Revision hip surgery using the CLS expansion shell.

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Medical Imaging

Background:

• Revision hip surgery addresses complications from primary hip replacements.
• Aseptic loosening of acetabular components is a common challenge.
• The CLS (Cormet Locking Shell) expansion shell is an uncemented option for acetabular reconstruction.

Purpose of the Study:

• To evaluate the clinical and radiological outcomes of the uncemented CLS expansion shell in revision hip surgery.
• To assess the survivorship and complication rates associated with this implant.
• To determine the efficacy of the CLS shell in cases with poor bone quality and acetabular defects.

Main Methods:

• A retrospective study of 215 patients (230 hips) undergoing revision hip surgery with the CLS expansion shell between 1991 and 2000.
• Evaluation of 196 patients (211 hips) with failed acetabular components, including Paprosky defect classifications.
• Clinical outcomes assessed using Merle d'Aubigné and Postel scores and Harris Hip scores; radiological assessment via plain radiographs.

Main Results:

• Mean follow-up was 8.5 years. Clinical scores significantly improved (Merle d'Aubigné: 7.8 to 14.9; Harris Hip: 38.6 to 82.5).
• Osteointegration observed in 70.6% of hips. Clinical survivorship was 90% at 5 years and 84% at 8.5 years.
• Radiological survivorship was 78% at 5 years and 70% at 8.5 years. 15% of cases required a second revision due to complications.

Conclusions:

• The uncemented CLS expansion shell provides a viable alternative for revision hip surgery, particularly in patients with poor bone quality or acetabular defects.
• The implant demonstrates favorable clinical outcomes and acceptable long-term survivorship.
• Complication rates necessitate careful patient selection and surgical technique.