The influence of meniscal lesions on reflex activity in the hamstring muscles.

Meniscal lesions are among the most common knee injuries and substantially affect the mechanical function of the knee joint. In addition, the presence of mechanoreceptors in the meniscus suggests that the menisci are also involved in the sensorimotor control of the knee. The objective of this study was to investigate the influence of an isolated meniscal lesion on the reflex behaviour of the hamstring muscles, which are involved in the sensorimotor control of the knee joint. For this purpose, we mechanically induced tibial translation in 19 patients in a standing position and analysed the biphasic response of the hamstrings consisting of a short-latency response (SLR) and a medium-latency response (MLR). Moreover, we determined anterior tibial translation. A comparison of electromyographic data for the healthy legs versus the injured legs showed no significant differences in either SLRs or MLRs. Although there was a tendency to an increase in tibial translation, no significant difference between the legs in anterior tibial translation was found. In conclusion, our experimental work did not reveal any substantial effects of a meniscal lesion on the reflex behaviour of the hamstrings. Our data suggest that the menisci appear to play only a minor role for the sensorimotor induced anterior posterior knee stability.