Updated: 10/25/2018

ACL Tear

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Cases
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https://upload.orthobullets.com/topic/3008/images/MRI - sagital - ACL tear_moved.jpg
https://upload.orthobullets.com/topic/3008/images/acl_anatomy_1.jpg
https://upload.orthobullets.com/topic/3008/images/acl_anatomy_2.jpg
https://upload.orthobullets.com/topic/3008/images/segond fx.jpg
https://upload.orthobullets.com/topic/3008/images/aclbonebruise2.jpg
https://upload.orthobullets.com/topic/3008/images/MRI - coronal - bone bruise_moved.jpg
Introduction
  • Incidence
    • ~400,000 ACL reconstructions / year
  • Mechanism is a non-contact pivoting injury
    • video showing ACL tear in elite athlete
  • Often associated with a meniscal tear
    • lateral meniscal tears in 54% of acute ACL tears  
  • Chronic ACL deficient knees associated with
    • chondral injuries
    • complex unrepairable meniscal tears
    • relation with arthritis is controversial
  • Sex-related differences
    • ACL injury more common in female athlete (4.5:1 ratio) due to
      • landing biomechanics and neuromuscular activation patterns (quadriceps dominant) play the biggest role  
      • females get ACL injuries at a younger age than males
      • females get more ACL injuries on the supporting leg (males get more ACL injuries on the kicking leg)
      • table of differences  
Anatomy
  • ACL 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
  • ACL Anatomy
    • 32mm length x 7-12mm width in size
      • anteromedial bundle
        • more isometric
        • tight throughout knee ROM, but tightest in flexion
        • primarily responsible for restraining anterior tibial translation (anterior drawer test)
      • posterolateral bundle 
        • greater length changes
        • tightest in extension, slack in mid-flexion
        • primarily responsible for rotational stability (pivot shift test)
    • femoral attachment  
      • lateral intercondylar ridge demarcates the anterior edge of the ACL
      • bifurcate ridge separates the anteromedial and posterolateral bundle attachment
    • tibial attachment
      • anterior tibia, between intercondylar eminences
  • ACL Blood supply
    • middle geniculate artery   
  • ACL Innervation
    • posterior articular nerve ( a branch of tibial nerve)
  • ACL Composition
    • 90% Type I collagen 
    • 10% Type III collagen
  • ACL Strength: 2200 N (anterior)
Presentation
  • Presentation
    • felt a "pop"
    • pain deep in the knee
    • immediate swelling (70%) / hemarthrosis
  • Physical exam
    • effusion
    • quadricep avoidance gait (does not actively extend knee)
    • Lachman's test  
      • most sensitive exam test
      • grading
        • A= firm endpoint, B= no endpoint
        • Grade 1: 3-5 mm translation
        • Grade 2 A/B: 5-10mm translation
        • Grade 3 A/B: > 10mm translation
      • PCL tear may give "false" Lachman due to posterior subluxation
    • Pivot shift   
      • extension to flexion: reduces at 20-30° of flexion
      • patient must be completely relaxed (easier to elicit under anesthesia)
      • mimics the actual giving way event
    • KT-1000 
      • useful to quantify anterior laxity
      • measured with the knee in slight flexion and externally rotated 10-30° 
Imaging
  • Radiographs
    • usually normal
    • Segond fracture (avulsion fracture of the proximal lateral tibia) is pathognomonic for an ACL tear
      • 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.
  • MRI
    • findings of torn ACL
      • sagittal view
        • ACL fibers
          • discontinuity of fibers on T2
          • abnormal orientation 
            • too "flat" compared with intercondylar roof / Blumensaat's line  
            • this acute angle is common in chronic cases where ACL scars to the PCL
          • non-visualization of ACL
        • bone bruising in > half of acute ACL tears  
          • middle 1/3 of LFC (sulcus terminalis)
          • posterior 1/3 of the lateral tibial plateau
          • subchondral changes on MRI can persist years after injury
      • coronal view
        • discontinuity of fibers (do not reach the femur)  
        • fluid against the lateral wall ("empty notch sign")  
    • findings of normal ACL
      • fibers steeper than the intercondylar roof
      • continuity of fibers all the way from the tibia to femur
Treatment
  • Nonoperative
    • physical therapy & lifestyle modifications
      • low demand patients with decreased laxity
      • increased meniscal/cartilage damage linked to
        • loss of meniscal integrity
        • the frequency of buckling episodes
        • level I and II activity (e.g. jumping, cutting, side-to-side sports, heavy manual labor)
  • Operative
    • ACL reconstruction
      • indications
        • younger, more active patients (reduces the incidence of meniscal or chondral injury)
        • children (strongly consider operative as activity limitation is not realistic)
        • older active patients (age >40 is not a contraindication if high demand athlete)
        • prior ACL reconstruction failure
      • associated injuries
        • MCL injury
          • allow MCL to heal (varus/valgus stability) and then perform ACL reconstruction
          • varus/valgus instability can jeopardize graft
        • meniscal tear
          • perform the meniscal repair at the same time as ACL reconstruction
            • increased meniscal healing rate when repaired at the same time as ACL
