INTRODUCTION
Injuries to the ACL in children and adolescents are becoming an increasingly common
clinical presentation (1,6,19,26,28,38,39,95,141,153).
The increased participation in high-risk sports at younger age and the increased interest in the
cruciate ligaments on the part of the surgeon requires an improvement in the means of
managing such injuries (6,58,108,147).
Classicaly these ligaments injuries were well tolerated and could wait until skeletal maturity
to be surgically treated.
But controlling the activities of children is very difficult and quite impossible and more and
more studies have shown that the incidence of repeat injuries and subsequent meniscal
damage is very high in non surgically treated children.
EPIDEMIOLOGY
Injuries to the cruciate ligaments of the knee in children and adolescents have only recently
received increased attention.
Clanton in 1979 noted one lesion per year ; frequency of such tear is six per year in recent
studies. This is due to an increase participation of children in high-risk sports and an
improvement of our diagnostic tools :arthroscopy,MRI.
Mid-substance tears of the ACL have previously been reported as a rare injury in children.
However the incidence of these injuries in children and adolescents regularly increases, but
faster in children between 13 and 15 years old (30 cases per year in the litterature),some cases
are reported in 7 to 8 y.o. children,and even one case in a 3 year-old child.
 DeLee in 1983,treated 3 ACL ruptures in children and 335 in adults during a 3-year
period (0.9%)
 Lipscomb,in 1986,operated on 24 ACL ruptures in adolescents out of a total of 710 ACL
tears (3.4%).
 Mc Carroll et al, in 1988, reported on 57 patients under the age of 14 years with anterior
cruciate ligament tears out of a total of 1722 anterior cruciate ligament injuries, making the
incidence of adolescent involvement 3.3 %.

Only 3 to 4 % of ACL tears occur in skeletally immature patients.
In addition to injuries of the ACL itself, it is appropriate to discuss fractures of the
intercondylar eminence of the tibia.
Fracture of the anterior tibial spine mainly occur in children between 10 and 12 years old (25
cases per year in the litterature), with a second peak of frequency in children of 14-15 years
old (45 cases per year in the litterature).
As yet no male of female predominance has been shown for ACL injuries in skelatally
immature patients.
In Lipscomb’s report, 21 of 24 patients were boys.
In the study of Mc Carroll, the number of boys and girls was exactly the same.
16 of the 18 patients of Mizuta were girls.
Diagnostic methods have also improved.

In 1987, Skak and associates analysed 91 consecutive knee injuries in 89 children
aged 0-14 years..Children with ligament injuries had a median age of 12 years. No
lesions of the cruciate ligaments without bony avulsion were diagnosed. There were
18 fractures of the tibial spine.But the authors didn’t perform any examination under
anaesthesia,arthroscopy nor stress X-rays or MRI.

In 1987, Eiskiaer and Larsen noted in their review of arthroscopy of the knee in over
300 children, that of 25 children with hemarthrosis of the knee, 9 had sustained a
partial or complete injury to the ACL (36 %).

