Changes in muscular activity after knee arthrotomy and arthroscopy.

The object of this study was to find out whether an arthrotomy of the knee would damage joint proprioception. Twenty patients who underwent arthrotomy, and 20 patients after arthroscopy, were tested on a modified ergometer and the electromyographic action of their quadriceps and hamstrings recorded. The quadriceps action started later and had a shorter duration (20 ms) after arthrotomy. The differences are statistically significant in intra-individual comparison both for vastus lateralis and medialis, in comparison with the normal group for only the vastus medialis. There were no significant differences in muscle control after arthroscopy. These results are in favor of preferring arthroscopy to arthrotomy whenever possible.