[The role of the quadriceps muscle for the patello-femoral malalignment syndrome]

Department of Orthopaedic Surgery, Jichi Medical School, Tochigi, Japan.

At knee extension on the Cybex Machine II (Lumex, Co. Ltd.), electromyograms (EMG) from the vastus medialis (M) and the vastus lateralis (L) were picked up by surface electrodes. The L/M ratio was calculated by the integrated value of the EMG and the power spectrum dealt with the frequency analysis of the EMG. There was a correlation between the L/M ratio and Q angle for the normal group, a constant relation for the hypermobile patella group, and an inverse correlation for the group with recurrent subluxation of patella. The vastus medialis (M)-dominant group, intermediate group and the vastus lateralis (L)-dominant group from the value of the L/M ratio was also classified. In the control group, subgroup 2 with clinical signs or their past histories around the knee included relatively more L-dominant than subgroup 1 without clinical signs. In the patello-femoral malalignment group, more cases were L-dominant.

PMID: 3693995 [PubMed - indexed for MEDLINE]