Custom and modular components in primary total hip replacement

Area of Science:

• Orthopedic Surgery
• Biomaterials Engineering

Background:

• Custom cementless implants aim to improve fit for diverse hip anatomies using CT scans.
• Modular prostheses offer intraoperative adjustments for leg length, offset, and fixation, beneficial in complex hip conditions.

Purpose of the Study:

• To evaluate the clinical efficacy and drawbacks of custom and modular hip implants compared to traditional options.
• To provide guidance on judicious use of these advanced implant types in primary hip arthroplasty.

Main Methods:

• Review of clinical studies and experience with custom and modular hip implant designs.
• Analysis of advantages, including surgical versatility and inventory reduction.
• Assessment of disadvantages such as corrosion, fretting, dissociation, fracture, and wear.

Main Results:

• Custom implants are costly and have not demonstrated superior clinical success or longevity.
• Modular implants offer intraoperative benefits but are associated with corrosion, fretting, dissociation, and fracture risks.
• Thin acetabular polyethylene in modular designs contributes to higher wear rates and osteolysis.

Conclusions:

• The use of custom or modular implants in primary hip arthroplasty requires careful consideration due to cost and potential complications.
• Modularity beyond the head and neck junction should be reserved for cases where monolithic implants are insufficient.