Dynamic Knee Stability and Perturbation Training

1
Dynamic Knee Stability and Perturbation Training
2
Dynamic Knee Stability

• Rudolph et al, KSSTA 2001
• 31 active subjects
• 10 uninjured
• 11 copers
• 10 non-copers
• Screening evaluation
• Quadriceps strength testing
• Knee joint laxity testing

3
Testing

• EMG testing
• Normalized to maximum EMG
• Variables
• Muscle onset (threshold 2.5x ave rest EMG)
• Termination of activity
• Magnitude (Integration over weight acceptance
  interval)
• Co-contraction of VL-LH, VL-MG

4
Testing

• 3D motion analysis
• Self-selected walking, jogging speeds
• Joint motions, moments
• Support moments

5
Walking
Coper Coper Non-coper Non-coper Control Control
Involved Uninvolved Involved Uninvolved Involved Uninvolved
Vert GRF at loading (F8.499, P0.017) 1.25BW (0.030) 1.23BW (0.022) 1.22BW (0.031) 1.26BW (0.033) 1.31BW (0.031) 1.29BW (0.033)
Peak knee flexion angle (negativeflexion) (F8.499, P0.017) -22.8 (1.9) -24.5 (1.8) -21.9 (1.9) -25.9 (1.9) -26.5 (1.9) -26.5 (1.9)
Knee moment at PKF (F6.212, P0.034) 0.368 (0.07) 0.437 (0.68) 0.314 (0.071) 0.542 (0.071) 0.558 (0.074) 0.601 (0.071)
Soleus integral over wt acceptance (t2.894, P0.020) 8.655 (1.292) 7.489 (0.679) 9.811 (1.362) 6.626 (0.716) 8.302 (1.292) 7.612 (0.679)
Control group different from copers and
non-copers (Plt0.05) Non-copers' involved side
different from all others (Plt0.05)
6
Walking
Distribution of support moments on the involved
side during weight acceptance, walking.
Non-copers had lower knee moments (F5.402,
P0.045) and higher hip moments (F3.979,
P0.056) than copers or uninjured subjects
7
Walking
Non-coper Coper
Quadriceps strength (t4.033, P0.001) 75.3 (11) 97.1 (12.7)
Knee flexion angle External knee flexion moment
Quadriceps index Copers Copers
Quadriceps index r0.029, P0.932 r0.135, P0.693
Quadriceps index Non-copers Non-copers
Quadriceps index r0.933, P0.000 r0.716, P0.030
Lateral hamstrings Onset-to-peak EMG Copers Copers
Lateral hamstrings Onset-to-peak EMG r0.672, P0.030 r0.765, P0.010
Lateral hamstrings Onset-to-peak EMG Non-copers Non-copers
Lateral hamstrings Onset-to-peak EMG r0.095, P0.824 r0.408, P0.316
8
Walking

• Regression analyses
• 79.5 of the variability in the knee moment at
  peak knee flexion accounted for by the
  variability in the onset-to-peak of the
  hamstrings and quadriceps muscles (F6.009,
  P0.030) in the copers only.

9
Jogging
Copers Copers Non-copers Non-copers Controls Controls
Involved Un-involved Involved Un-involved Involved Un-involved
Velocity m/s per LL (F4.00, P0.03) 4.041 (0.23) 4.00 (0.19) 4.137 (0.24) 4.236 (0.21) 4.745 (0.23) 4.885 (0.19)
Stride length m/LL (F4.30, P0.029) 3.089 (0.13) 3.034 (0.11) 3.194 (0.18) 3.297 (0.15) 3.575 (0.15) 3.592 (0.13)
Vertical ground reaction force (F2.849, P0.075) 2.172 (0.07) 2.204 (0.07) 2.084 (0.07) 2.156 (0.07) 2.322 (0.07) 2.357 (0.07)
10
Jogging
Knee flexion
Knee moment
11
Jogging
Non-copers had significantly greater hip
(F3.3994, P0.030) and less knee (F4.727,
P0.017) extensor moments on the involved sides
12
Jogging
Peak knee flexion angle Knee moment at peak knee flexion
Passive laxity Copers NS
Passive laxity r0.203, P1.000 NS
Passive laxity Non-copers NS
Passive laxity r-0.866, P0.015 NS
Quadriceps index Copers NS
Quadriceps index r-0.133, P1.000 NS
Quadriceps index Non-copers NS
Quadriceps index r-0.798, P0.060 NS
VL-LH co-contraction Copers NS
VL-LH co-contraction r-0.417, P0.231 NS
VL-LH co-contraction Non-copers NS
VL-LH co-contraction r-0.670, P0.048 NS
Non-copers had significantly greater
co-contraction between vastus lateralis and
medial gastrocnemius in the involved limb
(F3.609, P0.041)
13
Jogging

