Constrained liners, dual mobility or large diameter heads to avoid dislocation in THA.

Area of Science:

• Orthopedic surgery
• Biomaterials engineering
• Implant design

Background:

• Dislocation is a frequent cause of failure in total hip arthroplasty (THA).
• Existing solutions like constrained liners and large heads have limitations, including impingement, wear, and mechanical failures.
• Instability in THA necessitates innovative implant designs.

Purpose of the Study:

• To compare the efficacy of constrained liners, dual mobility implants, and large diameter heads in preventing THA dislocation.
• To evaluate implant-related options for improving THA stability and reducing failure rates.

Main Methods:

• Review of implant designs: constrained liners, large diameter heads, and dual mobility cups.
• Analysis of range of motion (ROM), impingement, wear, and mechanical failure modes.
• Comparison of clinical outcomes and failure rates at 10-year follow-up.

Main Results:

• Constrained liners can lead to impingement and failure due to restricted ROM.
• Large diameter heads offer increased ROM and stability but face limitations with liner thickness and cup abduction.
• Dual mobility implants address head-neck ratio, constraint, and jump distance, showing improved outcomes over other methods.

Conclusions:

• Dual mobility THA demonstrates superior performance in preventing dislocation compared to constrained liners and large diameter heads at 10 years.
• Modern dual mobility designs mitigate concerns regarding wear and intra-prosthetic dislocation.
• Dual mobility is emerging as a leading solution for managing THA instability.