title: [Isokinetic torque of quadriceps in patients with untreated anterior cruciate ligament injury of the knee joint].
abstract: In order to study the role of muscle strength in patients with untreated anterior cruciate ligament (ACL) injury of the knee joint, the torque of the quadriceps was isokinetically measured during concentric contraction (CC) and passive eccentric contraction (PEC). The results were compared with those in normal individuals and sports players. Ninety patients with untreated ACL injury were subjected for the study. There were 50 men and 40 women. The normal group consisted of 20 students and the sports player group consisted of 20 soccer players. The peak torque and the torque at 30 degrees flexion of the quadriceps were isokinetically measured during CC and PEC by using a BIODEX machine.
  
  
  RESULTS
  In patients with ACL injury, the peak torque was smaller in the injured side as compared with the uninjured side. At the same angle velocity, decrease of PEC in the injured side was larger than that of CC. These results were compared with the normal group and the sports player group. There was significant difference in the peak torque per body weight among each groups. But, the torque per body weight at 30 degrees flexion was almost consistent in these three groups.
  
  
  CONCLUSIONS
  A considerable quadriceps atrophy occurs following ACL injury. In our experience, patients with functional absence of ACL are much more difficult to return to vigorous sports which require explosive eccentric contraction than to return to endurance sports which require repetitive concentric contractile efforts of the quadriceps. In the present study, decrease of the passive eccentric contraction in the injured side was more pronounced than that of the concentric contraction. From these results, the significantly decreased passive eccentric torque in the patients with untreated ACL injury can be a factor to cause instability of the knee joint in active daily life as well as in sports activities.
authors.affiliation: Department of Orthopaedic Surgery, Juntendo University, School of Medicine, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ikeda
mesh_terms: D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D001265:Athletic Injuries / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D009132:Muscles / Q000503:physiopathology*; D012916:Soccer / Q000293:injuries