Thursday, May 28, 2009

Why Men Don't Get It

*Picture by Lai Jun Wei/ Red Sports
Yes, now that I've gotten your attention. Here is the next follow up post for our current trends in anterior cruciate ligament (ACL) reconstruction management which started on Mar 19.

Why don't men get it, well, not as often as women anyway when it comes to getting an ACL tear. Are women more prone to ACL injuries? Yes, there seems to be a substantial body of research that now suggests that women are more prone to ACL injury than are men (e.g. Arendt & Dick, 1995; Bjordal, Arnoy, Hannestad 1997; Ferretti, Papandrea, Conteduca, 1992; Gwinn, Wilcken, McDevitt, 2000 and Messina, Farney, DeLee, 1999).

Many studies have attempted to explain the disproportionate incidence of ACL injuries among female athletes. Research implicates hormonal, anatomic, environmental, and neuromuscular factors that may predispose athletes, particularly women, to ACL injuries. Let's discuss each of these factors.

Specific hormonal factors may include rising estrogen levels which can relax soft tissue and predispose women to ACL tears. It has been suggested that during the midcycle of the menstrual period where ostrogen level rises, tensile strength in the ACL may decrease. 3 studies actually reported the risk of sustaining a non contact ACL injury during the ovulatory phase of the menstrual cycle (Beynnon et al, 2005)

Anatomic factors includes the shape of the intercondylar notch as a potential factor. Some studies have shown that women (who have smaller intercondylar notches compared to men) are at a greater risk for ACL injury, likewise for ACL volume. Those with smaller notches also had smaller ACL's and are more prone to tears. Other anatomical differences that may also play a role include women's wider pelvis and joint laxity.

Even your playing style can result in injury. Women tend to play sports in a more upright posture compared to men. Being more upright increases loading forces on the knee and causes higher shearing forces thus increasing susceptibility of an ACL tear.

Men usually have more developed thigh muscles and better control in muscle activation of the quadriceps and hamstring muscles compared to women. Our hamstrings act to "protect" the ACL when the quadriceps are activated. Studies show that women relied more on their quadriceps and took significantly longer time (compared to men) to activate their hamstrings in weight bearing.

Incidently, most of the ACL injuries that occur in females during sports are from non-contact situations, meaning it usually does not happen in a tackle or when someone nudges you say when you both are jumping for the same ball.
Studies show three main non-contact mechanisms that can cause the injury. They are: planting and cutting, straight-knee landing, and one-step stop landing on a hyperextended (straightened) knee. Other common mechanisms of ACL non-contact injury are pivoting and sudden deceleration. What sports have some og these movements? Majority of female patients with ACL injuries that I have seen play netball, rugby, basketball and soccer.

Where do we go from here? What do we do with this knowledge? Based on our experience in working with athletes, as a preventative strategy, we've found that it is important for us to identify risks factors by looking at patterns of incidence and prevalence of ACL injuries and educating athletes, patients (such as you), parents, coaches, teachers etc.
Research is currently pointing towards gender and sport specific training and rehabilitation programs. Please contact us if you are keen as we have the rationale and clinically researched techniques to help prevent ACL injuries.


Beynnon, BD et al (2005). Treatment of Anterior Cruciate Ligament Injuries, Part 2. Am J Sports Medicine 33(11) pp 1751-67

Park, SY et al (2009). Alterations in Knee Joint During the Menstrual Cycle in Healthy Women Leads to Increases in Joint Loads During Selected Athletic Movements. Am J Sports Medicine 37(6) pp 1169-77

Moller, JL and Lamb, MM (1997). Anterior Cruciate Ligament Injuries in Female Athletes: Are Women More Susceptible? The Physician and Sports Medicine 25(4) pp 1272-83.

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