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New PhD on children, ACL injuries and non-operative treatment


Håvard Moksnes defend his doctoral thesis "Functional and radiological outcomes following a non-operative treatment algorithm after ACL injuries in skeletally immature children" at the Norwegian School of Sport Sciences on May 24, 2013.


Why are ACL injuries in children different from adult injuries?



Alpine skiing and football have been identified as sports with the highest prevalence of ACL injuries in children.


An ACL injury in a skeletally immature child has to be handled different in children than adults because of the immature skeleton.


Surgical treatment involves the drilling of holes through the femur and tibia, which in skeletally immature children will incorporate an increased risk of complications such as growth disturbances.


In Norway and the Scandinavian countries it is more common to treat ACL injuries in skeletally immature children with primary non-operative treatment compared to the practice in southern Europe and the USA.


What are the outcomes of non-operative treatment after ACL injury in children?

Since 2006, Håvard Moksnes and co-workers have prospectively investigated knee function in 46 children who suffered an ACL injury at age 12 years and younger. The majority of injuries occurred during alpine skiing and football.


All children underwent an active rehabilitation program focusing on establishing dynamic knee stability and strength after the injury.


The children have been assessed with annual tests of muscle strength, single legged hop tests, and a monthly online activity survey.

Additionally, high resolution MRI investigations have been performed throughout the project.


Majority of children regained strength and knee function

The main results show that the vast majority of children regained adequate muscle strength and knee function following the rehabilitation program, and 88% reported continued participation in sports and physical education in school throughout the project.


However, 1/3 also reported abandoning pivoting sports such as football and handball due to their knee injury. Secondary injuries to the menisci were low compared to previous studies in children with ACL injury.


13 children underwent surgical reconstruction during the follow-up period due to recurrent knee instability. No growth disturbances have been observed.


Future perspectives

This study in the world’s largest in which children have been assessed through a non-operative treatment algorithm following ACL injury. The results are encouraging as children continued to uphold an active lifestyle with few restraints after completing the rehabilitation program. 


The research group will continue the development of adequate treatment options and search for preventive measures to decrease the risk for serious knee injuries in the future.



The current project was initiated in 2006 with Professor May Arna Risberg and Professor Lars Engebretsen as supervisors.


Read more about Håvard´s projects.



Trial lecture and PhD defense May 24, 2013

10:15-11:00: "Give an overview of different functional tests used in clinical settings for subjects with knee injury. Discuss validity and reliability of these tests and to what extent they can be used in children, adolescents and adults. In case you consider existing tests inadequate, discuss how to develop and evaluate a valid assessment method"

13:00-16:00: PhD presentation and defense


Dissertaition Committee

Chair: Lars Bo Andersen (Norges idrettshøgskole)

1. opponent: Mininder S. Kocher, MD, MPH. Boston Children's Hospital, USA
2. opponent: Eva Weidenhielm Broström, PT, PhD, Karolinska Institutet, Department of Women's and Children's Health, Sweden

Both the trial lecture and the PhDdefense is open for public.

Norges idrettshøgskole, Auditorium A