ACL Injury in Immature Athletes 

 

Don Johnson MD

Director Sports Medicine Clinic Carleton University

Associate professor Orthopedic Surgery University of Ottawa

Ottawa On, Canada KIS5B6

 

Introduction

Mechanism

Types of injuries – avulsions, mid substance tears

Diagnosis

Management

Controversy

Surgical options

Current consensus on surgical procedure

Outcome

 

Introduction

            With a greater number of young children participating in sports,  ACL injuries in the immature athlete are becoming more common.  Improvement in the diagnosis and imaging is leading to better recognition. Now the controversy of operative versus conservative treatment must be resolved. There is some reason to be cautious with surgical treatment after a case report by Koman has described a valgus deformity after ACL reconstruction.

This is the problem under consideration, the 8 year old athlete with an ACL tear and open epiphyseal plates.

 

Mechanism of Injury

            Similar to the adult, the non-contact pivot mechanism of injury is the most common mechanism of injury to the ACL.

The Pattern of Injury

            Children sustain both bony avulsions and mid-substance tears of the ACL. Partial tears can occur, but are uncommon. 

Diagnosis

            The diagnosis of the anterior cruciate ligament tear is by history, physical examination and imaging. The history and physical examination is similar to the adult situation. Most ACL injuries should be diagnosed by the clinical examination. Plain x-rays should be done to rule out tibial avulsion fractures. The MRI is performed to assess the damage to the meniscus and articular cartilage. The association of both an ACL tear and meniscal injury is a strong factor to favor surgical treatment.

 

Management of Injuries to the ACL in the skeletally immature athlete

The management of the bony avulsions is well documented in the pediatric literature. If the fracture is undisplaced, conservative treatment will suffice. If the displaced fragment reduces with extension, then cast immobilization is indicated. If the fragment does not reduce in extension, then arthroscopic reduction and internal fixation is indicated. The usual reason for the inability to reduce the fragment is that the intermeniscal ligament is flipped under the fragment preventing reduction. This ligament must be lifted out with a hook and the anterior aspect of the fragment will reduce. The fragment can be held in place with a standard ACL tibial guide, and 2 beath needles place up on either side of the fragment. Multiple sutures can be placed through the distal end of the ACL and retrieved with the beath needles. The sutures are tied over the bone bridge on the tibia. The large fragments can be secured with a small fragment AO screw either from below, or from the inside through a proximal mid-patellar portal.

The more controversial treatment concerns the immature athlete who sustains a mid-substance complete tear of the ACL. Should this be treated by early surgical reconstruction or conservatively, with activity modification, a functional brace and a view to late reconstruction after the physeal closure? The literature supports both of these treatment regimes. The main concern with the conservative program is that the athlete will continue to be active, and sustain a tear of the meniscus or damage to the articular cartilage that is irreparable.

Aichroth at ISAKOS in 2001 reported on 33 children treated over the 10 years from 1980-1990. 23 were treated conservatively and had disastrous results,  in spite of rehab, bracing and counseling for activity modification.  Meniscal and chondral injuries were noted during the follow up period and at maturity 10/23 showed degenerative changes by x-ray.

            The literature (Arnoczky) showed minimal physeal change when drilling a small tunnel through the growth plate and filling the tunnel with soft tissue. However, Letts et al, showed premature epiphyseal closure in mice when tibial tunnels were drilled.

            In the study by Aichroth, from 1990 to 2000, 55 children underwent ACL reconstruction with hamstrings. 47 knees were followed for 11-96 months.

The Tanner ages were:

Pre-puberty    6

At puberty    18

Adolescents 21

 

The results were:

 

A)Open physis

Pivot shift

0        - 27

1        –15

2        – 2

3        – 3

IKDC

A 45%

B 32%

C 17%

D  4%

 

B)Adolescents

IKDC

A 52%

B 20%

C24%

D  4%

The conclusion of this study was that there is a increase in damage to the meniscus and articular cartilage with conservative treatment, there is a greater re-rupture rate in children and the results are not as good as adults.

 

Transphyseal ACL reconstruction in the skeletally immature patient. Jeff Thompson

            This study was a retrospective chart review of 36 patients who were less than 15 years of age who were reconstructed with transphyseal tunnels on both sides. Of the 36 patients, 24 returned for clinical examination. The average age was 14 years.

