Abstract
Background:
Injuries to the anterior cruciate ligament (ACL) in the pediatric population have been exponentially increasing over the years. However, surgical techniques typically employed for ACL reconstruction (ACL-R) in adults may injure the physes of skeletally immature patients, resulting in growth disturbances.
Indications:
Currently, ACL-R is recommended for most patients, aiming to return the patient to their previous activities as well as reduce the risk of further instability, meniscal and chondral injuries, and early osteoarthritis. Pediatric ACL-R techniques may vary widely. In this video, the technique chosen was over-the-top on the femur with a vertical tibial tunnel, in addition to a lateral extra-articular tenodesis, using the iliotibial (IT) band as the graft.
Technique Description:
The patient is positioned in standard supine arthroscopic position. An incision is made over the lateral epicondyle and the IT band is exposed. A 2-cm-wide graft is harvested. The proximal aspect of the graft is truncated as high as possible, and the distal aspect is left attached to Gerdy tubercle. Arthroscopic portals are established, and the remanent ACL is debrided, exposing the posterior aspect of the lateral femoral condyle. The capsule is penetrated using a Schnidt tonsil to establish the over-the-top position, which is subsequently exchanged for a cardiac clamp. The graft sutures are grasped using the clamp and pulled into the joint. The tibial tunnel is drilled at the anatomic footprint of the ACL. The graft is threaded over-the-top of the lateral femoral condyle and through the tibial tunnel. Finally, femoral graft fixation is performed on the lateral femoral condyle using interrupted sutures through the IT band and periosteum, and tibial graft fixation is performed with standard interference fixation.
Results:
Previous literature shows low re-rupture rates, excellent postoperative patient-reported outcomes, and high return to sport rates.
Conclusion:
In the pediatric population, there is still no ACL-R technique defined as the gold standard. The described technique is a valuable option for ACL-R in skeletally immature patients, with low revision rates and excellent postoperative outcomes. In addition, this technique minimizes the risk of growth disturbances and effectively stabilizes the knee, allowing patients to return to previous activities.
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.
This is a visual representation of the abstract.
Keywords
Video Transcript
This is a technique description of the femoral physeal-sparing ACL reconstruction (ACL-R) with iliotibial band autograft over-the-top with associated lateral extra-articular tenodesis (LET).
These are our disclosures.
As an overview, this video will begin with a case, discuss the background of pediatric ACL injury, detail the surgical technique, and finish with a discussion of outcomes.
Our case is a 13-year-old boy with a left knee noncontact twisting injury, with swelling and difficulty weightbearing. On examination, he had a large effusion, limited range of motion, a grade 2B Lachman, and a glide on pivot shift.
Imaging shows a skeletally immature individual but is otherwise normal.
A magnetic resonance imaging (MRI) was obtained showing an acute isolated ACL tear in a skeletally immature patient.
As a background on pediatric ACL injuries, there is increasing incidence owing to increased participation in competitive sports with year-round competition and early specialization. 1 Adult operative techniques risk physeal injury and growth disturbance in this population, leading to potential coronal angular deformities, leg length discrepancy, and tibial recurvatum. 3
Clinical evaluation of these patients involves an injury history and a growth history, which can involve parental height and menarche. This can help illuminate how much growth the patient has remaining and helps dictate reconstruction technique. Physical examination should include assessment of ligamentous laxity with a Beighton score as well as alignment and gait.
Management of ACL injury in the pediatric population historically was nonoperative until skeletal maturity. Now, reconstruction is recommended in most all patients more acutely due to a reduced risk for further instability as well as meniscal and chondral injury. 3 Pediatric reconstruction techniques include all epiphyseal, partial transphyseal, transphyseal, or extra-articular, which is over-the-top on the femur with an associated lateral extra-articular tenodesis, or LET.2,3
Preoperative planning involves full-length radiographs of the lower extremity to assess alignment as well as a bone age radiograph if the patient is skeletally immature. 2 In a prepubescent patient with extensive growth remaining, surgery should avoid all physes. This may include an over-the-top femoral technique, and, on the tibia, passing the graft underneath the intermeniscal ligament and suturing it to the periosteum.2,4 If the patient is nearing completion of growth, the femoral physis should be avoided, given that it has the most growth of the physes in the lower extremity, but the tibial physis may be crossed by a tunnel. This video details this technique—an over-the-top technique on the femur and a vertical tibial tunnel, with a vertical tunnel used to minimize the physeal surface area involved. Graft choice with open physes is generally soft tissue only. This can be hamstring tendon, quadriceps tendon, or IT band autograft.
Here, a modified Kocher technique was selected. The patient had closing physes, but appreciable growth remaining, based in part on parental height. Therefore, the femoral physis—the physis with the most growth in the lower extremity—was spared using an over-the-top technique, while a tibial tunnel was drilled. An LET was incorporated. All of this was accomplished using an IT band autograft.
