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http://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 (conditioning and strength) play biggest role
    • females get ACL injuries at 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 secondary restraint to tibial rotation and varus/valgus rotation
  • ACL Anatomy
    • 32mm length x 7-12mm width in size
    • goes from LFC to anterior tibia (tibial insertion is broad and irregular and inserts just anterior and between the intercondylar eminences of the tibia)
    • two bundles
      • anteromedial bundle
        • more isometric
        • tight in flexion
      • posterolateral bundle
        • tightest in extension (where it likely contributes greatest to rotational stability)
  • ACL Blood supply
    • middle geniculate artery
  • ACL Innervation
    • posterior articular nerve (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 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 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
  • 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 lateral tibial plateau
          • subchondral changes on MRI can persist years after injury
      • coronal view
        • discontinuity of fibers (do not reach the femur)  
        • fluid against lateral wall ("empty notch sign")  
    • findings of normal ACL
      • fibers steeper than intercondylar roof
      • continuity of fibers all the way from 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
        • 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 incidence of meniscal or chondral injury)
        • children (strongly consider operative as activity limitation is not realistic)
        • older active patients (age >40 is not 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 meniscal repair at 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 psycholgical, demographic and functional outcomes  
    • ligament repair
      • traditionally has 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 tunnel and posterior cortex of femur
      • coronal plane
        • tunnel should be placed on lateral wall (9-10 o'clock position) to create more horizontal graft
  • Tibial tunnel placement
    • proper placement
      • sagittal plane
        • center of tunnel entrance into joint should be 10-11mm in front of anterior border of PCL insertion
      • coronal plane
        • tunnel trajectory of < 75° from horizontal
          • obtain by moving tibial starting point halfway between tibial tubercle and posterior medial edge of 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 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 prn)
      • reharvesting BTB contraindicated
    • postoperative
      • conservative rehab
Graft Selection
  • Bone patellar bone autograft post post
    • advantage 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
      • longest history of use, considered the "gold standard"
      • bone to bone healing
      • ability to rigidly fix at the joint line (screws)
      • 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 
  • 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 periop 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 in young athletes  
        • odds of graft rerupture 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 strength of graft
      • 4% chlorhexidine gluconate: destroys cells but does not affect strength of graft
  • Quadriceps tendon autograft
    • taken with patella bone plug
    • much less common
Pediatric Considerations
  • Physis
    • < 14 yrs with open physis
    • onset of menarche is 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 proxiaml 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 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 vertical position in 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 abx (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 incidence of arthrofibrosis
    • operative prevention
      • proper tunnel placement is critical to have 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
    • physical exam will show decreased patellar translation    
  • Patella Tendon Rupture
    • will see patella alta on 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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Questions (41)

(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%

(160/3695)

2

Rotator cuff tear

7%

(254/3695)

3

Lateral patellar dislocation

9%

(319/3695)

4

Anterior cruciate ligament rupture

74%

(2729/3695)

5

Torn discoid meniscus

5%

(195/3695)

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PREFERRED RESPONSE 4

A genotype within the COL5A1 gene is associated with reduced risk for ACL ruptures in women.

Females are at increased risk of ACL injuries when compared to males with a male:female injury ration of 1:4.5. In females these injuries are more often noncontact injuries. Other factors that help explain the increased incidence in women include neuromuscular forces and control, landing biomechanics, smaller femoral notches, genetic factors related to collagen production, smaller ligaments, hormone levels, and valgus leg alignment.

Posthumus et al. found that the CC genotype of the COL5A1 BstUI RFLP was underrepresented in female participants with ACL ruptures. This is the first study to show that there is a specific genetic risk factor associated with risk of ACL ruptures in female athletes.

Padua et al. evaluated a clinical screening tool called LESS (the Landing Error Scoring System) to identify patients at risk for ACL injury. It is scored from a video of subjects performing a jump-landing-rebound task. They found it to be a valid and reliable tool for identifying potentially high-risk movement patterns which could predispose to ACL injury.

Chappell et al. analyzed videos of athletes performing a stop-jump task. Female subjects prepared for landing with decreased hip and knee flexion at landing, increased quadriceps activation, and decreased hamstring activation, which may result in increased ACL loading and risk for noncontact ACL injury.

Illustration A shows a schematic of lower extremity internal rotation and knee valgus that can predispose to ACL injury. Illustration V is a video that shows an athletic trainer discussing and demonstrating the importance of correct mechanics for jumping and landing.

Incorrect Answers:
Answer 1,2,3,5: Studies have not shown a correlation between these conditions and the COL5A1 gene.

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(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

2%

(59/3932)

2

Medial facet of patella and lateral femoral condyle

1%

(20/3932)

3

Posterolateral tibia and lateral femoral condyle

78%

(3063/3932)

4

Posterolateral tibia and medial femoral condyle

9%

(364/3932)

5

Medial tibial spine and lateral femoral condyle

10%

(406/3932)

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PREFERRED RESPONSE 3

Bone bruising occurs in more than half of all ACL tears and is seen most commonly on the posterolateral tibia and middle 1/3 of the lateral femoral condyle (sulcus terminalis).

ACL tears usually occur as a result of a non-contact pivoting injury. Bone bruise patterns correlate with the direction of the abnormal anterior translation and abutment of the posterolateral tibia against the middle 1/3 of the lateral femur during the injury.

Viskontas et al., in a prospective cohort study, looked at the correlation between the mechanism of ACL injury and presence of bone bruise patterns in 100 patients. They found that bone bruising was more frequent, deeper, and more intense in non-contact ACL injuries (P < .001).

Yoon et al. reviewed 81 patients with bone contusions and associated meniscal and medial collateral ligament (MCL) injuries in patients with anterior cruciate ligament ruptures. They found patients with more severe bone contusions tended to have more concomitant injuries of the menisci and the MCL.

Illustration A shows an example of the abnormal anterior translation and abutment of the posterolateral tibia against the middle 1/3 of the lateral femoral condyle during the injury. Illustration B shows a T2 sagittal MRI with characteristic bone bruising from an ACL injury.

Incorrect Answers:
Answer 1,4,5: These bone bruise patterns are not characteristic with ACL injury.
Answer 2: Is the characteristic bone bruise pattern for lateral patellar dislocation.

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(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%

(225/2424)

2

Slow transphyseal tunnel reaming

5%

(112/2424)

3

Hamstring autograft

0%

(9/2424)

4

Small transphyseal tunnel diameter

1%

(17/2424)

5

Horizontal and oblique transphyseal tunnel position

85%

(2055/2424)

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PREFERRED RESPONSE 5

When considering transphyseal ACL reconstruction techniques in skeletally immature patients, a horizontally oriented tunnel and interference screw has the greatest potential to cause tibial physeal injury.

