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




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






Some stretch of ligament occurs, but most knees are stable




Occasionally fragment can block full extension


ACL Avulsion MalunionACL Avulsion MRI Malunion