        • posterolateral corner injury
          • reconstruct at the same time as ACL or as 1st stage of 2 stage reconstruction
      • outcomes
        • return to play
          • largely influenced by psychological, demographic and functional outcomes  
    • ligament repair
      • traditionally has a high failure rate
      • arthroscopic bridge-enhanced ACL repair (BEAR) trial with a bridging scaffold is ongoing  
    • revision ACL reconstruction
      • indications
        • failure of prior ACL reconstruction
Surgical Techniques
  • Femoral tunnel placement  
    • proper placement    
      • sagittal plane
        • 1-2 mm rim of bone between the tunnel and posterior cortex of the femur
      • coronal plane
        • the tunnel should be placed on the lateral wall (9-10 o'clock position) to create a more horizontal graft
  • Tibial tunnel placement
    • proper placement
      • sagittal plane
        • the center of tunnel entrance into joint should be 10-11mm in front of the anterior border of PCL insertion, 6mm anterior to the median eminence, 9mm posterior to the inter-meniscal ligament  
      • coronal plane
        • tunnel trajectory of < 75° from horizontal
          • obtain by moving tibial starting point halfway between tibial tubercle and a posterior medial edge of the tibia.
  • Graft placement
    • graft preconditioning
      • can reduce stress relaxation up to 50%
    • graft tensioning 
      • graft tensioning at 20N or 40N had no clinical outcome effects in a level 1 study
      • fix the graft in 20-30° of flexion
  • High tibial osteotomy
    • limb malalignment in both the coronal and sagittal plane must be addressed before or at the same time as ligament reconstruction
  • Revision ACL reconstruction
    • technique post
      • use high strength grafts (quad tendon, hamstring, allograft)
      • use dual fixation (suspension + interference screws)
      • bone grafting (tunnel dilation, decreased bone stock, staged)
      • re-harvesting BTB is contraindicated
    • postoperative
      • conservative rehab
Graft Selection
  • Bone-patellar-bone autograft post post
    • advantages of autograft
      • using patient's own tissue 
      • most common source of graft
      • faster incorporation
      • less immune reaction
      • no chance of acquiring someone else's infection
    • pros and cons of bone-patella-bone
      • the longest history of use and considered the "gold standard"
      • bone to bone healing
      • ability to rigidly fix the joint line (screws)
      • the highest incidence of anterior knee pain (up to 10-30%)  
      • maximum load to failure is 2600 Newtons (intact ACL is 1725 Newtons)
    • complications
      • patella fracture (usually postop during rehab), patellar tendon rupture 
      • re-rupture
        • associated with age < 20 years and graft size < 8mm 
  • Quadruple hamstring autograft
    • technique
      • may be taken from contralateral side in revision situation when allograft is not desirable or available
    • pros and cons
      • smaller incision, less perioperative pain, less anterior knee pain 
      • fixation strength may be less than Bone-PT-Bone
      • maximum load to failure is approximately 4000 Newtons  
      • decreased peak flexion strength at 3 years compared to Bone-PT-Bone
      • concern about hamstring weakness in female athletes leading to increased risk of re-rupture
    • complications
      • "windshield wiper" effect (suspensory fixation away from joint line causes tunnel abrasion and expansion with flexion/extension of knee)
      • residual hamstring weakness
  • Allograft
    • pros & cons
      • useful in revisions
      • longer incorporation time
      • risk of disease transmission (HIV is < 1:1 million, hepatitis is even greater)
      • increased risk of re-rupture in young athletes  
        • odds of graft re-rupture are 4.3 x higher in allograft for athletes aged 10-19
    • graft processing
      • supercritical CO2: decreases the structural and mechanical properties 
      • radiation3 Mrads is required to kill HIV (this, however, decreases the structural and mechanical properties)
        • 2-2.8 Mrad decreases stiffness by 30%
        • 1-1.2 Mrad decreases stiffness by 20%
      • deep freezing: destroys cells but does not affect the strength of the graft
      • 4% chlorhexidine gluconate: destroys cells but does not affect the strength of the graft
  • Quadriceps tendon autograft
    • taken with patella bone plug
    • much less common
Pediatric Considerations
  • Physis
    • < 14 yrs with open physis
    • the onset of menarche is the best determinant of skeletal maturity in females 
  • Treatment  
    • Nonoperative
      • indications
        • compliant, low demand patient with no additional intra-articular pathologies 
        • partial ACL tear (60% of adolescents have partial tears) with near normal Lachman and pivot shift
    • Surgery
      • indications
        • complete ACL tear
  • Techniques
    • intra-articular
      • physis-sparing (all intra-epiphyseal)  
      • transphyseal (males ≤13-16, females ≤ 12-14)
      • partial transphyseal 
        • leave either distal femoral or proximal tibial physis undisturbed 
      • no significant difference in growth disturbances between techniques
    • combined intra- and extra-articular (males ≤12, females ≤ 11)  
      • autogenous ITB harvested free proximally, left attached distally to Gerdy's tubercle
