No Association Between Return to Play After Injury and Increased Rate of Anterior Cruciate Ligament Injury in Men's Professional Soccer.
BACKGROUND
Studies have shown that previous injury, not necessarily anatomically related, is an important injury risk factor. However, it is not known whether a player runs an increased risk of anterior cruciate ligament (ACL) injury after returning to play from other injury types.


OBJECTIVE
To analyze whether professional soccer players are more susceptible to ACL injury after returning to play from any previous injury.


METHODS
Case-control study; Level of evidence, 3.


METHODS
A total of 101 elite male soccer players suffering a first-time complete ACL injury between 2001 and 2014 were included and matched according to team, age, and playing position with control players who did not have a current injury (1:1 match). For each injured player, the 90-day period prior to the ACL injury was analyzed for injuries and compared with that of control players by using odds ratios (ORs) and 95% CIs.


RESULTS
The odds of a player with an ACL injury sustaining a previous injury in the 90-day period did not differ significantly from that of controls (OR, 1.20; 95% CI, 0.66-2.17;P= .65). Testing the frequency of absence periods due to injury between the groups revealed that the odds of a player with an ACL injury having a previous period of absence due to injury did not differ compared with controls (OR, 1.14; 95% CI, 0.64-2.01;P= .77).


CONCLUSIONS
Players with ACL injury did not have a greater occurrence of absence due to injury in the 3 months preceding their ACL injury compared with matched controls. This indicates that previous injury of any type does not increase the risk of suffering an ACL injury.
Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg, Sweden.; Football Research Group, Linköping University, Linköping, Sweden.
Matilda
M
Lundblad
Football Research Group, Linköping University, Linköping, Sweden.; Division of Community Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
Markus
M
Waldén
Football Research Group, Linköping University, Linköping, Sweden.; Division of Physiotherapy, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
Martin
M
Hägglund
Football Research Group, Linköping University, Linköping, Sweden.; Division of Community Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
Jan
J
Ekstrand
Football Research Group, Linköping University, Linköping, Sweden.
Christoffer
C
Thomeé
Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg, Sweden.; Football Research Group, Linköping University, Linköping, Sweden.
Jón
J
Karlsson
ACL; ACL injury; ACL risk factors; knee injury