Anterior Cruciate Ligament Repair With Internal Bracing Augmentation

Abstract

Background:

The incidence of anterior cruciate ligament (ACL) injuries has rapidly increased, and patients with ACL injuries frequently have concomitant meniscal pathologies. Given the advantages in restoring patient anatomy, retaining proprioceptive fibers, and eliminating risks of donor site morbidity, ACL repair has reemerged as a treatment option for indicated patients. For proximal tears, augmentation of the native ACL with an internal brace has been thought to reinforce ligament strength, facilitate improved ligamentization, and have a protective effect as a secondary stabilizer. As such, there has been a growing interest in improving ACL repair techniques through augmentation with an internal brace implant.

Indication:

Patients are indicated for surgery when presenting with symptomatic ACL insufficiency, as observed on provocative testing and confirmed by advanced imaging, such as magnetic resonance imaging. Repair can be indicated in acute and proximal tears or subacute-to-chronic, proximal tears in patients with reducible remnant tissue who have persistent instability.

Technique Description:

Viewing the ACL from the anteromedial portal, the native ACL was found to be insufficient and avulsed from its femoral attachment. A gentle notchplasty and microfracture of the footprint were performed, taking care to protect and preserve the residual stump. Sutures were passed through both bundles of the ACL, starting distally and progressing proximally toward the avulsed end in an interlocking fashion. The anteromedial bundle footprint was identified and marked on the lateral femoral wall. A tunnel was drilled, and the previously passed sutures were used to restore ACL attachment to the native femoral site. After proximal footprint fixation, an ACL guide was used to drill a tunnel anterior to the native ACL tibial insertion. A suture lasso was placed through this hole, and preloaded fiber tape threads were shuttled with the ACL substance down the tibia. Fixation was achieved with a suture anchor perpendicular to the tibial cortex.

Results:

Within 2 years postoperatively, patients are expected to have improved knee-specific quality of life, improved stability, and a successful return to activities.

Discussion/Conclusion:

Advancements in our understanding of the ACL should prompt surgeons to consider ACL repair augmentation techniques to improve outcomes and restore native anatomy in select patients with proximal ACL avulsions.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

Background

Here we present our technique for an anterior cruciate ligament repair (ACL) with internal bracing. Our conflicts of interest can be seen here.

The ACL is a ligamentous tissue that prevents rotational instability and anterior translation of the tibia over the femur. An increasingly common condition, particularly in athletic activities, injury to the ACL has a reported incidence rate of around 61 per 100,000 persons. ⁴ Given the advantages in restoring patient anatomy, retaining proprioceptive fibers, and eliminating risks of donor site morbidity, surgical techniques for ACL repair have reemerged as a treatment option for indicated patients. ⁵ Particularly in the case of proximal tears, augmentation of the native ACL with an internal brace has been thought to reinforce ligament strength while serving as a secondary stabilizer. ⁵ This makes the prospect of combining the ACL procedure with internal bracing augmentation an attractive alternative to ACL reconstruction for acute proximal tears.

Indications

Our patient presents after a pop in their knee while doing jumping jacks. They report a 5-month history of constant soreness with associated swelling and buckling. After failed conservative management, they came to our practice seeking additional treatment options. The patient demonstrates a normal range of motion with intact strength on flexion and extension. They are tender over the posterior fossa and have a positive anterior drawer and unstable Lachman and pivot shift. Postoperative radiographs showed no signs of arthritis, malalignment, or major pathology. Sagittal and coronal magnetic resonance imaging (MRI) demonstrated an elongated and avulsed ACL from its femoral attachment without any evidence of rupture, in addition to a complex tear of the posterior horn of the medial meniscus. Surgical indications for ACL repair with internal brace augmentation include an acute, proximal tear with a reducible remnant bundle, chronic in nature as to support the failing ligament. Given the physical examination and imaging findings, we concluded a diagnosis of a deficient ACL and proceeded with the repair.

