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3/6/2017 1 Anterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute Anatomy Anatomy Function Primary restraint to anterior tibial translation Secondary restraint to internal tibial rotation Anatomy Length: 32mm (range 22 to 41mm) Width: 10mm (range 7 to 12mm) Innervation: Tibial nerve (posterior articular nerve) Infiltrates capsule posteriorly Golgi tendon receptors Blood supply: middle genicular artery Strength: 2200N Anatomy Background Incidence of ACL rupture: 50 per 100,000 persons per year ~200,000 ACL ruptures in USA per year ~175,000 ACL recons per year in USA Initial cost of ACL recon exceeds 2 billion dollars

Anterior Cruciate Ligamentandrewsref.org/docs/ACL_Ostrander Short 2_Final.pdfAnterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute A tomy A tomy nction • Primary

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Page 1: Anterior Cruciate Ligamentandrewsref.org/docs/ACL_Ostrander Short 2_Final.pdfAnterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute A tomy A tomy nction • Primary

3/6/2017

1

Anterior Cruciate LigamentSurgery

Roger Ostrander, MD

Andrews Institute

Anatomy

Anatomy

Function• Primary restraint to

anterior tibial

translation

• Secondary restraint to

internal tibial rotation

Anatomy

• Length: 32mm (range 22 to

41mm)

• Width: 10mm (range 7 to

12mm)

• Innervation: Tibial nerve

(posterior articular nerve)

– Infiltrates capsule

posteriorly

– Golgi tendon receptors

• Blood supply: middle genicular

artery

• Strength: 2200N

Anatomy Background

• Incidence of ACL

rupture:

• 50 per 100,000 persons

per year

– ~200,000 ACL ruptures in

USA per year

– ~175,000 ACL recons per

year in USA

– Initial cost of ACL recon

exceeds 2 billion dollars

Page 2: Anterior Cruciate Ligamentandrewsref.org/docs/ACL_Ostrander Short 2_Final.pdfAnterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute A tomy A tomy nction • Primary

3/6/2017

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7

Epidemiology

» 70% of ACL injuries occur during sport participation.

» Peak age group: 15-30

» Females: 4-6 times rate of ACL injury when compared to males.

0

150

300

450

600

10-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54

Num

ber

of C

ases

Age in Years

Male Female

8

Mechanism of Injury30% of ACL injuries occur with direct contact

9

Mechanism of Injury

70% of ACL injuries occur via non-contact mechanism

10

Clinical Presentation

» Feel a pop in the knee

» Knee buckles

» Difficulty with weight bearing

» Cannot continue to participate

» Large effusion

11

Associated Injuries

» Meniscal tears

» Meniscocapsular injuries

» Chondral injury

» Bone contusion

» Other ligaments

Acute ACL tears can be associated with:

12

Initial Treatment

» Rest

» Ice

» Compression

» Elevation

» Physical Therapy

» Arthrocentesis **

Page 3: Anterior Cruciate Ligamentandrewsref.org/docs/ACL_Ostrander Short 2_Final.pdfAnterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute A tomy A tomy nction • Primary

3/6/2017

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13

TreatmentNon-operative versus Operative treatment

Operative

» Younger & Higher demand patients

14

TreatmentNon-operative versus Operative treatment

Non-operative

» Lower demand and sedentary patients

» No concomitant injury

Goals of Reconstruction

• Reproduce the normal

anatomy of the native ACL

• Restore knee stability

– Eliminate anterior translation

– Improve rotatory function

• Improve long term outcomes

16

Graft Options

» Patellar Tendon

» Quadrupled hamstring

» Quadriceps tendon

» Allograft

17

Graft Options

Patellar Tendon Graft

» Dimension: 9,10 or 11 mm width x 4mm thick

» Ultimate load to failure: 2,977N

» Advantages: Good biomechanical tensile strength, bone-to-bone healing (6-8wks), stiffer graft.

» Disadvantages: Increased risk of anterior knee pain, patellar fracture.

Surgical TechniqueGraft Harvest

Page 4: Anterior Cruciate Ligamentandrewsref.org/docs/ACL_Ostrander Short 2_Final.pdfAnterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute A tomy A tomy nction • Primary

3/6/2017

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Graft Harvest Graft Prep

Surgical TechniqueClosure and Bone Graft

Closure & Bone Graft

Notchplasty

PCL

Notchplasty

Page 5: Anterior Cruciate Ligamentandrewsref.org/docs/ACL_Ostrander Short 2_Final.pdfAnterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute A tomy A tomy nction • Primary

3/6/2017

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Diagnostic ScopeMeniscus Repair

Meniscocapsular Repair

Lateral Meniscus Repair

Drilling Tunnels

Tibial Tunnel Guide Wire

Drilling Tunnels

Ream Tibial Tunnel

Drilling Tunnels

Ream Femoral Tunnel

Drilling Tunnels

Page 6: Anterior Cruciate Ligamentandrewsref.org/docs/ACL_Ostrander Short 2_Final.pdfAnterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute A tomy A tomy nction • Primary

3/6/2017

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Graft Passing Pin Graft Pulled into Knee

Screw in FemurGraft Passage

Tibial Fixation

Screw in TibiaTibial Fixation

Page 7: Anterior Cruciate Ligamentandrewsref.org/docs/ACL_Ostrander Short 2_Final.pdfAnterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute A tomy A tomy nction • Primary

