All Epiphyseal ACL Reconstruction in Skeletally Immature Patients Using Quadriceps Tendon Autograft

Abstract

Background:

The incidence of anterior cruciate ligament (ACL) tear in the skeletally immature pediatric population has been steadily increasing due to multiple factors, including multiple sports participation, year-round training, and the increase in the number of athletes. Reconstruction in these patients is challenging due to the open physes at the distal femur, proximal tibia, and tibial tuberosity apophysis. Violation of the physis can result in angular deformities or leg length discrepancies.

Indications:

To demonstrate steps of all epiphyseal ACL reconstruction in skeletally immature patients using quadriceps tendon autograft.

Technique Description:

After the patient is positioned, prepped, and draped, the quadriceps tendon autograft is harvested and prepared to be used as the autograft. Using the all-inside technique, femoral and tibial tunnels are created as all-epiphyseal to prevent violating the physes. The ends of the graft are then passed through the tunnels and fixed with an adjustable loop on the femur and a button on the tibia.

Results:

Although excellent clinical outcomes and a high return to sports rates have been reported after ACL reconstruction, the technique to be chosen is not clear yet.

Discussion/Conclusion:

Quadriceps tendon autograft provides an excellent alternative as a graft choice in skeletally immature patients.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

Hello, this is Paul Saluan. I will present the surgical technique for all-epiphyseal anterior cruciate ligament (ACL) reconstruction in skeletally immature patients using autologous quadriceps tendon graft.

These are my disclosures.

The incidence of ACL injuries and reconstructions has been increasing in the pediatric population. This may be related to multiple factors, including year-round training and increasing sports participation, among many other factors.

Reconstruction in these patients is challenging due to the open physes at the distal femur, proximal tibia, and tibial tuberosity apophysis. Violation of the physis can result in angular deformities or leg length discrepancies. Variable reporting has shown this.

There is no consensus yet on the preferred technique for skeletally immature patients. A lot of surgeons prefer to use the complete physeal-sparing technique in patients with more than 2 years of growth remaining. If there are less than 2 years of growth remaining, then it is dealer’s choice and one could potentially do an adult form of reconstruction in this age group with minimal risk of creating angular or leg length deformities.

We choose to use the quadriceps tendon autograft in these younger patients, currently, due to the fact that we feel this is a stiffer graft and has more integrity than a hamstring autograft in these youngest of the young patients. MOON data have suggested that younger patients are at higher risk of failure, and we have data that correlate with this. Thus, the quad tendon appears to be an opportunity to minimize that risk of reinjury.

Patients usually present with pain, instability, and swelling following a non-contact injury—this is the most common mechanism. Most often, it is the result of a twisting mechanism of the knee. Clinical evaluation is based on physical examination findings, including a positive Lachman test for gross abnormal laxity and quality of the end point and pivot shift test—awake, asleep, or both.

Radiographic findings include the assessment of the physeal status and assessing the distal femoral physis and proximal tibial physis, including the tibial tuberosity apophysis. Also, I am looking for discontinuity of the ACL fibers and where those fibers actually become discontinuous. If these are avulsion-type injuries from the tibia or from the femoral side, then this patient will be more amenable for a primary repair as opposed to a reconstruction. An empty wall sign and pivot shift bone contusions are also very helpful regarding determining the instability of the knee.

This case in particular is of a 12-year-old girl who presented with instability of the left knee after a non-contact twisting injury while jumping off a trampoline. On physical examination, she had normal gait without antalgia, a 1+ effusion, near full range of motion, minimal tenderness to palpation of the medial joint line, a positive Lachman test for gross abnormal laxity, and a very spongy end point. Posterior drawer test and varus/valgus stress test were negative.

Radiographs of the left knee did not show any fractures. Physeal regions were open. Magnetic resonance imaging (MRI) demonstrated an empty wall sign on the lateral femoral condyle with discontinuity of the ACL consistent with a tear.

The patient is placed in the supine position with the nonoperative leg in a moderate degree of hip flexion—not flexed too much to avoid a femoral nerve palsy and not extended too much at the hip to minimize the chance of compartment of the lower leg. The peroneal nerve is padded on the nonoperative leg. A tourniquet is used to help keep a visible field.

Plain radiographs of this 12-year-old showed open physes in the distal femur, and proximal tibia, and tibial tuberosity apophysis. The MRI findings showed mid-substance ACL tear with pivot-shift bone contusion. A Lachman test is performed showing gross abnormal laxity and no stable end point. Pivot shift while asleep is very sensitive, showing significant shifting while testing.

A small incision is made over the quadriceps tendon distally, to retrieve the graft, and then the soft tissue is cleared over the top of the tendon. This is the endoscopic view of the quad tendon that will soon be harvested. I go straight to harvest with this harvester. This is a new harvester that is of a single use only. Put an ink mark around the edge and then mark the distal aspect of where the quad tendon attaches on the superior aspect of the patella. This allows me to be able to cut on the inferior aspect of that circular region to start the quad tendon harvest from that region.

