The Evolution of ACL Deficient Classification

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The Evolution of ACL Deficient Classification

• ACL Journal Club
• April 17, 2009
• Andrew Lynch, PT

2
Clinical Differentiation of ACLD Patients

• Who are those people who can return to jumping,
  pivoting and cutting sports without surgery?
• How do we identify them in the clinic?
• What measures will allow us to confidently tell a
  patient that they may be able to return to
  sports?
• Conversely, who absolutely needs surgery?

3
Eastlack ME, Axe MJ and Snyder-Mackler L

• Laxity, Instability and Functional Outcome after
  ACL Injury Copers versus Noncopers
• MSSE 31 (2)210-215

Eastlack et al, MSSE, 1999
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What defines a Coper?

• ACL Deficient (ACLD) who coped with their
  injuries without ligament surgery. (Daniel)
• Not highly active
• This is has since been termed an Adapter
• Avoid instability by decreasing activity levels

Eastlack et al, MSSE, 1999
5
What defines a Coper?

• They are not a non-coper
• Those unable to complete activity at the same
  level as before their injury without repeated
  episodes of giving way
• The sensation of giving way has been reported as
  similar to a pivot-shift test for anterior
  lateral rotary instability (McDaniel and Dameron,
  1980)
• Also associated with pain, swelling and knee
  buckling

Eastlack et al, MSSE, 1999
6
What defines a Coper?

• Snyder-Mackler et al, JBJS 1997
• Copers are those who returned to full sports
  participation without surgery
• Function is not linked to laxity
• This was the operational definition of a coper
  used by Eastlack et al.

Eastlack et al, MSSE, 1999
7
What Clinical Measures May Help Delineate?

• Outcome measures
• Joint laxity (KT-2000)
• Lysholm Scale
• Knee Outcome Survey
• Activities of Daily Living (ADL)
• Sports
• Global Rating Score
• Strength Testing (Burst)
• Hop Series (Noyes, AJSM 1991)

• Subjective Questionnaires
• Time from injury
• Chronic gt6mos
• Sub-acute 1-5mos
• Brace usage
• Episodes of Giving Way
• 0, 1, 2, 3, gt3
• Extension of Previous Injury

Eastlack et al, MSSE, 1999
8
Clinical Characteristics of Copers

• Highest amount of laxity 5.5 mm (no significant
  difference)
• Scored higher on functional outcome measures
• KOS-ADLS and SAS
• Lysholm
• Global Rating
• Quadriceps Index
• All 4 Hop Scores
• 25 of copers reported more than 3 episodes of
  giving way
• 73 of chronic ACLD patients

Eastlack et al, MSSE, 1999
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Multiple Regression Analysis

• Global Rating Score
• KOS-SAS
• Quadriceps Index
• Cross-over Hop
• R2 0.66
• Specificity 92
• Sensitivity 97

Eastlack et al, MSSE, 1999
10
Fitzgerald GK, Axe MJ and Snyder-Mackler L

• A decision making scheme for returning patients
  to high-level activity with non-operative
  treatment after ACL rupture.
• KSSTA (2000) 876-82

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Purpose

• Propose classification system for acute ACLD
  patients to determine who may be capable of
  returning to sport without surgery (in the short
  term).
• Present results from a preliminary study of these
  rehabilitation candidates (potential copers) and
  their attempts at non-operative management.

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Subjects

• 93 patients were classified and included
• Exclusions included
• Multi-ligament injured knee
• Fracture/dislocation
• Bilateral involvement
• MRI findings

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Screening Exam

• Functional Hop Series (Noyes)
• Quadriceps Burst Superimposition Testing
• Global Rating of Knee Function
• KOS-ADLS
• Frequency of giving way

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Development

• Surgical Candidates
• Multiple episodes of giving way
• Unstable during ADLs
• Rehabilitation Candidates
• No indicators of instability

• Multiple Regression
• r2 0.72
• Global Rating
• Give-ways
• KOS-ADLS
• Timed-hop test
• Cutoffs established 2SD below mean for rehab
  candidates

15
Non-operative Management

• Aggressive rehabilitation to prepare subject for
  sport
• Success return to pre-injury activity without
  giving way
• 28 PC attempted non-op, 22 succeeded (79)
• 9 with subsequent ACLR
• 1 with contralateral injury
• 12 chose to forego ACLR

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Discussion

• 58 of ACLD proceeded with surgery without
  attempting non-op rehab
• 54 classified as non-copers
• 11 classified as PC, opted for surgery
• 79 of rehab candidates were successful in their
  return to sports
• Significantly higher than in any other reported
  cohort
• Those who failed had a significantly lower timed
  hop performance

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Biomechanical Differentiation

• With a screening system in place, rehabilitation
  candidates can be identified. But what makes
  them better candidates?
• Muscular control?
• Specific movement patterns?
• If these patterns can be identified, then they
  could be taught to patients through
  rehabilitation, thus, decreasing the need for
  surgery.