In 1992, Stanitski reported that of 70 young athletes with hemarthrosis following knee
injury, 47% of the children and 65% of the adolescents had sustained an injury to the
ACL as identified at arthroscopy.
MRI is now as common as arthroscopy was in the early eighties (5,116,149).Several authors
(28,111,154) demonstrated that clinical diagnosis is less reliable in children’s knee injuries
than in adults,wiyh 45 to 77% of errors.
PHYSIOPATHOLOGY
In children, the knee ligaments are known to be stronger than the adjacent physeal plate (139).
Trauma that might rupture the ACL in an adult will usually cause an avulsion fracture because
the incompletely ossified tibial eminence fails before the ligaments.
These are the most common patterns of injuries :
1) Bony avulsion of the intercondylar eminence of the tibia
2) Avulsion of the femoral and/or the tibial attachment of the ACL
3) Complete mid-substance tear of the ACL
Lesions of the ACL are a complete mid-substance tear in 74 % of the cases, a proximal
desinsertion in 17 % and a tibial avulsion without bony lesion is noted in only 9 % of the
cases.
4) Partial tears of the ACL seem more common in children than in adults
(6,13,45,81,118,147,166).Angel reported 18 partial tears among 27 ACL ruptures(6),and
Stanitski a rate of 65% partial ruptures (147).Noyes demonstrated that 38% of the partial tears
became secondarily complete (118).Although functional future looks better in partial tear than
in complete,there is no long follow up report of such lesions in children (6,81).
CLASSIFICATION OF AVULSION FRACTURES OF THE ANTERIOR TIBIAL
EMINENCE
Meyers and Mc Keever developed the classification into 3 types based on the amount of
displacement of the avulsed fragment on the lateral radiographic view :
TYPE I : the avulsed fragment of bone is minimally displaced, with only slight elevation of its
anterior margin.
TYPE II : had greater displacement. The anterior third to half of the avulsed fragment is
elevated from its bone bed.
TYPE III : the avulsed fragment is completely elevated from its bed on the tibia with total
lack of bony apposition. In some cases the avulsed fragment is rotated (type III +).
Zaricznyj added an additional category IV which included comminution of the displaced
fragment.
MECHANISM OF INJURY
Rinaldi and Mazzarella showed that prior to fusion of the tibial growth plate, the intercondylar
eminence offers less resistance to traction forces than does the ACL itself.
Injuries that result in stretching or progressive disruption of the ACL in adults may result in
an avulsion of the tibial eminence in children.

Avulsion fractures of the anterior tibial spine :
The most common mechanism of injury is a fall from a bicycle (37 %).
Meyers and Mc Keever stated that a child who has a swollen knee after falling from a bicycle
should be considered to have a fracture of the intercondylar eminence until proven otherwise.
This injury can also occur following a fall while participating in sports such as running or
playing baseball or american football (18 %).
In opposition the incidence of anterior tibial eminence fracture in soccer is only 2 % in
children.
The mechanism of such an injury is not rotation but mainly hyperextension or direct contact
on the knee.

Mid-substance tears of the ACL :
They result of twisting or hyperextension deceleration injury in sporting activities mainly in
adolescents : ski (22 %), american football and basketball (70 %).
Severe knee ligament disruption injuries tend to be associated with motor vehicular accidents.
ASSOCIATED LESIONS
Meniscal lesions are present in 8% of anterior tibial spine fractures,and 64% of midsubstance
ACL tear in children and adolescents.
Systematic arthroscopy has shown that meniscal injuries were associated to ACL rupture in 6
to 100% cases. Comparison of different series showed that medial and lateral meniscal lesions
occured with the same frequency. Compilation of 190 cases reported in 11 studies, showed
that a meniscal injury, either lateral or medial was associated in approximatively 50% of ACL
acute injuries (5,6,47,58,77,102,108,124,126,141,166).
AUTHORS
N
LATERAL MENISCUS
MEDIAL MENISCUS
Andrews
Angel
Engebretsen
Graf
Janarv
Menou
Mizuta
Parker
Patel
Scammell
Williams
8
31
8
12
28
33
18
6
33
4
9
4
4
9
1
4
3
9
5
5
6
0
3
4
3
9
8
2
8
4
5
Angel stated that these immediate meniscal lesions were more frequent in complete ACL tears
than in partial . He reported 4 meniscal lesions in 18 partial ACL tears and 5 meniscal lesions
out of 7 complete ACL ruptures.
In 1992 ,Graf et al. evaluated 12 skeletally immature patients with acute,intrasubstance tears
of the anterior cruciate ligament and open physis for meniscal pathology.Arthroscopy
confirmed 8 meniscal tears (4 medial,4 lateral) in 6 patients (50%).4 patients with repairable
menisci underwent arthroscopic meniscal repair and stabilization (2 extraarticular iliotibial
band tenodesis and 2 intraarticular semitendinosis tendon).8 patients received rehabilitation
and returned to sports with a brace.They all developped instability within 7 months.7 patients
sustained further meniscal damage an average of 15 months after initial injury.
In 1996,Williams et al. retrospectively reviewed 24 children under 15 y.o. with suspected
meniscal or nonosseous ACL injury.56 % of the patients with nonosseous ACL tear had
coexistent meniscal lesions (5 medial,9 lateral).21% of the meniscal tears were peripheral and
showed evidence of spontaneous healing at time of arthroscopy.
In 1997, in the Trousseau hospital’s serie, 6 of the 13 midsubstance tears are associated with a
medial meniscal tear,and 2 out of the 9 femoral avulsions.
Meniscal pathology is commonly associated with ACL tears in skeletally immature
patients.Brace management did not prevent instability or new meniscal tears .
Numerous anatomical reports (Arnoczky,Shin,Clark)suggest that the meniscus in the young
patient up to the age 10 years,has a better blood supply and greater cellularity,and therefore
greater potential for healing if torn.
Associated osteochondral lesions are very few in children (Patel 3/33,Andrews 1/8,Stanitski
7%).
Concomittent collateral ligament lesions are less numerous than in adults (Patel
9/33,Engebretsen 3/8,Angel 2/31).
NATURAL HISTORY AND CONSERVATIVE TREATMENT
Little information is available on the natural history of these injuries in skeletally immature
patients, although there have been small or short-term studies of conservative treatment.
Long-term studies and prospective datas are not yet available to give the answers to several
important questions.

