ACL Injuries In The Adolescent Female
I shared a link to a paper on LinkedIn recently regarding landing technique in adolescent females during a growth spurt. This research indicated that, during a growth spurt, the female athlete will change their landing pattern in a way that is similar to the pattern of movement that results in an ACL injury (valgus collapse at the hip/knee) (1). This information is extremely valuable to us as health care providers, coaches and parents, because if you know that your athlete or child is going through a growth spurt, it will allow you to modify their training program, and playing schedule, to minimise the risk of ACL injury.
Which brings me to the point of this article..
ACL injuries suck!
As we all have probably figured out by now, an ACL injury is a long term injury. In the active population that wishes to return to sport, ACL injury often involves surgery and a very lengthy stint on the sidelines. There is plenty of research regarding ACL injury that I could talk all day on it, but I am far from being an authority figure on ACL injuries, so i'll keep it fairly brief. I'm just going to keep it simple and focus this post on the age group with the highest prevalence - you guessed it, the teenage female - and some things that you can do as a health care provider, coach and parent to identify those at risk of sustaining an ACL injury, and things you can do to help minimise the risk of injury in this age group.
Firstly, just a brief overview. Adolescent girls have ACL injury rates that are, depending on which paper you read, 2-10x greater than their male counter-parts (2). Sports that are known to be "high-risk" for ACL injury in this female age group are; netball, touch football, soccer, volleyball and basketball.
There are many documented risks factors associated with ACL injury, some modifiable, some not. Non-modifiable ones include, a narrow intercondylar notch, age and family history. I will focus however on the modifiable risk factors as these are the ones us as health professionals have the most control over. The most researched modifiable risk factor is impaired neuromuscular control of the athlete. The other risk factor that I feel we have good control over is an abnormal quads to hamstring ratio.
Injury prevention programs designed to improve neuromuscular control and reduce the risk of ACL injury have shown excellent results. A systematic review and meta-analysis of all ACL prevention programs, such as the PEP (Prevent Injury and Enhance Performance), have shown a 73% reduction in non-contact ACL injuries, and 44% reduction in total ACL injuries (3). Furthermore all knee injuries have been shown to be reduced by 27% with the addition of these programs (4).
In regards to quads to hamstring ratio, it has been found that females, compared to males, have a tendency to be "quad dominant" in functional tasks such as jumping and landing. Without this balance between the quads and the hamstrings, the ACL is thought be at a biomechanical risk of injury. One study has shown a direct link between lack of hamstring strength in ACL injured knees, compared to non-injured subjects [endif]--(5). The general rule of thumb is that, the greater the quads:hamstring above 1.5:1, the greater the risk of ACL injury.![endif]--
Before I finish, I'm just going to quickly point out one other factor that has received attention in recent years, which has been linked to ACL injury - the presence of patello-femoral joint (PFJ) pain. Now PFJ pain is a completely seperate blog on its own, so I wont go too deeply into right now, but adolescent girls also have higher rates of PFJ pain compared to males, and very interestingly, literature has suggested that PFJ pain can be a precursor to ACL injury - Largely in part due to the same poor cutting, landing and pivoting patterns of movement (ie. valgus collapse) seen in both injury profiles (2).
So what can you do as a health care provider, coach or parent? The moral of my story today is this:
Screen your young female athletes well!!
This is definitely not an exhaustive list of what you should be looking for, but it sure is a very good place to start if you're dealing with young females in "high-risk" non-contact sports. At the start of the season:
1) Check to see if they have a family history of ACL injury. If so, implement PEP program.
2) Check to see if they have a current or past history of PFJ pain. If so, look to address reasons why with a sports doctor and physio, and implement PEP program.
3) Observe how they land, jump and pivot - do the have valgus collapse? If so, look at some dedicated one-on-one jumping and landing training. Also implement PEP.
4) Assess their Quads:Hamstring ratio. If quads strength >1.5 that of hamstrings, start hamstring strengthening program with physio, exercise physiologist or S&C coach.
5) Implement the PEP program anyway, because whats the worst that could happen? You reduce your chances of ACL injury by 50% and the athletes will improve their functional performance.
6) Finally, monitor them at least once a month for a growth spurt. Anecdotally if your child has grown more than 2cm in a month, they should be on a modified training and playing program until their growth plateaus.
That will do for today and thanks for your time! As you all know, I have a strong passion for injury prevention, particularly in the athletic adolescent age group, so please feel free to share this blog far and wide to people that you think will benefit from this information. It is my firm belief that the better job we do with this age group now, the better sports performances and long term health outcomes we'll see long into the future!
For more on all things ACL injury, download my ACL rehab guide by clicking here, and/or watch my online ACL tutorials by clicking on the following links:
1) www.mickhughes.physio/lectures (delayed access, password required)
2) www.learn.physio/videos/100018 (instant access)
1. Wild CY, Munro BJ, Steele JR. How Young Girls Change Their Landing Technique Throughout the Adolescent Growth Spurt. The American journal of sports medicine. 2016 May;44(5):1116-23. PubMed PMID: 26912286. Epub 2016/02/26. eng.
2. Myer GD, Ford KR, Di Stasi SL, Foss KDB, Micheli LJ, Hewett TE. High knee abduction moments are common risk factors for patellofemoral pain (PFP) and anterior cruciate ligament (ACL) injury in girls: Is PFP itself a predictor for subsequent ACL injury? British journal of sports medicine. 2015 January 1, 2015;49(2):118-22.
3. Sugimoto D, Myer GD, McKeon JM, Hewett TE. Evaluation of the effectiveness of neuromuscular training to reduce anterior cruciate ligament injury in female athletes: a critical review of relative risk reduction and numbers-needed-to-treat analyses. British journal of sports medicine. 2012 November 1, 2012;46(14):979-88.
4. Donnell-Fink LA, Klara K, Collins JE, Yang HY, Goczalk MG, Katz JN, et al. Effectiveness of Knee Injury and Anterior Cruciate Ligament Tear Prevention Programs: A Meta-Analysis. PloS one. 2015;10(12):e0144063.
5. Myer GD, Ford KR, Barber Foss KD, Liu C, Nick TG, Hewett TE. The relationship of hamstrings and quadriceps strength to anterior cruciate ligament injury in female athletes. Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine. 2009 Jan;19(1):3-8. PubMed PMID: 19124976. Epub 2009/01/07. eng.