[Total hip replacement in osteoarthritis with acetabular protrusion]

Area of Science:

• Orthopedic surgery
• Biomaterials science
• Radiology

Background:

• Acetabular protrusion alters hip joint anatomy, complicating total hip replacement (THR) surgery.
• This condition necessitates specialized surgical techniques for optimal acetabular component implantation.

Purpose of the Study:

• To evaluate and compare different surgical approaches for acetabular component implantation in patients with acetabular protrusion.
• To assess the efficacy of cemented versus uncemented acetabular cups in this patient cohort.

Main Methods:

• A retrospective study of 50 hips in 33 patients undergoing THR for acetabular protrusion between 1992 and 2000.
• Patients were divided into two groups: Group I (18 hips) received cemented polyethylene cups, and Group II (32 hips) received uncemented cups.
• Bone grafting of the acetabular bottom was utilized in 8 hips (Group I) and 25 hips (Group II). Follow-up averaged 7.1 years.

Main Results:

• In Group I (cemented cups), 10 hips achieved full osteointegration, while 8 experienced aseptic loosening or required revision. Failures were associated with cups implanted without bone grafting.
• In Group II (uncemented cups), 29 hips demonstrated full clinical survival and complete osteointegration, with 3 showing minor radiolucent zones.
• Uncemented cups, particularly the CLS type, showed better results, especially when combined with acetabular bottom grafting.

Conclusions:

• Uncemented acetabular components, especially when combined with bone grafting, yield superior clinical outcomes and osteointegration in THR for acetabular protrusion.
• The expansion, uncemented CLS cup is recommended for its peripheral fixation, suitability for thin acetabular floors, and ability to facilitate grafting.
• Key factors for success include firm component fixation, proper femoral component positioning, and centering the femoral head within the center of rotation.