ACL Repair of a Tibial Spine Avulsion Fracture Using a Dual Suspensory All-Suture Construct With Additional Physeal Sparing Modified Lemaire LET

Abstract

Background:

Tibial spine avulsion fractures are a relatively common pediatric injury that can be managed with a variety of operative techniques. No consensus exists on the optimal method of fixation, especially in patients with rotatory instability who are at a greater risk of rerupture.

Indications:

Dual suspensory all-suture constructs with physeal sparing modified Lemaire lateral extra-articular tenodesis (LET) is a novel technique that may offer excellent outcomes for the management of types 2 to 4 tibial spine fractures in patients with rotatory instability.

Technique Description:

A lateral thigh incision is utilized to obtain an 8 × 1–cm iliotibial band autograft that is whipstitched and passed deep to the lateral collateral ligament in a modified Lemaire fashion. Standard arthroscopic portals are used to reduce the anterior cruciate ligament (ACL) stump. Two separate tip-to-tip tibial guides are used to drill through the ACL stump at different angles, allowing nitinol wires to pass. A scorpion suture passer is used to pass 2 sutures through the mid-body of the ACL that is subsequently shuttled through the tibia. Two TightRope II RT implants are then passed through the suture mechanism and tightened to generate compression at the fracture site. Appropriate drill positioning for femoral fixation of the LET along the lateral epicondyle is confirmed with fluoroscopic guidance. The LET is secured via an onlay fashion and tensioned with the knee at 60° of flexion and neutral rotation.

Results:

Postoperative course was uncomplicated, and the patient reached 90° of flexion by 1 week postoperatively. The patient initiated a jogging program at 6 months and was cleared to return to sports at 12 months postoperatively without complication.

Discussion/Conclusion:

Dual suspensory all-suture constructs for ACL repair, with the incorporation of LET, are a viable treatment option for the management of pediatric tibial spine avulsion fractures. Our technique offers the advantages of multiple points of fixation, avoidance of tunnel convergence, reduction in risk of physeal injury, and added stability with LET. Given the high failure rates of ACL repair, especially in pediatric populations, this novel technique appears to offer satisfactory outcomes with rapid recovery in appropriately indicated patients.

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

This is our technique on an arthroscopic anterior cruciate ligament (ACL) repair of a tibial spine avulsion fracture using a dual suspensory all-suture construct with a physeal-sparing modified Lemaire lateral extra-articular tenodesis (LET).

Tibial spine avulsion fractures can be treated in a variety of ways—including open reduction internal fixation, arthroscopic anchor fixation, or arthroscopic suspensory fixation with and without physeal sparing techniques. In ACL injuries with additional rotatory instability, as evidenced by a positive pivot-shift maneuver, the addition of a LET to ACL repair and reconstruction has been shown to reduce ACL failure rates and provide additional stability. Here, we present our technique of an ACL repair of a tibial spine avulsion fracture using a dual-suspensory all-suture construct with a physeal-sparing modified Lemaire LET.

Indications

The patient is a 14-year-old male who sustained a noncontact pivoting injury to his knee while playing basketball 10 days before presentation. Past medical and surgical history was negative.

Physical examination of the affected knee demonstrated a closed injury with mild effusion. Range of motion was 5° to 90°, with an 8 cm difference in prone heel height. Anterior drawer maneuver was positive, and the patient had a 2A Lachman with a soft endpoint. The knee was stable to varus and valgus stress at 0° and 30°. The patient was motor and sensory intact to light touch from L2 to S1. Anterior-posterior (AP) and lateral radiographs of the knee demonstrated a skeletally immature patient with a small anterior bony fleck at the tibial eminence, concerning for a possible ACL injury. Coronal and sagittal magnetic resonance imaging of the knee confirmed a tibial spine avulsion fracture with associated distal stump ACL rupture. There was no evidence of injury to the meniscus, lateral collateral ligament (LCL), medial collateral ligament, or posterior cruciate ligament. Given the patient's injury pattern, ACL repair rather than reconstruction was indicated, with the goal of primary repair. The risks and benefits of the procedures were discussed, and the patient and family elected to proceed with an ACL repair.

Technique Description

The patient is placed supine on the operative table with an upper thigh tourniquet, a thigh post, and a foot bump to allow for 80° of knee flexion at rest. The C-arm is placed on the contralateral side of the operative extremity. A skin incision is marked from the Gerdy tubercle to 3 cm proximal to the lateral epicondyle in a curvilinear fashion for the LET. Standard anterolateral and anteromedial arthroscopic portals are marked. The limb is exsanguinated with a sterile Esmarch bandage, and the tourniquet is inflated to 250 mm Hg.

We begin with the LET, making a lateral thigh incision with a 10-blade. Skin flaps are elevated, and fat is removed from the iliotibial band (ITB). Using a 10-mm double blade, an 8 cm in length × 1 cm in width ITB autograft is harvested from the posterior two-thirds of the ITB, starting proximally and ending distally. The tendon is whipstitched with a FiberLoop (Arthrex) near its insertion at the Gerdy tubercle and bulleted at its free end. The needle on the FiberLoop is then removed. A right-angle clamp is then used to create a passageway deep to the LCL, allowing passage of the ITB autograft from distal to proximal. After passage of the graft deep to the LCL in modified Lemaire fashion, the lateral incision is covered with ioban. We then turn our attention to the arthroscopic portion of the case.

Standard anterolateral and anteromedial arthroscopic portals are made with an 11-blade. Anterior synovectomy is performed to improve visualization. The tibial stump of the ACL is completely avulsed from its origin, with remaining ACL fibers intact proximally. The footprint is then carefully debrided with an arthroscopic shaver. A passport cannula is placed in both the anteromedial and anterolateral portals.