      • looped through the knee in over the top position
      • passed through the notch and under intermeniscal ligament anteriorly
      • sutured to lateral femoral condyle and proximal tibia
    • adult type reconstruction (males >=16, females >=14)
  • Graft Selection
    • transphyseal soft tissue grafts rarely lead to growth disturbances
  • Instrumentation
    • Factors found to increase physeal injury include: 
      • large tunnel diameter (>12mm) is most important 
        • 8mm tunnel corresponds to <3% physeal cross-sectional area
        • 12mm tunnel corresponds to >7-9% of physeal cross-sectional area is violated
      • oblique tunnel position 
      • interference screw fixation
      • high-speed tunnel reaming 
      • lateral extra-articular tenodesis
      • dissection close to the perichondral ring of LaCroix
      • suturing near tibial tubercle
  • Complications
    • physeal disruption without growth disturbance (10%)
Rehabilitation
  • Early postoperative
    • immediate
      • aggressive cryotherapy (ice)
      • immediate weight bearing (shown to reduce patellofemoral pain)
      • emphasize early full passive extension (especially if associated with MCL injury or patella dislocation)
    • early rehab
      • focus rehab on exercises that do not place excess stress on graft 
        • appropriate rehab  
          • eccentric strengthening at 3 weeks has been shown to result in increased quadriceps volume and strength  
          • isometric hamstring contractions at any angle
          • isometric quadriceps, or simultaneous quadriceps and hamstrings contraction
          • active knee motion between 35 degrees and 90 degrees of flexion
          • emphasize closed chain (foot planted) exercises
        • avoid
          • isokinetic quadricep strengthening (15-30°) during early rehab
          • open chain quadriceps strengthening   
  • Injury prevention
    • female athlete
      • neuromuscular training/plyometrics (jump training)
      • land from jumping in less valgus and more knee flexion
      • increasing hamstring strength to decrease quadriceps dominance ratio
    • skier training
      • teach skiers how to fall
    • ACL bracing
      • no proven efficacy except for ACL-deficient skiers
Complications
  • Failure due to Tunnel Malposition
    • overview
      • is the most common cause of ACL failure    
      • improper tunnel placement causes failure in 70% 
    • femoral tunnel malposition
      • coronal plane
        • vertical femoral tunnel placement 
          • cause by starting femoral tunnel at the vertical position in the notch (12 o:clock) as opposed to lateral wall (9 o: clock)
          • will cause continued rotational instability which can be identified on physical exam by a positive pivot shift    
      • sagittal plane
        • anterior tunnel placement    
          • leads to a knee that is tight in flexion and loose in extension
          • occurs from failure to clear "residents ridge"
        • posterior misplacement (over-the-top)
          • leads to a knee that is lax in flexion and tight in extension
    • tibial tunnel malposition
      • sagittal plane
        • anterior misplacement
          • leads to knee that is tight in flexion with impingement in extension 
        • posterior misplacement
          • leads to an ACL that will impinge with the PCL
  • Other cause of failure
    • inadequate graft fixation
      • can be caused by graft-screw divergence >30 degrees 
    • missed diagnosis
      • in combined ACL and PLC injuries, failure to treat the PLC will lead to failure of ACL reconstruction
    • overaggressive rehab
  • Infection
    • septic arthritis
      • coagulase negative Staph (S. epidermidis) most common
        • Staph aureus 2nd most common
      • presentation
        • pain, swelling, erythema, and increased WBC at 2-14 days postop
      • treatment
        • perform immediate joint aspiration with gram stain and cultures 
    • treatment
      • immediate arthroscopic I&D
      • often can retain graft with multiple I&Ds and antibiotics (6 weeks minimum)
        • graft retention more likely to be successful with S. epidermidis
        • graft retention less likely to be successful with S. aureus
  • Loss of motion & arthrofibrosis 
    • preoperative prevention
      • be sure patient has regained full ROM before you operate ("pre-hab")  
      • wait until swelling (inflammatory phase) has gone down to reduce the incidence of arthrofibrosis
    • operative prevention
      • proper tunnel placement is critical to have a full range of motion
    • postop prevention
      • aggressive cryotherapy (ice)
    • treatment
      • < 12 weeks, then treat with aggressive PT and serial splinting
      • > 12 weeks, then treat with lysis of adhesions/manipulation under anesthesia
  • Infrapatellar contracture syndrome
    • an uncommon complication following knee surgery or injury which results in knee stiffness
    • the physical exam will show decreased patellar translation    
  • Patella Tendon Rupture
    • will see patella alta on the lateral radiograph 
  • RSD (complex regional pain syndrome)
  • Patella fracture
    • most fx occur 8-12 weeks postop
  • Hardware failure
  • Tunnel osteolysis
    • treat with observation
  • Late arthritis
    • related to meniscal integrity 
  • Local nerve irritation
    • saphenous nerve  
  • Cyclops lesion
    • fibroproliferative tissue blocks extension
    • "click" heard at terminal extension
 