Transphyseal reconstruction techniques have traditionally been approached with caution due to the possibility of growth disturbance. The likelihood of growth disturbance has been shown to be associated with the percentage of cross-sectional area of physis injured during surgical reconstruction. Different models have shown that 7% to 9% of the cross-sectional area of physis is enough to cause significant disturbance. Factors found to increase volumetric injury include: oblique tunnel position, high-speed tunnel reaming, and increasing tunnel diameter (>8mm).

Frosch et al. evaluated the clinical outcomes and risks of anterior cruciate ligament (ACL) surgery in children and adolescents. They found that the overall rate of leg-length difference was significantly less with transphyseal reconstruction techniques than physeal-sparing.

Kumar et al. looked at a series of 32 skeletally immature patients with Tanner scores between 1-3 that were treated with transphyseal reconstruction techniques. They showed that there were no leg limb discrepancies in all patients followed up to the age of 16 years old.

Kocher et al. retrospectively reviewed sixty-one knees in fifty-nine skeletally immature pubescent adolescents who underwent transphyseal reconstruction of the anterior cruciate ligament. No lower-extremity length discrepancies were detected clinically with this procedure. Three cases of arthrofibrosis required manipulation with the patient under anesthesia were required.

Illustration A shows a sagittal view, of a subacute ACL tear. There is complete ligament discontinuity. Only a small part of the distal ACL (white arrow) is seen inferiorly.

Incorrect Answers:
Answer 1: Decreasing the drill angle will decrease the volume of physis removed
Answer 2: Decreasing the speed of tunnel reaming will reduce the ‘penumbra’ of physeal injury
Answer 3: BPTB grafts have been shown to have a slightly higher risk of physeal injury compared to hamstring grafts with transphyseal reconstruction techniques
Answer 4: Small tunnel diameter will decrease the area of physis involvement and therefore decrease the overall risk of growth arrest.

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(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

2%

(33/2030)

2

Decreased patellar mobility

1%

(18/2030)

3

Loss of active but not passive flexion

68%

(1384/2030)

4

Loss of full extension

15%

(313/2030)

5

Loss of passive flexion

14%

(275/2030)

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PREFERRED RESPONSE 3

All of the listed responses are consistent with infrapatellar contracture syndrome EXCEPT for Answer #3 which is incorrect because the resulting stiffness affects both active and passive motion.

This is an uncommon complication following knee surgery or injury which results in knee stiffness. The resulting stiffness limits both active and passive range of motion (ROM) and usually results in loss of flexion, extension, and patellar mobility. The development of patella infera (baja) on lateral radiographs is a common sequela and also a poor prognostic sign.

Paulos et al. describe the risk factors and their results of treatment. ACL surgery is a risk factor, as is the use of a patellar tendon autograft, multiple knee surgeries, and non-isometric tunnel placement. In patients with this condition, the use of closed manipulation and the development of patella infera are negative prognostic factors. Surgical releases are recommended to improve motion, but residual functional impairment and only fair subjective scores should be expected.


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(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

79%

(1728/2195)

2

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

5%

(120/2195)

3

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

9%

(199/2195)

4

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

1%

(28/2195)

5

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

5%

(106/2195)

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PREFERRED RESPONSE 1

ACL reconstruction with 12 o'clock femoral fixation would lead to a vertically placed graft and result in continued instability with cutting activities, and a positive pivot shift exam due to failure to reconstruct the posterolateral bundle of the ACL. Current standards for anatomic ACL reconstruction stress the importance of more horizontal graft placement (10:30 in a right knee vs 1:30 in the left knee), to try and reconstruct both the anteromedial bundle which provides anterior-posterior stability, and the posterolateral bundle which provides the rotational stability. Improper femoral graft placement is one of the most common reasons for ACL revision surgery.

Denti et al studied results of patients undergoing ACL revision surgery and had moderate follow-up. Their results shows that patients undergoing revision ACL surgery can still have good results similar to those found in patient with primary ACL reconstruction with utilization of similar techniques in motivated patients.

Noyes et al also looked at patients undergoing revision ACL surgery with the use of patellar BTB autograft. In contrast, although functional limitations decreased and patient satisfaction improved, their results were not as good as the rate of graft failure was three times higher than their reported failure rate after primary ACL reconstructions. Additionally, they advocated correction of knee varus malalignment with high tibial osteotomy along with addressing any associated posterolateral ligament deficiencies prior to ACL surgery.

Illustration A shows appropriate ACL tunnel placement in the coronal and sagittal planes. Illustration B demonstrates a "clock face" for orientation of the femoral tunnel placement. Illustration V shows an example of a intra-operative positive pivot shift exam which would be seen after ACL reconstruction with a vertically placed graft.

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(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

51%

(872/1716)

2

Isolated quadriceps contractions with the knee at 30 degrees of flexion

10%

(167/1716)

3

Simultaneous quadricep and hamstring contractions at 15 degrees of knee flexion

26%

(453/1716)

4

Isolated quadriceps contractions with the knee at 15 degrees of flexion

10%

(166/1716)

5

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

3%

(48/1716)

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PREFERRED RESPONSE 1

Isometric hamstring contractions at 60 degrees of knee flexion will produce the lowest strain in this patient's ACL graft. Straight leg raises are also commonly used in post-ACL rehabilitation protocols as this exercise places little stress on an ACL graft. The other exercises mentioned have been shown to result in increased graft strain in patients with a reconstructed ACL.

Beynnon et al measured the strain behavior of the ACL during rehabilitation activities in vivo. They found that exercises that produce low or unstrained ligament values, and would not endanger a properly implanted graft, are either dominated by the hamstrings muscle (isometric hamstring contractions at any angle), involve quadriceps muscle activity with the knee flexed at 60 degrees or greater (isometric quadriceps, simultaneous quadriceps and hamstrings contraction), or involve active knee motion between 35 degrees and 90 degrees of flexion.

A bar graph from their study representing their findings is shown and explained in Illustration A.

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(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%

(76/1871)

2

Lack of sufficient physical rehabilitation prior to return to basketball

11%

(209/1871)

3

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

3%

(49/1871)

4

Surgical error in graft tensioning

2%

(41/1871)

5

Surgical error in tunnel position

79%

(1485/1871)

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PREFERRED RESPONSE 5

Failure following primary ACL reconstruction has been associated with surgical error in 65-75% of cases. Of these cases, tunnel malposition is the most common, accounting for 70% of the errors. Successful ACL reconstruction has been demonstrated with hamstring autograft as well as bone-patellar tendon bone autograft, quadriceps autograft and multiple allograft specimens. Appropriate rehabilitation is crucial for successful return to sport, but there is not a more frequent cause of failure than surgical error.

Battaglia et al review a surgical technique for revision ACL reconstruction utilizing freeze-dried allograft bone dowels to fill malpositioned tunnels. Grossman et al review 29 patients who underwent revision ACL reconstruction with bone patellar tendon bone allograft, contralateral bone-patellar tendon-bone autograft, or achilles allograft. All 29 patients reported satisfactory clinical results with an average 67 month follow-up.