The results:

Six of the 31 patients had failed. The KT arthrometer showed that 24 of 27 patients measured had a side to side difference of > 3 mm. The growth plates were open in 12 and partial open in 12. There was no angular deformity seen but some were short on the injured side.

The conclusion of the study was that the degree of open growth plates did not correlate with the outcome  and surgical reconstruction did not result in any angular deformity.

 

ACL reconstruction in the Skeletally Immature Patient.

            Peter Simonian MD presented an overview of ACL reconstruction in the skeletally immature patient. The concern is in the prepubescent patients of Tanner 1, age <10 years, and Tanner 2, age 10-13 where there is potential of premature epiphyseal growth plate closure and subsequent angular deformity with continuing growth. Simonian reviewed the existing literature and made the following points:

–        Post-pubertal patients who are nearing skeletal maturity should be treated as adults.

–        Treat partial tears conservatively, especially if stable

–        Drill holes as small as possible

–        Centrally placed tunnels are less likely to cause angular deformity with growth.

–        Only soft tissue grafts should traverse the physis. Bone blocks or fixation devices that traverse the physis are more likely to cause growth arrest.

–        Extra-articular procedures that require extensive dissection or fixation devices near the physis may be more damaging than transphyseal tunnels.

–        A careful follow up plan must be in place to monitor the growth and plan for intervention if premature physeal closure occurs.

Based on this knowledge, Simonian recommends using the hamstring tendons through a central tibial tunnel, and a normal endoscopic femoral tunnel. Proximal femoral fixation is done with an endobutton, and distally with sutures tied over a post.

These x-rays are 3 years post ACL reconstruction in an 8 year old athlete. Now, at 11 years of age, there is no premature closure of the epiphysis, and no malalignment. He has been active, the knee is stable and has not re-injured his knee. The reconstruction done with standard tibial and femoral endoscopic tunnels with a hamstring graft fixed on the proximal side with an endobutton and on the tibial side with sutures tied over a button.

This seems to be a more satisfying outcome compared to activity modification and the use of a brace.

A good comprehensive review of the topic is presented as a point counterpoint discussion by Barber, Saunders and Clarke in the Journal of Arthroscopy May/June 2000 Vol 16 No 4

References

1.                  Aronowitz, E.R., T.J.; Goode,J.R.; Gregg,J.R.; Meyer,J.S., Anterior cruciate ligament reconstruction in adolescents with open physes. Am J Sports Med, 2000. 28(2): p. 168-75.

2.                  Andrews M, Noyes FR, Barber-Westin SD: Anterior cruciate ligament allograft reconstruction in the skeletally immature athlete. Am J Sports Med 1994, 22(1) 48-54

3.                  Bisson, L.J., et al., ACL reconstruction in children with open physes. Orthopedics, 1998. 21(6): p. 659-63.

4.                  Koman JD, Sanders JO. Valgus deformity after reconstruction of the anterior cruciate ligament in a skeletally immature patient. A case report. J Bone Joint Surg Am 1999;81:711-715

5.                  Lo, I.K., et al., The outcome of operatively treated anterior cruciate ligament disruptions in the skeletally immature child. Arthroscopy, 1997. 13(5): p. 627-34.

6.                  Matava MJ, Siegal MG. Arthroscopic reconstruction of the ACL with semitendinosus-gracilus autograft in skeletally immature adolescent patients. Am J Knee Surg 1997, 10:60-69

7.                  Parker AW, Drez D, Cooper JL: Anterior cruciate ligament injuries in patients with open physes. Am J Sports Med 1994, 22(1): 44-47

8.                  Shelbourne, K. D. P., D.V.; McCarroll,J.R.: Management of anterior cruciate ligament injuries in skeletally immature adolescents. Knee.Surg.Sports Traumatol.Arthrosc., 4(2): 68-74, 1996.

9.                  Simonian, P. T. M., M.H.; Larson,R.V.: Anterior cruciate ligament injuries in the skeletally immature patient. Am.J.Orthop., 28(11): 624-628.

10.             Stadelmaier DM, Arnoczky SP, Dodds J, Ross H. The effect of drilling and soft tissue grafting across open growth plates. A histologic study. Am J Sports Med 1995;23:431-435.