C Surgical Reconstruction Issues

Issues

 

Immediate ACL reconstruction

Early v delayed ACL reconstruction

Repair v Reconstruction

Graft choices

Allograft

Synthetic

Single versus double bundle

Anterolateral ligament (ALL) reconstruction / Extra-articular tenodesis

Trans-tibial v anteromedial drilling

Position of knee during tibial fixation

Tunnel placement

 

Immediate ACL Reconstruction

 

Issue

 

Does early ACL reconstruction in the acute injury period increase risk of stiffness?

 

Results

 

Deabate et al Am J Sports Med 2020

- meta-analysis of 8 RCTs

- 3 with 3 week cut off, 5 with 10 week cut off

- no evidence of increased risk of stiffness, complications, or poorer outcomes

https://pubmed.ncbi.nlm.nih.gov/31381374/

 

Early versus delayed ACL reconstruction

 

Issue

 

Does delayed ACL reconstruction or long wait to surgery result in increased injury?

 

Results

 

Prodomidis et al Am J Sports Med 2020

- systematic review and meta-analysis of timing of ACLR and meniscal tears

- meta-analysis of 5 RCTS demonstrated surgery > 3 and > 6 months after injury associated with increased medial meniscal tears

- https://pubmed.ncbi.nlm.nih.gov/33166481/

 

Repair versus Reconstruction

 

Concept

 

Early after ACL injury

Suture repair +/- internal splint +/- scaffold

 

Results

 

Murray et al Am J Sports Med 2020

- RCT of 100 patients average age 17

- injury < 45 days, midsubstance tear

- suture repair + scaffold

- no difference in laxity or functional outcome

- 14% repair v 6% reconstruction required revision at 2 years

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7227128/pdf/10.1177_0363546520913532.pdf

 

Graft Choices

 

Options

 

Bone patella tendon bone

Hamstring tendons

Quadriceps

 

Patella tendon

 

ACL BPTB IncisionsBPTB GraftACL BPTB

 

Disadvantages

- risk of patella fracture

- increased anterior knee pain compared to hamstring / quadriceps

 

ACL BPTB Patella Fracture APACL BPTP Patella Fracture LateralACL BPTB Patella ORIF APACL BPTB Patella ORiF Lateral

 

Hamstring

 

Advantage

- less PFJ pain compared with patella tendon

 

Disadvantage

- some weakness of hamstrings which may be important in some athletes (sprinters)

 

Quadriceps

 

Advantage

- reduced AKP compared with patella tendon

- potentially thicker graft compared to hamstring

 

Revision Results

 

Persson et al Am J Sports Med 2014

- Norwegian ACL registry of 12,600 patients

- at mean follow up of 5 years, revision rate 4.2%

- revision rate patella tendon 2.1%

- revision rate hamstring 5.1%

- in 15 - 19 age group, 5 year revision rate 9.5% (HS) v 3.5% (PT)

- > 30 age group, 5 year revision rate 2.1% (HS) v 1.2% (PT)

https://pubmed.ncbi.nlm.nih.gov/24322979/

 

Lind et al KSSTA 2020

- Danish ACL registry, revision rate at 2 years

- revision rate quadriceps tendon 4.7%

- revision rate hamstring tendon 2.3%

- revision rate patella tendon 1.5%

https://pubmed.ncbi.nlm.nih.gov/31641810/

 

Anterior knee pain

 

Marques et al Orthop J Sports Med 2020

- 438 patients, overall incidence of 6%

- 10% in PT, 3% in HS group

- risk increased by extension deficit (24% v 5%)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7605008/

 

Allograft

 

Advantage

 

No donor site morbidity

 

Indications

 

Revision

Older patient

 

Disadvantage

 

Disease transmission 

Cost

Slower incorporation

Increased failure rate

 

Results

 

Zeng et al Arthroscopy 2016

- meta-analysis of 9 RCTs autograft v allograft

- increased failures rates and poorer outcomes for irradiated allograft

- no difference for non irradiated allograft

https://pubmed.ncbi.nlm.nih.gov/26474743/

 

Synthetics

 

Advantage

 

No donor site morbidity

 

Disadvantage

 

Synovitis

 

Results

 

Tulloch et al KSSTA 2019

- 55 cases single surgeon LARS at mean follow up 7 years

- 33% mechanical failure

- 40% secondary surgery

- giant cell synovitis seen at arthroscopy

https://pubmed.ncbi.nlm.nih.gov/30903217/

 

