Today’s blog was sparked by Virgil Villanueva reporting on Clutchpoints.com that Klay Thompson has given an update on his progress from ACL reconstruction surgery. I have no direct knowledge of Klay’s progress but since we see anywhere between 100,000 and 200,000 reconstructions per year in the United States I thought it would be a good topic to blog about today.
There is no shortage of what-if stories about athletes that injured their anterior cruciate but none more prolific than two of my childhood idols, Mickey Mantle and Joe Namath. As great as these two became, what might have they accomplished if what is known now was known then.
At 19 years old Mickey Mantle played right field for the New York Yankees during the 1951 World Series vs the New York Giants. The team was managed by the famous Casey Stengel with Joe DiMaggio playing center field. Stengel told the young Mantle that DiMaggio was aging and slowing down and that he should get everything he could get to in right field. The great Willie Mays hit a ball between right and center and Mantle went after it at top speed but when he arrived for the catch DiMaggio called for the ball. Not wanting to be the kid that ran over DiMaggio, Mantle put the breaks on, stepped in drain grate and tore his Anterior Cruciate Ligament (ACL). With an Anterior Cruciate deficient knee, he went on to win the Triple Crown in 1956, appeared in 16 All-Star Games, won the Al League MVP 3 times and played in 12 World Series winning 7. He also holds the World Series record for home runs, RBI’s, extra-base hits, runs, walks and stolen bases.
In 1964 at 21 years old Joe Namath played quarterback for Bear Bryant’s Alabama Crimson Tide in a game vs North Carolina State. He rolled out and with no one near him, he collapsed writhing in pain. He described the injury as feeling like he was shot in the knee. With the lack of imaging in those days, he was diagnosed with a twisted knee. He returned to play in just one-week post-injury. One year later, the New York Jets drafted him with the #1 pick of the AFL draft. Team physician, Dr. James Nicholas stated after his physical exam that he had the knees of a 70-year-old. Even with his injury-plagued knees he won rookie of the year honors and went on to be the MVP and win Super Bowl III. He was known to have his knees drained at half time to complete games.
The common denominators of the ACL injuries to Mickey Mantle and Joe Namath are they were both non-contact injuries that resulted in knee joint degeneration requiring multiple surgeries. The majority of ACL injuries occur with non-contact mechanisms, i.e. there was no physical contact to the knee by another player or object at the time the injury occurred. This would indicate that there are biomechanical factors that can be identified and addressed to reduce the risk of ACL injury.
There seems to be correlations between ACL injury and knee geometry (notch width and tibial slope), neuromuscular control, ACL size, ligamentous laxity, high BMI, jump landing mechanics, the relationship between playing surface and footwear, previous injury, fatigue, muscle imbalances and genetics. All of these factors play a role but it’s not one factor or all of the factors. It’s certain combinations of factors that make up the perfect storm at the moment or moments that lead to ACL rupture.
Studies have shown that the incidence of an ACL tear is 2 to 8 times greater in the female athlete compared to the male. Add two more factors (high estrogen concentrations and a smaller ACL) to the ones mentioned above to see the female athlete is at greater risk.
There have been studies on top of studies trying to create the perfect ACL prevention training program but how do you train for all of the variables associated with ACL rupture.
Yes, the best way to treat an injury is to prevent it and no truer words have ever been spoken when it comes around to the ACL but as I’ve said in other blogs the two things the body doesn’t like is eccentric load (deceleration) and torque (pivoting) which are the two common mechanisms in the non-contact ACL rupture. The biomechanics people are looking at things like knee flexion angles, patella tendon force, ground reaction force, different shearing forces, etc. which is what we want them to do. But until they get it all figured out what can you do reduce risk of ACL injury.
The whole thing is complex but a simple answer is a three-pronged approach:
First and foremost is to control knee valgus. Knee valgus is when the knee collapses inward towards the midline of the body upon landing. Correcting knee valgus is through a combination of increasing the flexibility of the hip flexors and hamstrings while increasing the range of motion of the ankle (dorsiflexion) and activating the glutes.
Second is to correct muscle imbalances between the quadriceps and the hamstring muscle groups. The hamstring/quadriceps strength ratio and it’s relationship to ACL tears has been studied for years and there is a strong correlation to overly strong quadriceps in ratio to overly weak hamstrings is a predisposing factor to an ACL injury. There was an old belief that the hamstring needed to be 60% as strong as the quad. That number is ok but studies have shown that ham/quad ratios function differently based on whether you are moving at high speeds vs slow speeds and/or accelerating vs decelerating. The bottom line is people spend too much time working and looking at the front of their body and not the back of the body. Hamstring strength lowers the risk of ACL injury.
Third is to avoid competition while in a fatigued state. The more fatigued the athletes is the poorer movement efficiency there is. Poor movement efficiency will drop the athletes into compensatory postures that lead to a dysfunctional transfer of load through the pelvis causing knee valgus and increased risk of knee injuries including ACL rupture.
Today we have affordable high-speed camera and sensor technology to evaluate an athlete’s movement efficiency and predisposition to ACL injury. Evals take about 20 minutes and range in price from $75.00 to $250.00 depending on where you live and the equipment. I think it’s a small investment to help identify ACL injury risk and correction.