Gender differences in tibio-femoral kinematics and quadriceps muscle force during weight-bearing knee flexion in vitro.
OBJECTIVE
Females have a higher risk in terms of anterior cruciate ligament injuries during sports than males. Reasons for this fact may be different anatomy and muscle recruitment patterns leading to less protection for the cruciate- and collateral-ligaments. This in vitro study aims to evaluate gender differences in knee joint kinematics and muscle force during weight-bearing knee flexions.


METHODS
Thirty-four human knee specimens (17 females/17 males) were mounted on a dynamic knee simulator. Weight-bearing single-leg knee flexions were performed with different amounts of simulated body weight (BW). Gender-specific kinematics was measured with an ultrasonic motion capture system and different loading conditions were examined.


RESULTS
Knee joint kinematics did not show significant differences regarding anteroposterior and medial-lateral movement as well as tibial varus-valgus and internal-external rotation. This applied to all simulated amounts of BW. Simulating 100 N BW in contrast to AF50 led to a significant higher quadriceps overall force in female knees from 45° to 85° of flexion in contrast to BW 50 N. In these female specimens, the quadriceps overall force was about 20 % higher than in male knees being constant in higher flexion angles.


CONCLUSIONS
It is indicated by our results that in a squatting movement females compared with males produce higher muscle forces, suggesting an increased demand for muscular stabilization, whereas tibio-femoral kinematics was similar for both genders.
Department of Orthopaedic Surgery, University Hospital Tübingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany, Markus.Wuenschel@med.uni-tuebingen.de.
Markus
M
Wünschel
Nikolaus
N
Wülker
Otto
O
Müller
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016118:Anterior Cruciate Ligament / Q000503:physiopathology; D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D005269:Femur / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D052097:Quadriceps Muscle / Q000503:physiopathology; D016059:Range of Motion, Articular; D012737:Sex Factors; D013977:Tibia / Q000503:physiopathology; D016474:Weight-Bearing