Single v Double Bundle

 

Concept

 

Anatomically reproduce both bundles of ACL

? increase stability

 

Issues

 

Technically difficult

 

Results

 

Mascarenhas et al Arthroscopy 2016

- systematic review of meta-analysis

- improved stability in AP planes and rotational

- no difference in clinical outcomes or retear

https://pubmed.ncbi.nlm.nih.gov/25595691/

 

Anterolateral ligament reconstruction / Extra-articular tenodesis

 

Concept

 

Injury to ALL at time of ACL injury

Contributes to rotational instability

 

Results

 

Kunz et al Arthroscopy 2021

- meta-analysis

- addition of ALL improves pivot shift

https://pubmed.ncbi.nlm.nih.gov/33864833/

 

Getgood et al Am J Sports Med 2020

- RCT of hamstring ACL +/- lateral extra-articular tendosis

- 600 patients, grade 2 pivot, ligamentous lax, < 25

- addition of LET reduced clinical failure and re-rupture

https://pubmed.ncbi.nlm.nih.gov/31940222/

 

Trans-tibial v anteromedial portal drilling

 

Concept

 

Transtibial

- drill tibial tunnel

- insert guide through tibial tunnel to drill femoral tunnel

- tunnels more vertical

- tibial tunnel position dictates femoral tunnel position

 

Anteromedial portal drilling

- drill femoral tunnel through anteromedial portal

- anatomic ACL reconstruction

- allows femoral tunnel position at anatomic site of ACL insertion

- less vertical graft

- potentially more stable knee

 

Results

 

Loucas et al Orthop J Sports Med

- systematic review

- anteromedial drilling associated with improved AP and rotational stability

- anteromedial drilling associated with improved clinical outcome scores

https://pubmed.ncbi.nlm.nih.gov/34277881/

 

Knee position during graft fixation

 

Concept

 

Secure ACL graft on tibial side at full extension

- don't lose knee extension

- graft potentially not as tight

 

Secure ACL graft on tibial side at 30 degrees of flexion

- graft will tighten as go to full extension, potentially more stable knee

- can limit patient's ability to achieve full extension

 

Results

 

Chahal et al Arthroscopy 2021

- RCT of patella tendon fixation at 0 versus 30 degrees

- 169 patients

- no difference in reoperation, knee extension loss, stability or functional outcome

- patients fixed in full extension had increased activity scores and less pain

https://pubmed.ncbi.nlm.nih.gov/34952186/

 

Tunnel Placement

 

1.  Intra-operative tunnels

 

Isometricity does not exist

- no point on femur that maintains fixed distance from point on tibia

- up to 3 mm elongation acceptable

- graft should tighten with increased extension

 

A. Tibial tunnel 

 

Sagittal plane

- 7 mm anterior to PCL & central

- posterior 1/2 ACL footprint

 

Coronal plane

- 2/3 way towards medial tibial spine from anterior horn of lateral meniscus

 

Tunnel angle

- usually 55o

- reduce angle to shorten tunnel if have short graft

 

B. Femoral tunnel 

 

More vertical placement of tunnel

- increased AP stability

- less rotational stability / pivot shift

 

Coronal plane

- 2 o'clock rather than 1 (right knee)

- 10 o'clock rather than 11 (left knee)

 

Sagittal plane

- want to be posterior

- identify back wall in flexion

- want 2mm of back wall behind tunnel

 

2.  X-ray assessment

 

Lateral x-ray

 

Femoral tunnel

- intersection of line posterior femoral cortex and Blumensaat's line

 

Tibial tunnel

- posterior to Blumensaat's line in full extension

- parallel to Blumensaat's line

 

ACL Reconstruction Femoral Tunnels SagittalACL Reconstruction Sagittal Tibial Tunnel

 

Pinczewski JBJS Br 2008

- 200 patients followed up over 7 years

 

1.  Posterior femoral tunnel placement

- 86% along Blumensaat's line 

 

2. Anterior tibia tunnel placement

- 48% along tibial plateau

- parallel to Blumensaat's

 

ACL Reconstruction Sagittal Tunnel Measurement

 

AP Xray

 

1.  Medial tibial tunnel placement

- 46% (towards medial)

 

2.  Lateral femoral tunnel placement

- 42% from lateral LFC

 

3.  Graft inclination

- 19o

 

