Lateral and Anterior Closing Wedge “9/9” Degree Osteotomy to Correct Both Tibia Vara and Excessive Tibial Slope

Abstract

High tibial osteotomy is a key option for patients with unicompartmental overload or instability. Although coronal correction for varus deformity is well established, excessive posterior tibial slope (PTS) is increasingly recognized as a contributor to anterior cruciate ligament graft failure. Conventional strategies often require staged procedures, potentially delaying recovery and compromising bone stock. The “9/9 osteotomy” allows simultaneous correction of varus and excessive PTS in a single stage. The technique combines a lateral closing wedge osteotomy with an anterior retrotubercle closing maneuver. Preoperative planning uses long‐leg standing and lateral radiographs to determine mechanical axis, medial proximal tibial angle, and PTS, which guide wedge dimensions and hinge position. Through a lateral approach, a lateral closing wedge is created toward a posteromedial hinge, followed by removal of an anterior wedge behind the tibial tubercle to decrease PTS. Fixation is performed with a lateral locking plate. The 9/9 osteotomy offers a reproducible single‐stage solution for combined varus and excessive PTS, preserving bone stock and facilitating early rehabilitation.