Intraoperative Laximetry-Based Selective Transtibial Anterior Cruciate Ligament Reconstruction Concomitant With Medial Open Wedge High Tibial Osteotomy for Treating Varus Knee Osteoarthritis With Anterior Cruciate Ligament Deficiency

Abstract

High tibial osteotomy (HTO) is used in the treatment of varus knee osteoarthritis (KOA) in young and active patients. At times, a concomitant anterior cruciate ligament (ACL) deficiency is found, and there is no conclusive evidence comparing the osteotomy options for an ACL-deficient knee despite the popularity of medial opening-wedge (MOW) HTO in varus KOA with ACL deficiency. To minimize the incidence of an unnecessary ACL reconstruction with MOW-HTO, we developed an intraoperative laximetry-based selective technique for transtibial ACL reconstruction concomitant with MOW-HTO using a sterilizable metal laximeter. To successfully use the device required for this procedure, surgeons must understand the proper techniques. Hence, this Technical Note aims to give a comprehensive description of the technique.

Fig 1

The patient with right varus knee osteoarthritis with anterior cruciate ligament deficiency is positioned supine on a radiolucent table in the orthopedic theater and subjected to the preoperative measurement of anterior drawer test immediately after administering the general or regional anesthesia using a nonsterilized Rolimeter in 30° knee flexion for baseline measurement. The maximum manual force is applied to the tibia relative to the femur both anteriorly and posteriorly. The anteroposterior laxity is calculated as the difference in average anterior and posterior laxities, according to the manufacturer’s instructions. Yellow arrow indicates the force direction when anterior force is applied to the tibia.

Fig 2

Fluoroscopic image of the right proximal tibia with first guidewire. The starting point of the first Kirschner wire is ∼2 cm medial to the medial border of the tibial tuberosity. The entry point of this wire is approximately 4 to 4.5 cm below the medial joint line. Yellow arrow indicates the entry point. The depth of the saw cut is 5 mm less than the value measured against the wires to leave a lateral bone hinge to avoid unstable hinge fracture. It is important to ensure that there is sufficient space cranially for the locking bolts of the plate fixator.

Fig 3

Fluoroscopic image of the spreader placement. The spreader is placed as close to the posterior cortex as possible to minimize tibial slope alteration while opening the horizontal osteotomy to the desired correction angle. Yellow arrow indicates the width of medial opening wedge.

Fig 4

Intraoperative fluoroscopic evaluation of the mechanical axis of the lower limb set at 55% using a long alignment rod. The medial tibia is temporary fixed with the TomoFix anatomical medial high tibial plate (DepuySynthes, Solothurn, Switzerland). Yellow arrow indicates the long alignment rod from center of the femoral head to center of the talus.

Fig 5

Intraoperative measurement of the anteroposterior laxity of the operated knee using the Rolimeter. Change in the side-to-side difference (SSD) is determined to consider performing an anterior cruciate ligament (ACL) reconstruction. For an SSD <3 mm, ACL reconstruction is not performed; when the SSD is over 3 mm, the ipsilateral semitendinosus tendon (and gracilis tendon if needed) is extracted using a tendon harvester. Yellow arrow indicates the force direction when anterior force is applied to the tibia.

Fig 6

Arthroscopic image of the femoral bone tunnel of the right knee in the figure-four position from the anteromedial portal. Transtibial ACL reconstruction aimed at a femoral bone tunnel created behind the resident’s ridge is performed to create the femoral tunnel with a diameter of 8.5 to 9 mm using an offset guide inserted through the tibial tunnel to prevent posterior wall blowout with a figure-four position so that the femoral bone tunnel is created lower and deeper, thus resulting in a placement behind the resident’s ridge. Yellow arrow indicates a femoral socket-shaped tunnel with a diameter of 4.5 and 8 mm created behind the resident’s ridge.

Fig 7

Arthroscopic image of the right knee in the hanging-leg position from the anterolateral portal. A quadrupled hamstring graft is introduced from the tibial tunnel to the femoral tunnel; turn-buckle stapling is done, so that the two staples do not interfere with distal locking screws. Yellow arrow indicates quadrupled hamstring graft.