A model-based radiostereometric analysis (RSA) randomized control trial evaluating the stability of the cementless...

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Arthroplasty research

Background:

• The Taperloc Complete hip stem is an advancement over the Taperloc hip stem.
• It aims to improve range of motion and femoral fit using intermediate stem sizes.

Purpose of the Study:

• To evaluate if design changes in the Taperloc Complete hip stem impact fixation.
• To compare 2-year migration patterns between different Taperloc stem designs using radiostereometry analysis (RSA).

Main Methods:

• A prospective, multi-arm study randomized 100 patients undergoing cementless total hip arthroplasty (THA).
• Four stem types were compared: Taperloc Complete full profile (TCFP), Taperloc Complete reduced distal (TCRD), Taperloc full profile (TFP), and Taperloc reduced distal (TRD).
• Migration was assessed using model-based RSA at postoperative, 3, 12, and 24 months.

Main Results:

• RSA data from 74 patients at 2 years showed initial subsidence in the first 3 months, followed by stabilization for all stem types.
• The Taperloc Complete full profile (TCFP) demonstrated statistically significant less retroversion compared to TFP and TCRD at 2 years.
• While reduced distal groups showed larger initial migration than TCFP, these differences were not statistically significant, potentially linked to implantation in Dorr B, C femur types.

Conclusions:

• Cementless total hip arthroplasty (THA) with Taperloc stems demonstrates stable fixation after initial subsidence, as confirmed by RSA.
• The Taperloc Complete stem is anticipated to achieve long-term fixation comparable to Taperloc stems.
• Femur shape should be considered when selecting between full profile and reduced distal stems to minimize migration.