INHIBITION OF THE QUADRICEPS MUSCLES IN PATIENTS WITH ANTERIOR KNEE PAIN

The present study was aimed at determining muscle inhibition (MI) and knee extensor moments in 42 subjects with unilateral anterior knee pai n syndrome. The results were compared to a normal, healthy population with no history of knee injury. Also, the effects of 1 week of a nonst eroidal anti-inflammatory drug (NSAID) on MI and knee extensor moments were tested in a randomized controlled trial. At baseline, the involv ed leg showed significantly higher MI than the noninvolved leg. In bot h legs, MI was significantly higher and knee extensor moments lower th an the corresponding values of the nonimpaired subjects. There was a d irect relationship between knee pain during testing and the extent of MI. Higher MI, in turn, was associated with lower knee extensor moment s. The study demonstrated significant MI in the quadriceps muscles of the involved and noninvolved legs of subjects with unilateral anterior knee pain syndrome. The results indicate that the noninvolved leg can not be considered a normal control for a contralateral injury. NSAIDs did not affect MI or knee extensor moments, despite significantly redu cing pain. This finding suggests that factors other than pain are resp onsible for the MI observed in this specific subject population, or th at after removal of pain, more time is required to fully restore muscl e function.