Avulsion of the intercondylar eminence :
Even though the fracture heals in its anatomical position, mild degrees of anterior cruciate
ligament laxity often will result by lenghthening of the ACL.
No evidence of arthrosis was found on radiographs but longer follow up is needed.

Mid-substance tears of the ACL :
There is no evidence to suggest that knee ligaments in children have the potential to heal
any better than those in adults.
The outcome of the conservative treatment of anterior cruciate ligament injuries in
children has been disappointing.
 Kannus and Järvinen reviewed 32 adolescents with an age range of 10-18 years with knee
ligament injuries. All the patients were treated conservatively by plaster immobilization and
followed up for an average of 8 years. The long term outcome of unrepaired complete midsubstance tears was poor and not acceptable.

Mc Carroll and associates reported on 40 skeletally immature patients with ACL tears.
16 were treated conservatively. 9 patients in the conservative treatment group ceased
sports participation. Another 4 patients sustained at least one reinjury. Only 3 patients
appeared to be able to participate in sports without significant problems.
Mc Carroll further reported on a group of 73 junior high school athletes with midsubstance ACL tears treated with conservative management and/or patellar tendon graft
reconstruction.
Every individual in the conservatively treated group reported an episode of giving way
and 94 % developed meniscal pathology. Mc Carroll concluded that conservative
management often fails and predisposes the patient to subsequent knee pathology.
 Mizuta et al described the results of conservative treatment for complete mid-substance
tears of the ACL in 18 skeletally immature patients followed for a minimum of 36 months.
All patients had symptoms when reviewed. The modified Lysholm score showed 1
excellent, 1 good, 8 fair and 8 poor with a mean score of 64.3. Only one patient had
returned to her preinjury level of athletics. The remainder had to modify their activities
because of instability and six required late ACL reconstruction. Secondary meniscal tears
were confirmed in 6 patients, and 3 more had the clinical signs of a tear at follow-up (50
%). Using Fairbank’s criteria, radiological evidence of degenerative changes was found in
11 of the 18 patients (61 %) at an average of 51 months after injury.
Mizuta concluded that the results of non-operative treatment for ACL injuries in this age
group are poor and not acceptable.
 Patel and Aichroth reported an interesting prospective study of 33 patients who sustained
ACL injury in their childhood or adolescence. 14 children had concomitant meniscal tears(8
medial and 6 lateral).
27 had a mid-substance ACL tear and 6 an avulsion of the femoral attachment.
All patients were initially treated by rehabilitation bracing and counselling on activity
modification. 10 children had undergone ACL reconstruction at skeletal maturity.
The majority of the children were unable to participate in competitive or recreational
sports in view of recurvent giving way, pain and effusion.
They concluded that children with anterior cruciate deficient knees appear to be more
prone to repeated meniscal injuries.

