Mechanism of quadriceps femoris muscle weakness in patients with anterior cruciate ligament reconstruction

• Published in: Scandinavian journal of medicine & science in sports Vol. 12; no. 6; pp. 371 - 375
• Main Authors: Konishi, Y., Fukubayashi, T., Takeshita, D.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Munksgaard International Publishers 01.12.2002; Blackwell
• Subjects: ACL reconstruction; Adult; Analysis of Variance; Anterior Cruciate Ligament - surgery; Biological and medical sciences; Case-Control Studies; Electromyography - methods; EMG; Female; Humans; Isometric Contraction - physiology; Male; Medical sciences; Muscle Weakness - diagnosis; Orthopedic surgery; Postoperative Complications - diagnosis; reflex inhibition; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Thigh; vibration stimulation; Knee; Human; Postoperative; Pathophysiology; Isometric muscular contraction; Exploration; Fatigue; Anatomical reconstruction; Anterior cruciate ligament; Neurophysiology; Electrodiagnosis; Orthopedic surgery; Quadriceps muscle; Complication; Electromyography
• ISSN: 0905-7188; 1600-0838
• DOI: 10.1034/j.1600-0838.2002.01293.x

The purpose of this study was to investigate gamma loop function in the quadriceps femoris muscle in patients who with less than 6 month‐history of anterior cruciate ligament (ACL) reconstruction. For this purpose, we compared the response to vibration stimulation in 10 patients with ACL repair and 12 normal healthy subjects, by measuring the maximal voluntary isometric contraction (MVC) and integrated electromyograms (I‐EMG) of the quadriceps muscles. Pre‐vibration data were obtained from each subject by measuring the MVC of the knee extension and the I‐EMG from the vastus medialis, vastus lateralis, and rectus femoris muscles. Vibration stimulation was applied to the infrapatellar tendons, followed immediately by repeating the MVC and I‐EMG recording. Prolonged vibration resulted in a significant decrease of both MVC and I‐EMG in the control group. In contrast, the same stimulus failed to elicit changes in ACL‐repair group. Our results suggest the presence of abnormal gamma loop function in the quadriceps femoris muscle of patients with ACL repair, which may explain the muscle weakness often described in such patients.