Pediatric Anterior Cruciate Ligament Reconstruction

Davide Edoardo Bonasia, MD

Roberto Rossi, MD

Brian R. Wolf, MD, MS

Annunziato Amendola, MD

Dr. Bonasia or an immediate family member serves as a board member, owner, officer, or committee member of the Società Italiana Ginocchio, Artroscopia, Sport, Cartilagine,Tecnologie Ortopediche. Dr. Rossi or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of Biomet, DePuy, A Johnson & Johnson Company, Smith & Nephew, and Zimmer. Dr. Wolf or an immediate family member serves as a paid consultant to or is an employee of CONMED Linvatec; has received research or institutional support from the Orthopaedic Research and Education Foundation; has received nonincome support (such as equipment or services), commercially derived honoraria, or other non-research-related funding (such as paid travel) from Arthrex, Inc. and Smith & Nephew; and serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Science, the American Orthopaedic Society for Sports Medicine, and the Mid-America Orthopaedic Association. Dr. Amendola or an immediate family member has received royalties from Arthrex, Inc., Arthrosurface, and Smith & Nephew; serves as a paid consultant to or is an employee of Arthrex, Inc.; serves as an unpaid consultant to Extremity Development Corporation, First Ray, and Rubber City Bracing; has stock or stock options held in First Ray; and serves as a board member, owner, officer, or committee member of the American Board of Orthopaedic Surgery, Inc. and the American Orthopaedic Society for Sports Medicine.

INTRODUCTION

Although the exact incidence of anterior cruciate ligament (ACL) tears in skeletally immature patients is still unknown, the higher participation rate of children and adolescents in competitive sports led to an increase in ACL injuries in the past decade.¹ An increase in pediatric ACL injury of 2.3% annually over a 20-year period (1994-2013) has recently been reported.¹ The treatment of ACL tears in patients with open physes remains controversial and the debated issues mainly regard the surgical timing (early versus delayed reconstruction) and the most reliable operative technique.²

FIGURE 1 Illustrations show most commonly used techniques for pediatric ACL reconstruction. A, Intra-articular physeal-sparing technique; B, partial transphyseal technique, with proximal over-the-top positioning of the graft; C, partial transphyseal technique, with all-epiphyseal proximal tunnel drilling; and D, complete transphyseal technique.

Early ACL reconstruction may improve knee function, avoid strict activity modification in competitive athletes, and reduce progressive chondral and meniscal injuries, because of recurrent instability.²^,³ Nevertheless, a wide range of growth disturbances have been reported in animal and clinical studies.⁴^,⁵ Many techniques have been described for pediatric ACL reconstruction, in an attempt to reduce the risk of epiphyseal plate damage.² These can be divided into (1) physeal-sparing techniques (intra-articular, extra-articular, and combined intra-/extra-articular); (2) partial transphyseal techniques; and (3) complete transphyseal techniques (Figure 1).

Extra-articular and combined intra-/extra-articular procedures are nonanatomic types of ACL reconstruction.²^,³ Extra-articular tenodesis reported poor outcomes and for this reason did not raise in popularity.²^,³

Intra-articular physeal-sparing procedures have been developed to provide ligamentous restraint similarly to adult-type reconstruction, with all-epiphyseal femoral/tibial tunnels and without damage to the physes.²

The partial transphyseal techniques are a hybrid of the physeal-sparing and adult-type reconstructive procedures. The tibial or, most commonly, the femoral physis is left intact in an attempt to decrease the risk of growth disturbance. The graft is passed through a 6- to 8-mm drill hole that involves the physis for less than 5% of its cross-sectional area. The tunnel is placed more vertically than in the adult technique to further decrease epiphyseal plate damage.²

The femoral physis is left intact through an epiphyseal tunnel drilling, as described for the physeal-sparing procedures. Alternatively, the femoral epiphyseal plate is left intact with an over-the-top positioning of the graft. A partial transphyseal technique with proximal over-the-top positioning of the graft will be described in this chapter and shown step by step in the video. Complete transphyseal reconstruction is comparable to conventional adult-type reconstruction.²

