Minimum 10 years clinical results of an anatomical short stem with a proximal hydroxyapatite coating

Abstract

Objectives

The CentPillar stem (Stryker Orthopaedics), an anatomical short stem, was designed to match the proximal femoral canal shape in both patients with normal hips and those with developmental dysplasia of the hip (DDH). The long-term outcomes of the CentPillar stem was examined herein.

Methods

In total, 222 hips that underwent total hip arthroplasty using the CentPillar stem were analyzed. DDH was the main reason for surgery (79.3%). Implant survivorship was assessed using Kaplan–Meier analysis. For radiographic evaluation, stress shielding was assessed using the Engh classification. For functional evaluation, patients’ ability to perform deep hip bending activities (sit on the floor, squat, and sit straight) was assessed.

Results

During a median follow-up of 13.1 years, 2 stem revisions were performed (aseptic loosening and late hematogenous periprosthetic infection), and the overall cumulative implant survival rate was 99.0% at 15 years. In the radiographic evaluation, grade >3 stress shielding was found in only one hip. More than 80% of the patients were able to perform each of the three deep hip bending activities.

Conclusions

Good fixation at the proximal part of the femur was obtained, and the implant survival rate of the CentPillar stem was excellent during a long-term follow-up.

Keywords:

• Anatomical stem
• developmental dysplasia of the hip
• hip functional score
• Japanese lifestyle
• metaphyseal fixation

Conflict of interest

The authors K.U., W.A., and N.S. declare that Stryker, Zimmer Biomet, and Kyocera fund the department, which has no relevance to the study conducted herein. All other authors have declared no conflicts of interest.