Tapered wedge stems decrease early postoperative subsidence following cementless total hip arthroplasty in Dorr type...

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Implant design

Background:

• Cementless total hip arthroplasty (THA) is a common procedure.
• Dorr type C femurs present unique challenges due to their morphology.
• Femoral stem design impacts implant stability and subsidence.

Purpose of the Study:

• Compare stem subsidence between fit-and-fill and tapered wedge femoral stems.
• Identify risk factors for stem subsidence in Dorr type C femurs.
• Evaluate the suitability of different stem designs for challenging femur morphologies.

Main Methods:

• Retrospective review of 104 cementless THA cases in Dorr type C femurs.
• Comparison of fit-and-fill (55 hips) and tapered wedge (49 hips) stems.
• Radiographic measurement of stem subsidence at immediate, 1-week, and 6-week postoperative intervals.

Main Results:

• No significant difference in early subsidence (0-1 week) between stem types.
• Significantly higher subsidence with fit-and-fill stems at later time points (1-6 weeks and 0-6 weeks).
• Higher rate of >3 mm subsidence (18.2%) with fit-and-fill stems compared to tapered wedge stems (2.0%), with fit-and-fill identified as a risk factor.

Conclusions:

• Tapered wedge stems are more suitable for Dorr type C femurs than fit-and-fill stems.
• Tapered wedge stems reduce early postoperative subsidence in cementless THA.
• Choosing appropriate femoral stem design is crucial for optimal outcomes in challenging femur types.