Collarless Taper Slip and Collared Composite Beam Stems Differ in Failure Modes and Reoperation Rates

Area of Science:

• Orthopedic Surgery
• Biomaterials Engineering

Background:

• Cemented femoral components are preferred in elderly patients due to lower risks of periprosthetic fracture and implant loosening.
• This study compares the long-term outcomes of two distinct cemented femoral stem designs.

Purpose of the Study:

• To evaluate and compare survivorship rates free of periprosthetic femoral fracture (PPFX), femoral loosening, all-cause revision, and reoperation between two cemented stem philosophies.
• To identify specific failure modes associated with each stem type in a hybrid total hip arthroplasty cohort.

Main Methods:

• A retrospective single-center study of 1,306 primary hybrid total hip arthroplasties for osteoarthritis (2000-2018).
• Comparison of 798 EON composite beam (CB) stems versus 508 Exeter collarless taper slip (CTS) stems.
• Utilized an inverse treated probability weighted model to control for confounding risk factors.

Main Results:

• No significant difference in overall PPFX risk at 10 years (CB 5% vs. CTS 9%).
• Increased intraoperative fractures in the CB cohort (5%) versus CTS (0%).
• Increased Vancouver B2 PPFX in the CTS cohort (7/508) versus CB (0/798).
• Higher risk of femoral loosening in the CB cohort (6/798) versus CTS (0/508).
• CB cohort demonstrated higher survivorship free of revision (98% vs. 91%) and reoperation (96% vs. 88%) at 10 years.

Conclusions:

• The Exeter collarless taper slip (CTS) stem is associated with an increased risk of periprosthetic femoral fracture requiring revision.
• The EON composite beam (CB) stem shows a higher propensity for femoral component loosening and intraoperative fractures.
• Surgeons should carefully consider the differential failure modes of these cemented stems when selecting an implant design for elderly patients undergoing total hip arthroplasty.