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Technique Guides (4)
Questions (82)
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(OBQ04.19) You are called by a 35-year-old male patient who had ACL reconstruction with hamstring autograft 5 days ago. He reports his knee pain and swelling have significantly increased in the last day, and now it is difficult for him to raise his leg off the bed and is having more difficulty tolerating the CPM machine. Upon questioning he denies fever, chills, or any new trauma to the knee. What is the next step in management? Review Topic

QID: 130
1

Ice, NSAIDS, elevation, compression wrap and restart therapy once symptoms improve

27%

(118/437)

2

Recommend immediate knee aspiration with gram stain and cultures

67%

(294/437)

3

Increase CPM use to 10 hours a day

0%

(2/437)

4

Call the office staff in the morning to schedule an appointment

5%

(21/437)

5

Start physical therapy visits once daily

0%

(2/437)

ML 2

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(OBQ06.112) A 25-year-old male soccer player twisted his left knee 4 days ago and developed immediate swelling and pain. On exam, he has a 2+ effusion and pain with active range of motion. Passively, he tolerates range of motion from 0-90 degrees. He has difficulty performing a straight leg raise exercise. MRI scan is shown in Figure A. What is the most appropriate initial management for his injury? Review Topic

QID: 298
FIGURES:
1

Knee immobilization

7%

(87/1286)

2

Physical therapy for range of motion

74%

(950/1286)

3

Acute reconstruction followed by mobilization

11%

(145/1286)

4

Arthrocentesis to rule out infection

0%

(2/1286)

5

Rest, nonsteroidal anti-inflammatories, and follow-up in 4 weeks

8%

(100/1286)

ML 2

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PREFERRED RESPONSE 2
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(OBQ07.155) Increased ACL injury rates in women athletes compared to male athletes may be due to muscular imbalance and relative weakness in which of the following muscle groups? Review Topic

QID: 816
1

Quadriceps

40%

(256/641)

2

Hamstrings

57%

(364/641)

3

Gluteus muscles

1%

(6/641)

4

Adductors

1%

(8/641)

5

Abdominals

0%

(3/641)

ML 3

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PREFERRED RESPONSE 2

(SBQ07SM.14) During anterior cruciate ligament (ACL) reconstruction divergence between the graft and screw fixation within the bone tunnel can lead to complications. Which of the following statements regarding graft-screw divergence is true? Review Topic

QID: 1399
1

Risk of failure is eliminated using an accessory anteromedial drilling portal

2%

(14/795)

2

Complications occur more commonly with soft tissue grafts

4%

(28/795)

3

Loss of fixation becomes a greater risk if the graft-screw divergence is >30 degrees

86%

(681/795)

4

Excessive graft-screw divergence more commonly occurs during tibial fixation

3%

(20/795)

5

Graft-screw divergence is a common cause of late failure of ACL reconstructions

6%

(46/795)

ML 2

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PREFERRED RESPONSE 3

(OBQ12.249) A 12-year-old female sustained a right knee injury during a high-level gymnastic competition. Physical examination revealed a significant effusion, positive anterior drawer, and 3+ Lachman. She is a Tanner 3 on the scale of physical development. When considering transphyseal reconstruction techniques, which of the following factors has the greatest potential to cause physeal injury in the tibia? Review Topic

QID: 4609
1

Vertical transphyseal tunnel position

9%

(288/3251)

2

Slow transphyseal tunnel reaming

5%

(148/3251)

3

Hamstring autograft

0%

(13/3251)

4

Small transphyseal tunnel diameter

1%

(29/3251)

5

Horizontal and oblique transphyseal tunnel position

85%

(2756/3251)

ML 2

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PREFERRED RESPONSE 5

(OBQ04.9) When evaluating patients that needed revision surgery, what is the most common cause of a failed primary ACL reconstruction? Review Topic

QID: 120
1

Tunnel malposition

90%

(497/554)

2

Obesity

0%

(2/554)

3

Smoking

1%

(4/554)

4

Returning to sport too early

5%

(30/554)

5

Inadequate physical therapy

3%

(17/554)

ML 1

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PREFERRED RESPONSE 1

(OBQ07.87) A patient sustains a knee injury. The MRI image shown in Figure A is indicative of which of the following injuries? Review Topic

QID: 748
FIGURES:
1

ACL tear

90%

(1097/1216)

2

PCL tear

7%

(81/1216)

3

Medial meniscus tear

0%

(4/1216)

4

Lateral meniscus tear

1%

(15/1216)

5

Patellar tendon tear

1%

(14/1216)

ML 1

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PREFERRED RESPONSE 1

(OBQ07.66) A 16-year-old high school basketball player sustains a non-contact knee injury when she lands from a rebound. She develops immediate swelling and is noted to have a hemarthrosis. What is the most likely diagnosis? Review Topic

QID: 727
1

MCL tear

1%

(4/504)

2

Medial meniscus tear

2%

(11/504)

3

ACL tear

94%

(472/504)

4

Patellar dislocation

2%

(8/504)

5

Contusion

1%

(4/504)

ML 1

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PREFERRED RESPONSE 3

(OBQ06.138) Following ACL reconstruction, which of the following tests most closely correlates with patient satisfaction with their reconstructed knee? Review Topic

QID: 324
1

KT-1000 manual maximum value

15%

(73/480)

2

Lachman's test

11%

(55/480)

3

Anterior drawer test

3%

(15/480)

4

Pivot shift test

60%

(288/480)

5

Cybex testing

10%

(46/480)

ML 3

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PREFERRED RESPONSE 4

(OBQ04.174) Which of the following factors concerning ACL reconstruction has demonstrated definitive evidence of adverse effect on clinical outcomes? Review Topic

QID: 1279
1

Center of tibia tunnel placement in-line with the posterior aspect of the anterior horn of the lateral meniscus

3%

(15/460)

2

Horizontal femoral tunnel placement (10 or 2 o’clock position)

9%

(41/460)

3

Femoral tunnel placement anterior to the lateral intercondylar ridge

75%

(345/460)

