Clinical and Radiological Results of the Integrated Acetabular MUTARS® RS Cup System in the Revision of Geriatric Patients.

Introduction: Acetabular revision surgery is challenging due to the occurrence of bony defects that complicate the fixation of implants after removal of loose components. In addition to multimorbidity and increased risk of falling, poor bone quality in geriatric patients makes it even more difficult to secure implant anchoring. The aim of this study was to evaluate the clinical and radiographic results after revision arthroplasty with the MUTARS® RS cup system (implantcast GmbH, Buxtehude, Germany) in geriatric patients (age >70 years).

Materials and methods: From 2019 to 2023, 24 geriatric patients, six males and 18 females, with a mean age of 79.2 years (range, 70-94 years) underwent a revision surgery and were provided with the MUTARS® RS cup system at the geriatric center of the Dessau Municipal Hospital. After a mean follow up of 2.5 years (range, 1-4 years), the clinical evaluation and patient-reported outcomes were measured using the Harris Hip Score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Oxford Hip Score (OHS), and EQ-5D-5L. Radiographs were taken to evaluate radiolucent lines and component migration.

Results: A total of 19 patients (79.2%) remained without any revision until the latest follow up. The average HHS was 71.1 (range, 56-93), the average OHS was 23.7 (range, 10-40), and the average WOMAC was 20.4 (range, 1-70). According to EQ-5D-5L, there were 10 patients (52.6%) with slight problems, seven patients (36.8%) with moderate problems, and two patients (10.5%) with severe problems. The x-ray showed no migration of the components; 15 cases (78.9%) had radiolucent lines around the caudal flap in the os ischii.

Conclusion: The RS Cup is a suitable implant for revision surgery with large bone defects or acetabular fractures. "Clinically satisfactory" to "good" results are shown, with mild and moderate problems for geriatric patients which are already predominantly constrained by pre-existing multimorbidity.