ACL Tears and Osteoarthritis

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ACL Tears andOsteoarthritis

• Emily Jones, MD
• Grand Rounds
• June 11, 2009

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Objectives

• What causes Osteoarthritis after ACL tears?
• Role of the Articular Cartilage
• Role of the Meniscus
• Does surgical intervention affect the progression
  of Osteoarthritis?

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Our patient.

• 40 y.o. male
• Worsening lateral left knee
• pain when he plays soccer
• No acute injury
• Hx of ACL tear at age 29
• ACL reconstructed with BTB graft
• Not sure if he had any other damage at the time
  of initial injury 11 years ago

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Physical Exam

• Fit, BMI 23
• Normal gait
• No swelling, erythema
• Tenderness lateral joint line
• ROM 0 to 125
• Equivocal Steinmann, McMurray
• Lachman 1 bilaterally
• Negative valgus/varus

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Differential Diagnosis

• Repeat ACL tear
• Meniscal Tear
• Osteoarthritis
• Contusion
• LCL sprain
• IT band

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Radiographs
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Probable Diagnosis

• Osteoarthritis

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Epidemiology

• 1 in 3,500 U.S. residents tear ACL each year
  95,000/year
• Development of osteoarthritis after ACL tear
• 45 within 10 years (42,750 develop knee OA
  within 10 yrs)
• 60 to 90 within 10 to 15 years
• 16 to 90 in 10 to 15 years
• Onset 10 to 20 years earlier in non-ACL knee
• Estimated that acl rupture ages knee 30 years
• ACL rupture gt5 fold increase risk of knee OA
• RR of 1.7 for increased weight

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Epidemiology OA Soccer

• 67 Female soccer players
• 12 yrs after ACL tear
• Average age 31, BMI 23
• 60 had reconstruction
• 82 radiographic changes in knee
• 51 had changes consistent with OA
• 75 sxs affecting their quality of life
• Surgical reconstruction no effect

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Epidemiology OA Soccer

• Male soccer players s/p ACL tear
• 219 patients, 14 years later
• Radiographic changes 78 injured knees
• Kellgren-Lawrence grade 2 or higher 41
• seen in 4 of uninjured knees
• 80 had reduced activity level and said knees
  contributed to this
• No difference with surgical reconstruction

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Iatrogenic ACL tear Model

• ACL-transection (ACLT) model is extensively used
  to study osteoarthritis and its treatment
• Ligament is sectioned to initiate osteoarthritis
• Biochemical changes to the cartilage shown to
  occur within 3 weeks of the surgical intervention
• Bone marrow edema beneath the medial compartment
  of the tibial plateau is detected with MRI within
  6 weeks of ACLT in the dog
• Evidence of cartilage erosion by the 12th week
• Osteophytosis and subsequent meniscal damage
  occur by the 24th week
• Long-term progression has been shown to mimic
  that of humans

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Acute injury Risk

• ACL tear is usually a non-impact, rotational
  injury
• Tibia subluxes anteriorly
• Impacts the lateral femoral condyle
• High shear forces across tibiofemoral articular
  cartilage

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Articular Cartilage

• Extracellular matrix surrounding chondrocytes
• Chondrocytes are responsible for production
• and maintenance of extracellular matrix
• ECM primarily type 2 cartilage
• 90-95 of the collagen present in articular
  cartilage
• Designed to help resist shear stress
• Articular cartilage continually undergoes
• metabolic activity to synthesize degrade
  its matrix
• Disrupted by injury
• Cartilage is aneural and avascular
• Chondrocyte viability depends on
• diffusion of metabolites from synovial fluid

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Articular Cartialge

• Articular cartilage is 4 layers superficial,
  middle, deep, calcified
• Tidemark calcified cartilage separated from
  non-calcified deep cartilage layer
• Cadaver models have shown that tidemark may be
  the weak link to shear forces

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Articular Cartilage

• Likely to have insult to articular cartilage at
  time of ACL disruption
• May not be visible initially
• Especially if at tide mark
• May progress to communicate with the joint
  surface and surface lesion may become evident
• Study of ACL deficient knees and cartilage
  lesions
• 40 at 1 year
• 60 at 5 years
• gt80 at 10 years

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Articular Cartilage

• Injured cartilage does not heal
• Chondrocytes loose ability to migrate
• Acutely injured chondrocytes produce collagen and
  proteoglycans
• Insufficient to fill injured region and does not
  result in hyaline cartilage
• Fibrocartilage

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Articular Cartilage

• Gold standard for identifying chondral lesions is
  arthroscopic viewing and probing of articular
  surfaces
• Visible lesion often only 1/3 size total
• Closed lesions softened, /- surface changes
• Open classified by size and depth
• Full-thickness have exposed subchondral bone

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How diagnose articular cartilage injuries?

• Often not initially visible on initial
  arthroscopy (as previously stated)
• MRI sensitivity 21
• 3D SPGR up to 62
• What about a correlation
• with MRI finding of
• bone bruises?