In 1989,we reported on 18 ACL tears in children ranged from 12 to 15 y.o
11 children were treated at the acute stage,7 were chronic laxity.11 were due to sport
injury (6 ski injuries).
Among the 11 acute cases,there were 4 proximal desinsertion,2 tibial avulsion and 5 midsubstance tears with dilaceration.8 patients conservatively treated were followed during 5
years.In 5 cases the result was bad with anterior laxity,and positive pivot-shift.
The 7 chronic patients were surgically treated after skeletal maturation (MacIntosh
procedure),with good result.In these cases,we observed that the fonctionnal instability
ocurred in less than 18 months after the initial injury.

In 1997,we reviewed at a 3 year follow-up,11 conservatively treated ACL tears out of 13
with 4 poor anatomical and functional results.
Despite « aggressive » physiotherapy, with quadriceps and hamstrings strenghening and
proprioceptive rehabilitation, results of non operative treatment of ACL ruptures in children
and adolescent are usualy poor (6,99,108,124,126,149).The regimen of post-injury
immobilization does not have any influence on the evolution. Mizuta treated his patients
with a long-leg cast for 3 weeks, with progressive return to full weight bearing in 6 weeks,
when MacCarroll did immediate rehabilitation with bracing during sport activities. Results
were even worse after complete immobilization.
The knee function and activity level seem to deteriorate with passage of time.
TREATMENT
The treatment of an ACL disruption in a patient with open physis is controversial.Most
surgeons prefer to delay surgical treatment until growth at the distal femur and proximal tibia
is near completion and an isometric reconstruction can be safely performed.
But the results of conservative management of these ACL tears is often poor and not
acceptable.Moreover,meniscal lesions are associated in more than 50% of the cases.
Therefore,we have to develop a concept of surgical management of these young
patients.But,the surgical procedure must avoid damage to the physeal plates when there is a
significant growth potential remaining.The age of the child and the growth remaining in the
limb must be known before the type of surgical treatment can be selected.
Accurate determination of growth remaining in the distal femoral and proximal tibial
epiphysis requires evaluation of skeletal age,using the Greulich-Pyle atlas (63),and evaluation
of skeletal maturity using the Tanner-Whitehouse method(156).In this method,the
development of secondary sex characteristics produces a « maturity score » which determines
for each patient whether skeletal growth is advanced or delayed.
Patients determined to have less than 1 cm of growth remaining at the distal femur and
the proximal tibia can be treated as adults,drilling holes across the growth plates with no
concern about the development of significant limb deformity.
Patients with more than 1 cm of growth remaining must be treated very carefully.The
consequences of drilling tunnels through the growth plates cannot only be a leg length
discrepancy,but also an angular deformity : varus,valgus and/or recurvatum.
About this concern,I will report our bad experience with a few extraarticular procedures
(Lemaire) we unfortunately performed in the early eighties.A valgus deformity
appeared,probably due to the compression of the growth plate of the lateral condyle because
of the tenodesis effect of the iliotibial band across the plate.In 1 patient we had to perform a
varus femoral osteotomy and an ACL intraarticular reconstruction (bone-patellar tendonbone) at the age of 18.
SEVERAL OPTIONS OF SURGICAL TREATMENT

Primary repair
In 1983,DeLee reported on 3 midsubstance tears of the ACL in 9,11 and 12 year-old
patients who all underwent primary repair by the technique of Marshall. At follow-up
examinations 2 years after operation,2 patients complained of knee giving way in
athletics.Both of these patients had a positive pivot shift test.The third one had no
complaints of instability and no pivot shift test but he had the shortest follow-up (20
months) and was not as athletically active as the other two patients (39).
In 1988,Engebretsen followed 8 adolescents 3-8 years after primary suture of a
midsubstance tear of the ACL. Only 3 patients had good function and 5 were unstable.He
concluded that the Palmer-Marshall technique should not be used in children and
adolescents (47).
In 1997,we reviewed 29 patients : 13 mid-substance tears,9 femoral and 7 tibial
avulsions.6 of the 9 femoral avulsions were primary repaired, leading to 3 poor
anatomical results (50 %),6 of the 7 tibial avulsions were reinserted with 6 excellent
results (100 %) with a 3 year follow-up.2 out of the 13 mid-substance tears were
primarily repaired (Marshall technique suture without augmentation) with a poor
anatomical result.

