The anatomy of the proximal tibia in pediatric and adolescent patients: implications for ACL reconstruction and prevention of physeal arrest

Abstract

Although the treatment of anterior cruciate ligament (ACL) tears in skeletally immature patients is still controversial, several studies have advocated ACL reconstruction in selected patients to prevent secondary injury. The proximal tibial physis is a structure at risk during ACL reconstruction in young patients, and physeal growth complications have been reported after surgery in this area. The relationship between the ACL and the proximal tibial physeal/apophyseal regions is poorly understood. This study examined the MRI anatomy of the ACL and the proximal tibia apophysis and epiphysis. MRIs of 59 skeletally immature knees were reviewed (Average age = 12.75 years, range 6-15) to define the anatomy of the epiphyseal and apophyseal regions. Measurements were recorded in three parasagittal planes: (1) at the lateral border of the patellar tendon, (2) the lateral edge of the ACL insertion, and (3) the medial edge of the ACL insertion. A single three-dimensional (3D) computed tomography (CT) scan was used to evaluate the position of standard drill holes used in ACL reconstruction to assess for potential degree of injury to the epiphyseal and apophyseal growth plates. In the parasagittal planes, the average height of the epiphysis was 19.6, 20.7, and 21.5 mm at the lateral border of the patellar tendon, the lateral border of the ACL, and the medial border of the ACL, respectively. At the level of the same landmarks, the apophysis extended below the physis at an average of 20.2, 16.8, and 7.0 mm, respectively. Expressed as a percentage of epiphysis height this was an average of 104, 82, and 33%, respectively. Examination of 3D CT images revealed that variations in drill hole placement had effects on the volume of injury to the proximal tibial physis and apophysis. Drill holes that started more medial, distal, and with a steeper angle of inclination reduced the amount of physis and apophysis violated when compared with holes placed more lateral, proximal, and with a shallow angle of inclination. The proximal tibial physis and apophysis is vulnerable to injury by drill hole placement during ACL reconstruction in skeletally immature patients. This paper defines the anatomic relationship of the apophyseal and epiphyseal regions of the physis in the proximal tibia. The volume of injury to the physis can be reduced by avoiding tunnel placement that is too lateral or too proximal on the tibia. A better understanding of these relationships may guide the placement of tibial drill holes, which have a lower risk of producing significant physeal damage.

Anterior cruciate ligament recostruction with bone-patellar tendon-bone autograft in Tanner 3 stage patients with open physes

“…In accordance with the literature, we conclude that to minimize the risk of damaging the open physes, it is necessary to perform central tunnel of less than 10 mm [18]. We also point out that drilling more vertical tunnels (50-551) when bone-tendon-bone autograft has been chosen to avoid partial epiphysiodesis, gives good functional and isometric results [25,26]. All our patients returned to their preinjury level of activity and athletic participation.…”

“…Our study is focused on the importance of the placement of the tibial tunnel. The influence of the diameter of the tunnel on the potential damages of the growth plate is well known [18,25,26]. The importance of the angle of the tibial tunnel has been pointed out only by radiological studies, which have underlined that the more the tunnel is drilled vertically, the lower is the risk of potential damages [25,26].…”

“…Holes of 7-9 mm in diameter were drilled across the proximal tibial and distal femoral physes (30 mm of length in the femur) to avoid damaging the open physes [25,26]. The grafts were fixed to the distal femur with two pins (rigid-fix system) and to the proximal tibia with an interference reabsorbable screw.…”

“…Important radiological studies about the anatomy of the tibial growth plate using three-dimensional MRI and computed tomography scans have been performed during earlier years showing the importance of the diameter of the tunnels and their angle to avoid physeal damage [25,26]. The less the diameter and more vertical the tunnel, the lower is the risk.…”

Die großen Apophysen

“…Die in der deskriptiven Anatomie wenig beachtete und in der funktionellen Anatomie noch nicht beforschte Tibiaapophyse [26] The great apophyses. Functional strain and relevance Abstract Background.…”