Establishing a popliteal portal using the METRx system under ultrasound guidance.

This report describes a special technique for safe establishment of a popliteal portal with the METRx system (Medtronic Sofamor Danek, Memphis, TN) under ultrasound guidance with the patient in the awake state. Herbert screws located at the posterior tibial plateau were removed via this portal in a minimally invasive way. Before surgery, we performed surface mapping of the screw tract with an image intensifier and target needling under ultrasound guidance. The METRx system was used to establish the soft-tissue corridor along the guide pin. Screw removal and tibial plateau resurfacing were performed with the Acufex Mosaicplasty system (Smith & Nephew Endoscopy, Andover, MA). In our review of the literature, no similar method establishing the knee popliteal portal was found. The method is recommended especially for minimally invasive surgery in regions rich with neurovascular structures.