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(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%

(15/1611)

2

Use of a stair climbing machine

2%

(39/1611)

3

Vertical squat with light dumbbells in each hand

5%

(87/1611)

4

Seated leg extensions

90%

(1455/1611)

5

Use of a stationary bike

1%

(11/1611)

Select Answer to see Preferred Response

PREFERRED RESPONSE 4

Open chain extension exercises, such as seated leg extensions, are generally not allowed in the first 6 weeks of rehabilitation after reconstruction of the ACL because they put increased stress on the graft. Closed kinetic chain exercises, in which the foot remains in constant contact with the ground or the base of a machine, provide a more significant compression force across the knee while activating co-contraction of the hamstring muscles. It has been suggested that these two factors help to decrease the anterior shear forces in the knee that would otherwise be taken up by the ACL graft. Choices 1,2,3, and 5 are all examples of closed kinetic chain exercises.


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(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%

(30/1369)

2

Improper bone tunnel placement

95%

(1302/1369)

3

Reconstruction with a single bundle

1%

(8/1369)

4

Improper graft selection

0%

(6/1369)

5

Meniscal injury

1%

(18/1369)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

Battaglia et al report that "More than 75% of all cases of failed ACL reconstruction are the result of technical error and, of these, more than 70% are attributed specifically to malpositioned tunnels." Varus malalignment (answer 1) can lead to ACLR failure if not also addressed at the time of surgery, but is a less common cause of failure. Anatomic double bundle ACLR (answer #3) has been shown to be better biomechanically, but not clinically. Graft selection (answer #4) among autograft BTB, autograft hamstring, and allograft have not been shown consistently to affect revision rate. Meniscal (answer #5) and articular cartilage injury may affect the long-term satisfaction following ACLR, but are not a common cause of need for revision surgery. The study by Grossman et al reviewed 29 ACL's that underwent revision surgery with good results. All had a positive pivot shift preoperatively..


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(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

4%

(14/358)

2

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

5%

(19/358)

3

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

8%

(28/358)

4

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

21%

(75/358)

5

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

61%

(219/358)

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PREFERRED RESPONSE 5

Tunnel placement is the most critical aspect of ACL reconstruction. The most common error in an ACL reconstruction is to place either the tibial or femoral tunnel too anteriorly, leading to graft impingement and failure.

If the femoral tunnel is drilled through the tibia tunnel (transtibial drilling), it is important to understand that the direction of the tibial tunnel influences femoral tunnel placement. A tibia tunnel placed too far anteriorly can lead to a vertical (12:00) graft orientation relative to the intercondylar notch. This problem can also be potentially be avoided by drilling the femoral tunnel through a medial portal.

Pinczewski et al reviewed radiographs of 200 ACL reconstructed patients over 7 years. There was an 11% rate of graft failure and they found if the tibial tunnel was placed >50% posteriorly along the length of the anterior tibial plateau, the incidence of rupture was 17% (11 of 66) vs 7% (8 of 115) if the graft was placed <50% posteriorly. They conclude that optimal results at seven years after operation are associated with the radiolographic orientation of the tunnels.

Illustration A is a summary of the results described by Pinczewski et al. Taking 0% as the anterior and 100% as the posterior extent, the femoral tunnel was a mean of 86% along Blumensaat’s line and the tibial tunnel was 48% along the tibial plateau. Taking 0% as the medial and 100% as the lateral extent, the tibial tunnel was 46% across the tibial plateau and the mean inclination of the graft in the coronal plane was 19°. Illustration B reinforces the concept described in Option #3 and demonstrates an ideal tibial tunnel placement, whereby it is placed posterior to a line extending from Blumenstaats line when the knee is in full extension.

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(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

4%

(11/300)

2

Quadraceps tendon repair

2%

(6/300)

3

WBAT in a cylinder cast

1%

(2/300)

4

Patellar tendon repair or reconstruction

93%

(279/300)

5

Revision ACL reconstruction with hamstring autograft

1%

(2/300)

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PREFERRED RESPONSE 4

Patellar tendon rupture is a rarely reported complication of using a bone-patella tendon-bone (BPTB)autograft in ACL reconstruction. Most cases have been reported in the early post-operative period and should be treated with patellar tendon repair or reconstruction to restore the extensor mechanism. The reference from Cain et. al details management options for intraoperative complications of patella tendon grafts.

The reference from Lee et.al demonstrated a 0.2% complication rate from BPTB harvest including 2 patella fractures and 1 patellar tendon rupture treated with reconstruction.


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(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

11%

(32/301)

2

Infrapatellar branch of the saphenous nerve

80%

(242/301)

3

The common peroneal nerve

2%

(5/301)

4

The superficial femoral nerve

3%

(8/301)

5

The lateral femoral cutaneous nerve

5%

(14/301)

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PREFERRED RESPONSE 2

Injury to the infrapatellar branch of the saphenous nerve (IBSN) during ACL reconstruction is common and can lead to numbness and paresthesias over the anterolateral aspect of the knee and proximal leg. It can also be a cause of anteromedial pain in the proximal stump.

The saphenous nerve arises as a division of the femoral nerve and leaves the adductor canal between the tendons of the gracilis and semitendinosus. It then divides into the main saphenous branch and the infrapatellar branch which crosses the knee below the patella. Therefore, it can be injured when making the incision for the tibial tunnel or when harvesting hamstring or patellar tendon grafts. Injury to the IBSN can result in anteromedial pain and decreased sensation over the anterolateral infra-patellar area of the knee and leg.

Portland et al noted that the IBSN is often injured with the traditional vertical incision for central patellar tendon harvest. They suggest that a horizontal incision may result in a lower injury rate but is technically more challenging.

Illustration A shows a right leg with the infrapatellar branch of the saphenous nerve tagged.

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(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%

(5/956)

2

Concussion

0%

(4/956)

3

Anterior cruciate ligament ruptures

97%

(923/956)

4

Frieberg's infarction

0%

(4/956)

5

Patellofemoral instability

2%

(19/956)

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

Anterior cruciate ligament (ACL) prevention strategies currently focus on increasing patient neuromuscular control and has been shown to decrease ACL tear rates in certain populations. Women have different muscle fiber distribution, increased ratio of quadriceps to hamstring strength, electromechanical firing delay, and different knee kinematics. As described in the reference by Griffin et al., neuromuscular training reduces these factors and has been shown to decrease rates of ACL tears in women.