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Rudolph KS, Eastlack ME, Axe MJ, Snyder-Mackler L

• 1998 Basmajian Student Award Paper
• Movement Patterns After Anterior Cruciate
  Ligament Injury a Comparison of Patients Who
  Compensate Well for the Injury and Those Who
  Require Operative Stabilization
• Journal of Electromyography and Kinesiology 8
  (1998)349-362

Rudolph et al, J EMG and Kines, 1998.
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Subjects

• Eight (8) Non-copers
• Instability during activities of daily living
• Planned surgical reconstruction

• Eight (8) Copers
• Returned to pre-injury activity without
  limitation
• Global Rating of 85
• lt1 give way since injury

Rudolph et al, J EMG and Kines, 1998.
20
Methods

• Clinical Measures
• Arthrometry (KT2000)
• Burst Superimposition Testing
• Quadriceps Index
• Global Rating

• Laboratory Measures
• Motion Analysis
• 5 VICON cameras (120 Hz)
• Kinetic Data
• Bertec FP (480 Hz)
• 3 Activities
• Free Speed Walking
• Free Speed Jogging
• 10-inch Step Over

Rudolph et al, J EMG and Kines, 1998.
21
Clinical Results

• Laxity
• 6.7mm in Non-copers
• 6.4mm in Copers
• Quadriceps Strength
• Statistical trend (p0.088) toward greater
  strength in copers
• Global Rating
• Copers (92) significantly better than non-copers
  (54)
• Quadriceps Index showed correlation to global
  rating in both groups

Rudolph et al, J EMG and Kines, 1998.
22
Walking

• Copers
• No kinematic difference between knees
• Involved Kinetic Changes
• ?peak vertical GRF
• ? knee extensor moment
• ? knee extensor power absorption

• Non-copers
• Initial Contact and Loading Response
• Less knee flexion
• Involved Kinetic Changes
• ?peak vertical GRF
• ? knee extensor moment
• ? knee extensor power absorption

No differences between groups at mid- and
terminal-stance.
Rudolph et al, J EMG and Kines, 1998.
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(No Transcript)
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Jogging

• Copers
• No kinematic differences
• Decreased involved vertical GRF

• Non-copers
• Decreased knee flexion at initial contact through
  loading response to peak knee flexion
• Decreased involved vertical GRF more than copers

Rudolph et al, J EMG and Kines, 1998.
25
(No Transcript)
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Step Task

• Copers
• Similar flexion bilaterally to ascend
• Increased involved extension during support

• Non-copers
• Decreased knee flexion to ascend stair with
  involved
• Increased involved extension during support
• Peak vertical GRF decreased on both limbs

Rudolph et al, J EMG and Kines, 1998.
27
Conclusions

• Ubiquitous decrease in knee extensor moments and
  vGRF
• Increase in plantarflexor power absorption
• Non-copers
• Decreased KF
• Decreased vGRF
• Copers
• Decreased power absorption
• Similar kinematics

• Non-copers may exhibit increased co-contraction
• Causing articular compression
• Non-copers exhibit increased frequency of giving
  way
• Causing articular shear
• Quadriceps strength is not the primary stabilizer
  of the knee

Rudolph et al, J EMG and Kines, 1998.
28
Conclusions

• Non-copers use a stiff knee strategy
• Stability at the sacrifice of mobility
• Increased instability
• Copers move with more symmetry
• Precise, selective movement patterns as opposed
  to gross co-contraction
• allowing them to manage without an intact ACL

Rudolph et al, J EMG and Kines, 1998.
29
Chmielewski TL, Rudolph KS, Fitzgerald GK, Axe MJ
and Snyder-Mackler L

• Biomechanical evidence supporting a differential
  response to acute ACL injury
• Clinical Biomechanics 16 (2001) 586-591

Chmielewski et al, Clin Bio, 2001.
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Purpose

• Investigate the movement patterns of potential
  copers as identified by the screening process.
• Non-copers, copers and healthy subjects already
  studied.

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Methods

• Similar to Rudolph
• Walking
• Jogging
• Variables of Interest
• Peak knee flexion angle (both)
• Knee extensor moment at PKF (both)
• Knee flexion at initial contact (jog)
• Vertical GRF at PKF (walk)
• Peak vertical GRF (jog)
• Total support moment at PKF (and components)

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Comparisons with Healthy

• Walking at peak knee flexion
• Knee flexion angle
• Decreased compared to control and contralateral
• Knee extensor moment
• No difference
• Vertical GRF
• Decreased compared to control
• Components of Total Support Moment
• Decreased control at the knee
• Increased control at the ankle

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Comparisons with Healthy

• Jogging
• Knee flexion at initial contact
• Decreased
• Knee flexion at PKF
• Decreased
• Knee Extensor Moment
• No difference
• Peak vertical GRF
• No difference

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Conclusions

• Potential copers resemble uninjured subjects
  kinetically
• Potential copers resemble non-copers
  kinematically
• Stiff knee strategy
• Support moment alterations are similar to copers
• Move support to ankle
• Non-copers shift to the hip

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Clinical Themes

• Laxity does not predict instability or function
• Functional hop scores are able to distinguish
  between copers, non-copers and potential copers
• May also be predictive of those who will give-way
  with return to sport
• Self-report scores are discriminant between those
  with good knee stability and those without
• No one measure can predict dynamic knee
  stability, therefore a cluster must be used.
• Selective determination of those who can attempt
  non-operative management improves outcomes.

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Biomechanical Themes

• Non-copers use a stiffening strategy and decrease
  moments to prevent further episodes of
  instability in walking and jogging
• May be due to quadriceps weakness
• Copers move symmetrically, without gross
  co-contraction to maintain stability.
• Potential copers display an intermediate
  strategy.
• Imperfect precision to move like a true coper.
• Still demonstrate knee stiffening, similar to
  non-copers.