4

One-incision instead of two-incision tunnel drilling technique

5%

(25/460)

5

Tibial tunnel is parallel and posterior to Blumenstaat's line when knee is fully extended

7%

(33/460)

ML 1

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PREFERRED RESPONSE 3

(OBQ12.94) Which of the following bone bruise patterns seen on magnetic resonance imaging (MRI) is most consistent with an anterior cruciate ligament (ACL) tear? Review Topic

QID: 4454
1

Medial tibial spine and medial femoral condyle

1%

(79/5364)

2

Medial facet of patella and lateral femoral condyle

1%

(27/5364)

3

Posterolateral tibia and lateral femoral condyle

79%

(4221/5364)

4

Posterolateral tibia and medial femoral condyle

9%

(509/5364)

5

Medial tibial spine and lateral femoral condyle

9%

(500/5364)

ML 2

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PREFERRED RESPONSE 3

(OBQ05.174) A high school girls basketball player sustains a non-contact knee injury and develops an acute hemarthrosis. What is the likelihood that she has an ACL tear? Review Topic

QID: 1060
1

0-15%

1%

(11/1923)

2

15-30%

4%

(71/1923)

3

30-45%

6%

(114/1923)

4

45-60%

11%

(215/1923)

5

>60%

78%

(1505/1923)

ML 2

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PREFERRED RESPONSE 5

(OBQ12.41) A genotype within the COL5A1 gene is associated with a reduced risk of which of the following injuries in women? Review Topic

QID: 4401
1

Glenohumeral dislocation

4%

(213/5178)

2

Rotator cuff tear

7%

(347/5178)

3

Lateral patellar dislocation

8%

(416/5178)

4

Anterior cruciate ligament rupture

75%

(3896/5178)

5

Torn discoid meniscus

5%

(259/5178)

ML 3

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PREFERRED RESPONSE 4

(OBQ10.223) A collegiate men's basketball point guard undergoes ACL reconstruction with hamstring autograft. One year following reconstruction, he returns to playing and complains of recurrent instability episodes. He has an acute giving way episode on the court and is found to have an effusion and a positive pivot shift. Which of the following is the most likely cause of his injury? Review Topic

QID: 3322
1

Improper graft selection

4%

(101/2448)

2

Lack of sufficient physical rehabilitation prior to return to basketball

10%

(247/2448)

3

Overly aggressive physical rehabilitation during the first 3 months following reconstructive surgery

3%

(73/2448)

4

Surgical error in graft tensioning

3%

(81/2448)

5

Surgical error in tunnel position

79%

(1935/2448)

ML 2

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PREFERRED RESPONSE 5

(OBQ05.28) At what range of motion do seated leg extension exercises place the greatest amount of stress on the anterior cruciate ligament? Review Topic

QID: 65
1

0 to 30 degrees

45%

(874/1928)

2

30 to 60 degrees

32%

(625/1928)

3

60 to 90 degrees

13%

(258/1928)

4

90 to 120 degrees

5%

(102/1928)

5

flexion greater than 120 degrees

3%

(60/1928)

ML 4

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PREFERRED RESPONSE 1

(OBQ09.147) Tunnel malposition is thought to be a primary etiology for ACL graft failure. All of the following are true of tunnel position EXCEPT: Review Topic

QID: 2960
1

Vertical placement of the femoral tunnel can result in rotational instability and impingement against the PCL

3%

(20/584)

2

Anterior placement of the femoral tunnel can result in elongation of the graft

7%

(39/584)

3

Tibial tunnel placement should be placed posterior to a line extending from Blumenstaat's line when the knee is in full extension

10%

(58/584)

4

Transtibial drilling through a tibia tunnel that is too far anterior can result in a vertical (12:00) graft

24%

(143/584)

5

Transtibial drilling through a tibia tunnel that is too far anterior can result in an oblique (10:30 or 1:30 position) graft

54%

(318/584)

ML 3

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PREFERRED RESPONSE 5

(OBQ07.274) Which of the following risk factors is felt to contribute greatest to the higher rate of ACL rupture in female compared to male athletes? Review Topic

QID: 935
1

Body mass index

1%

(3/519)

2

Femoral notch width

4%

(20/519)

3

Generalized ligamentous laxity

8%

(44/519)

4

Neuromuscular factors

72%

(372/519)

5

Limb alignment

15%

(79/519)

ML 2

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PREFERRED RESPONSE 4

(SBQ07SM.37) You are considering performing an anterior cruciate ligament reconstruction on an adolescent female athlete but are concerned about the possibility of a resultant leg length discrepency. Which of the following history or physical findings is most reliable at predicting the amount of growth remaining? Review Topic

QID: 1422
1

Cessation of changes in shoe size

1%

(2/339)

2

Onset of menarche

87%

(294/339)

3

Secondary sex characteristics

9%

(30/339)

4

Doubling the child’s height when she was 2 years of age to determine final height

1%

(2/339)

5

Age at which patellar ossification began

2%

(8/339)

ML 2

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PREFERRED RESPONSE 2

(OBQ04.91) A 30 year-old tennis player sustains the injury seen in Figure A and is considering nonoperative treatment of this injured structure. With nonoperative treatment, which of the following additional findings correlate most closely with the development of future arthritis? Review Topic