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(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%

(17/1840)

2

Decreased pivot shift

0%

(7/1840)

3

Decreased incidence of anterior knee pain

95%

(1755/1840)

4

Increased knee flexion strength on Cybex testing

1%

(21/1840)

5

Increased stability on KT-1000

2%

(33/1840)

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PREFERRED RESPONSE 3

Beynnon's randomized JBJS study compared bone-patellar tendon-bone autograft with two strand hamstring autograft for ACL reconstructions. They followed 22 subjects in each group for an average of 3 years and evaluated them in terms of clinical test findings, patient satisfaction, activity level, functional status, and isokinetic muscle strength. The patients in whom a hamstring graft had been used had significantly lower peak knee-flexion strength than those who had a bone-patellar tendon-bone graft (p = 0.039). In contrast, the two treatments produced similar outcomes in terms of patient satisfaction, activity level, and knee function (ability to perform a one-legged hop, bear weight, squat, climb stairs, run in place, and duckwalk). BTB autograft patients tend to have a higher incidence of knee pain and knee stiffness not affecting function. Hamstring autograft does not generate less tunnel widening or a smaller pivot-shift test or KT-1000 reading than patellar autograft.


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(SBQ07.14) 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

1%

(5/399)

2

Complications occur more commonly with soft tissue grafts

4%

(15/399)

3

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

83%

(331/399)

4

Excessive graft-screw divergence more commonly occurs during tibial fixation

3%

(13/399)

5

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

8%

(33/399)

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PREFERRED RESPONSE 3

Graft-screw divergence greater than 15-30 degrees from the trajectory of the femoral tunnel may lead to failure of fixation and early ACL failure.

Technical tips to avoid this complication include: inserting the screw and drill from the same portal (no divergence at all), hyperflexing the knee when inserting the screw if the femoral tunnel was drilled through the tibial tunnel, and using a guide wire to help gauge mismatch. Suspicion should be raised if there is difficulty inserting the screw. Intraoperative and postoperative radiographs can also help detect divergence.

Lemos et al. performed a bovine biomechanical study which noted that only 1/12 cows with parallel placed screws failed, while 4/12 with 15 degree divergent screws failed. They concluded that the pullout strength is highest when screws are placed with divergence 15 degrees or less.

Dworsky et al. reviewed 73 consecutive ACL reconstructions using interference screw fixation. They concluded that femoral screws with under 30 degrees of divergence did not lead to early clinical failure.

Incorrect Answers:
Answer 1: Risk of failure is eliminated by inserting the screw and the drill from the same tunnel.
Answer 4: Excessive graft-screw divergence more commonly occurs during femoral fixation.
Answer 5: Graft-screw divergence is a common cause of early failure in ACL reconstructions


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(SBQ07.37) 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

2%

(3/170)

2

Onset of menarche

89%

(152/170)

3

Secondary sex characteristics

4%

(7/170)

4

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

1%

(1/170)

5

Age at which patellar ossification began

4%

(7/170)

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PREFERRED RESPONSE 2

Age of menarche is the most accurate clinical factor to assess the degree of skeletal maturity in the female athlete.Skeletal maturity is usually within 2 years from menarche with approximately 9mm of distal femoral and 6mm of proximal tibial growth per year.

Stanitski presents a Level 5 review of ACL tears and tibial eminence fractures in the pediatric patient. Familial height and recent change in shoe size are only moderately useful in predicting final growth, and hence, skeletal maturity. The presence of secondary sex characteristics as determined by Tanner staging is a good predictor of skeletal maturity however it is worth noting that menarche may be delayed in high performance female athletes.


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(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%

(2/324)

2

Medial meniscus tear

2%

(6/324)

3

ACL tear

94%

(304/324)

4

Patellar dislocation

2%

(6/324)

5

Contusion

1%

(3/324)

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

This is the classic history for an ACL tear. Women's basketball has one of the highest rates of ACL tears. While all of the answers are possible, the incidence of ACL tears in adolescents with an acute knee injury with hemarthrosis is the highest.

Stanitski et al reported that 65% of adolescents with an acute knee hemarthrosis had and ACL tear compared to 45% having a meniscal tear. Likewise, Bomberg et al reported that 71% of patients with an acute hemarthrosis had sustained an ACL injury.


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(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%

(938/1044)

2

PCL tear

7%

(75/1044)

3

Medial meniscus tear

0%

(3/1044)

4

Lateral meniscus tear

1%

(11/1044)

5

Patellar tendon tear

1%

(13/1044)

Select Answer to see Preferred Response

PREFERRED RESPONSE 1

This image shows a bone bruise pattern consistent with an ACL tear. The pattern of bone bruise on the middle 1/3 of the lateral femoral condyle and posterior 1/3 of the lateral tibial plateau is indicative of ACL tear. It makes sense because the tibia is allowed to subluxate anterior more than usual and make abnormal contact and experiences forces inappropriately.

Viskontas et al. correlated the mechanism of ACL tear with the degree of bone bruising and found that a noncontact mechanism caused more severe bone bruising in both the medial and lateral compartments.

In another MRI review study, Collins et al. found that the presence of bone contusions in the lateral compartment increased the specificity and positive predictive value in determining ACL injury.


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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

38%

(158/413)

2

Hamstrings

59%

(242/413)

3

Gluteus muscles

1%

(3/413)

4

Adductors

1%

(5/413)

5

Abdominals

1%

(3/413)

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PREFERRED RESPONSE 2

Imbalanced or excessive knee extensor power causes abnormal tension on the ACL. Strengthening and proprioreceptive control of the knee flexors/hamstrings protects against excessive or unopposed knee extensors which protect the ACL from excessive tensioning.

The Ahmad reference states that "female athletes after menarche increase their quadriceps strength greater than their hamstring strength, putting them at risk for anterior cruciate ligament injury. Anterior cruciate ligament-prevention programs based on improving dynamic control of the knee by emphasizing hamstring strengthening should be instituted for girls after menarche."

The Vescovi paper examines the effects of such a program on athletic performance. The Baratta paper looked at EMG results of quad and hamstrings and suggested exercise of the antagonist muscle to add to dynamic stability.


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(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%

(2/322)

2

Femoral notch width

4%

(12/322)

3

Generalized ligamentous laxity

9%

(30/322)

4

Neuromuscular factors

72%

(232/322)

5

Limb alignment

14%

(45/322)

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PREFERRED RESPONSE 4

Hewett showed that increased valgus moments when jumping and landing and a relative weakness of hamstrings compared to quadriceps are present in female athetes and may contribute to higher ACL tear rates. It has subsequently been shown that neuromuscular training to address these issues can result in a reduction of ACL injuries in select groups of female athletes.

Uhorchak conducted a 4 year study on 895 US Military cadets, there were 24 noncontact ACL tears. Significant risk factors for noncontact ACL tears included small femoral notch width, generalized joint laxity, and in women, higher than normal BMI and KT-2000 arthrometer values (indicating laxity). In the second study 205 females in high-risk sports were prospectively measured for neuromuscular control during a jump-landing task. It appears that increased valgus motion and valgus moments at the knee joint during the impact phase of jump-landing tasks are key predictors of an increased potential for ACL injury in females.

The Alentorn-Geli paper reviews these risk factors in the soccer population.


