ACL Rupture

Issues

 

1.  More common recently

- more high level sport

 

2.  High risk of reinjuring knee from instability

- can suffer permanent severe chondral and meniscal damage

 

3.  Risk of physeal arrest high if bone block across physis

- risk is growth arrest with ACL reconstruction

 

Epidemiology

 

Hemarthrosis

- 60% children have ACL tear

 

ACL tear

- 20% have mensical injuries

 

Most occur within 6-12 months of skeletal maturity

 

Management

 

Non operative

 

Issues

 

1. Non complicance children / young adolescents high

- high risk of chondral and meniscal damage

 

2.  Best to delay surgery if able til close to maturity

- avoid growth arrests

 

Technique

 

No sport / ACL brace / ACL rehabilitation

- until 2 years from skeletal maturity

 

Results

 

Aichroth et al JBJS Br 2002

- 60 children with ACL deficient knees 1980-1990 

- average age 12.5 years

- 23 patients treated conservatively, NHx was severe instability & poor knee function

- 15 knees had meniscal tear, 3 osteochondral fractures, 10 knees developed OA changes

- 37 knees with Hamstring ACL reconstruction average age 13 years

- no physeal arrest and satisfactory results in 80%

 

Operative

 

Indications

 

1.  Meniscal tear / displaced / blocking extension

 

2.  Failure non operative treatment

- continued instability

- high risk of chondral damage

 

3.  Within 2 years of maturity

 

Problems

 

Growth arrest / angular deformity / LLD

 

Predicting growth potential

 

Skeletal age with Greulich-Pyle atlas

Anderson table predict growth remaining using height and growth potential

 

Options

 

Extra-articular / over the top

Intra-articular

- physeal sparing

- partial transphyseal

- transphyseal

 

Extra-articular / Over the Top

 

Indications

- > 5 years to maturity

- avoid physeal injury

 

Procedures

 

McIntosh procedures

- ITB over the top

- combined intra-articular and extra-articular reconstruction

 

Technique Kocher JBJS Am 2005

 

Harvest

- lateral incision

- entire ITB taken

- left attached distally, detached proximally

- tubularised with no 5

 

Arthroscopy performed

- removal of ACL stump

- minimal notchplasty to avoid injury perichondral ring distal femur

 

Femur

- ITB passed extra-articular around lateral femoral condyle

- over the top position

- passed out anteromedial portal

 

Tibia

- 4 cm incision over anteromedial tibia

- clamp passed into knee under intermeniscal ligament

- groove for tendon made in epiphysis in this area

- graft passed through

 

Fixation femur

- knee 90o and foot ER 15o

- sutured to lateral intermuscular septum / extra-articular

 

Fixation tibia

- 20o flexion

- II used to assess location of growth plates

- groove made in proximal tibia

- graft sutured in place

 

Post op

- TWB 6/52

- restricted ROM 0 - 90o first 2 weeks

 

Results

 

Kocher et al JBJS Am 2005

- 44 patients average age 10

- ITB extra-articular physeal sparing / McIntosh modification

- 2 revisions for graft failure at 5 and 8 years

- no angular or leg length deformity

- excellent IKDC and Lysholm scores

- pivot shift normal in 31 and nearly normal in 11

 

Intra-articular reconstruction

 

Indications

- < 5 years to maturity

 

Assessment of Bone Age

 

Xray right hand / Greulich-Pyle atlas

- estimate bone age

- estimate amount of growth from femur and tibia

 

Theory

 

4 strand hamstring graft

 

Tunnels < 5% physeal area do not cause growth disturbance

- i.e. 6 - 8 mm drill hole

- need to keep vertical to minimise area

 

Tunnels 7 - 9% of growth area

- if leave transphyseal tunnels empty or have bone inside

- will form physeal bars

- if place soft tissue across (i.e. graft) will not form physeal bar

 

Options

1.  Physeal sparing

2.  Partial transphyseal

3.  Transphyseal

 

A.  Physeal sparing / transepiphyseal

 

Technique

 

Avoiding tibial physis

- tunnel anterior tibial epiphysis / trans epiphyseal

- graft secured with screw post / staple into tibial metaphysis

 

Avoiding femoral physis

- femoral tunnel horizontal and remains in femoral epiphysis

- transphyseal

- entrance in ACL origin

- use II guidance to spare the physis

- tunnel at 90o

- secured with endobutton

- 'over the top' position

 

Results

 

Anderson et al JBJS Am 2003

- 12 immature patients

- no LLD, stable knees

 

B.  Partial transphyseal

 

Technique

 

Tibial tunnel transphyseal

- keep small (6 mm)

- keep vertical

 

Femoral tunnel as above

- over the top

- physeal sparing

 

C.  Transphyseal

 

Technique

 

Analogous to adult reconstruction

 

Preventing growth arrest

- tunnels < 7% physeal area (7mm tunnels)

- soft tissue interposition across physis

- tunnels are vertical as possible

- central in the physis to avoid angular deformity

- single pass, wash +++

- anchorage away from physis

- endobutton for femur

- short screw / staple / post for tibia

- graft only across physis

 

Results

 

Kocher et al JBJS Am 2007

- 61 knees in patient average age 14

- 3% / 2 patients revision for graft failure at 14 and 21 months postoperatively

- pivot shift normal in 51 and nearly normal in 3

- no angular or LLD

- 3 cases of arthrofibrosis requiring MUA