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MRI

• Bone bruising seen on MRI 80 of the time with
  ACL tear
• Location posteriorlateral tibia lateral
  femoral condyle
• Reticular lesion in gt70 less severe hemm and
  edema, minimal damage to subchondral bone
• geographic lesions 25 more severe changes
  in subchondral bone
• Correlated with histological degeneration of
  overlying chondrocytes and loss of proteoglycan
  component of the cartilage

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MRI

• 3D MRSI and T1 mapping
• Difference in bone marrow bruising lateral tibia
  s/p ACL seen
• Arthroscopic softening posteriorlateral tibia
  corresponding

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The Studies Bone Bruising Articular Cartilage

• Study Articular Cartilage Injury of the
  Posterior Lateral Tibial Plateau associated with
  acute ACL Injury
• 39 patients with recent ACL rupture
• Findings - statistically significant correlation
  b/w proportion of bone bruise and cartilage
  injury of the lateral femoral condyle,the
  posterior lateral tibial plateau and that of
  tears in the LM posterior horn seen on
  arthroscopy during ACL reconstruction
• Conclusion Pay attention to cartilage damage of
  the posterior lateral tibial plateau, lateral
  femoral condyle, as well as to posterior horn
  tears in LM with acute ACL when bone bruising
  seen on MRI

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Causes of Osteoarthritis after ACL tear

• 1 Acute Articular Chondral damage
• No evidence that treating these changes the
  progression of osteoarthritis
• Possible role for fixing ACL to decrease shearing
  forces overtime. More on this later

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What about the meniscus?

• Meniscal pathology resulting in menisectomy is
  known to correlate with joint degeneration
• Menisectomy might be the most important risk
  factor for developing TF OA s/p ACL
• Not known if menisectomy risk for PF OA
• Stable reconstructed knees with intact menisci
  also progress to OA more rapidly

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The Meniscal/ACL studies

• ACL Reconstruction After 10 to 15 Years,
  Association between Meniscectomy and
  Osteoarthritis
• Reconstruction used patellar graft
• Statistically significant association between
  medial or lateral OA and meniscal injury
• If had meniscal injury at time of reconstruction
  developed OA in the compartment where the
  meniscal injury was by 10 to 15 years out
• Meniscectomy was also assoc with poorer results
  on objective test of knee fx even with stable
  joint

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The Meniscal/ACL studies

• StudyPrimary ACL reconstruction vs no surgical
  treatment for ACL
• If menisectomy was performed 2/3 showed OA
  changes (vs 15 overall in study) regardless of
  initial treatment of ACL with surgical or
  non-surgical
• This included PF OA in addition to TF OA

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The Meniscal/ACL studies

• Study Starting with OA and seeing if lack of ACL
  incidentally matters in progression
• 265 patients with symptomatic OA over 30-months
• Presence of complete ACL tear at baseline
  increased risk for greater cartilage loss at
  medial tibiofemoral compartment
• But, once presence of concurrent medial meniscal
  tears was taken into account, no independent risk
  of complete ACL tear on cartilage loss
• Trend for an increase in cartilage loss at
  lateral compartment also related to meniscal
  pathology in lateral compartment
• No assoc b/w complete ACL tear and cartilage loss
  at patellofemoral joint
• Meniscal tears more frequent in those without ACL
  not known if happened at time of ACL or
  afterwards

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The Meniscal/ACL studies

• Conclusion findings suggest that concurrent
  meniscal pathology, which may have occurred at
  the time of possible knee injury causing the ACL
  tear, or which resulted from an ACL tear, or
  which was independent of the ACL tear, is
  responsible for the accelerated cartilage loss,
  at least seen in short-term follow-up.
• How such individuals with symptomatic knee OA,
  acl tear, accelerated cartilage loss at medial
  tibiofemoral compartment due to concomitant
  meniscal tears should be txd not determined.

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Causes of Osteoarthritis after ACL tear

• 1 Acute Articular Chondral damage
• No evidence that treating these changes the
  progression of osteoarthritis
• Possible role for fixing ACL to decrease shearing
  forces overtime. More on this later
• 2 Acute Meniscal Injury
• Early ACL reconstruction can reduce risk of
  secondary meniscal tears

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Surgical reconstruction

• Does improve stability
• Probably decreases new meniscal and chondral
  injuries
• Not proven to prevent long term OA
• Patellar Tendon Graft increase harvest-site
  symptoms and PF radiographic osteoarthritis vs
  hamstring tendon graft

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The Surgical Reconstruction Studies

• Function, OA and activity after ISOLATED
  ACL-rupture 11 years follow-up results of
  conservative versus reconstructive tx
• 109 patients 60 reconstructions
  (bone-tendon-bone graft)
• Retrospective cohort
• Similar physical activity
• ACL reconstruction increased stability,
  increased OA (42 vs 25)
• Decreased secondary meniscal tears in
  reconstructed ACLs

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The Surgical Reconstruction Studies