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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

8%

(36/448)

2

Physical therapy for range of motion and strength

69%

(311/448)

3

Acute reconstruction followed by mobilization

13%

(58/448)

4

Arthrocentesis to rule out infection

0%

(1/448)

5

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

9%

(41/448)

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PREFERRED RESPONSE 2

The clinical presentation, physical exam, and imaging are consistent with an acute anterior cruciate ligament (ACL) tear. If the patient wants to return to sports requiring twisting/pivoting, an ACL reconstruction is recommended. He currently has an acute effusion (hemarthrosis) with decreased motion. Acute ACL reconstructions in patients with limited range of motion and weakness have been shown to lead to postoperative arthrofibrosis and weakness.

Shelbourne and Patel noted several factors that go into optimizing ACL reconstruction results: Mental preparation of the patient; school, work, family, and social schedules; preoperative condition of the knee [i.e., minimal or no swelling, good strength, good leg control, and full range of motion including full hyperextension] and lack of associated ligamentous and/or meniscal injuries.

Eitzen et al. recommended waiting until the affected quadriceps was within 20% of the strength of the contralateral unaffected one in order to mitigate postoperative strength deficits.

Sterett et al found that acute reconstruction (within 3 weeks) yielded good range of motion and strength results but in patients in whom the parameters were excellent preoperatively. The other answers would not optimize postoperative results. Immobilization would promote arthrofibrosis, as would an acute reconstruction in this stiff, weak knee. Arthrocentesis is a reasonable diagnostic/therapeutic option acutely. However, it does expose the patient to a risk of infection. Furthermore, in this patient with a 4 day old injury, the hemarthrosis is likely mostly coagulated and would frustrate attempts at aspiration. Rest and NSAIDs would not help to promote range of motion and strength.


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(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%

(44/296)

2

Lachman's test

10%

(29/296)

3

Anterior drawer test

3%

(10/296)

4

Pivot shift test

61%

(180/296)

5

Cybex testing

10%

(29/296)

Select Answer to see Preferred Response

PREFERRED RESPONSE 4

The pivot-shift examination may be a better measure of "functional instability" than instrumented knee laxity or Lachman examination following anterior cruciate ligament reconstruction.

Kocher et al in a study looking at 202 post ACL-reconstruction patients found that the pivot shift test was the only test significantly associated with patient satisfaction, knee giving away, difficulty cutting and twisting, activity limitation, sports participation, Lysholm score, and overall knee function. KT-1000 is an instrument to measure the anterior translation of the tibia.

Video V demonstrates the pivot shift test.

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(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

6%

(16/265)

2

Inferior genicular

27%

(71/265)

3

Saphenous

65%

(171/265)

4

Superficial peroneal

2%

(5/265)

5

Tibial

0%

(1/265)

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

The saphenous nerve is at risk during hamstring harvest for ACL reconstruction both at the site of the harvest incision and more proximally as a result of the tendon harvester. The saphenous nerve arises as a division of the femoral nerve and leaves the adductor canal and pierces the fascia lata between the tendons of the gracilis and sartorius. It then divides into the main saphenous branch and the infrapatellar branch (IBSN) which crosses the knee below the patella. Injury to the IBSN can result in anteromedial pain and decreased sensation over the anterolateral infra-patellar area of the leg.

Figueroa et al. reported that injury rates to the IBSN during autologous hamstring harvesting for ACL reconstruction was higher than previously reported 30-59%. They found hypoesthesia of the IBSN territory was found in 17 knees (77%) with an average area of 36 cm(2) (1-120 cm(2)). Injury to the IBSN was electrophysiologically detected in 15 knees (68%). Two patients also had an injury to the saphenous nerve more proximally (9%) likely as a result of the tendon harvester.

The Hoppenfeld and Medvecky references review the surgical approaches and relevant anatomy. The IBSN can be seen in Illustration A.

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(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

46%

(771/1688)

2

30 to 60 degrees

33%

(553/1688)

3

60 to 90 degrees

14%

(228/1688)

4

90 to 120 degrees

5%

(81/1688)

5

flexion greater than 120 degrees

3%

(47/1688)

Select Answer to see Preferred Response

PREFERRED RESPONSE 1

Open chain leg extension exercises cause the most anterior shear stress that would affect the ACL. The Wilk article summarizes that isotonic closed kinetic chain exercises produced significantly greater compressive forces compared to the open kinetic chain knee extension. In addition, during closed kinetic chain exercises, a posterior shear force (PCL stress) was generated throughout the entire range with maximal shear occurring from 85° to 105° of flexion. During knee extension, there is an anterior shear force (ACL stress) from 38° to 0° and a posterior shear force from 40° to 101°. According to Beynnon, a closed chain program results in anteroposterior knee laxity values that are closer to normal, and earlier return to normal daily activities, compared with rehabilitation with an open chain program.


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(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%

(150/1807)

2

Femoral tunnel is too anterior

71%

(1288/1807)

3

Femoral tunnel placed at 12:00 position

4%

(71/1807)

4

Tibial tunnel is too anterior

14%

(262/1807)

5

Tibial tunnel is too medial

1%

(16/1807)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

The majority of early ACL reconstruction failures are felt to be due to errors in surgical technique. The most common error in ACL reconstruction is aberrant tunnel placement. The femoral tunnel can be placed too anteriorly, thereby causing increased strain on the graft in flexion because of the cam effect of the femoral condyle which can result in graft stretching, laxity in extension, and subsequent failure. Chhabra et al. performed a cadaveric study to demonstrate the anatomic footprints of the anteromedial and posterolateral bundles of the ACL. Markhof et al. performed a cadaveric study analyzing the effects of aberrant placement of the femoral tunnel. Illustration A is a table demonstrating the effects of tunnel malposition. Illustrations B and C are gross anatomy illustrations of normal ACL anatomy.

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(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

9%

(27/285)

2

Seated leg extensions

75%

(215/285)

3

Straight leg raises

6%

(16/285)

4

Active range of motion

1%

(4/285)

5

Closed chain exercises

8%

(23/285)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

Seated leg extensions are open chain exercises that are generally avoided early after ACL surgery. Closed chain exercises are emphasized because it allows for physiologic contraction of the muscles around the knee. Closed chain exercises load an extremity with the most distal segment stabilized, preventing joint shear forces. This is ideal for post-operative rehab for an ACL. For open chain exercises, the foot is unsupported. Quad sets and straight leg raises are generally allowed to help regain quadriceps function. They produce less graft strain because they are isometric about the knee, compared to a seated leg extension in which the quad force is pulling the tibia anteriorly and potentially stressing the graft.

Ross et al reviewed the literature and found support for both closed chain exercises and modified open chain exercises for quadriceps strengthening at different timepoints after ACL reconstruction without causing excessive ACL strain or patellofemoral joint stress.

Beutler et al examined EMG activity of the quad in normal subjects doing single-leg squats and step-ups. They found high sustained quad activity suggesting that these exercises would be effective in muscle rehabilitation and that as functional, closed chain activities, they may also be protective of anterior cruciate ligament grafts.

