A Remnant Preservation Technique for All-Inside Anterior Cruciate Ligament Reconstruction

Abstract

Most knee sports injuries involving the anterior cruciate ligament (ACL) are proximal ACL tears. The all-inside ACL reconstruction technique has drawn great attention, aiming to minimize tissue disruption while restoring ACL function. Arthroscopic ACL remnant preservation has shown great potential in repairing ACL anatomic and biological function by facilitating the revascularization and reinnervation of implanted grafts. Although many techniques for ACL remnant preservation have been developed, preserving the integrity of the ACL remnant in all-inside ACL reconstruction is still challenging. To further improve operational convenience and reliability, we have developed a remnant preservation technique for all-inside ACL reconstruction. This technique uses preset sutures on the ACL remnant, with an longitudinal incision on the anterolateral side of the ACL remnant, along with an auxiliary anteromedial portal, to better reveal the tibial footprint area while preserving the integrity of the ACL remnant. The preset sutures also allow for the fixation of the remnant on a femoral cortical button through our all-inside ACL reconstruction technique. This technique offers the benefits of being both economical and safe for preserving the ACL remnant, as well as being convenient for securing the remnant to the bone cortex, with the goal of facilitating the repair of proximal ACL tears.

Fig 1

Identification of proximal anterior cruciate ligament (ACL) tear and pruning of ACL remnant (yellow arrows). (A, B) Arthroscopic views from anterolateral portal to examine proximal ACL tear (A) and ACL remnant after pruning using arthroscopic shaver and radiofrequency ablation device (B). The patient lies supine with the right knee joint flexed at 90°.

Fig 2

Preset suturing processes of high-strength suture on anterior cruciate ligament (ACL) remnant with anterolateral portal for observation, anteromedial portal for operation, and knee in 120° of flexion. (A) A left-curved 45° suture hook (black arrow) passes through the ACL and introduces a guidewire. (B) The wire guides the high-strength suture passing through the ACL, and the hook passes through the ACL again. (C) Preset high-strength suturing on the ACL remnant is completed. The yellow arrows indicate the ACL remnant, and the blue arrows indicate the high-strength suture.

Fig 3

Construction of femoral socket with anterolateral portal for observation, anteromedial portal for operation, and knee in 120° of flexion. (A) A 6-mm eccentric positioner is inserted into the femur with a guide pin. (B) The reamer prepares a socket with a diameter of 8 mm and depth of 20 mm. (C) View of prepared socket with anteromedial portal for observation.

Fig 4

Preparation of tibial socket and anterior cruciate ligament (ACL) remnant with anterolateral portal for observation, anteromedial portal for operation, and knee in 90° of flexion. (A) The blade cuts the ACL remnant longitudinally on the anterolateral side. (B) The radiofrequency ablation device clears the tibial insertion point of the ACL to reveal the tibial footprint area. (C) The ACL tibial guide with marking hook is shown in the portal position. (D) The socket is drilled with the retrograde reamer. An auxiliary anteromedial portal is used for pulling the ligament remnant tissue with preset sutures to avoid iatrogenic injury to the ligament.

Fig 5

Placement of ligament graft traction suture with anterolateral portal for observation, anteromedial portal for operation, and knee in 90° of flexion. (A) Insertion of tibial tunnel traction suture (green arrow). (B) Placement of femoral tunnel traction suture (blue arrow). (C) The preset sutures (blue arrow) on the anterior cruciate ligament remnant are pulled out through the auxiliary anteromedial portal using a grabber (purple arrow) to avoid suture interference.

Fig 6

Ligament graft drawn into socket with anterolateral portal for observation and anteromedial portal for operation. (A) The ligament graft is pulled into the joint cavity through the anteromedial portal. (B) The preset sutures on the anterior cruciate ligament (ACL) remnant bypass the suture loop of the femoral cortical button (orange arrow). (C) The ligament graft is pulled in a retrograde manner into the tibial socket. (D) The ACL remnant covers the graft surface and is not knotted in place. The red arrows indicate the ligament graft; yellow arrows, ACL remnant; and blue arrows, high-strength suture. The patient lies supine with the right knee joint flexed at 90 degrees.

Fig 7

Arthroscopic view of all-inside anterior cruciate ligament (ACL) reconstruction with remnant preserved. (A) Arthroscopic view of ligament graft (red arrow) and ACL remnant from anterolateral portal. (B) The ACL remnant is fixed on the femoral side by looping 1 end of the remnant around a femoral cortical button and knotting it. (C) Arthroscopic view from anteromedial portal. The yellow arrows indicate the ACL remnant.