Anterior cruciate ligament injury

1. Anterior cruciate ligament
injury
Dr lukman
Omsb
AFMS

2. Outline
 Introduction
 Pathophysiology
 Anatomy
 Clinical presentation
 Imaging.
 Manegments

3. Introduction
 ACL tears are common athletic injuries leading to anterior and lateral rotatory
instability of the knee.
 Common
 more common among female athlete (4.5:1 ratio)

4. Pathophysiology
 non-contact pivoting injury
 tibia translates anteriorly while knee is in slight flexion and valgus
 blow to the lateral aspect of the knee
 common activities are soccer, basketball, skiing, and football
 Associated conditions
 meniscal tears
 lateral meniscal tears in 54% of acute ACL tears, medial in chronic cases
 PCL, LCL/PLC injuries
 chronic ACL deficient knees associated with
 chondral injuries
 complex, unrepairable meniscal tears and bucket handle medial meniscus tears

5. Anatomy
 two bundles
 anteromedial bundle
 tightest in flexion
 primarily responsible for restraining anterior tibial translation (anterior drawer test)
 posterolateral bundle
 tightest in extension
 primarily responsible for rotational stability (pivot shift test)
 Femoral attachment
 lateral intercondylar
 bifurcate ridge separates the anteromedial and posterolateral bundle attachment
 tibial attachment: anterior tibia, between intercondylar eminences

7.  Composition
 90% Type I collagen
 10% Type III collagen
 Blood supply: middle geniculate artery
 Innervation: posterior articular nerve (branch of tibial nerve)
 Function
 provides 85% of the stability to prevent anterior translation of the tibia relative to the
femur
 acts as a secondary restraint to tibial rotation and varus/valgus rotation
 2200 N strength (anterior)

8. Clinical presentasion
 History
 felt a "pop"
 pain deep in the knee
 immediate swelling (70%) / hemarthrosis
 feelings of instability preventing return to sport
 difficulty weight bearing
 Physical exam
 effusion
 lack of full extension secondary to meniscal injury or arthrofibrosis
 evaluate for meniscal or concomitant ligamentous injuries (McMurray, Dial test, varus/valgus stress)
 Provocative tests:
 ADT
 Lachman's test, most sensitive exam test
 Pivot shift : knee brought from extension (anteriorly subluxated) to flexion (reduced) with valgus and internal
rotation of tibia , reduces at 20-30° of flexion due to IT band tension

9. Imaging
X ray : often normal
 Segond fracture (avulsion fracture of
the proximal lateral tibia) is
pathognomonic for an ACL tear . It
represents bony avulsion by
the anterolateral ligament (ALL)
 associated with ACL tear 75-100% of
the time
 deep sulcus (terminalis) sign:
depression on the lateral femoral
condyle at the terminal sulcus, a junction
between the weight bearing tibial
articular surface and the patellar articular
surface of the femoral condyle

10. MRI
discontinuity of fibers on T2
Bone brusing too "flat"

11. MRI
discontinuity of fibers (do
not reach the femur)
fluid against the lateral wall
("empty notch sign")

12. treatment
 Treatment individualized to patient based on activity level, age, demands, and
concomitant pathology
 Non operative: physical therapy, lifestyle modifications
 low demand patients with decreased laxity
 recreational athlete not participating in cutting/pivoting activities
 Outcomes: increased meniscal/cartilage damage linked to loss of meniscal integrity, high
physical activity (e.g. jumping, side-to-side sports, heavy manual labor)

13. ACL reconstruction
 must have full motion of knee restored following injury (unless meniscal tear causing
mechanical block)
 lack of pre-operative motion risk factor for post-operative arthrofibrosis
 younger, more active patients (reduces the incidence of meniscal or chondral injury)
 older active patients (age >40 is not a contraindication if high demand athlete)
 partial/single bundle tears with clinical and functional instability

14. ACL repair
 indications
 previously abandoned but increased interest recently in pediatric populations and
avulsion rupture patterns
 outcomes
 previously abandoned due to high failure rates

15. Graft selection
Bone-patellar tendon-bone (BPTB) autograft
 the longest history of use and considered the "gold
standard"
 bone to bone healing leads to faster incorporation
time
 the highest incidence of anterior knee pain (up to
10-30%) and kneeling pain
 maximum load to failure is 2600 Newtons (intact
ACL is 1725 Newtons)
 complications
 patella fracture (usually postop during rehab), patellar
tendon rupture
 re-rupture
 Quadrupled hamstring autograft
 smaller incision, less perioperative pain,
less anterior knee pain
 maximum load to failure is
approximately 4000 Newtons
 complications
 residual hamstring weakness
 parasthesias due to injury to saphenous
nerve branches during harvest

16. Quadriceps tendon autograft
 small incision in area that does not see
pressure during kneeling
 maximum load to failure 2185 Newtons
 similar patient-reported and functional
outcomes as other autografts
 may include bone block or completely
soft tissue
 less commonly used so is often
available in revision setting
 same disadvantages as hamstring
autograft with suspensory fixation
Allograft
 useful in revisions
 longer incorporation time
 risk of disease transmission (HIV is <
1:1.6 million, hepatitis is even greater)
 increased risk of re-rupture in young
athletes