ACL Reconstruction AP Tunnel MeasurementsACL Reconstruction Graft Inclination Measurement

 

11% rupture rate over 7 years

- associated with posterior tibial tunnel placement

 

Good rotational stability

- 19o inclination in coronal plane

- avoid too vertical orientation

 

3.  Incorrect tunnel positions

 

Tibial Tunnel

 

A.  Anterior tibial tunnel

- impingement / limits extension / cyclops lesion

 

B. Posterior tibial tunnel

- impinge on PCL

- extension strain in extension

 

C.  Lateral tibial tunnel

- impinges on lateral wall femoral condyle

 

Femoral Tunnel

 

A.  Anterior Femoral Tunnel

- limits flexion

- increased strain in flexion / stretches graft

- increases risk of failure

 

B.  Posterior Femoral Tunnel

- excessive strain in extension

 

C.  Vertical Graft

 

Fu etal Arthroscopy 2003

- cadaver study of graft in 10 v 11 o'clock position

- demonstrated increased rotational instability in 11 o'clock

 

Options for drilling femur

 

1.   Trans - tibial 

 

Traditional techique

- drill tibial tunnel first

- place guide up tibial tunnel onto femur

 

ACL Transtibial Tunnel

 

Advantage

- cannot damage MFC

 

Potential disadvantage

- tibial tunnel sets position of femoral tunnel

- tends to make the graft more vertical

 

Technique

- drill femur with knee at 90o

 

2.  Anteromedial portal

 

Advantage

- allows separation of femoral from tibial tunnel

- can place femoral tunnel lower on femoral wall

 

ACL Anteromedial Femoral Tunnel

 

Disadvantage

- places drills and reamers close to MFC

- must be careful not to damage cartilage

 

Technique

- must hyperflex knee

- or femoral tunnel may exit in PFJ

 

Femoral Tunnel Back wall blow-out

 

Problem

 

Cannot use RCI screw to secure femoral side

 

Avoid by

 

1. Using posterior offset femoral guide

- divide tunnel size required in half and add 2

- 6mm for 7.5 mm hamstring tunnel

- 7mm for 10 mm BPTB tunnel

 

2.  Appropriate knee flexion when drilling femoral tunnel 

- hyperflexing knee if using AM portal

- 90o of flexion if using transtibial technique

 

Options

 

1.   Endo-button 

- don't need back wall for fixation

 

2.  Redrill tunnel 

- change angle by flexing knee +++

- get in good bone stock

 

3.  Fix in over the top position

- pass graft around back of femoral condyle using curved hemostat

- may need medial parapatella approach

- lateral approach to femur

- fix to femur with screw / staple

- can pass around lateral intermuscular septum and LCL

 

Notchplasty

 

ACL Large Notch OsteophyteACL Post Notchplasty

 

Issue

- smaller notch increases risk of re-rupture / stretching by causing graft impingement

- more necessary with larger grafts i.e. BPTB

- required if presence of notch osteophytes

 

Disadvantage

- notchplasty can lateralise

- important to only debride anterior portion of notch

- do not debride lateral wall or will lateralise the femoral graft

 

Techique

- trial with guide wire / reamer / chondrotome / graft

- check for lateral wall impingement

- check for roof impingement

- notchplasty as required

 

Graft Fixation

 

Graft fixation is weakest link first 6-12 weeks

- BPTB 6-10 weeks to incorporate

- HS 12 weeks (bone grows into tendon resembling Sharpey's fibres)

 

After 12 weeks the weak link is the graft

 

Options

 

Aperture Fixation

 

Interference screw

- metal / bioabsorbable

 

Suspensory Fixation

 

Endobutton

Transfix

 

ACL Transfix Pin

 

Fauno et al Arthroscopy 2005

- compared transfix and endobutton

- demonstrated increased tunnel widening with fixation away from joint i.e endobutton

 

Screws

 

Diameter

- biomechanical studies in tibia with hamstring

- line to line screw size less strong than tunnel diameter + 1

 

Length

- probably more important than diameter in hamstring

- has been demonstrated than increasing length increases fixation

- increase number of threads available for fixation

 

Divergence

- important with bone block

- must keep divergence below 200

 

Central / eccentric placement

- no significant difference

 

Metal v bioabsorbable

 

Mascarenhas Arthroscopy 2015

- meta-analysis

- no difference in outcome

- increased knee effusion, femoral tunnel widening, and screw breakage with bioabsorbable