Extraarticular procedure
The use of extraarticular procedures in adult has diminished drastically because the
efficacity has not been proven,and similar results can be expected in the skeletally
immature athlete.In 1988 McCarroll et al. performed extraarticular iliotibial band
tenodesis on 8 acute and 2 chronic ACL injuries.5 of whom had mild recurrent
instability(97) .In 1996 ,the same author recommend intraarticular reconstruction(141 bis)
In 1992 Pearl and Bergfeld concluded that extraarticular
procedures are not indicated in the skeletally immature
patient because of a high risk of damaging the growth plate
by the use of fixation devices as well by the interruption of
physeal vessels that occurs during periosteal stripping (127
bis).

Intraarticular reconstruction with allograft
The procedure is infrequently used because of the risk of disease transmission and the
question of immunogenicity.Andrews and Noyes reviewed 8 patients (10 to 15 y.o.) with
a mean 58 months follow up,who had reconstruction with fascia lata or Achilles tendon
allograft tissue (1 fresh-frozen,2 irradiated,5 freeze-dried).A 7mm drill hole through the
tibia and the over-the-top position in the lateral femoral condyle were utilized.The
difference in lower limb length was not significant.On KT-1000 arthrometer testing,5
patients had less than 3 mm of increased of AP displacement,and 3 had between 3 and 5
mm.The final overall ratings were 6 excellent,1 good,and 1 fair(5).

Reconstruction with hamstring tendons
In 1986, Lipscomb and Anderson reported good fonctionnal and anatomical results. 23
patients out of 24 returned to sport. They reported some limb lengh discrepancies, superior
to 5 mm in 7 cases, due to the stapling technique of both the tibial and the femoral physis.

Reconstruction with patellar tendon
- Bergfeld described the « tomato stake » procedure using the medial one third of the patellar
tendon without harvesting the tibial insertion. The graft is often too short.
- In France, Bonnard harvests the central one third of the patellar tendon with periosteal
sleeves on the tibial tuberosity and the patella. The distal graft is stapled in a tibial groove, the
other end is secured in a femoral tunnel and stiched to the femoral periost. Bonnard reported
his results on 7 patients : KT 1000 side to side is less than 2 mm in 4 cases and 3 mm
maximum in 3 cases.