Retention suture is in the end, and the sutures are then placed through the harvesting apparatus. Tension is put on the graft using the suture and then the angle is slightly posteriorly angled to make sure that we get both lamina of the quad tendon. I go in for full-thickness quad tendon, not for single lamina. This is a slow rotational movement with forward pressure, and it tends to cut the quad tendon fairly uniformly all the way through. This is a size 9 measurement based on preoperative evaluation to make sure that our appropriately sized graft is there. Sutures are then pulled through the window. The graft is pulled through the window itself. Then, the cutter apparatus is sent down the area and amputates the quad tendon graft with some force. Care must be taken to hold on to the graft while doing this because it will pop back.

The graft is then prepared on the back table. Endoscopic closure is then preformed. The quad tendon is harvested through small 2-cm incision. Multiple sutures are thrown and tied. Once complete, this is the final product of the repair of the quad tendon. Attention is directed toward preparing the graft, measured at 55 mm long for this patient, in particular, and 9 mm wide.

The suture apparatus is placed over the leading edge of the tendon and then one is placed at the other edge. Sequentially, these throws are made through the fiber tape to capture the ligament appropriately when traction is placed on either end so that the suture apparatus stays in place.

Arthroscopy is performed at this point and the mid-substance ACL tear is debrided. A cautery mark is made at the appropriate spot for placement at the anatomical location of the ACL on the femur. The guide is then placed into appropriate position, placing a 2.4-mm smooth pin into the region. Tunnel placement is well below the physis. The 2.4-mm pin is then removed and a 3.5-mm pin is drilled, knowing that we will not injure the physis. Then the flip cutter is placed into position by hand and deployed and a 25-mm tunnel is made. Sutures are then placed through the tunnel, pulled through, and held in position. The tibial tunnel is then made in an appropriate position. The flip cutter is also used in this area. First, the 2.4-mm pin, the 3.5-mm pin and then the flip cutter placed by hand are deployed and then a 15-mm socket is drilled. The adjustable loop button and graft are then pulled into the femoral tunnel, and the button is deployed. The graft is approximated in the femur and then the tibial portion of the graft is pulled into position. The button is then placed and the graft is tightened into position in full extension. This is the final view of the graft.

Potential complications following an ACL reconstruction in skeletally immature patients are defined. They might include graft failure, angular deformity, leg length discrepancy, and some weakness with knee extension. Leg length discrepancy and angular deformities are fairly minimal in patients with less than 5 years of growth remaining and are most often clinically insignificant. In patients with greater than 5 years of growth remaining, these deformities are more common with a trans-physeal technique. Quad tendon grafts have been shown to have less weakness with knee extension postoperatively than other graft types, and there is also less pain with kneeling compared with a bone-tendon-bone (BTB) graft.

We follow MOON ACL rehabilitation guidelines. Rehabilitation starts preoperatively with achieving knee extension, followed postoperatively by rehabilitation in 5 phases as shown. Return to sport and full activities is typically allowed around the 8- to 12-month mark, but it is dependent on many variables such as age, expectations, elimination of significant strength deficits, and type of sport they are returning to. Criteria for return to sport include no functional complaints or pain; confidence while running, cutting, or jumping at full speed; at least 85% contralateral values on hop test; and at least greater than 9 on the International Knee Documentation Committee question #10.

A recent systematic review on 10 studies with 482 patients reported that the re-rupture rate at 47 months of follow up was 9% in the all-epiphyseal group and 7.2% in the IT band over-the-top group. Angular deformity was reported in 3 patients in the over-the-top IT band group.

Another systematic review showed that 93% of patients were able to return to sport and 77% returned at preinjury level. The re-rupture rate was 5%.

Recently, the PLUTO group published a systematic review on early operative versus delayed operative versus nonoperative treatment of ACL injuries in the adolescent population. A total of 30 articles were included in the final qualitative analysis and 21 articles in the quantitative analysis. Nonoperative treatment in pediatric and adolescent ACL injuries resulted in unsatisfactory outcomes, including development of secondary meniscal tears, chronic knee instability, and low rates of return to sport. The most important finding in this study is that delaying ACL reconstruction in pediatric and adolescent patients for greater than 12 weeks significantly increased the risk of meniscal pathology to 4.3 times greater odds and the presence of irreparable meniscal tears by 3.2 times greater. Even so, early and delayed operative ACL reconstruction resulted in restoration of knee stability as assessed by KT-1000 arthrometry and no difference in Lysholm scores at follow-up.

The PLUTO group is a multicenter prospective cohort that has looked at this entity, and we have achieved 2-year follow-up with our data and we are now in the data analysis phase looking at multiple aspects of skeletally immature ACL reconstruction.