Direct repair has been described as well for the treatment of ACL lesions, reporting inferior outcomes compared with reconstruction, most of all for midsubstance tears.²

PATIENT SELECTION

Clinical examination begins with a thorough history investigation. An audible pop at the time of injury and rapid onset of hemarthrosis are commonly reported by the patients. The mechanism of injury should be evaluated as well, with flexion-valgus-external rotation being the most common. The examination of an injured knee in children is more difficult than in adults.² The patients are often in acute pain, frightened, and unable to relax. Joint effusion should be noted. Bony and soft-tissue palpation should pinpoint the areas of tenderness and rule out possible bony and epiphyseal plate injuries. Meniscal signs should be noted, if present. Range of motion and instability in all planes should be evaluated. Lachman, drawer, pivot shift, and varus/valgus stress tests should be performed.

Conservative treatment entails range of motion exercises, muscle strengthening, proprioception, functional braces, and activity modification. Considering the lack of evidences regarding pediatric ACL reconstruction and the postoperative risks of growth disturbance,⁴^,⁵ conservative management with ACL reconstruction at skeletal maturity should always be mentioned as a possible treatment, most of all for inactive patients.

Surgery is usually recommended when (1) the conservative treatment fails (persistent effusion, pain, and recurrent episodes of instability); (2) the patient is unwilling or unable to modify the activity level; and (3) meniscal/chondral tears amenable to repair are associated with the ACL tear.² In older adolescents with closing physes (Tanner stage 5, males >16 years old, females >14 years old), a complete transphyseal technique with either hamstrings or patellar tendon can be used. In younger adolescents with open physes (Tanner stage <3, males <16 years old, females <14 years old), the technique remains a matter of preference of the surgeon. Either physeal-sparing or partial transphyseal techniques with hamstrings autograft can be used.

The authors’ preferred procedure in patients with open physes is a partial transphyseal technique with proximal over-the-top positioning of a semitendinosus tendon autograft.

In case of acute proximal or distal avulsion of the ACL, a pull-out technique can be used for repair, with or without autologous graft augmentation.

ACL reconstruction is contraindicated in tibial spine avulsions. These, when completely displaced or inadequately reduced, need to be reduced and fixed back to their bony bed with rigid fixation (screws) or pull-out techniques.

PREOPERATIVE IMAGING

Imaging evaluation of the knee begins with a routine four-view radiographic series (anterior-posterior, lateral, Merchant, and tunnel views) of both knees. Plain radiographs are used to rule out: (1) tibial and/or femoral epiphyseal fractures; (2) tibial spine avulsions; and (3) malformation in the tibial spine and/or femoral notch, which is a common finding in patients with congenital absence of the ACL. The amount of tibial and femoral physeal closure can be evaluated as well on routine radiographs.

MRI is fundamental in (1) demonstrating the ACL tear, when the diagnosis at physical examination is in question; (2) assessing combined soft-tissue injuries, when suspected; (3) evaluating the status of maturity of the femoral and tibial physes, when needed; and (4) evaluate the length of the ACL stump, for a possible direct repair (Figure 2).

VIDEO 20.1 Pediatric Anterior Cruciate Ligament Reconstruction. Davide Edoardo Bonasia, MD; Roberto Rossi, MD; Brian R. Wolf, MD; Annunziato Amendola, MD (18 min)

View Quicktime Video

Video 20.1

FIGURE 2 Preoperative MRI of an ACL tear in a patient with open physes. A, ACL tear (white arrow); B, impaction edema (white circles) and lateral meniscus posterior horn tear (white arrow) associated with the ACL tear.

PROCEDURE

Room Setup/Patient Positioning

The patient is administered general (or spinal, in older patients) anesthesia and positioned supine on the operating table. A tourniquet is positioned on the proximal thigh. Intravenous antibiotic prophylaxis is performed. The operative leg is stabilized with an arthroscopic leg holder and the distal extremity of the bed is dropped down. The table is slightly reflexed to achieve 10° of hip flexion and reduce the tension to the neurovascular structures of the anterior thigh.

Alternatively, a lateral post can be used with the bed intact, to obtain leg abduction away from the table and knee flexion up to 120°.

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