ACL Avulsion Fracture

Myers & McKeever classification

 

Type I:   Undisplaced avulsion fracture

 

Type II:  Anterior portion displaced & hinged

 

ACL Avulsion Type 2

 

Type IIIA:   Displaced

Type IIIB:   Displaced & Rotated

 

Type 3 ACL Avulsion

 

Management

 

I - III A 

 

Attempt closed reduction

- anaesthesia / II control

- long leg cast in full extension

- trap fragment under condyles

 

Block to reduction

- usually medial meniscus / intermeniscal ligament

 

ACL avulsion reduced in extension

 

IIIB & Failed MUA

 

1.  Medial arthrotomy / arthroscopically

- need to remove portion of fat pad for visualisation

- intermeniscal ligament usually blocks reduction

- removed callus / hematoma

- replace fragment under intermeniscal ligament

- want to impact fragment to tension stretched ACL

 

2.  Repair Options

 

A.  No 2 suture

- bunnell suture through ACL above bony fragment

- pass 2 x limbs through bony fragment

- insert beath pins to retrieve suture limbs through tibial insertion

- two separate tunnels

- tie over bony bridge in tibia

- protect in plaster in extension

 

B. ORIF physeal sparing screw

- II guided

- directed posteriorly and obliquely

 

Outcomes

 

Stability

 

Some stretch of ligament occurs, but most knees are stable

 

Malunion

 

Occasionally fragment can block full extension

 

ACL Avulsion MalunionACL Avulsion MRI Malunion