Quadriceps atrophy after knee traumatisms and immobilization: Electrophysiological assessment

Automatic analysis of EMG (TIA analysis) and invasive muscle fiber conducti on velocity in situ (MFCV) were performed in 15 patients after traumatic le sions of the knee and immobilization with quadriceps atrophy. T/A analysis showed transient reduced number of turns, consistent with inhibition of qua driceps motoneurons, that recovered within the first 2 weeks after the plas ter cast had been removed. MFCV was significantly slowed and showed a gradu al improvement, reaching normal values after 6 weeks. These results suggest that decrement in activated motor units may be the cause of the disproport ionate weakness of the quadriceps muscle on the first days after immobiliza tion by the plaster cast, The recovery of MFCV was related with functional improvement of strength after the first weeks. Copyright (C) 2000 S. Karger AG, Basel.