Gesture and Posture As Important Factors in 3D Kinematic Assessment of the Knee Lavoie F 1, Laplante M 2, Parent G 1, Duval N 1,3, Doré S 1,2, de Guise J 1,2 1. Laboratoire de recherche en imagerie en orthopédie du CRCHUM (LIO) 2. École de Technologie Supérieure (ÉTS) 3. Pavillon des Charmilles

Introduction Accurate 3D kinematic assessment combined with computer-assisted surgery will bring a whole new dimension to knee arthroplasty and ligament reconstruction Diagnosis and surgical indications Surgical technique Follow-up

Current problem Three-dimensional kinematics of the normal knee are still ill-defined Differences between studies Differences between subjects of the same studies

Possible causes of kinematic differences between subjects and between studies Artefact motion Skin-bone movement (up to 1 cm, Sati et al ) Invasive methods not appliable to large populations (Lafortune et al. 1992, Ishii et al. 1997) Analysis of the movement recorded Axes system position (Marin et al. 2003) Different Gesture = Different Movement?

Hypothesis Knee kinematics are altered by the gesture accomplished when it is recorded

Knee-bend Standardizer

Purposes: Control the movement of the trunk along a fixed axis Control the position of the feet Rotation, DF/PF, AP position, Width Allow to test in different predetermined positions Weight-bearing normal, increased or decreased

Previous Findings Knee-bend standardization increases kinematic reproducibility

Previous Findings Knee-bend standardization decreases between- subject kinematic variability

Objective of this Study Evaluate the impact of different gesture parameters on measured knee kinematics: Foot rotation Hip rotation Knee excursion Foot A-P position Ankle flexion Weight-bearing Speed

Materials and Method 17 male participants Avg 25.5 y.o. (21-30) No lower limb pathology Optotrak position sensors mounted on special harness purpose: minimizing mvt between sensors and bone, allowing assessment of axial rotation at the knee ref. Sati et al. 1996, Ganjika et al. 2000

Harness

Materials and Method 13 squat series for each subject 0-60 degrees of flexion 20 seconds recording Speed controled Left knee kinematics recorded 8 gesture parameters tested

Standard Gesture

Knee excursion Knee In Knee Out

Foot Rotation 30 degrees internal rotation 30 degrees external rotation

Hip Rotation

Ankle Flexion 30 degrees plantiflexion 10 degrees dorsiflexion

Foot A-P Position Feet advanced (70% of femur length) Ref.: Kvist et al. 2001

Load-bearing 25% weight increase Ref.: Yack et al % weight decrease

Speed of gesture Standard gesture: 2 seconds for each cycle Slow gesture: 4 seconds for each cycle Fast gesture: 1 second for each cycle

Analysis 3D Kinematics analyzed as rotations Tibial rotation vs Knee flexion Leg abduction/adduction vs Knee flexion

Analysis Comparison each gesture condition with standard gesture Comparison with inverse gesture condition e.g. Slow pace vs Fast pace Average of the differences were calculated

Results

Average Kinematic Differences Between Gesture Conditions Gesture Parameter Comparison Translations (mm) Rotations (degrees) APMLPDAdduction External Rotation Knee excursion Knee In vs Knee Out Knee In Knee Out Hip rotation External Rotation (Knee Neutral) Foot rotation External Rotation (Knee Neutral) vs External Rotation (Knee-In) External Rotation (Knee In) vs Internal Rotation External Rotation (Knee In) Internal Rotation = Statistically Significant = Scientifically Significant (>2mm or >2degrees)

Average Kinematic Differences Between Gesture Conditions Gesture Parameter Comparison Translations (mm) Rotations (degrees) APMLPDAdduction External Rotation Knee excursion Knee In vs Knee Out Knee In Knee Out Hip rotation External Rotation (Knee Neutral) Foot rotation External Rotation (Knee Neutral) vs External Rotation (Knee-In) External Rotation (Knee In) vs Internal Rotation External Rotation (Knee In) Internal Rotation = Statistically Significant = Scientifically Significant (>2mm or >2degrees)

Average Kinematic Differences Between Gesture Conditions Gesture Parameter Comparison Translations (mm) Rotations (degrees) APMLPDAdduction External Rotation Knee excursion Knee In vs Knee Out Knee In Knee Out Hip rotation External Rotation (Knee Neutral) Foot rotation External Rotation (Knee Neutral) vs External Rotation (Knee-In) External Rotation (Knee In) vs Internal Rotation External Rotation (Knee In) Internal Rotation = Statistically Significant = Scientifically Significant (>2mm or >2degrees)

Average Kinematic Differences Between Gesture Conditions Gesture Parameter Comparison Translations (mm) Rotations (degrees) APMLPDAdduction External Rotation Knee excursion Knee In vs Knee Out Knee In Knee Out Hip rotation External Rotation (Knee Neutral) Foot rotation External Rotation (Knee Neutral) vs External Rotation (Knee-In) External Rotation (Knee In) vs Internal Rotation External Rotation (Knee In) Internal Rotation = Statistically Significant = Scientifically Significant (>2mm or >2degrees)

Discussion In the studied population, no significant effect found for: Foot A-P position Ankle flexion Weight-bearing Speed

Discussion Current studies of knee kinematics during a knee bend gesture don’t control for foot position, knee excursion and hip rotation Our results show that these parameters affect knee kinematics > 15 degrees of impact on tibial rotation for a ROM of degrees

Conclusion Gesture needs to be controled in kinematic studies of the knee: Better reproducibility Comparisons between studies Follow-up comparisons

Financial Help IRSC (Programme MENTOR) Fondation de Recherche et d’Éducation en Orthopédie de Montréal (FRÉOM) Département de Chirurgie de l’Université de Montréal CRSNG Fonds Québécois pour la Recherche Nature et Technologie (FQRNT) Chaire de recherche du Canada

Future Directions Characterization of normal knee kinematics Axes system Residual skin movement ACL-deficient participants: Kinematic effect of injury Impact of ACL reconstruction on knee kinematics