The surgical technique follows. The patient may be positioned according to the surgeon’s standard ACL-R technique. Of note, the tourniquet must be high without a leg holder in case access to the proximal IT band is needed. Equipment involves 3 meniscotomes to help cut and free the IT band graft; a cardiac clamp, which is a larger Kelly clamp; a Schnidt or tonsil; and a long, curved rasp.
A 4-cm longitudinal incision is made with the lateral epicondyle centered at the distal third. Dissection is taken down to the iliotibial band, where the IT band is freed of all adhesions on its superficial surface with a Cobb. Two nicks are made in the IT band to harvest a 2-cm-wide graft. This width may vary based on the size of the patient. Sufficient anterior and posterior IT band is necessary. The graft is freed up at the nicks. The undersurface of the IT band is freed of adhesions and mobilized. A meniscotome is placed in the anterior nick and used to extend the incision in the IT band. The appropriate meniscotome has the long tine deep to the IT band and the handle angling toward the midline IT band. The meniscotome is advanced as high in the thigh as possible to harvest maximal graft length. A Kocher clamp may be used to retrieve it. The same process is repeated with the other meniscotome with the handle that angles in, toward the central IT band. This harvests the posterior aspect of the graft. A Cobb is used to meticulously free the undersurface of the IT band of all adhesions. The third meniscotome is advanced and used to truncate the graft proximally. This can be challenging and may take multiple attempts. The proximal aspect of the graft is whip-stitched and bulletized to facilitate passage. The graft is sized with a cylindrical sizer, often about 8 mm in diameter.
Standard anteromedial and anterolateral arthroscopy portals are established. Here the menisci are healthy. Here the completely torn ACL can be seen. It is debrided entirely, revealing the posterior aspect of the lateral femoral condyle. A Schnidt is used to poke through the capsule just posterior to the lateral femoral condyle to establish the over-the-top position. A cardiac clamp is too blunt to pierce the capsule, hence the use of the Schnidt. It is important that this hugs the femur closely. The Schnidt is exchanged for the cardiac clamp or large Kelly clamp, which is advanced around the posterior aspect of the lateral femoral condyle. This may be a tight fit, so the clamp is oscillated back and forth until it is slowly advanced.
Attention is turned to the lateral thigh incision, where dissection is taken down to the posterior aspect of the lateral femoral condyle until the tip of the clamp is seen. The sutures from the proximal end of the graft are grasped and pulled back into the joint through the anteromedial portal.
Attention is turned to drilling of the tibial tunnel. The tip aimer guide is placed at the anatomic footprint of the ACL. The guide pin and then a reamer, sized according to the diameter of the graft, are then passed. This is a more vertical tibial tunnel than in the adult. The graft is threaded in the over-the-top position by pulling firmly on the sutures. The graft can be seen on the arthroscopic picture here. The graft is fixed to the lateral aspect of the lateral femoral condyle by passing suture through the graft and then through the periosteum. The surgeon must feel the needle hit the bone to ensure he or she is going deep enough to grasp the periosteum. Multiple interrupted sutures are placed. No other fixation is needed on the lateral aspect of the femur. This fixates both the proximal aspect of the ACL and the LET. After the graft is pulled through the tibial tunnel, with tension on the graft and a posterior drawer at 15° knee flexion, a biocomposite screw is advanced to fixate the graft. This leads to a grade 1A Lachman and no pivot shift. Seen is the fixation on the lateral aspect of the femur. Wounds are closed in standard fashion.
Postoperatively, the patient is placed in a hinged knee brace at all times for the first 6 weeks, with range of motion advanced as shown. The patient is made touchdown weightbearing with crutches for 6 weeks and progressed thereafter.
Physical therapy protocol is shown here, focusing on regaining range of motion initially, alongside quadriceps activation, and eventually progressing toward strengthening, running, and sport-specific activity.
Potential complications of the procedure include graft failure, infection, angular deformity, limb length discrepancy, and neurovascular injury.8,9 Of note, the neurovascular bundle may be less than 1 cm away from the tip of the cardiac clamp during over-the-top passage. 8
Return-to-sport is considered at 9 months at the earliest but is preferred at 1 year to minimize the risk of re-rupture.
The largest study of outcomes, in 237 patients at mean follow-up of 6 years, showed a 6.6% re-rupture rate with excellent International Knee Documentation Committee (IKDC), Lysholm scores, and return to sport. 5 This study and the next used a tibial-sparing approach, limiting exact comparisons to the present technique.5,7
This study of knee function of an IT Band ACL-R versus the contralateral knee showed no statistically significant differences in knee moment or ground reaction forces in response to vertical jump and single-limb hop. 7
Finally, this study of an over-the-top femoral technique with a tibial tunnel and no LET showed significantly reduced anterior laxity with the over-the-top technique in both skeletally immature and mature patients. There were 14% re-ruptures in the adolescent group, and 5% in the revision group. 6
Thank you.
Footnotes
Submitted November 10, 2022; accepted January 20, 2023.
The authors declared that they have no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
