[Acetabular metastatic defect reconstruction using the modular revision support cup MRS-C].

OBJECTIVE: Stabilization of metastatic acetabular defects with a bone cement-augmented revision support cup for remobilization of oncological patients in advanced cancer stages.

INDICATIONS: Metastatic acetabular defects (Metastatic Acetabular Classification, MAC 2-4) in patients with a prognostic medium or long-term survival.

CONTRAINDICATIONS: Highly limited survival due to metastatic disease (< 6 weeks). Local bone or soft tissue infection. Primary bone tumor with curative treatment option. Advanced pelvic discontinuity. Recent wound compromising systemic therapy.

SURGICAL TECHNIQUE: Standard hip approach. Curettage of the metastatic defect and careful reaming of the acetabulum before insertion of the cup. Predrilling of the dome und flange screws before application of the bone cement through the center hole of the implant and filling of the acetabular defect. Complete insertion of the screws for compound osteosynthesis. Implant of a modular inlay or dual mobility system.

POSTOPERATIVE MANAGEMENT: Full weight bearing or mobilization with two crutches according to the level of pain. Adjuvant local radiation therapy after wound consolidation. Continuation of systemic therapy according to tumor board decision.

RESULTS: Between 2012 and 2019, we treated 14 patients with metastatic acetabular defects using the modular revision support cup "MRS-TITAN® Comfort", MRS-C, Peter Brehm GmbH, Weisendorf, Germany) at our institution. Mean Harris Hip Score improvement was 23.2 with a mean patient's survival of 9.7 months due to the reduced cancer-related prognosis; 13 of the 14 implants endured the patient's prognosis. One implant had to be removed due soft tissue defect-related periprosthetic joint infection.