Quadriceps Femoris Activation Changes in Genu varum: A Possible Biomechanical Factor in the Pathogenesis of Osteoarthrosis

• Published in: Journal of theoretical biology Vol. 170; no. 3; pp. 283 - 289
• Main Authors: Marks, R., Percy, J.S., Semple, J., Kumar, S.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 07.10.1994
• Subjects: Adult; Female; Humans; Knee Joint - physiopathology; Leg - abnormalities; Muscles - physiopathology; Osteoarthritis - etiology; Osteoarthritis - physiopathology
• ISSN: 0022-5193; 1095-8541
• DOI: 10.1006/jtbi.1994.1189

This study was designed to determine whether the presence of an alignment deformity of the lower leg, known as genu varum, causes abnormalities in individual- or group-activation of the surrounding knee extensors, a situation which might accelerate knee deterioration. Nine healthy women with normal tibial alignment were compared with nine age-matched healthy women with genu varum. The outcome measure of maximal quadriceps femoris activity was recorded during successive maximal concentric isometric and isokinetic contractions of the knee extensors performed on a dynamometer using surface electromyography. The results showed that, taken as a whole, the percentage utilization of quadriceps motor units was higher for those subjects with genu varum (p < 0·01). These findings demonstrate that the extensors surrounding a varus knee might function less efficiently than those surrounding a normally aligned knee. As such they suggest that pathological force generation across a varus knee might be caused, in part, by associated alterations in quadriceps tension generating capacity.