Technique Description

We begin by viewing the ACL from the anterolateral portal. Notchplasty is then performed using a bone cutter. Ligament integrity is sufficient, but the femoral attachment, particularly on the anteromedial bundle, is insufficient and avulsed from the femoral side. Microfracture of the footprint is performed to improve the biological environment for the subsequent healing of the repair. Then, ACL suture passing is done through the posterolateral portal using a first-pass ST self-retrieving suture passer (Smith & Nephew), as well as suture tape and No. 2 FiberWire (Arthrex). Sutures are passed through both the anteromedial bundle and posterolateral bundle from the intact distal end toward the avulsed proximal end in an interlocking pattern. Three to four passes through a passport button cannula, and the anteromedial portal can usually be made before the final pass exits the proximal end toward the femur.

Next, tension of the ACL and the footprint is checked by pulling the threads with the suture retriever. Tape sutures are then retrieved through the accessory portal. Similarly, the suturing of the posterolateral bundle is performed using a suture passer and No. 2 FiberWire in the same fashion. Sutures are retrieved through the accessory portals accordingly. With the knee at 90° of flexion, a 4.5×20-mm punch is used to create a 20-mm hole at the origin of the anteromedial bundle on the femur. This hole is subsequently tapped to facilitate the insertion of the anchor for fixation of the proximal ACL stump.

The suture threads are loaded into a 4.75-mm vintage biocomposite swivel lock suture anchor that is preloaded with the internal brace and placed on the prepared footprint. The internal brace tape is then retrieved through the anteromedial portal/cannula for later use, and the remaining suture ends, loaded through the SwiveLock (Arthrex), are then cut flush. After proximal footprint fixation, a 2.4-mm guide pin is drilled through the tibial footprint of the ACL, and a suture lasso is placed through this drill hole to retrieve and pass the previously loaded internal brace suture tape. Preloaded FiberWire threads are then passed through the suture lasso and shuttled along with the ACL substance down through the tibia. This is fixated with the suture anchor perpendicular to the tibial cortex. A final view of the repaired ACL and examination of its tension with an arthroscopic probe is seen from the anterolateral and anteromedial portals, respectively. Postoperative rehabilitation includes a nonweightbearing status for 6 weeks. This approach is adapted to minimize anterior tibial translation and protect the healing ligament, particularly in patients with increased posterior tibial slope or concomitant meniscal repairs, which may predispose them to increased graft strain. The patient will then undergo physical therapy to regain their strength and range of motion as tolerated, with a return to activities at 6 to 8 months.

Results

Initial case reports have found good functional outcomes, as well as radiographic and arthroscopic evidence of a healed, anatomic ACL following repair. ⁶ Further, the repair was seen to improve ACL strength and stability. This was verified in subsequent biomechanics studies, demonstrating significantly higher load to failure, stiffness, and energy to failure. ³ Finally, clinical studies reporting on the outcomes of internal bracing have shown improved subjective outcomes after repair with the internal brace, demonstrating similar results compared to those without it and highlighting the potential role of additional bracing in improving patient outcomes. ² However, it is important to note that not all reports have been uniformly favorable—some report significantly higher early failure rates following ACL repair with suture ligament augmentation in adolescent patients compared to traditional reconstruction techniques, highlighting the need for careful patient selection and longer-term outcome data. ¹

Discussion/Conclusion

Additionally, several technical considerations can enhance the success of this technique. First, it is essential to preserve the integrity of the remnant ACL fibers, as extensive debridement may impair healing and compromise healing potential. It is also beneficial to use an interlocking suture pattern, which distributes tension evenly across the ligament and reinforces the stability of the repair. Equally important is the accurate placement of tunnels within the anatomic footprint, which helps prevent graft impingement and maintain rotational control. Accessory portals should also be strategically positioned to facilitate suture retrieval and minimize soft tissue entanglement. Finally, it is critical to avoid overtensioning the internal brace, as excessive tension may restrict postoperative range of motion and hinder recovery.

Thank you for watching our technique demonstration of an ACL repair with internal bracing.