Short review series
ACL avulsion fractures in children. Part I- Overview
Series Author – Dr AK Shyam MS Orth
ACL avulsion fractures in children. Part I- Overview
Series Author – Dr AK Shyam MS Orth
Introduction:
These injuries were first described by Poncet in 1875 [1]. In adults the anterior cruciate ligament directly inserts on the tibia bone [2]. However in children a sleeve of perichondrium connects the ligament to the epiphyseal cartilage, thus making this as the weakest part of the link. The ACL avulsion injuries are generally secondary to either bicycle or other sports injuries and are commonly seen between 6 to 15 years of age [3]. Most commonly the ACL is avulsed distally from the proximal tibial eminence. Avulsion from femur and simultaneous avulsions from both sites are also reported [4,5,6]. These injuries may be associated with other ligament injuries and especially meniscal injuries [7,8].
These injuries were first described by Poncet in 1875 [1]. In adults the anterior cruciate ligament directly inserts on the tibia bone [2]. However in children a sleeve of perichondrium connects the ligament to the epiphyseal cartilage, thus making this as the weakest part of the link. The ACL avulsion injuries are generally secondary to either bicycle or other sports injuries and are commonly seen between 6 to 15 years of age [3]. Most commonly the ACL is avulsed distally from the proximal tibial eminence. Avulsion from femur and simultaneous avulsions from both sites are also reported [4,5,6]. These injuries may be associated with other ligament injuries and especially meniscal injuries [7,8].
Classification:
Myers and McKeever classified this avulsion fracture by degree of displacement [9]:
Type I: minimally displaced, with only slight elevation of the anterior margin;
Type II: hinged posteriorly, producing a beak-like appearance on the lateral radiograph;
Type III: completely displaced and elevated from its bed.
Type III fractures may be further classified. IIIa fractures are displaced but not rotated and IIIb fractures are displaced and rotated.
Commonly the fractures are of type II or III.
The radiographs underestimate the size of the fragment due to presence of radiolucent cartilage [similar to as seen in lateral condyle humerus fracture]
Mechanism of injury: valgus stress on flexed knee or hyperextension
Management options:
Type I injuries – conservative management with cylinder cast in 20⁰ flexion (position of relaxed ACL) [10,11]
Type II injuries – Reduce by extension and pressure on the lateral femoral condyle and if reduced are immobilized with cast in extension [12,13]. The reduction can be facilitated by joint aspiration. Few authors immobilize the limb in flexion for a similar reason of decreasing the tension on ACL.
There are several difficulties associated with arthroscopic reduction of type II and III fractures including potential meniscal entrapment, nonreduction of the fracture site, and bowstringing of the fragment between ACL and anterior meniscus and laxity of the ACL tissue after repair [12,14]
An unreduced type II fracture should be treated as displaced type III
Type III fracture – closed reduction and arthroscopic fixation is current gold standard. Two different modalities like screw fixation and non screw fixation eg wire loop, absorbable sutures, suture anchors etc are used and will be elaborated in following parts of this review series.
Next in this series – ACL avulsion injuries treated with Sutures – Evidence for advantages and disadvantages
1. Burstein DB, Viola A, Fulkerson JP. Entrapment ofthe medial meniscus in a fracture of the tibial eminence. Arthroscopv 1988 ; 4 :47
2. Matz SO, Jackson DW. Anterior cruciate ligament injury in children. Am J Knee Surg,1988;1:59.
3. Nichols JN, Tehranzadeh J. A review of the tibial spine fractures in bicycle injury. Am J Sports Med, 1987;15:172.
4. Eady JL, Cardenas CD, Sopa D. Avulsion of the femoral attachment of the anterior cruciate ligament in a seven-year-old child. J Bone Joint Surg Am, 1982;64:1376.
5. Robinson SC, Driscoll SE. Simultaneous osteochondral avulsion of the femoral and tibial insertions of the anterior cruciate ligament. J Bone Joint Surg Am, 1981;63:1342.
6. Marina VR, Taco G, Jacob C, Diederik G. Femoral avulsion fracture of the anterior cruciate ligament in an 11-year-old girl. Injury Extra (2006) 37, 129—132
7. Chandler JT, Miller TK. Tibial eminence fracture with meniscal entrapment. Arthroscopy. 1995 Aug;11(4):499-502.
8. Kocher MS, Micheli LJ, Gerbino P, Hresko MT. Tibial eminence fractures in children: prevalence of meniscal entrapment. Am J Sports Med. 2003 May-Jun;31(3):404-7.
9. Meyers MH, McKeever FM. Fracture of the intercondylar eminence of the tibia. J Bone Jt Surg Am 1970;52A: 1677–84.
10. Oostvogel HJM, Klasen HJ, Reddingius RE. Fractures of the intercondylar eminence in children and adults. Arch Orthop Trauma Surg. 1988;107:202–247.
11. van Loon T, Marti RK. A fracture of the intercondylar eminence of the tibia treated by arthroscopic fixation. Arthroscopy. 1991;7:385–388.
12. Lowe J, Chaimsky G, Freedman A, Zion I, Howard C. The anatomy of tibial eminence fractures: arthroscopic observations following failed closed reduction. J Bone Joint Surg Am. 2002 Nov;84-A(11):1933-8.
13.Moran M, Macnicol MF. II Paediatric epiphyseal fractures around the knee. Curr Orthop 2006;20(4):256–265.
14. Siparsky PN, Kocher MS. Current concepts in pediatric and adolescent arthroscopy. Arthroscopy. 2009 Dec;25(12):1453-69.