The study by Wright et al is a systematic review of the recent literature regarding ACL rehabilitation.


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(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%

(10/1739)

2

15-30%

4%

(65/1739)

3

30-45%

6%

(107/1739)

4

45-60%

11%

(191/1739)

5

>60%

78%

(1360/1739)

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PREFERRED RESPONSE 5

The classic scenario is a non-contact deceleration, jumping or cutting action. The patient might hear or feel a "pop". The acute hemarthrosis is caused by bleeding from branches of the middle geniculate artery. Women's basketball has one of the highest rates of ACL injury. With the above history, the literature states that the likelihood of ACL injury is greater than 70%. The reference by Maffulli et al. prospectively evaluated 106 acute hemarthroses in athletes and found 71 had an injury to the ACL.


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(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

3%

(10/315)

2

Lateral collateral ligament

1%

(2/315)

3

Medial meniscus

9%

(27/315)

4

Lateral meniscus

0%

(1/315)

5

Anterior cruciate ligament

87%

(273/315)

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PREFERRED RESPONSE 5

Contrary to popular belief, the major blood supply to the ACL does not originate from its bony attachments. The ACL is supplied mainly by the vessels that originate from the middle genicular artery which leave the popliteal artery and directly pierce the posterior capsule (Illustration A). Branches enter the synovial membrane at the junction of the joint capsule distal to the infrapatellar fat pad. The ligament is ensheathed by the synovial plexus along its entire length. Smaller connecting branches penetrate the ligament and anastomose with a network of endoligamentous vessels that are oriented in a longitudinal direction and lie parallel to the collagen bundles within the ligament.

The vascular supply to the medial and lateral menisci of the knee originates predominantly from the lateral and medial genicular arteries (both inferior and superior). The middle genicular artery, along with a few terminal branches of the medial and lateral genicular arteries, also supplies vessels to the menisci through the vascular synovial covering of the anterior and posterior horn attachments.

The referenced study by Toy et al is a cadaveric study that reported ACL vascularization arises primarily from the middle genicular artery; the artery gives rise to periligamentous vessels which form a web-like network within the synovial membrane. They also found that the extremities of the ACL seem to be better vascularized than the middle part, and the proximal portion seems to have a greater vascular density than the distal portion.

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(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%

(85/488)

2

It may cause graft over-stretching and failure

9%

(42/488)

3

It is the most common technical error

15%

(71/488)

4

It may cause interference screw divergence

55%

(266/488)

5

It is often due to poor visualization

4%

(21/488)

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PREFERRED RESPONSE 4

All of the given responses are true except for Answer 4, because an excessively anterior femoral tunnel does not cause interference screw divergence.

Anterior placement of the femoral tunnel is the most common surgical error during arthroscopic ACL reconstruction. Errors in surgical technique are one of the most common reasons for graft failure in patients who present with recurrent instability after ACL reconstruction. Technical shortcomings that result in graft failure after primary reconstruction include nonanatomic tunnel placement, graft impingement, improper tensioning of the graft, inadequate fixation of the graft in bony tunnels, graft material problems, and the failure to address insufficiency of the secondary stabilizers of the knee during ACL reconstruction.

The papers by Allen and Harner et al stress the importance of determining the cause of failure prior to revision surgery. It is estimated that 70% to 80% of graft failures are caused by malpositioned tunnels. The consequences of nonanatomic tunnel placement are well described in the literature.

Sommer et al note that inappropriate positioning of either the tibial or femoral tunnels results in excessive changes in graft length as the knee moves through its functional range of motion and can effect clinical results. Because biologic ACL grafts can only accommodate small changes in length before undergoing plastic deformation, a mal-positioned graft may result in either capturing of the knee or lengthening of the graft over time; this results in either a loss of motion or recurrent instability, respectively. Improper femoral tunnel placement is most often caused by the failure to adequately visualize the most posterior aspect of the notch (the “over-the-top” position). Because the femoral attachment of the ACL is closer to the center of rotation of the knee, small errors in femoral tunnel placement may have deleterious effects on knee kinematics.


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(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%

(291/323)

2

Obesity

0%

(1/323)

3

Smoking

1%

(3/323)

4

Returning to sport too early

6%

(18/323)

5

Inadequate physical therapy

2%

(8/323)

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PREFERRED RESPONSE 1

Many factors may be involved in the failure of ACL reconstructions, including the surgical technique, the selection of graft material, the integrity of the secondary restraints, the condition of the articular and meniscal cartilage, postoperative rehabilitation, and the motivation and expectations of the patients. Early failure, usually within the first 6 months, most often is the result of technical errors, incorrect or overly aggressive rehabilitation, premature return to sports, or failure of graft incorporation. Later failure, usually after one year, is more typically the result of recurrent injury.

The most avoidable and most common cause of failure is surgical technique. These errors include improper tunnel placement (most common), and errors in graft selection, size, physiognomy or tensioning. Anterior tunnels (most common) results in a graft tight in flexion and loose in extension.

The Azar paper is an instructional course of revision ACL surgery. The Wolf paper and the Allen paper review both the causes for ACL graft failure and the planning steps needed to address them during revision reconstruction.


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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

29%

(82/286)

2

Go to the ER immediately for knee aspiration with gram stain and cultures

62%

(178/286)

3

Increase CPM use to 10 hours a day

1%

(2/286)

4

Call the office staff in the morning to schedule an appointment

8%

(22/286)

5

Start physical therapy visits once daily

1%

(2/286)

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PREFERRED RESPONSE 2

Any patient who presents with a sudden increase in knee effusion in a delayed manner after ACL surgery should raise suspicion for infection, whether or not a fever is present. If suspected, an aspiration should be performed immediately and fluid sent for gram stain and cultures. If positive, immediate arthroscopy is indicated.

Mangine et al recommend aspiration of all post-operative knees if there is any suspicion of infection.

Shelbourne and Gray discuss their excellent results after ACL reconstruction with autologous bone-patellar tendon-bone graft followed by an accelerated rehab protocol. They did not discuss post-operative infections.


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(SBQ04.32) 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

74%

(1169/1571)

2

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

15%

(230/1571)

3

Bone-quadriceps tendon with a width on 10mm

3%

(40/1571)

4

Tibialis tendon allograft

1%

(18/1571)

5

Native anterior cruciate ligament (ACL)

7%

(105/1571)

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PREFERRED RESPONSE 1

Biomechanical studies show that the quadruple semitendinosus and gracilis tendons are the strongest of the tissues on maximal load to failure testing. All of the potential ACL grafts mentioned are stronger than native ACL.

Wilson et al looked at cadaveric specimens (mean age 40) and found average load to failure for the patellar tendon grafts was 1784 +/- 580 N compared with 2422 +/- 538 N for the quadrupled hamstring tendon grafts, which was significantly different.

