A Novel Tripod Percutaneous Reconstruction Technique in Periacetabular Lesions Caused by Metastatic Cancer

BACKGROUND: Metastatic lesions in the periacetabular region can cause pain and immobility. Symptomatic patients are often treated surgically with a total hip replacement using various modified Harrington methods. These open surgical procedures confer inherent risks. Prolonged recovery and potential complications may delay adjuvant radiation and systemic therapy. METHODS: We describe a novel technique for acetabular reconstruction. Three large-bore cannulated screws are placed percutaneously under fluoroscopy in a tripod configuration to reinforce the mechanical axes of the acetabulum. Increased stability improves pain control and permits weight-bearing. RESULTS: Twenty consecutive patients with periacetabular metastases were treated using the tripod technique. Eighteen patients (90%) had Harrington class-III lesions, and 2 patients had Harrington class-II lesions. The mean surgical time was 2.3 hours. Sixteen patients (80%) were able to get out of bed on postoperative day 1. At 3 months postoperatively, there was significant improvement in pain as documented on their visual analog scale (p 6 months postoperatively. They were found to have either new bone formation filling the defects or healing of the pathological fractures. There has been no implant loosening or failure. CONCLUSIONS: The tripod technique is a novel application to provide safe and effective pain relief in the context of periacetabular metastatic disease. It can be easily converted to support a cemented acetabular cup for a total hip replacement should disease progression occur. This technique provides an alternative to open surgery as currently practiced in these patients. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.