Ablation-First Balloon-Assisted Acetabuloplasty for Painful Acetabular Metastases: Clinical Outcomes and Mechanical Rationale

Purpose: To evaluate the safety, technical feasibility, and clinical outcomes of a strict two-step protocol—CT/fluoroscopic-guided thermal ablation followed by Balloon-Assisted Acetabuloplasty (BAA)—for the treatment of painful acetabular metastases, utilized as an immediate mechanical stabilization bridge prior to radiotherapy. Materials and Methods: A retrospective study was conducted on 16 consecutive patients treated for severe mechanical pain (VAS ≥ 6) and impaired mobility due to osteolytic acetabular metastases. The physiological rationale mandated a strict procedural sequence: (1) preliminary thermal devitalization using radiofrequency or microwave ablation to reduce tumor pressure and vascularity, followed subsequently by (2) balloon-assisted cavity compaction and polymethylmethacrylate (PMMA) cement injection. Clinical outcomes included VAS for pain and the Functional Mobility Scale (FMS) assessed before treatment and up to 6 months post-procedure. Results: Technical success was 100% with a mean procedural time of 58 ± 14 min. No major complications occurred. At a mean follow-up of 8.2 months, all 16 patients were alive. The procedure yielded dramatic acute pain relief: mean baseline VAS dropped from 7.4 ± 0.8 to 2.3 ± 1.0 at 1 week, and to 0.9 ± 0.9 at 1 month (p < 0.001), remaining stable at 6 months. Functional mobility was rapidly restored, with mean FMS improving from 2.9 ± 0.7 pre-procedure to 1.1 ± 0.3 at 1 month (p < 0.001), allowing independent ambulation in 87.5% of patients. Conclusion: The strict “ablation-first” BAA strategy is safe and highly effective. It abolishes load-bearing pain and restores biomechanical stability immediately, allowing previously immobilized patients to rapidly regain independent ambulation and seamlessly transition to necessary consolidative radiotherapy.