Woo et al tested native ACL ultimate load in cadavers and reported a mean of 2160 +/- 157 N in young patients tested in the anatomical orientation, which was higher than previous reports.

Staubli et al compared preconditioned quad to patellar tendon grafts and found ultimate failure at 2353 +/- 495 N for QT-B complexes and 2376 +/- 152 N for B-PL complexes. However, all of these grafts are reasonable and other structural properties such as graft size, stiffness, creep, and strength of fixation are also important considerations.


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(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%

(288/1019)

2

Failure to cycle the knee prior to final tibial fixation

5%

(53/1019)

3

Femoral tunnel drilled too vertically

10%

(103/1019)

4

Tibial tunnel drilled too vertically

3%

(27/1019)

5

Tibial tunnel drilled too anteriorly

53%

(544/1019)

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PREFERRED RESPONSE 5

A tibial tunnel drilled too anteriorly will limit full extension and causes tightness in flexion.

The majority of early ACL reconstruction failures are felt to be due to errors in surgical technique. The most common error in ACL reconstruction is aberrant tunnel placement. Placing the tibial tunnel too far anterior may cause notch impingement of the graft limiting full extension. It also causes tightness in flexion. Loss of full extension of the knee prevents appropriate heel-strike and alters the normal gait cycle.

Markolf et al used cadaveric knees to evaluate the effects of different femoral tunnel placements on the stability of an ACL reconstruction. They found that anterior and posterior errors resulted in greater laxity than errors medial or lateral around the notch clockface.

Chabra et al and Zantop et al review the anatomy and biomechanics of the two bundles of the ACL. The posterolateral (PL) bundle is tight in extension, while the anteromedial (AM) bundle becomes tight with flexion. The PL bundle appears to be more prevalent in providing rotatory stability.

Illustration A is a table demonstrating how aberrant tunnel placement affects knee range of motion. Illustration B shows an example of tunnel placement with label A being correct placement, label B being anterior tibial and femoral tunnel malposition.

Incorrect Answers:
1. Femoral tunnel drilled too anterior will lead to tightness in flexion and laxity in extension.
2. Failure to cycle the knee may lead to stretching out of the ACL and residual laxity in flexion and extension.
3. Femoral tunnel drilled to vertically is associated with transtibial drilling and will result in rotational instability.
4. Tibia tunnel drilled to vertically is not typically a problem with ACL reconstruction.

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(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

5%

(18/370)

2

Presence of pivot shift

36%

(135/370)

3

Tenderness over MCL origin without opening on valgus

2%

(9/370)

4

Positive Ober test

0%

(1/370)

5

Painful pop on McMurray test

55%

(205/370)

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PREFERRED RESPONSE 5

Factors that have been implicated in the progression of OA in the ACL deficient knee include meniscal lesions, osteochondral lesions, malalignment, and concomitant ligamentous pathology. The painful pop on McMurray test is indicative of a meniscal tear.

In the ACL-deficient knee, the posterior horn medial meniscus is felt to be a stabilizer to anterior translation of the tibia – therefore placing it under high loads with translation and leading to a high incidence of secondary meniscal tears in chronic ACL insufficiency. Rupture of the posterior horn leads to even greater anterior translation, increased instability, and ensuing arthritis. Studies have shown ACL combined with PCL rupture to increase the incidence of OA significantly; however, several studies have shown no arthritic progression with associated collateral ligament injury.

Louboutin et al reported that the risk of developing osteoarthritis is lower after ACL reconstruction (14%-26% with a normal medial meniscus, 37% with meniscectomy) to untreated ruptures (60%-100%) at 20 year follow-up.

The Gillquist paper noted that meniscus tears and subsequent repair, or ACL tears without major concomitant injuries, seem to increase the risk 10-fold (15 to 20% incidence of gonarthrosis) compared with an age-matched, uninjured population (1 to 2%).


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(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%

(9/321)

2

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

9%

(29/321)

3

Femoral tunnel placement anterior to the lateral intercondylar ridge

77%

(248/321)

4

One-incision instead of two-incision tunnel drilling technique

3%

(11/321)

5

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

7%

(24/321)

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PREFERRED RESPONSE 3

Tunnel placement has a crictical role in clinical outcomes. AAOS COR review book states "The most common error in an ACL reconstruction is to place either the tibial or femoral tunnel too anteriorly, leading to graft impingement and failure." The text also states that graft type and the number of incisions do not appear to affect outcome. It is important to note that initial graft tension decreases shortly after the anterior cruciate ligament graft is retrieved.

The article by van Kampen et al was a prospective study looking at 38 patients treated with bone patella bone autografts with interference screws and the tibial block secured at 20 degrees of flexion. The patients were split into two groups: One group was tensioned at 20N, the other at 40N. They found no clinically significant difference in stability in these two patient groups one year out and thus graft tensioning does not appear to be as important as graft tunnel placement.

Miller's review states "Significant controversy exists regarding the double-bundle ACL reconstruction" and the literature has not shown a definitive clinical outcome benefit compared to single bundle reconstruction.

Kopf et al provides a 3D CT model to provide the following illustrations and discussion on ACL tunnel placement.

Illustration A shows orientation of the AM and PL bundle insertions is well demonstrated. When the knee is in extension (0°), the ACL insertion is nearly vertical with the AM insertion proximal to the PL insertion. When the knee is in flexion (90°), the ACL insertion is nearly horizontal.

Illustration B shows that the lateral intercondylar and bifurcate ridges are visualized arthroscopically and by 3D CT. The area anterior the AM and PL insertions is outlined (circular dots) to demonstrate that the entire femoral ACL insertion lies posterior to the lateral intercondylar ridge on the medial wall of the lateral femoral condyle.

Illustration C demonstrates a timeline of ACL reconstruction techniques and compares their associated tunnel placements to the native ACL footprint.

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(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%

(1549/1738)

2

Figure B

2%

(38/1738)

3

Figure C

4%

(73/1738)

4

Figure D

2%

(32/1738)

5

Figure E

2%

(41/1738)

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PREFERRED RESPONSE 1

This patient has most likely sustained an ACL tear. This is supported by the history and positive Pivot Shift Test on physical exam. The most common bone bruise pattern resulting from an acute tear of the ACL is the central third of the lateral femoral condyle and posterior third of the lateral tibial plateau (shown in Figure A).

The article by Graf et al found that 43% of ACL tears had an associated bone bruise on MRI if the image was taken within 6 weeks of injury. There was no correlation between the presence of a bone bruise and articular alterations or meniscal tears observed at surgery.

In a prospective study (MOON Database) Dunn et al found that 418 of 525 (80%) patients with an ACL tear had bone bruising. They found that bone bruising is not associated with symptoms/pain at the time of index anterior cruciate ligament reconstruction.

Yoon et al found that 84% of patients with ACL tears had bone bruises. The lateral femoral condyle was the most common location (68%). They found injuries of the menisci and the MCL tended to increase with the progression of bone contusion.