QID: 1196
FIGURES:
1

Grade IIB Lachman

6%

(33/558)

2

Presence of pivot shift

34%

(189/558)

3

Tenderness over MCL origin without opening on valgus

2%

(10/558)

4

Positive Ober test

1%

(4/558)

5

Painful pop on McMurray test

57%

(320/558)

ML 2

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PREFERRED RESPONSE 5

(SBQ04SM.32) In biomechanical testing, which of the following tissues has the highest maximum load to failure? Review Topic

QID: 5
1

Quadruple semitendinosus and gracilis tendons

73%

(1293/1760)

2

Bone-patellar tendon-bone with a width of 10 mm

15%

(268/1760)

3

Bone-quadriceps tendon with a width on 10mm

3%

(47/1760)

4

Tibialis tendon allograft

1%

(20/1760)

5

Native anterior cruciate ligament (ACL)

7%

(120/1760)

ML 2

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PREFERRED RESPONSE 1

(OBQ04.56) An 18-year-old athlete is now 3 months out from anterior cruciate ligament reconstruction. He has been unable to obtain full extension of the knee. His range of motion is from 12° to 125° compared to 0° to 140° on the contralateral knee. He has no effusion, no pain at rest, and a stable Lachman’s test. He is having difficulty ambulating without crutches. What is the most common technical error which can account for these findings? Review Topic

QID: 2
1

Femoral tunnel drilled too anteriorly

28%

(491/1750)

2

Failure to cycle the knee prior to final tibial fixation

5%

(81/1750)

3

Femoral tunnel drilled too vertically

10%

(180/1750)

4

Tibial tunnel drilled too vertically

2%

(40/1750)

5

Tibial tunnel drilled too anteriorly

54%

(952/1750)

ML 4

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PREFERRED RESPONSE 5

(OBQ05.96) Most surgeons prefer to avoid or limit which of the following exercises in the initial post-operative rehabilitation following ACL reconstruction? Review Topic

QID: 982
1

Quadriceps sets

10%

(52/517)

2

Seated leg extensions

74%

(380/517)

3

Straight leg raises

6%

(31/517)

4

Active range of motion

3%

(15/517)

5

Closed chain exercises

8%

(39/517)

ML 2

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PREFERRED RESPONSE 2

(OBQ11.271) A 23-year-old soccer player suffers an ACL rupture and undergoes reconstruction. Post-operatively she begins a rehabilitation program and her therapist develops a series of knee conditioning exercises to help her regain strength and range of motion. Which of the following exercises places the lowest strain in this patients properly placed ACL graft? Review Topic

QID: 3694
1

Isometric hamstring contractions at 60 degrees of knee flexion

49%

(1020/2079)

2

Isolated quadriceps contractions with the knee at 30 degrees of flexion

10%

(210/2079)

3

Simultaneous quadricep and hamstring contractions at 15 degrees of knee flexion

27%

(553/2079)

4

Isolated quadriceps contractions with the knee at 15 degrees of flexion

11%

(221/2079)

5

Active resisted knee motion from terminal extension to 30 degrees of flexion

3%

(62/2079)

ML 4

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PREFERRED RESPONSE 1

(OBQ04.240) In laboratory testing of quadrupled hamstring grafts (doubled over semitendinosis and gracilis), all of the following statements are true EXCEPT: Review Topic

QID: 1345
1

Two equally tensioned semitendinosus strands have an average of 220 percent of the strength of one semitendinosus strand

6%

(21/340)

2

Single semitendinosis strand has a higher tensile strength than a single gracilis strand

4%

(13/340)

3

All strands of a hamstring graft must be equally tensioned to achieve optimum biomechanical properties

7%

(24/340)

4

Quadrupled grafts have tensile properties that are higher than 10mm patellar-ligament grafts

15%

(50/340)

5

Quadrupled hamstring grafts have lower tensile strength than the native ACL

68%

(230/340)

ML 2

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PREFERRED RESPONSE 5

(OBQ10.229) Which of the following exercises should typically be avoided during the initial therapy following ACL reconstruction? Review Topic

QID: 3328
1

Light leg press

1%

(20/1947)

2

Use of a stair climbing machine

2%

(48/1947)

3

Vertical squat with light dumbbells in each hand

6%

(119/1947)

4

Seated leg extensions

90%

(1743/1947)

5

Use of a stationary bike

1%

(12/1947)

ML 1

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PREFERRED RESPONSE 4

(OBQ03.166) A patient undegoes an uncomplicated anterior cruciate ligament reconstruction. Which of the following activities are generally not recommended during the first 6 weeks of physical therapy? Review Topic

QID: 3
1

Patellar mobilizations

1%

(5/443)

2

Passive extension

2%

(10/443)

3

Heel slides to improve flexion

4%

(19/443)

4

Isometric quadriceps strengthening

16%

(71/443)

5

Isokinetic quadriceps strengthening

76%

(337/443)

ML 2

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PREFERRED RESPONSE 5

(OBQ11.129) A patient develops infrapatellar contracture syndrome after undergoing ACL surgery. All of the following findings are consistent with this diagnosis EXCEPT? Review Topic

QID: 3552
1

Patella infera

1%

(36/2448)

2

Decreased patellar mobility

1%

(27/2448)

3

Loss of active but not passive flexion

67%

(1640/2448)

