a Ra of less than 20 micro inches.