Reconstruction with quadriceps tendon and bone tunnels
Quadriceps tendon graft is used for several years in primary ACL reconstruction in adults
by some authors (H.U. STAUBLI and John FULKERSON) (149 bis).Structural
properties of the quadriceps tendon and the patellar tendon are equal.As H.U.Staubli did
on 10 children ,we began to utilize the quadriceps tendon to reconstruct the ACL in
children.In this technique the anterior tibial tuberosity is not harvested,avoiding the risk
of iatrogenic recurvatum.The blind femoral tunnel arthroscopically assisted technique is
used .The 6 mm femoral tunnel is drilled in the middle of the posterior part of the
intercondylar notch.The patellar bony fragment is secured in the femoral blind tunnel
with an absorbable interference screw (polylactic acid),and the quadriceps tendon is
either secured in the tibial tunnel by an absorbable interference tendon screw or tied on
the tibial cortex by a screw and a washer.
FRACTURES OF THE ANTERIOR TIBIAL EMINENCE
In 1996 Courtivron reviewed 13 papers published in the last 25 years (1970-1995),reported
417 fractures of the intercondylar eminence of the tibia (18)
Fracture of the anterior tibial eminence or spine in childhood is the equivalent of the anterior
cruciate ligament (ACL) rupture in adults.It is a bony avulsion of the ACL,and the mechanism
of injury is the same.
Classification utilized is always the Meyers and MacKeever’s classification into 3
types,completed by the type 4 of Zaricznyj.
Tibial eminence fractures may have associated medial collateral ligament injury and
associated meniscal lesion.The rate of these meniscal lesions is much lower (8%) than those
encountered associated with midsubstance ACL tears (64%).The anterior horn of the medial
meniscus can also be stuck under the osteocartilagenous displaced fragment,preventing
anatomical reduction.
Past studies have been nearly unanimous in recommending cast immobilization as the sole
treatment for McKeever type 1 fractures,and reduction and internal fixation for type 3
fractures,but have differed on what treatment is best for type 2 fractures.
Reduction can be open or arthroscopic,fixation can be done with pins,screws or
sutures.Results are the same.
The incidence of residual ACL laxity following treatment of tibial eminence avulsions is
drawing more attention.In 1970,Meyers and McKeever found that only 1 of 35 patients had
residual anterior laxity.More recent studies (Smith,Gronkvist) found 1/3 of patients with
anterior laxity.
In a long-term follow-up (mean 16 years) of 61 children with anterior tibial spine
fractures,subjective knee function (Lysholm score) was excellent or good in 87% of the
subjects.Pathological knee laxity (3mm or more of side to side anterior Lachman measured
with the KSS system) was found in 38% of the patients (76).Age at injury did not influence
the outcome.There was no indication that young children can eliminate slackness of the ACL
by further growth.Only in type 3 fractures there was a correlation between fracture
displacement after healing and knee laxity,as well as between knee laxity and Lysholm score.
The 38% of knee laxity can be explained by a simultaneous damage to the ACL proper,in the
form of plastic elongation or partial ruptures as demonstrated experimentally by Noyes et
al.Therefore,radiographic measurement of fragment displacement may not be appropriate for
prediction of future knee laxity.
For these reasons we advocate to manage these lesions as true ligament tears and not fractures
and :
1.test the anterior laxity under anesthesia
2.obtain a good tension of the ACL at the end of the procedure
The reduction can be arthroscopically guided or open,it may be not sufficient to do an
anatomical reduction and sometimes the fragment will have to be countersink to get the
proper tension of the ACL.
In some cases,simultaneous partial ruptures of the ACL will lead to early necrosis of the
ligament and chronic anterior knee laxity.
Internal fixation must always be stable to allow early mobilization.In our opinion,stable
osteosynthesis in fractures of the anterior tibial spine is best achieved with a small caliber
screw.
Pseudarthrosis is a possible complication in non-immobilized type 1 fracture.We treated such
a lesion in a 10 y.o. country-bike champion with an excellent result.
INDICATIONS
1. ACUTE ACL TEARS
A. Patients determined to have less than 1 cm of growth remaining are treated as adults
B. Patients with more than 1 cm of growth remaining are carefully managed.
We continue to be reluctant in recommending intraarticular ACL reconstruction as a routine
procedure in the skeletally immature patient,and our indications depend on :

the type of rupture

the association with meniscal lesions

type of rupture :
-tibial avulsions can be primary repaired,with augmentation
-femoral avulsions and midsubstance tears :conservative treatment is recommended.

associated meniscal lesion :
-if there is a large,peripheral vertical medial meniscal tear,surgery is recommended sooner
rather than later : meniscal repair and intraarticular reconstruction are performed
-if a posterior one-third peripheral lateral meniscal tear is detected surgery can be delayed
because of the potential of spontaneous healing of the meniscal lesion
2 . CHRONIC ACL INSTABILITY
Indications are quite the same depending on the importance of the instability evaluated by the
frequency of giving-way episodes and associated meniscal lesions
The criteria for ACL reconstruction in patients with a chronic ACL instability are :

history of repeated episodes of giving-way, pain ,and swelling

instrumental side to side Lachman test superior to 5 mm

reparable meniscal tear

unwillingness to modify sporting activities
CONCLUSIONS

 many authors have reported poor or unacceptable results after conservative treatment of
ACL injuries in children and adolescent.

extraarticular tenodesis is not recommended in children.
 intraarticular ACL reconstruction that avoids penetration of growth plate involves a
nonisometric graft .
 intraarticular ACL reconstruction using different autografts such as patellar,quadriceps,or
hamstring tendons have been reported.
Long-term studies are required before definitive conclusions can be drawn regarding the
efficiency and the non-iatrogenicity of these techniques.