4

Loss of full extension

16%

(391/2448)

5

Loss of passive flexion

14%

(345/2448)

ML 3

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PREFERRED RESPONSE 3

(OBQ06.177) A patient develops anteromedial pain and altered sensation over the anterolateral infrapatellar region of the knee after autologous hamstring tendon harvest for an ACL reconstruction. Which of the following nerves has been injured? Review Topic

QID: 363
1

Medial retinacular

5%

(24/458)

2

Inferior genicular

28%

(129/458)

3

Saphenous

65%

(296/458)

4

Superficial peroneal

2%

(7/458)

5

Tibial

0%

(1/458)

ML 2

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PREFERRED RESPONSE 3

(OBQ11.215) A 25-year-old male is one year status post anterior cruciate ligament (ACL) reconstruction using patellar bone-tendon-bone (BTB) autograft. He complains of persistent instability with certain activities. His operative dictation notes excellent stability intra-operatively with femoral fixation at the 12 o'clock position. Based on his femoral tunnel position, his history and examination are most likely to reveal which of the following? Review Topic

QID: 3638
1

Positive pivot shift test and instability with cutting activities due to failure to reconstruct the posterolateral bundle of the ACL

77%

(2001/2589)

2

Positive Lachman's test and instability with forward running activites due to failure to reconstruct the anteromedial bundle of the ACL

6%

(155/2589)

3

Positive pivot shift test and instability with cutting activities due to failure to reconstruct the anterolateral bundle of the ACL

9%

(233/2589)

4

Positive Lachman's test and instability with forward activites due to failure to reconstruct the posteromedial bundle of the ACL

2%

(43/2589)

5

Positive pivot shift test and instability with forward running activities due to failure to reconstruct the posterolateral bundle of the ACL

5%

(139/2589)

ML 2

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PREFERRED RESPONSE 1

(OBQ05.190) The middle genicular artery is the primary blood supply of which of the following structures? Review Topic

QID: 1076
1

Medial collateral ligament

2%

(12/490)

2

Lateral collateral ligament

0%

(2/490)

3

Medial meniscus

9%

(43/490)

4

Lateral meniscus

0%

(1/490)

5

Anterior cruciate ligament

88%

(429/490)

ML 1

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PREFERRED RESPONSE 5

(OBQ08.186) Patients may complain of numbness over the anterolateral aspect of the knee following ACL reconstruction. This is most commonly due to injury of which of the following? Review Topic

QID: 572
1

Suprapatellar branch of the saphenous nerve

10%

(56/538)

2

Infrapatellar branch of the saphenous nerve

81%

(435/538)

3

The common peroneal nerve

1%

(7/538)

4

The superficial femoral nerve

3%

(14/538)

5

The lateral femoral cutaneous nerve

5%

(26/538)

ML 1

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PREFERRED RESPONSE 2

(OBQ04.212) A 16-year-old female volleyball player presents 1 week after sustaining a knee injury while landing from a jump. There was an audible popping sound at the time of injury and she developed swelling later that evening. On physical examination, the surgeon applies a valgus force to the fully extended and internally rotated knee. As the knee is then brought into flexion, a loud clunk occurs at 30° of flexion. Which of the following patterns of bone contusion shown on MRI in Figures A-E is most likely to be evident on this patient's MRI? Review Topic

QID: 1317
FIGURES:
1

Figure A

89%

(1822/2049)

2

Figure B

2%

(47/2049)

3

Figure C

4%

(90/2049)

4

Figure D

2%

(40/2049)

5

Figure E

2%

(44/2049)

ML 1

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PREFERRED RESPONSE 1

(OBQ04.258) The saphenous nerve is most likely to be injured with which of the following steps during an anterior cruciate ligament (ACL) reconstruction with hamstring autograft? Review Topic

QID: 1363
1

Incision for an anteromedial portal with the knee flexed

6%

(26/452)

2

Incision for an anteromedial portal with the knee extended

10%

(45/452)

3

Incision for an accessory medial portal the with knee flexed

11%

(49/452)

4

Hamstring harvest with the knee extended

71%

(319/452)

5

Tibial tunnel aperture fixation with the knee at 30 degrees of flexion

2%

(10/452)

ML 2

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PREFERRED RESPONSE 4

(OBQ04.262) Which of the following physical exam maneuvers would be MOST expected for a patient with the following radiograph? Review Topic

QID: 1367
FIGURES:
1

Positive Lachman's test

79%

(863/1099)

2

Positive McMurray's test with leg internally rotated

3%

(29/1099)

3

Positve McMurray's test with leg externally rotated

4%

(41/1099)

4

Positive external rotation dial test with knee flexed at 30 degrees

10%

(110/1099)

5

Positive external rotation dial test with knee flexed at 30 degrees and 90 degrees

5%

(55/1099)

ML 2

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PREFERRED RESPONSE 1

(OBQ04.246) A 23-year-old soccer player sustains an anterior cruciate ligament (ACL) tear and is scheduled for reconstruction. He has questions regarding the use of autografts. Which of the following statements is true regarding bone-patellar tendon-bone (BTB) autograft in comparison to quadrupled hamstring autograft for ACL reconstruction? Review Topic

QID: 1351
1

BTB autograft is biomechanically stronger than quadrupled hamstring autograft

5%

(25/506)