• Study Long-term results after primary repair or
  non-surgical treatment of anterior cruciate
  ligament rupture a randomized study with a
  15-year follow-up
• 100 patients, 15 yrs after random allocation to
  surgical repair vs. conservative
• No difference activity level, knee injury, OA
  (subjective or radiographic)
• More instability in non-surgical
• One-third of the patients in the non-surgically
  treated group underwent secondary ACL
  reconstruction due to instability problems
• This group had the most OA and secondary mensical
  injuries
• Surgery does improve stability
• Surgery did not decrease late OA (50 regardless
  of treatment)
• There were significantly more secondary meniscus
  injuries in patients initially treated
  non-surgically (12 vs 35)

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The Surgical Reconstruction Studies

• Johma et al. reported that 11 of the patients
  who underwent acute ACL reconstruction and 50 of
  the patients who underwent chronic ACL
  reconstruction presented radiographic evidence of
  osteoarthritis after 7 years
• suggests that cartilage damage becomes more
  severe as the time between injury and surgery
  increases
• Daniel et al. in a 5-year prospective follow-up,
  determined that both acute and chronic
  ACL-reconstructed knees had significantly greater
  radiographic evidence of osteoarthritis compared
  with the conservatively treated group

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The Surgical Reconstruction Studies

• 100 patients with an acute ACL injury without
  reconstruction for observed for 15 years
• concluded that early modification of activity and
  neuromuscular rehabilitation resulted in good
  knee function and an acceptable activity level in
  the majority of patients
• On the other hand.
• Strehl and Eggli, found that almost two-thirds of
  those patients initially selected for
  conservative treatment required surgical
  reconstruction in the long-term

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The Surgical Reconstruction Studies

• Study Hamstring vs Patellar grafting for ACL
  reconstruction
• Prospective Cohort
• 90 hamstring grafts, 90 patellar grafts
• At 10 years no significant difference in graft
  rupture rates (7 vs 12)
• In patellar group harvest site symptoms and
  kneeling pain more common, and more reported pain
  with strenuous activity
• Radiographic OA more common in patellar at 10
  years(P0.04)

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The Surgical Reconstruction Studies

• Study The effects of functional Knee brace
  during early tx of patients with a nonoperated
  acute ACL
• Prospective randomized, 95 patients
• 53 excluded (or dropped out)
• Articular cartilage injury
• Other injuries that negatively affected rehab
• Desire for surgery
• Patients experienced effect of the brace
  regarding sense of instability and rehab
• No objective findings on knee OA outcome score,
  strength

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Surgical Technique

• Tunnel placement
• Anterior tibial tunnel
• placement results in graft impingement against
  the intercondylar roof
• posterior tunnel vertical graft laxity
• Anterior femoral tunnel places the graft under
  high tissue strains with knee flexion, resulting
  in decreased knee flexion or increased graft
  stretching
• Inversely, the over-the-top position may cause
  the graft to tighten in the last degrees of
  extension and results in an increased
  anteroposterior laxity when knee is in flexion

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Surgical technique

• Notchplasty
• Recent study showed that aggressive intercondylar
  notchplasty can cause articular cartilage
  histopathologic changes at 6 months, consistent
  with those found in knees with early degenerative
  arthrosis
• A prospective, randomized study involving 100
  patients found no beneficial short-term effect of
  performing a notchplasty - minimizing the
  notchplasty reduced the postoperative bleeding,
  pain, swelling, and potential notch regrowth
• Therefore, extensive notchplasty or roofplasty
  should be performed only if deemed necessary
  after having tested the graft clearance
  intraoperatively

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Causes of Osteoarthritis after ACL tear

• 1 Acute Articular Chondral damage
• No evidence that treating these changes the
  progression of osteoarthritis
• Possible role for fixing ACL to decrease shearing
  forces overtime. More on this later
• 2 Acute Meniscal Injury
• Early ACL reconstruction can reduce risk of
  secondary meniscal tears
• 3 Recurrent Instability
• Improved by surgical reconstruction
• ?Surgical Technique

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Other factors gait?

• Study Gait Mechanics in patients who underwent
  ACL reconstruction exhibited altered gait that
  may be associated with progression to OA
• 17 patients
• Dynamic frontal plane knee malalignment
• Possibly promotes degredation of medial
  tibiofemoral compartment
• Every 1 increase in internal abduction moment,
  risk of knee OA increases 6.46 times

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Other Factors gait?

• Using stereofluoroscopy, Tashman et al. found
  that patients with reconstructed knees
  consistently run with their reconstructed knee
  externally rotated (by 3.8) and more adducted
  (by 2.8) than the control knee after 12 months
  of healing
• Cant reproduce original anatomy and kinematics
  with reconstruction

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Due to lack of native ACL
Technique? Type?
At time Of injury
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Summary

• Osteoarthritis after ACL tear is prevalent
• Articular cartilage
• Likely to be damaged at time of injury
• Likely to contribute to osteoarthritis
• Meniscal injuries are one of the main
  determinants of developing OA
• Surgery seems to decrease secondary meniscal
  injuries
• Surgery improves stability
• Reconstructive surgery has not been shown to
  decrease Osteoarthritis