Hamstring Autograft

Endobutton + Interference screw +/- staple or post

 

ACL Reconstruction Hamstring Endobutton RCI Screw APACL Hamstring Graft

 

Advantage

- endobutton simple yet strong fixation

- endobutton eliminates problem if blow out back wall

- can still use femoral RCI screw if run into problems with endobutton

 

Set up

 

GA, tourniquet, IV antibiotics

- knee roll, lateral support

- knee at 90o for optimum access to notch

- but need to be able to hyperflex for femoral tunnel

- EUA to confirm positive pivot shift

- +/- pressure pump

 

Harvest graft

 

Kulinski et al AJSM 2023

- RCT of doubled semiT/gracilis versus 4 strand semiT

- 126 patients

- worse outcomes with 4 strand semiT in female patients

 

Knee flexed 90o

- usually roll tendons under finger

- longitudinal incision

- 2cm below joint line / 2 cm medial to crest / 2 cm long

- superior aspect of incision at level of tibial tuberosity

- separate skin and subcutaneous fat

- view sartorius fascia

- roll tendons again

- use knife and make cut above and parallel to gracilis

- elevate fascial flap

- used curved hook, identify both tendons first

- isolate gracilis (say Grace before Tea)

- divide vinculae (usually one)

- use tendon harvester in straight line aiming towards ischial tuberosity

- isolate ST, divide larger vinculae (there is nearly always two), strip

 

Hamstring 1Hamstring 2Hamstring 3Hamstring 4

 

Prepare graft

 

Leave tendons attached to tibia or remove and prepare on table

- remove muscle with scissors / spoon

- loop both tendons through endobutton to create 4 strand

- can suture all 4 ends together or do each 2 separately

- no 1 ethibond / ticron / fibrewire

 

Tensioner

- 10 - 15 lb

 

Hamstring Graft Tensioned

 

Endobutton Choices

 

30mm / 20mm / 15mm loops

- if shorter graft / longer tunnel use longer lopp

 

Size graft

 

Will be usually 7.5 - 8.5 mm in man

- 6.5 - 7.5 in woman

- ream a tunnel to the same size as the graft

- a tight tunnel fit may mean less fluid to cause tunnel widening

- will potentially make passing the graft / flipping the endobutton harder

 

Arthroscopy

 

Lateral portal

- high and midline

- need to be able to see around corner medial wall of LFC

 

Medial portal

- low and midline

- if too medial risk damaging MFC with reamers

- too lateral means graft too vertical

- low position gives good angle on femoral tunnel

- best to trial with needle first

 

ACL Reconstruction Anteromedial Portal

 

Assess and manage mensicus as appropriate

- assess and manage chondral lesions as appropriate

 

Debride ACL

 

Debride stump back to PCL fibres (preserve synovium over PCL)

- can leave some stump to identify tibial tunnel and provide vascularisation

- clean lateral wall

- remove periosteum with curette, chondrotome and electrocautery

- identify resident's ridge and posterior wall clearly

 

ACL Stump ArthroscopyACL Stump Arthroscopy

 

ACL Clear Lateral WallACL Identify Back Wall

 

Femoral tunnel

 

Entry Point

- 1.30 o'clock on R, 10.30 o'clock on L

- 6 mm offset guide through anteromedial portal

- aim to leave 2 mm posterior wall

 

Femoral tunnel beath pin

- hyperflex knee, pass beath pin

- if don't hyperflex, tunnel can be very long

- want wire to emerge anterior to lateral intermuscular septum

- if tunnel too vertical, can emerge in PFJ

 

ACL Reconstruction Long Femoral TunnelACL Reconstruction PFJ APACL Reconstruction Lateral

 

Femoral Tunnel Drilling

- pass 4.5mm endobutton drill completely through femoral cortex

- remove beath pin and insert depth gauge

- measure femoral tunnel (between 34 and 46 mm)

- drill appropriate sized tunnel with acorn reamer to within 10mm of cortex (for 20 mm endobutton)

- gives room to pull through and flip 10 mm endobutton

- if 15 mm endobutton need to be within 5 - 7 mm

- carefully clean out all bone fragments with shaver / depth gauge or may prevent graft passage

- insert loop 1 nylon to pass graft later

 

ACL Anteromedial Beath PinACL Femoral Acorn Reamer

 

If blow out cortex, can also use extended endobutton

- wider than 10 mm

- often when this is pulled through, will go too far and lodge in vastus lateralis

- in which case cut down to endobutton and seat securely on femur

 

Tibial tunnel

 

Use drill guide set at 55o

- use < 55o if short graft

- entry medially through hamstring incision

- set for wire to exit either tip or elbow

- anterior to PCL

- posterior half of ACL stump

- identify medial tibial spine and anterior horn of lateral meniscus

- 2/3 along this line towards medial tibial spine

- pass beath wire

- drill tunnel line to line

 

ACL Tibial JigACL Reconstruction Tibial Beath Pin

 

Pass Graft

 

Retrieve end of 1 nylon loop via tibial tunnel with grasper / probe

- place all 4 sutures of endobutton into loop and pull up through femoral tunnel

- separate sutures

- visualise femoral tunnel with camera

- use the pulling sutures to pull graft up into femoral tunnel

- helpful to wrap about artery forcep for traction

- then use both sutures to ensure that endobutton has flipped (rock each end back and forth)

- tension other end of graft and ensure cannot flip endobutton any further

 

ACL Reconstruction Loop 1 Prolene Passing Suture

 

Uncertain if endobutton has flipped

- check with II

- cut down on lateral femoral cortex

- supplement with interference screw

 

Tension graft

 

Hold distal sutures

- flex and extend multiple times

- check to see where graft is longest (i.e. pulled into knee)

- should secure graft where it is longest, or will have to stretch to get ROM back

- debate whether best at 0 or 30o

 

Washout Joint

 

Many bone fragments in joint

- may contribute to arthrofibrosis / cyclops / chondral damage

 

Tibial fixation

 

Place beath wire and pass RCI screw anteriorly

- usually 8 or 9 mm for men and women

- the tibial bone is soft

- will usually take a 25 mm screw / up to 35 mm

- +/- supplemental post / screw / staple

 

ACL Hamstring Autograft Arthroscopy

 

Range

 

Ensure no anterior or lateral impingement of graft

- can perform careful notchplasty

 

ACL Reconstruction No Anterior Graft Impingement in Full Extension

 

2 x RCI screws

 

ACL Hamstring 2 x RCI Screws APACL Hamstring 2 x RCI Screws Lateral

 

Tunnels

 

Tibial tunnel

- as above

 

Femoral tunnel

- pass beath pin

- drill line to line for graft size

- usually 25 mm long

 

Pass graft

 

Insert screw

 

Femur

- forward thread RCI in left, reverse in right

- allow the head of the screw to always be visible (in case need to remove)

- always slightly smaller screw in femur as bone very hard

- i.e. 7 mm tunnel for 8 mm tunnel

 

Tibia

- tibial screw is 1 mm bigger i.e. 8mm for 7 mm tunnel