2

BTB autograft shows less evidence of post-operative pivot shift

1%

(6/506)

3

Quadrupled hamstring autograft shows lower rate of graft failure

3%

(13/506)

4

BTB shows higher incidence of anterior knee pain

90%

(456/506)

5

Quadrupled hamstring autograft shows lower incidence of knee hardware removal

0%

(2/506)

ML 1

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PREFERRED RESPONSE 4

(OBQ05.40) During anterior cruciate ligament reconstruction, a graft that is tight in flexion but lax in extension may be due to which technical error? Review Topic

QID: 1
1

Femoral tunnel is too posterior

8%

(177/2093)

2

Femoral tunnel is too anterior

72%

(1505/2093)

3

Femoral tunnel placed at 12:00 position

4%

(79/2093)

4

Tibial tunnel is too anterior

14%

(293/2093)

5

Tibial tunnel is too medial

1%

(17/2093)

ML 2

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PREFERRED RESPONSE 2

(OBQ08.120) A 25-year-old male undergoes an ACL reconstruction with an ipsilateral bone-patella tendon-bone autograft. At his two week followup he is noted to have complete loss of his extensor mechanism on exam, stable Lachman and posterior drawer tests, and patella alta radiographically. Management should consist of? Review Topic

QID: 506
1

Continued standard ACL rehab protocol

3%

(18/529)

2

Quadraceps tendon repair

3%

(15/529)

3

WBAT in a cylinder cast

1%

(3/529)

4

Patellar tendon repair or reconstruction

93%

(491/529)

5

Revision ACL reconstruction with hamstring autograft

0%

(2/529)

ML 1

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PREFERRED RESPONSE 4

(OBQ08.193) Strategies which focus on increasing patient neuromuscular control are most effective at preventing which of the following female sporting injuries? Review Topic

QID: 579
1

Shoulder dislocations

1%

(8/1215)

2

Concussion

0%

(4/1215)

3

Anterior cruciate ligament ruptures

96%

(1167/1215)

4

Frieberg's infarction

0%

(4/1215)

5

Patellofemoral instability

2%

(29/1215)

ML 1

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PREFERRED RESPONSE 3

(OBQ09.26) A 31-year-old male is 1 year status post primary anterior cruciate ligament reconstruction. Despite adequate physical therapy, he has been unable to return to sport due to recurrent instability and elects to proceed with revision surgery. What is the most common reason for failure of his primary ACL reconstruction? Review Topic

QID: 2839
1

Unrecognized varus malalignment preop

2%

(34/1633)

2

Improper bone tunnel placement

95%

(1554/1633)

3

Reconstruction with a single bundle

1%

(10/1633)

4

Improper graft selection

1%

(9/1633)

5

Meniscal injury

1%

(20/1633)

ML 1

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PREFERRED RESPONSE 2

(OBQ05.214) All of the following are true regarding excessively anterior femoral tunnel placement during ACL reconstruction EXCEPT? Review Topic

QID: 1100
1

It may cause loss of knee flexion

17%

(110/657)

2

It may cause graft over-stretching and failure

9%

(59/657)

3

It is the most common technical error

17%

(110/657)

4

It may cause interference screw divergence

51%

(338/657)

5

It is often due to poor visualization

5%

(36/657)

ML 3

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PREFERRED RESPONSE 4

(OBQ08.213) When comparing autologous graft options for ACL reconstruction, a hamstring graft is associated with which of the following findings when compared to a patellar tendon graft? Review Topic

QID: 599
1

Decreased tunnel widening

1%

(25/2210)

2

Decreased pivot shift

1%

(13/2210)

3

Decreased incidence of anterior knee pain

94%

(2084/2210)

4

Increased knee flexion strength on Cybex testing

2%

(36/2210)

5

Increased stability on KT-1000

2%

(45/2210)

ML 1

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PREFERRED RESPONSE 3
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CASES (13)

Multi-ligament knee injury 18 mos s/p BTB ACL in an 18M football lineman (C101037)

  • Knee & Sports
  • - ACL Tear

HPI - The patient is an 18-year-old male high school football player (position: offensive line) who is 18 months s/p RIGHT ACL reconstruction with an ipsilateral BTB autograft who injured his RIGHT knee while playing football. The mechanism of injury was an opposing player landing on the outside of his leg, resulting in a valgus-type, twisting knee injury. The patient was unable to bear weight following the injury and was carted off the field. Examination on the sideline immediately following the injury revealed a positive Lachman's and a grossly positive valgus stress test with the knee in full extension. An MRI revealed complete rupture of the ACL graft and a grade 3 (complete) tear of the MCL. Initial management included a hinged knee brace for 8 weeks in an attempt to treat the MCL tear conservatively. At 8 weeks post-injury, valgus-stress radiographs (XRays shown) showed: Medial grapping LEFT knee = 7mm Medial gapping RIGHT knee = 15mm A CT scan was also done to assess for osteolysis of the tunnels. Maximum tunnel diameters are 13mm (femoral tunnel) and 14mm (tibial tunnel). The position of the femoral and tibial tunnels looks adequate. Full-length standing XRays show neutral alignment.

An MRI one day after injury reveals a complete rupture of the ACL graft and a grade 3 MCL tear, no meniscal pathology. What is your initial management of this patient?

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