A tip-to-tip tibial drill guide set at 60° is inserted through the anteromedial portal and placed at the posterior aspect of the fracture bed. A 2.4-mm cannulated drill bit is drilled in retrograde fashion. The guide is then removed, and a grasper is used to reduce the ACL stump.

The drill bit is then used to drill through the ACL stump, and the insertion wire is removed. A nitinol wire is funneled through the cannulated drill bit and pulled out through the anterolateral portal.

The tip-to-tip tibial guide is changed to a 55° angle and is placed at a more anterior portion of the fracture bed to avoid tunnel convergence. The same steps are repeated, and both nitinol wires are shuttled out of the anteromedial portal. Next, a scorpion suture passer is used to pass 2 FiberRing (Arthrex) sutures through the midbody of the ACL. One of the FiberRing sutures and nitinol wires is pulled through the anterolateral portal. The cannulated drill bit is removed from the knee with care not to remove the nitinol wire. The FiberRing suture is then shuttled out of the knee through the tibia.

A probe is used to elevate the FiberRing suture to view the internal suture passing mechanism clearly. A TightRope II RT implant (Arthrex) is then shuttled through the FiberRing mechanism. The tightrope suture limbs are sequentially tightened, but not completely tightened, until the second TightRope II RT implant is passed. The same steps are repeated for the second FiberRing suture with a TightRope II RT implant. The arthroscope is removed, and the knee is brought into full extension and neutral rotation. With a posterior drawer maneuver, the tightropes are sequentially tightened until the endobuttons are visualized to abut the anteromedial tibial cortex. The Lachman maneuver is performed at this time.

The arthroscope is then reintroduced into the knee joint, and reduction is reassessed. Note, there is adequate compression of the tibial ACL stump along the previous fracture site. The reduction is assessed at 90° of flexion and in full extension. With the knee in full extension, there is no evidence of notching. The arthroscope is then removed.

We then redirect our attention to the LET. The LCL is traced to its femoral origin at the lateral epicondyle. Under fluoroscopic guidance, an all-suture knee FiberTak (Arthrex) drill guide is placed near the lateral epicondyle with care to avoid the distal femoral physis. Drill positioning is confirmed on both AP and lateral radiographs. The LET is secured via an onlay fashion and tensioned with the knee at 60° of flexion and neutral rotation. Any additional ITB autograft is used to augment the lateral capsule by suturing the graft back onto itself with the suture needles from the knee FiberTak anchor.

Results

The patient is placed in a hinged knee brace locked in extension and is made to bear partial weight for 2 weeks postoperatively. After 2 weeks, the patient is advanced to full weightbearing in the brace, unlocked. Physical therapy begins on postoperative day 2 with gentle passive range of motion exercises, aiming for a goal range of 90° by week 1. A jogging program is initiated at 6 to 9 months if quadriceps strength is greater than or equal to 85% of the contralateral extremity. Return to sports is at 12 months.

Discussion/Conclusion

Pearls that may be taken away from this case include preventing tunnel convergence with 2 cannulated drills and 2 pins, and using a tip-to-tip tibial guide set at 2 different angles. An adequately sized ITB autograft, measuring 8 × 1 cm in our case, should be utilized. All-suture knee FiberTak anchors can help reduce tunnel length and limit the risk of physeal injury. Additionally, one TightRope implant per Fiber Ring provides 2 separate points of fixation for ACL repair. The FiberRin implant provides the option to use a TightRope for fracture reduction, which would not be possible without this specific technology. The TightRope can be sequentially tightened to allow for fracture reduction at all knee flexion angles. Alternative methods for suture fixation include passing the suture through the ACL while tying over a bone bridge or a cortical button on the tibia. Lastly, carefully pulling on the FiberRing sutures with slow sequential pulls can help pass the TightRope II RT implant through the internal mechanism.

Pitfalls that can occur in this case may result from drilling of the femoral LET tunnel without perfect AP and lateral XRs, which can result in physeal violation. Sutures that are passed through a small volume of ACL tissue can result in suture pullout and construct failure. TightRope RT passage through the FiberRing may be difficult and result in passage failure. Harvesting the ITB autograft too close to the Gerdy tubercle can result in graft amputation. Inadequate fracture reduction can result in arthrofibrosis and/or a cyclops lesion. Improper indications for ACL repair can lead to poor outcomes. Lastly, if intraoperative findings demonstrate significant comminution of the tibial spine avulsion fracture or a midsubstance tear of the ACL, then an ACL reconstruction should be performed.

All suture constructs for arthroscopic ACL repair in the setting of tibial spine avulsion fractures allow for anatomic restoration of the native ACL with excellent functional outcomes and return to sports.^1,5,7 There is no donor site morbidity associated with ACL repair, and the proprioceptive fibers are maintained with anatomic restoration of the native ACL. ACL repair in the setting of tibial spine avulsion fractures can have high failure rates ranging from 8% to 12%, especially with improper indications.^1,5,7 Younger and elite athletes undergoing ACL repair had a higher risk of repair failure.^1,5,7 Higher failure rates were seen in patients with thinner tibial spine fracture fragments, interposed soft tissue at the fracture site, and vitamin D deficiency.^2,4,5-7 These patients may benefit from the addition of a LET as it reduces the risk of ACL rerupture, especially in pediatric populations.^3,6 Lastly, low complication rates with hybrid ACL repair in pediatric populations have been observed, with 1 study citing 21 of 23 patients having no evidence of leg length discrepancy or angular deformity at a mean of 21 months. ⁸