Migration of the uncemented CLS acetabular component.

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Radiology

Background:

• Assessing the long-term stability of uncemented acetabular components is crucial for total hip arthroplasty.
• Understanding migration patterns of press-fit cups informs implant design and surgical technique.
• Radiographic evaluation remains a primary method for assessing implant fixation.

Purpose of the Study:

• To retrospectively evaluate the migration of cementless press-fit CLS acetabular cups.
• To correlate radiographic migration with bone ingrowth and clinical outcomes.
• To analyze radiographic changes over a mean follow-up period of 3 years.

Main Methods:

• Retrospective analysis of 96 patients undergoing CLS acetabular cup implantation.
• Measurement of cup migration (cranial and medial) using digitized pelvic radiographs.
• Radiographic and clinical review to assess bone ingrowth, sclerotic/lucent lines, and patient outcomes.

Main Results:

• Mean cup migration at 2 years was 1.35 mm (cranial) and 2.15 mm (medial).
• Bone ingrowth was observed in 57.3% of patients, primarily in DeLee and Charnley zone 1.
• A significant correlation was found between acetabular bone ingrowth and reduced medial cup migration (P = .011 at 5 years).

Conclusions:

• Acetabular bone ingrowth is associated with improved stability of cementless CLS acetabular cups.
• Cup migration did not show a statistically significant relationship with radiographic features or clinical outcomes in this cohort.
• Radiographic appearances of the CLS acetabular cups remained largely unchanged throughout the study period.