Introduction: The time necessary to return to sports activities after ACL reconstruction is 6 months. Few authors have speculated on the possibility to reduce this time with accelerated rehabilitation. But nobody has considered the proprioceptive aspects. Recently some experiments have demonstrated that a perturbation training program can improve the functional stability in ACL injured and reconstructed knees. Nevertheless there are no studies showing the effects of these exercises in long period.

The aim of this study was to find out if a specific proprioceptive exercise as perturbation training permits a further and durable recovery of proprioception after ACL reconstruction for an early return to agonism.

Material and Methods: 70 sportsmen with an isolated ACL injury were recruited. They were undergone to arthroscopic ACL reconstruction with the ST+G tendons by the same team. At discharge they were randomly assigned to two homogeneous groups: the first one ‘self-controlled’ composed by patients that followed the standard rehabilitation protocol without any help of therapist; the second group ‘Perturbation’ constituted by patients that followed between the 2nd and the 3rd months a specific proprioceptive protocol that included perturbation exercises on support surfaces (perturbation training).

They have been clinically evaluated before surgery and after 2, 3, 6 and 12 months after surgery with a kinaesthetic device constituted by a tilting platform equipped by digitalized sensor connected to a computer. The protocol included three repetition of one and two legged standing balance. The statistical analyses with t-test considered significant value of p< 0.05.

Results: All the test shows a significant improvement between pre and post-operative values. The improvements in the Perturbation group are more significant than the ones in the ‘self-controlled’ group at the 3rd month (two legged stance test: p=0,001; one legged stance on the operated side: p=0,003; one legged stance on the healthy side: p=0,0001).

Best results in the Perturbation group are maintained at the 6th month only in the one legged stance on healthy side (p=0,014) but any difference is still present at 12 months.

Conclusion: The significant improvement of the Perturbation group’s values at 3rd month demonstrates that accelerated rehabilitation of proprioception after ACL reconstruction may enhance knee proprioception and suggests the possibility of an early return to sports activities. Nevertheless it must be considered the duration of benefits obtained is limited to the period of application. Therefore other studies are necessary to establish if it’s only a problem of time and duration of application and/or type of specific rehabilitative exercises.