Functional instability following lateral ankle sprain

Lateral ankle sprain (LAS) is an extremely common athletic injury. Despite extensive clinical acid basic science research, the recurrence rate remains high. Functional instability (FI) following LAS is hypothesised to predisp ose individuals to reinjury because of neuromuscular deficits which result following injury. This paper provides an overview of the potential causes o f FI which may manifest themselves clinically. The theoretical explanations of Fl are discussed, as are implications for assessment and treatment of F l following LAS. When LAS occurs, structural damage not only occurs to the ligamentous tissu e, but also to the nervous and musculotendinous tissue around the ankle com plex. While injury to the ligaments may result in laxity of the joints of t he ankle complex, neuromuscular deficits are also Likely to occur due to th e injury to the nervous and musculotendinous tissue. These neuromuscular de ficits may be manifested as impaired balance, reduced joint position sense, slower firing of the peroneal muscles to inversion perturbation of the ank le, slowed nerve conduction velocity, impaired cutaneous sensation, strengt h deficits and decreased dorsiflexion range of motion. Additionally, the ab normal formation of scar tissue after injury may lead to sinus tarsi syndro me or anterolateral impingement syndrome, which may also lead to Fl of the ankle complex. Assessment of patients with LAS must address not only joint laxity and swel ling, but should include examination for neuromuscular deficits as well. Th e treatment and rehabilitation goals must also address restoration of neuro muscular function, as well as restoration of mechanical stability to the in jured joints.