Are ACL Tears Hereditary?
A recent study by the Orthopaedic Journal of Sports Medicine reported a case of 4 brothers requiring surgical treatment for a rupture in their ACL – all between the ages of 15 and 22.1 The ruptures all occurred either in a football game or in football practice, and all brothers played a position that required immense pressure on the ACL, such as twisting, turning, jumping, etc. The study looked at all 4 brothers consecutively–their particular injury and operating procedures–and all elected ACL reconstruction using hamstring autograft. Though the report was as of this writing inconclusive, it was the determination of the doctors involved in the study that ACL injuries and meniscal tears requiring surgery may point to evidence of a familial predisposition to ACL injuries.
According to the Center for Orthopaedics, the knee is a very vulnerable joint, and often prone to trauma. Injuries to the knee are graded on three levels–Grade I strain, Grade II strain, and finally, Grade III tear. But perhaps it is helpful to first understand the ligaments that make up the knee and their specific functions.
Ligaments of The Knee And Their Function
- Medial Collateral Ligament (MCL) & Lateral Collateral Ligament (LCL). These ligaments rest on the outside of the knee and act as lateral stabilizers when the knee is in motion from side-to-side.
- Anterior Cruciate Ligament (ACL). This crucial ligament, found in the front of the knee, stabilizes the femur and tibia. Such movements as rotating, sliding forward, agility, jumping, and deceleration activities all require the plasticity and strength of the ACL. In part because of its importance, it is often the most susceptible to injury.
- Posterior Cruciate Ligament (PCL). This ligament is charged with preventing the sliding of the knee to the rear.
Sports and ACL Injuries
While all ligaments are important to the stability of the knee, it is the rupture of the ACL that researchers are finding on the rise, particularly in sports, and there’s cause for concern, especially among younger athletes.
It’s estimated that 47 out of 100,000 boys aged 10 to 19 will require surgery for an ACL injury each year. This figure has increased over the past two decades. ACL tears cause long-term consequences, “including chronic knee instability, cartilage damage, and osteoarthritis.” In fact, over 50% of this sub-group will develop signs of osteoarthritis, a degenerative disease, 10 to 20 years after diagnosis. Therefore, it is “imperative to identify young athletes that may be susceptible to ACL injuries and implement preventative training measures in these individuals.”
Risk Factors and Preparation
With so many young athletes putting themselves at risk in high-impact sports, identifying risk factors prior to injury could be very important. When risk is known, preventive measures can be taken, such as “education, training, and prophylactic bracing.”
The findings suggest the most probable reasons for this hereditary propensity are the formation of certain knee structures that are more susceptible to injury than others, and body type. Each boy evaluated in the study had a BMI (Body Mass Index) in the 98th percentile for their age and sex, with 2 or more standard deviations (for a full analysis of the BMI and SDs, go to the World Health Organization’s database online) recorded. Further, the structure of their knees all showed particular proclivities towards injury. In other words, these brothers were both cutting and twisting with some heavy weight on knees that couldn’t handle the pressure.
ACL tears are not uncommon in football, which makes education and early evaluation essential. Females are not immune to these structural affinities, either, however. In fact, females in the same age group make up for even MORE ACL tears than males do.
Football–and many sports–can be trying on bodies still developing and growing. It’s important to take precautions to avoid more serious injuries. Football may never be fully “safe,” but with more precautions, it may become a safer sport to play.
- Kay J et al. “Anterior Cruciate Ligament Rupture,” Orthopaedic Journal of Sports Medicine 41, no. 11 (November 25, 2015): 1, accessed December 13, 2015, doi:5, http://ojs.sagepub.com/content/3/11/2325967115616783.full.
- “WHO: Global Database on Body Mass Index,” World Health Organization, December 13, 2015, accessed December 13, 2015: http://apps.who.int/bmi/index.jsp?introPage=intro_3.html.