Fig 1.

Percutaneous medial collateral ligament (MCL) trephination to expand the medial compartment. Intraoperative photograph of a left knee with the patient in the supine position, demonstrating percutaneous trephination of the MCL to increase access to the medial compartment. The knee is flexed to ∼20° with a valgus force applied. An 18-gauge spinal needle (A) is inserted using an outside-in approach, aiming distal and deep into the joint. Entry point, denoted by the letter M, is the “magic point” just 1-2 cm distal to the medial epicondyle at the femoral side of the proximal MCL, with the needle placed proximal to the junction of the posterior horn and body of the medial meniscus. Controlled trephination in this location facilitates ligamentous release, increasing the medial joint space by ∼2-3 mm. This maneuver improves arthroscopic visualization and instrumentation for medial meniscus posterior root repair. The dashed line marks the medial joint line, and the medial epicondyle is denoted by the letter “M” for orientation.