Revison ACL Surgery

Graft selection


A.  Synthetic Grafts


Good initial results but unacceptably high failure rate with longer follow-up




1.   Too stiff (low ultimate strain) 

- poor resistance to abrasion

- ligament failure by attrition most common


2.  Recurrent synovitis, infection, loosening and osteolysis


B.  Autograft


1.  Contralateral BPTB / hamstring

2.  Reharvested central BPTB 


C.  Allograft

- many advantages (shorter surgery, decreased morbidity, larger bone blocks)

- disadvantages (disease risk, slower incorporation, higher cost)

- irradiation has dose dependent effect on mechanical properties with significant effect at 3 Mrads

- higher failure rates


Heffner et al AJSM 2023

- over 1700 revision ACL from ACL registry

- repeat revision 14% allograft

- repeat revision 6% autograft

- 70% lower risk of repeat revision with autograft compared to allograft


Pre-operative Assessment


Crucial to good outcome


Patient expectations

- results not as good as primary

- aim for ADL's, sports may not be possible



- history infection

- history arthrofibrosis

- has knee ever been good or always unstable

- was it good then traumatic injury







- patient hyperextension linked to poor outcomes


Confirm ACL deficient

- Lachman's / Anterior drawer / Pivot Shift


Check Secondary restraints

- assess PCL / PLC

- dial test important

- may need posterior and varus stress xrays


Old OT notes


Technique / graft

Fixation techniques

Tunnel sizes




AP and Lateral

- assess tunnel placement

- Assess metal work

- types of fixation

- metal v plastic


Revision ACL Lax Graft Anterior Femoral Tunnel


Stress xrays

- check PCL / PCL




1.  Is graft intact / non functional or ruptured


Revision ACL Intact but Lax GraftRevision ACL Graft Rupture


2.  Assess meniscus / chondral surfaces


3.  Evidence of other ligament injury (difficult)




Assess for tunnel lysis


Arthroscopy / EUA


Confirm graft lax or torn / + Pivot Shift


Revision ACL Lax BPTB Graft


4 Tunnel Situations in Revision Surgery


1.  Correct tunnel position, normal size


Reuse same tunnels

- remove hardware

- may require larger screws if some lysis


2.  Correct tunnel position, increased size secondary to lysis


Tibial and femoral tunnel Lysis


Staged bone grafting of tunnels

- use bone cores from iliac crest

- premade synthetic bone graft plugs

- wait for union / 3 - 6 months

- ACL revision


BTPB / Achilles allograft with larger bone block


3.  Slightly incorrect tunnel position


Staged bone grafting of tunnels


4.  Very incorrect tunnels


New tunnels anterior or posterior

- can leave old metalwork intact


Revision ACL Graft Placed posterior to old femoral tunnelRevision ACL New Posterior Femoral Tunnel






1.  Skin incisions


2.  Hardware removal

- screwdrivers for metal RCI screws

- drill through bioabsorbable screws

- ignore endobutton

- careful removal of all material in tunnels


3.  Revision Notchplasty

- roof and lateral wall

- often osteophytes in this area

- must leave sufficient bone stock


4.  Bony tunnels


Find femoral tunnel

- pass beath pin

- decide if tunnel reusable

- will usually be larger

- can use screw if posterior wall remains


Usually do tibial tunnel last

- will lose vision as water escapes

- can be difficult to find tunnel

- use needle to find tunnel


5.  Graft


BPTB good option

- larger bone blocks useful in enlarged tunnel


Contralateral hamstring

- involve normal knee

- fixation difficult


6.  Fixation



- screw if posterior wall remains

- otherwise endobutton

- can tie over screw on femur if need to 



- usually scew +/- post


6.  Secondary restraints


A.  Posteromedial instability

- reconstruction / advancement


B.  Posterolateral

- valgising HTO

- reconstruction