INVESTIGATION OF PRIMARY AND SECOND ANTERIOR CRUCIATE LIGAMENT TEARS USING A GEOGRAPHIC DATABASE

Abstract

The incidence of anterior cruciate ligament (ACL) injuries has been estimated at 1 in 3500 individuals in the literature. Second ACL tears represent 7-14% of all ACL tears. The location of ACL tears has been noted to be primarily proximal. The purpose of this study was to corroborate previous data as well as to add novel data to the literature regarding the location of ACL tears, risk factors associated with second ACL tears, and correlation between hearing a "pop" at the time of injury and concomitant injuries. Epidemiologic Review. A geographic database containing the medical records of individuals in a rural county in Midwest, USA was utilized to identify ACL injuries that occurred in the county from 2011 to 2016. A total of 743 ACL injuries were identified, which were reviewed and stratified by primary and second tears, sex, race, age, activity level, number of "pops" heard at time of injury, side of injury, location of tear, graft type used in reconstruction, location of fixation, and concomitant injuries. ACL tear location was noted to be primarily midsubstance (44.1%) or proximal (34.1%). The majority of individuals (56.3%) who reported hearing "multiple pops" at the time of injury sustained multiple types of concomitant injuries. The incidence of second ACL tears was 16.8% of total ACL injuries. Second ACL tears were associated with multiple factors, including tear type (p < 0.015) and tear location (p < 0.022). When comparing primary versus second ACL tears, no significant difference in concomitant injuries was noted. The majority of ACL tears (78.2%) occur in the midsubstance or proximal fibers. Hearing multiple "pops" at the time of injury may be associated with more concomitant injuries. The incidence of second ACL tears in this population was comparable to previous studies. Second ACL injuries differed statistically from primary injuries in association with tear type and location. 2C.