• Regression analyses
• 83.5 of the variability in the knee moment at
  peak knee flexion accounted for by the
  variability in the amount of VL-LH and VL-MG
  co-contraction (F15.231, P0.004) in the
  non-copers only.

14
Conclusions

• Copers

• Non-copers

• Normal knee motions and moments
• Less co-activation
• Muscle activation-important factor in stability

• Compensation related to quadriceps strength,
  passive knee laxity
• Reduced knee flexor moment
• Reduced knee motion
• Transfer control to hip
• Possible delayed force production?

15
Perturbation training

• Fitzgerald et al, PT 2000
• 26 subjects completed training
• 14 subjects in standard group
• 12 subjects in perturbation group
• Screening exam
• Pass rehab candidate criteria

16
Training programs

• Standard program

• Perturbation training

• Resistance training to quads and hams
• Cardiovascular endurance training
• Agility training
• Sport-specific skill training

• AP, ML on Balance Master
• AP, ML rotary on tiltboard
• Rollerboard/Platform
• Multi-directional on rollerboard

17
Treatment outcomes

• Unsuccessful rehab
• Episode of knee giving way
• Status reduction from rehab candidate to high
  risk for reinjury on retesting
• Outcome measures
• MVIC quadriceps
• Single-limb hop tests
• Knee joint laxity
• KOS-ADLs
• KOS-Sports
• Global Rating Scale

18
Results
Greater number of subjects in the standard group
had unsuccessful rehabilitation (?25.27,
critical value3.84, Plt.05)
Positive likelihood ratio was 4.88
(11/18/17/8)
19
Results
KOS-Sports interaction. P.12
KOS-ADLS interaction. Plt.05
20
Results
GRS interaction. Plt.05
X-over Hop interaction. Plt.05
21
Hop Testing
Perturbation (Immed after) Perturbation (F/u) Standard (Immed after) Standard (F/u)
Single Hop 101(14) 68(48)
X-over Hop 105(13) 104(16) 100(15) 64(55)
Triple Hop 99(12) 59(51)
Plt.05 at follow-up
22
Conclusions

• More subjects in standard group (50) had
  unsuccessful rehab compared to pert group (92)
• 5x more likely to successfully return to
  high-level activities if receive perturbation
  training
• Pre to post training
• ADLs, GRS, X-over hop improved in both groups
• Post training to follow-up
• Maintained in pert group, in standard group

23
Development of Dynamic Stability

• Chmielewski et al, J Electromyo Kinesiology
  2002
• 9 subjects
• Passed screen and wanted to attempt to return to
  activity
• Quadriceps strength testing
• Screening exam

24
EMG testing

• VL, LH, MG, SOL
• Muscle timing onset
• Termination of activity
• Muscle activity duration
• Time to peak amplitude
• Peak amplitude
• Integral of muscle activity during loading
  response

25
Training

• Perturbation training
• Agility training
• Resistance strength training for quads, hams, and
  gastrocs

26
Screening examination
Pre training Post training
Quadriceps index 90.9(12.5) 91.3(5.8)
Timed Hop 97.3(7.95) 96.0(4.9)
KOS-ADLs 91.8(6.6) 97.3(2.3)
GRS 83.7(13.6) 94.3(4.3)
Plt.05
27
EMG testing
VL integral of activity during walking is
significantly increased after perturbation
training (plt0.05)
VL activity integrated from 100 ms before initial
contact to peak knee flexion is less before
training (a) compared to after training (b).
28
EMG testing
Timing of muscle activity during walking before
and after perturbation training
29
Conclusions

• Quadriceps activity integral after training
• Relationship of quadriceps activity, peak
  magnitude, time-to-peak activity with hamstrings
  and soleus activation
• Influenced by training
• Self-reports sports , functional test