According to current knowledge, the normal ACL is innervated by mechanoreceptors such as Ruffini endings, Pacinian corpuscles and Golgi tendon organs. The integrated proprioceptive signals from these mechanoreceptors in the ACL contribute to successful neuromuscular control of the lower extremity, as well as maintenance of knee stability. Damage to the ACL may lead to a lack of sensory input from its mechanoreceptors, and may be one of the causes of functional instability of the lower extremity.
The principal finding of this systematic review was that a majority of the studies demonstrated no significant difference of proprioception in ACL-reconstructed knees when comparing patients to external controls.
However, outcomes of the proprioceptive function have been measured with a variety of methods. Testing equipment, tested ranges of motion, angular velocity used by the equipment, surgical techniques and chronicity of ACL injury were largely different between the studies.
This review demonstrated that there was no evidence of impaired proprioceptive function in subjects with ACL reconstruction. Most of the studies showed that there were no significant differences in TDPM and/or JPS measurement between the ACL-reconstructed knees and the uninjured external control knees. It has been shown that there is a statistically significant decrease in proprioceptive function in ACL-deficient knees. Therefore, ACL reconstruction may be successful in the restoration of knee proprioception. However, there is a lack of high-level evidence on proprioceptive function after ACL reconstruction. Higher quality studies and homogenisation on clinical assessment are required to perform a more definitive analysis in the future.