Fig. 2

Establishment of the LARAI portal in the right knee. A A 1.5 mm diameter guide needle was inserted at a point 20 mm lateral to the patellar tendon, closely adjoining the posterolateral margin of posterior cruciate ligament, and pierced through the medial skin of distal thigh. B The trajectory was widened from the medial skin of distal thigh using a 3.5 mm diameter cannulated switching stick. C A 5.0 mm diameter slotted cannula (Hakko Corp, Nagano, Japan) was inserted into the articular cavity along the switching stick. AL anterolateral portal, AM anteromedial portal