Swedish professional soccer players who experienced an anterior cruciate ligament injury and returned to play after treatment had a significantly greater risk of injury to either knee compared to players without ACL injuries, researchers from Linkoping University in Sweden have reported. The results were statistically significant whether the risk of knee injury was calculated for the ACL-injured knee or the ACL-injured player.
“The first few months after return to soccer is of major concern, since many injuries, especially synovitis, occurred during this period,” said Markus Walden, MD, the study’s lead author, an orthopedic resident at Central Hospital in Kristianstad, Sweden. “Surgeons should think twice before performing a revisional ACL reconstruction after a rerupture or primary ACL reconstruction in a knee with known osteoarthritis with the aim of bringing the athlete back to a highly knee-demanding sport.”
The subjects were 310 out of 312 first team squad players on the 14 Swedish professional soccer teams who gave consent to participate in the study. Prior to the season, 24 players had a history of 28 ACL injuries. All of the injuries, except the bilateral injuries of one player, were surgically treated.
During the 2001 season, 50% of the ACL-injured players suffered at least one knee injury, significantly more than the 21% of the other players, the researchers reported in the February issue of the British Journal of Sports Medicine. This was despite the fact that the ACL-injured group played significantly fewer days due to injury. The total number of injuries per hour played and the number of lower limb injuries unrelated to the knee did not differ significantly between the groups.
The ACL-injured group experienced one overuse injury and three traumatic injuries to the contralateral healthy knee, with the remaining 20 knee injuries occurring to the ACL-injured knee. The risk of both overuse knee injury and traumatic knee injury was significantly higher in the ACL-injured group than in the other players. Among the injuries the ACL-injured group sustained during the 2001 season were one ACL tear to a non-ACL-injured knee and 10 cases of synovitis of which nine were to ACL-injured knees and four recurrent injuries to three players. Of the 10 athletes who had undergone ACL reconstruction during the previous season, five suffered nine overuse injuries and another a secondary meniscus tear, all to their reconstructed knees.
“The picture sometimes put forward by the media is that a torn cruciate means surgery followed by six months of rehabilitation, and then the problem is solved,” Walden said. “However, in our clinical experience we have noticed that some of the players have knee symptoms in spite of optimal surgery and physiotherapy.”
The researchers suggested that the time to return to contact sports after ACL reconstruction, traditionally six months, may be too short and that significant thigh muscle strength deficits and reduced performance on the one-leg jump test are still often present then. Other possible reasons the researchers hypothesized for the high rate of overuse injuries in ACL-reconstructed knees include that the transition from rehabilitation to training and competitive games could result in overloading of remodeled or not-yet-healed tissues, that previously injured athletes may engage in a relatively high intensity of play to prove their performance ability to their coaches, and that the rehabilitated knee may experience altered kinematics and lower proprioception.