3/6/2017

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Outcomes

• ACL reconstruction

successful >95% of time

• Complications are rare

– Stiffness

– Fractures

– Infection

Thank You

Tibial Fixation

Screw in Tibia

Thank You

Page 8: Anterior Cruciate Ligamentandrewsref.org/docs/ACL_Ostrander Short 2_Final.pdfAnterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute A tomy A tomy nction • Primary

3/6/2017

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Function

• Primary restraint to anterior tibial translation

– Posterior horn of medial meniscus is major secondary restraint

• Secondary restraint to internal tibial rotation

45

Physical Exam

Comprehensive Knee Exam

» Range of Motion

» Anterior Drawer

» Posterior Drawer

» Lachman

» Pivot-shift

» Varus / Valgus

» Dial Test

Graft Options

47

Mechanism of Injury

» Impingement on the intercondylar notch

» Quadriceps contraction

» Quadriceps-Hamstring force balance

» Axial compressive forces

Several theories have been proposed to explain the

mechanism of non-contact ACL injury

48

Mechanism of Injury

» Impingement on the medial intercondylar

notch proposed as an anatomic cause for ACL

injury10 (hyper-extension).

» Most injuries occur with the knee in partial

flexion.11,12

Impingement

Page 9: Anterior Cruciate Ligamentandrewsref.org/docs/ACL_Ostrander Short 2_Final.pdfAnterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute A tomy A tomy nction • Primary

3/6/2017

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49

Mechanism of Injury

» The quadricep is the primary producer of anterior force with the knee at/near full extension.13

» Anterior vector of the quadriceps is the primary

contributing force to ACL injury.14

» Angle of the patellar tendon is shallow.15

(10o-25o in ext)

» Larger compressive force vector.

Quadriceps Contraction

50

Mechanism of Injury

» Hamstrings co-contraction provides a protective mechanism for the ACL.16

» Several authors have demonstrated that the hamstrings produce a small protective force vector.17,18

» Hamstrings contribute to knee compressive forces.

Hamstring Force Balance

51

Mechanism of Injury

» Numerous authors19-22 - axial compressive forces & increased tibial slope lead to anterior displacement of the tibia & ACL strain.

» Meyer, et al23 demonstrated that occult micro-cracks in subchondral bone were consistent with bone bruises found on MRI.

Axial Compressive Forces / Posterior Tibial Slope

52

Mechanism of Injury

» Hewett, et al. - landing with the knee in valgus as a factor contributing to ACL injury.24

» Chaudhari, et al. - valgus alignment compounds effect of axial compressive loading.25

Knee Abduction

54

Male vs Female

» 2 to 8 times risk for ACL injury in females.

» Risk of ACL injury in female collegiate soccer and basketball players is 5% per year (<2% for males).43

Gender as a risk factor

Page 10: Anterior Cruciate Ligamentandrewsref.org/docs/ACL_Ostrander Short 2_Final.pdfAnterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute A tomy A tomy nction • Primary

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X-rays

56

X-rays

Segond Fragment

Described by Paul Segond in 1879.66

Avulsion fracture of the anterolateral tibia.

High association with ACL injury.

Claes, et al. - Anterolateral Ligament (ALL) insertion.67

57

Imaging (MRI)

Confirm ACL disruption.

Diagnosis of associated injuries.

58

Graft Options

» Advantages: multiple sources, eliminates donor site morbidity, decreased OR time.

» Disadvantages: increased cost, slower rate of incorporation, increased risk of disease transmission, higher rate of failure.

» Good choice for older/lower demand population, revision cases.

Allograft

59

Graft Options

Allograft - Increased Failure Rate

» Kaeding, et al. - ACLr - 4x greater failure rate w/ allograft.78

» Krych, et al. - BPTB auto vs BPTB allo - 5x greater failure rate w/ allograft.79

» Keller, et al. - 120 cadets - 11% BTB, 13% HS, 44% Allograft failure rates.80

» Cooper, et al. - Mean total cost - $5,195 (allograft) & $4,072 (autograft).81

» OR time: avg 12mins longer with autograft.81

Allograft - Cost

60

Graft Options

Hamstring (gracilis & semitendinosus)83

Ultimate load to failure:

» Semitendinosus: 1216N

» Gracilis: 838N

» Quadrupled: 4590N

Page 11: Anterior Cruciate Ligamentandrewsref.org/docs/ACL_Ostrander Short 2_Final.pdfAnterior Cruciate Ligament Surgery Roger Ostrander, MD Andrews Institute A tomy A tomy nction • Primary

3/6/2017

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Graft Options

Hamstring (gracilis & semitendinosus)83

» Advantages: Highest ultimate tensile strength (4090N), decreased risk of anterior knee pain.

» Disadvantages: Tissue-to-bone fixation & healing (10-12wks), tunnel widening, loosening of graft, hamstring weakness.

» Must be at least 8mm in diameter

Goals for Graft

Tensioning• Provide a Stable Graft that Functions

Biomechanically

• “ISOMETRIC” Vs “ANATOMIC” tension

– ISOMETRIC=Equal tension throughout ROM

– ANATOMIC=Most tension in extension with less in flexion

• Allow full physiologic range of motion

• Potential for over constraint of the joint?

Anatomy

• Two functional bundles of ACL

– Anteromedial (AM)

• Tight in flexion

• Anterolateral stability

– Posterolateral (PL)

• Tight in extension

• Limits anterior

translation,

hyperextension, and

rotation

64

ACL Anatomy

Femoral Origin

Footprint size:

» Oval-shaped

» Vertically oriented

» 10mm x 18mm

Posterior

65

ACL Anatomy

Tibial Insertion

Anterior tibial plateau

Footprint size:

» 10mm coronal plane

» 18mm sagittal plane