Early Radiographic Fit and Fill Analysis of a New Metaphyseal-Filling Triple Taper Stem Designed Using a Large...

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Radiology

Background:

• Cementless stems are crucial for stability and longevity in total hip arthroplasty (THA).
• A novel metaphyseal-filling triple-taper collared stem was developed using extensive CT scan data of femoral morphology.
• Understanding implant fit and fill is key to predicting THA success.

Purpose of the Study:

• To radiographically assess the coronal and sagittal fit and fill of a new triple-taper collared femoral stem in THA.
• To validate the design principles of this novel implant based on femoral morphology data.

Main Methods:

• Retrospective analysis of postoperative radiographs from 55 patients (59 hips) who underwent THA with the new stem.
• Radiographs were taken 6 weeks postoperatively and analyzed for fit and fill parameters.
• Standardized measurements were used for coronal and sagittal proximal and distal fill, and calcar collar coverage.

Main Results:

• The new stem demonstrated strong proximal fill: 85.02% coronal and 86.51% sagittal.
• Distal fill was 75.21% coronal and 59.17% sagittal.
• Mean calcar collar coverage was 80.64%, with full collar seating in all cases and minimal overhang in 10.2% of hips.

Conclusions:

• The triple-taper collared stem shows excellent proximal fill in both coronal and sagittal planes, aligning with its design intent.
• This study is the first to report on the sagittal fit and fill of a femoral stem.
• Further long-term clinical follow-up is necessary to determine the clinical implications of these radiographic findings.