ACL Flashcards
Gene associated with ACL tears in females
COL5A1
ACL tissue composition
90% type 1 collagen
10% type 3 collagen
ACL tensile strength:
2200N anterior translation
Segond fracture is:
bony avulsion of the anterolateral ligament in ACL tear
ACL femoral tunnel placement should be:
on the lateral wall at 9/10 o’clock, and with 1-2mm of bone remaining between the tunnel and the lateral wall
ACL tibial tunnel placement should be:
10mm anterior the PCL insertion, 75 degrees entry point from the horizontal on the anteomedial tibia
Facts about BTB Allo:
30% rate of anterior knee pain
max load to fail = 2600N
complications:
- patella fracture or tendon rupture
- graft failure
BTB graft failure associated with
- age <20 years
- <8mm diameter graft
Facts about Quadruple Hamstring Auto:
- less painful
- high load to failure 4000N
- fixation strength may be less than BTB
- ?hamstring weakness in females leading to re-rupture
“Windshield Wiper Effect”
suspensory fixation of hamstring graft causes tunnel abrasion due to movement during knee flexion/extension
Allograft re-rupture rates?
4.3x higher than autograft for athletes <19 years
For peds ACL recon, risk of physeal injury is increased with:
- LARGE TUNNELS >12mm
- oblique tunnels
- interference fixation
- high speed reaming
- dissection near the perichondrial ring of Lacroix
Sagittal plane femoral tunnel malposition:
anterior graft causes knee tightness in flexion
- posterior graft causes knee to be tight in extension
Sagittal plane tibial tunnel malposition
anterior graft causes knee tight in flexion and impingement with knee in extension
Optimal graft-screw divergence should be:
< 30 degrees
Biggest factor affecting return to sports after successul ACL reconstruction?
psychological and lifestyle factors
early strengthening following ACL recon - advantages?
early eccentric strengthening at 3 weeks post-op
- higher quad strength and volume at 1 year wtihout increases in knee laxity
- immediate post-op wbat is safe
- immediate ROM 0-90 is safe
Is there a difference in early vs delayed rehab protocols following ACL recon?
no, literature says no difference
-
is bracing necessary following ACL recon?
not necessary
Pathomechanics of ACL deficient knees
anterior translation
internal tibial rotation
medial tibial translation at 15-90 deg flexion (may cause OA)
Classic bone bruise pattern in ACL injury predicts what?
prolonged range of motion deficit following reconstruction
How much physeal disruption with ACL recon can cause growth disturbance?
7-9% of cross-sectional area
Graft Strain During Rehab after ACL recon:
low strains with:
- isometric hamstring contractions at any knee flexion angle
- isometric quad contractions at knee flexion >60 deg (or combined quad and hamstring
- active knee ROM 35-90 deg
secondary stabilizer to anterior tibial translation in ACL deficient knee?
posterior horn of medial meniscus
