Injury risk is altered by previous injury: a systematic review of the literature and presentation of causative neuromuscular factors

Background: Active adults commonly present with lower extremity (LE) injuries from a variety of professional and amateur sports activities. Decreased LE function significantly alters daily life and subsequent injuries increase this impact. The purpose of this systematic review was to examine the association between previous injury and the risk of re-injury, and to describe the changes in kinematics and motor programming that may contribute to this relationship.

Methods: A preliminary search was conducted to determine the four most common LE injuries on PubMed, CINAHL and Web of Science. These injuries, in a healthy active adult population, were hamstring strain (HS), anterior cruciate ligament injury (ACL), achilles tendon pathology, and ankle sprain. After these injuries were established, the search for this systematic review found evidence relating these injuries to re-injury. Articles related to degenerative changes were excluded. Twenty-six articles were included in the systematic review detailing the risk of re-injury from a previous injury and were graded for quality.

Results: ACL injury was linked to a successive injury of the same ACL, and other injuries in the LE. HS was associated with subsequent ipsilateral HS and knee injuries. Previous achilles tendon rupture increased the risk of an analogous injury on the contralateral side. An ankle sprain was associated with a re-injury of either the ipsilateral or the contralateral ankle. Post-injury changes were present in strength, proprioception, and kinematics, which may have led to overall changes in motor control and function.

Conclusion: This review provides insight into the changes occurring following common LE injuries, how these changes potentially affect risk for future injury, and address the needs of the active adult population in rehabilitation.

Clinical relevance: Current research on previous injury and re-injury is of high quality, but scarce quantity. Deficits following an injury are known, but how these deficits correlate or lead to re-injury requires further exploration.

Level of evidence: 1.