Incorrect Answers:
Answer 2: Figure B shows an anterior tibia contusion.
Answer 3: Figure C shows a bone contusion pattern consistent with a patellar dislocation.
Answer 4: Figure D shows an anterior femoral condyle contusion.
Answer 5: Figure E (meniscotibial ligament avulsion) show bone contustion patterns are consistent with a hyperextension injury (an example would be a PCL tear).

Illustration A is a link to a video demonstrating the Pivot Shift Test.

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(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

7%

(17/244)

2

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

3%

(8/244)

3

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

8%

(19/244)

4

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

14%

(35/244)

5

Quadrupled hamstring grafts have lower tensile strength than the native ACL

67%

(164/244)

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PREFERRED RESPONSE 5

Quadrupled strand hamstring grafts actually have a higher tensile strength (approximately 4,000 N) than the native ACL (approximately 2,200 N).

Hamner et al. showed that four combined strands (2 gracilis and 2 semitendinosus) that were equally tensioned with weights and clamped were stronger and stiffer than all 10mm patellar ligament grafts and stronger than all double grafts. Graft tensioning by placing weights is equivalent to manual tensioning by hand and it is critical that each strand is equally tensioned. They also demonstrated that a single semitendinosis strand has a higher tensile strength than a single gracilis strand.

Chen et al report level 5 evidence that ACL reconstruction using a quadrupled hamstring autograft has little morbidity, a low reoperation rate, and excellent clinical results.

Incorrect Answers:
Answer 1: Two equally tensioned semitendinosus strands have an average of 220 percent of the strength of one semitendinosus strand - this is a true statement.
Answer 2: Single semitendinosis strand has a higher tensile strength than a single gracilis strand - this is a true statement.
Answer 3: All strands of a hamstring graft must be equally tensioned to achieve optimum biomechanical properties - this is a true statement.
Answer 4: Quadrupled grafts have tensile properties that are higher than 10mm patellar-ligament grafts - this is a true statement.


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(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

6%

(20/356)

2

BTB autograft shows less evidence of post-operative pivot shift

1%

(4/356)

3

Quadrupled hamstring autograft shows lower rate of graft failure

2%

(8/356)

4

BTB shows higher incidence of anterior knee pain

91%

(323/356)

5

Quadrupled hamstring autograft shows lower incidence of knee hardware removal

0%

(0/356)

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PREFERRED RESPONSE 4

Anterior knee pain is one of the most common concerns following ACL reconstruction using a bone- patellar tendon- bone (BTB) autograft.

In 2003, Freedman et al performed a meta-analysis comparing the results of BTB vs hamstring autografts in ACL reconstructions. Their findings showed that patients with BTB reconstructions had a lower rate of graft failure, better stability on KT-1000 (<3mm difference to contralateral knee), and patient satisfaction than in the hamstring group. The hamstring group had slightly higher incidence of hardware removal. The BTB group also showed higher rate of manipulation with or without lysis of adhesions, along with increased incidence of anterior knee pain (17% vs 12%). In cases of postoperative anterior knee pain after BTB ACL reconstruction, physical therapy with a focus on muscle strengthening is recommended with the goal of reaching strength symmetric to the nonoperative side. Bone grafting the patella donor site is also thought to potentially help.


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(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

7%

(20/294)

2

Incision for an anteromedial portal with the knee extended

10%

(29/294)

3

Incision for an accessory medial portal the with knee flexed

11%

(33/294)

4

Hamstring harvest with the knee extended

69%

(203/294)

5

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

2%

(7/294)

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PREFERRED RESPONSE 4

The saphenous nerve is most at risk during the hamstring harvest of an ACL reconstruction. At the joint line, the saphenous nerve is deep to the broad sartorious fascia, and superficial to the gracilis. Bertram et al describe a case report of a patient who sustained saphenous neuralgia following an ACL reconstruction utilizing a hamstring harvest. Symptoms can include paresthesias in the anteromedial region of the lower leg and tenderness at the medial side of the knee. They note that hip external rotation and knee flexion while harvesting the hamstring tendons allows the tendinous structures and saphenous nerve to relax, thus decreasing the chance of injury. Solman et al also stress the understanding of such anatomical relationships of the medial side of knee's anatomy to avoid pitfalls such as saphenous nerve injury during a hamstring harvest. Illustration A provides a depiction of the saphenous nerve with relation to the medial knee. Illustration B is an example of a cadaveric dissection showing the anatomic relationship of the saphenous nerve (black arrow) as it courses superficially along the sartorial fascia (labelled with S).

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(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

75%

(385/511)

2

Positive McMurray's test with leg internally rotated

2%

(12/511)

3

Positve McMurray's test with leg externally rotated

4%

(20/511)

4

Positive external rotation dial test with knee flexed at 30 degrees

13%

(64/511)

5

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

6%

(30/511)

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PREFERRED RESPONSE 1

The radiograph shows an example of a Segond fracture, most commonly caused by an anterior cruciate ligament (ACL) injury. An ACL injury would correspond best with a positive Lachman's test on physical examination. Hess et al describe the pathoanatomy of the Segond fracture which is an avulsion of the lateral tibia plateau caused by the menisco-tibial ligament. This capsular avulsion occurs during knee flexion and internal rotation of the knee, and is usually only possible after ACL injury. They found 9% of all ACL injury patients had a positive Segond sign present on plain radiographs. Stallenburg et al retrospectively reviewed radiographs of 25 patients who had sustained ACL tears and showed that posterior-lateral tibial plateau avulsion fractures were the most common radiographic finding of an ACL injury. Kezdi-Rogus et al also studied the plain-film manifestations of ACL injury and in their conclusion stressed the importance of clinical recognition of these bony avulsion injuries to raise suspicion of ACL injuries (illustration A). Furthermore, they further recommended MRI as the imaging method of choice in these patients. (Illustrations B and C show examples of an ACL tear and Segond sign on MRI respectively). Answers 2 through 5 represent a lateral meniscus tear, medial meniscus tear, PLC injury, and combined PLC and PCL injury, respectively.

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(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%

(3/345)

2

Passive extension

2%

(8/345)

3

Heel slides to improve flexion

5%

(16/345)

4

Isometric quadriceps strengthening

18%

(62/345)

5

Isokinetic quadriceps strengthening

74%

(255/345)

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PREFERRED RESPONSE 5

The initial goals of rehabilitation focus on achieving full extension, activation of the quadriceps muscles, progressive flexion, and restoring normal gait. Closed chain rehabilitation has been emphasized because it allows physiologic contraction of the musculature around the knee. Isometric exercises such as quad sets and straight leg raises are encouraged. Isokinetic exercises are generally reserved until after the graft attachment sites have healed.

The reference is a systematic review of topics related to ACL rehabilitation.

Video V demonstrates a vertical heel slide. They can also be performed in a horizontal position.

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