ACL in Children
Anterior Cruciate Ligament Reconstruction in Skeletal immature patients
Anterior cruciate ligament injuries were once considered rare in pediatric athletic population. Now a days because of marked rise in youth athletic participation, there is a threefold increase in the rate of ACL reconstruction in patients under the age of 20 years over past 2 decades.
During olden days, pediatric ACL injuries were treated by nonoperative management till they achieve bone maturity. Then it was followed by ACL reconstruction after completion of bone growth. This protocol was followed to prevent injury to growth plate which may cause growth disturbance. However, latest literatures have highlighted problems associated with of nonoperative or delayed surgical treatment of pediatric or adolescent knees.
A latest meta-analysis shows that, the operative reconstruction to have superior outcomes with respect to patient outcomes, knee instability, and development of additional injuries. It also showed that, delaying reconstruction more than 12 weeks was associated with increase in medial meniscal tears and medial and lateral compartment chondral damage. Treatment strategies of pediatric ACL tear should respect growing physes. A minimal growth of around less than 1 cm/ limb segment remains around the knee after the age of 12-13 years in girls (i.e., 1 year after menarche) and the age of 14 years in boys.
Commonly used techniques for pediatric ACL
- Physeal-Sparing ACL reconstruction: lliotibial Band Combined Extra and Intra-articular Reconstruction
In prepubescent kids (Tanner stage 1-2, bone age less than 12 years in male and 11 years in females) iliotibial Band Combined Extra and Intra-articular ACL Reconstruction by modified MacIntosh technique is used.
This is very beneficial because,
- it eliminates the need for bone tunnels and their associated risk of growth plate injury.
- It makes revision ACL reconstruction simpler as it avoids the commonly used autograft and preserves original bone stock
- and the LET procedure gives a secondary restraint to knee instability.
- This is a nonanatomic reconstruction. (but still restores knee kinematics)
Final outcomes of this technique are excellent. Patients will be able to return to their preoperative sporting activities and growth disturbances due to physeal injury are not seen.
- Physeal-Sparing (growth plate preserving): AII-Epiphyseal ACL reconstruction
This is one more option for ACL reconstruction in prepubescent children. In this technique hamstring autograft used, fixation done by creating all-epiphyseal sockets with epiphyseal fixation. Pre-tensioning and circumferential compression of the graft is done to minimize the bone loss.
- Physeal Respecting: Partial Transphyseal ACL Reconstruction
This is a reasonably good option for borderline pubescent children (tanner stage3) nearing skeletal maturity but have only limited growth remaining. Technique includes using all-epiphyseal femoral tunnel and a vertical and centrally located tibial tunnel.
Main idea behind this avoiding injury to the lateral distal femoral growth plate and vertical and centrally located tibial tunnel minimizes injury to tibial growth plate. Many studies have demonstrated clinical outcomes of this technique, with no significant length or angular deformity.
- Physeal Respecting: Transphyseal ACL Reconstruction
This is good option for older children and adolescents with little growth remaining. (Tanner 3; Bone age 12 years in females, 13 years in males) This is done by removing a small amount of physeal tissue and fixing soft-tissue grafts in metaphyseal area.
Both tibial and femoral tunnels are created in the standard transphyseal technique. Special care is taken so that only small physeal tissue is violated. Tunnels are created with more vertical trajectory; this leads to minimal physeal damage than oblique tunnels. Recent studies say that removing less than 7% area of growth plate is not associated with growth disturbances.