Editor’s Note: We’ve received messages for years asking for coverage of medical issues facing the NFL and fantasy football owners. We’re excited to unveil this article today and also to introduce a new mailbag of sorts. ”The Dynasty Doctor” will be a series we run on an as needed basis. If you have any questions in regards to concussions, ACL procedures, recovery times from specific injuries or anything else related to medical science, submit your question here and it may be featured in an upcoming article with our own resident M.D., Dr. Scott Peak. He’s a board certified neurologist, neuro-oncologist and is the Director of Neuro-Oncology in the Department of Neuroscience/Neurosurgery for a large health care system.
The anterior cruciate ligament (ACL) has received a lot of attention recently, both in the NFL and in fantasy football. Years ago, a torn ACL was a career-killer for an NFL athlete. More recently, we have seen several athletes return from an ACL tear and perform at a high level. Wes Welker. Willis McGahee. Adrian Peterson. The question then becomes, how are these athletes able to overcome such a previously devastating injury? Peter G asked this question in our first installment of the Dynasty Doctor column, and it is a great one. In this article, we will discuss an ACL injury, describe what an ACL is, how it is repaired, and lastly rehabilitation for it. We will also compare and contrast it with Achilles injuries for NFL players.
The ACL is a ligament that helps stabilize the knee joint against anterior and internal rotational force. The ACL is about 3 to 4 cm long and 5 to 10 mm thick. The exact size and angle of an ACL varies in subtle but important ways for each person, and that can impact surgical results. The ACL is in the middle of the knee, and attaches to the femur (upper leg) and tibia (lower leg). The insertion points can also vary in size, anywhere from less than 14 mm to more than 18 mm on the tibia. The ACL is made up of two parts, an anteromedial (AM) and a posterolateral portion (PL). The AM part helps stabilize anteriorly directed force on the tibia, while the PL part stabilizes internal rotational force in the knee joint.
An ACL injury is diagnosed on examination and with imaging. There are two common tests done to examine a patient with a torn ACL:
- Anterior Drawer’s Test: The patient lays flat on a table, knee bent at a 90 degree angle, the examiner places his/her hands behind the lower leg, and pulls forward. If the leg moves forward more than 5 mm, a torn ACL is suspected.
- Lachman’s Test: The patient lays down flat or sits up, the knee is bent to a 30 degree angle, and the lower leg is pulled forward. If the lower leg shifts forward farther than the uninjured lower leg, that is a positive test result and suspicious for a torn ACL.
The reason why both tests can diagnose an ACL injury is that, at both a 90 degree angle in the Anterior Drawer’s Test or a 30 degree angle in the Lachman’s test, the ACL should be tense and resist forward motion of the lower leg. The ACL will stabilize the knee joint in this position, and if the ACL is completely torn, the lower leg will shift forward more than it should. Not surprisingly, this can result in significant instability in the knee joint when athletes attempt to play a sport like football.
An MRI can be done, and is able to detect the injury in 90 to 95% of cases. Advances in imaging have definitely improved diagnosis of an ACL injury, as MRI machines were first available in the 1980’s. Before 1980, clinical examinations were the best means of finding it.
Surgery is the first step in the treatment of a torn ACL.
An important tenet of orthopedic surgery is to reconstitute normal anatomy as much as possible. After all, our bodies are a system of levers, and movements depend on precisely located muscles, tendons and ligaments. If ligaments are replaced in a manner that is not as close as possible to normal anatomy, movements after surgery will not be precise. An athlete will have their own unique ACL size and angle of insertion in the joint. It is important for an orthopedic surgeon to replace the torn ligament in a manner that closely replicates the original position of the ACL.
So, how have surgical techniques come along to improve ACL recovery for athletes?
In the recent past, torn ACLs were replaced in a ‘non-anatomic’ manner. As early as 2003, such surgeries were being performed using this technique. A non-anatomic graft is when an orthopedic surgeon inserts the new ACL in a position that does not precisely match original anatomy of the ligament. These grafts tend to be more vertical in orientation, and this changed the normal movement in the knee joint. The results were often meniscal tears, arthritis or a re-rupture of the graft after surgery.
A graft is the replacement ACL tendon, and can come from two sources. An autograft is a tendon that comes from the patient, usually taken from the patella or hamstring tendons. An allograft is taken from a cadaver. Autografts are generally preferred for athletes, as they are associated with a faster recovery and lower re-rupture rate compared to cadaver grafts. This is an advance that has helped improve recovery from a torn ACL.
Surgical placement of grafts has evolved considerably, and within the past decade surgical technique has improved quite a bit. Surgeries are now done using an ‘anatomic’ approach. This basically means that grafts are placed in a manner that replicates the original location of the ACL, specifically for each patient. This results in joint movements that are more natural, and hence lower risk of arthritis, meniscal tears or re-rupture of the graft. Even the grafts themselves are becoming more advanced. There are now ‘double-bundle’ grafts, and these more closely replicate the anatomy of an ACL, with AM and PL components. Thus, ‘double-bundle’ grafts, according to recent studies, may improve joint stability with both anterior and internal rotational force compared to single ‘non-anatomic’ grafts.
Surgical skills have also improved given the sheer number of cases. There are 50-60 torn ACLs per year in the NFL, and 200,000 ACL injuries per year in the United States, the majority of which are associated with athletic activity. Compare that to only five torn Achilles tendons per year in the NFL. NFL players benefit even more, as they are referred to famed orthopedic surgeons like Dr. James Andrews, who has performed over 40,000 surgeries in his career. Surgical skills are honed, and complications reduced, with more cases. NFL players benefit because they get the best possible surgeons with the most experience, and that helps them recover faster.
Once surgery is finished, rehabilitation becomes the next important step.
Rehabilitation techniques, like surgery, have improved over the years. Players used to be immobilized, non-weight bearing for 4 to 6 weeks or longer after an ACL surgery, but things have changed. Players will now be on crutches with an immobilizer two or three days after surgery. An immobilizer is basically a very large brace that prevents the knee joint from moving, but is removable to allow for gentle physical therapy. Players are typically off crutches at four weeks, running in 2-3 months, and may even return to play in six to nine months. It is important to get players mobile soon after surgery, as muscles can atrophy if kept non-weight bearing for too long. NFL players who were non-weight bearing for long periods of time, in the old days, had to overcome disuse atrophy in surrounding leg muscles, and this added to their list of problems, complicating their recovery.
Rehabilitation also includes modernized techniques to essentially retrain the athlete on how to use their repaired knee joint properly. Proprioception is a complex sensation, and it is the ability for a brain to understand where its body is in space. For example, if you close your eyes, extend your arms out, then touch your nose, that can be done because of proprioception. The way athletes land from a jump is an automatic function, almost like a reflex. Athletes who tend to use ‘valgus landings’ are at higher risk for ACL tears. A valgus landing is when the knee is bent inward, like being ‘knocked-kneed.’ For some athletes, this is how their body reacts to jumping, and unfortunately for them, it places them at higher risk for ACL injuries. If the knee is in a valgus position upon landing from a jump, the leg is extended fully, and this places a huge stress on an ACL, possibly tearing it. This is also why 70% of torn ACLs are non-contact injuries. Biomechanical testing with video taping can help an athlete visually see how their knees are positioned upon landing, and they can now be retrained, with intensive rehab, to change high-risk landing styles.
Other factors that improve recovery from ACL tears include greater knowledge on pain control, and also player dedication is huge. There is a reason why Adrian Peterson recovered quickly, and that is intense dedication to his craft. Ryan Broyles is already running, just two months out from his torn ACL. Meanwhile, Kenny Britt’s recovery has been slower, and that’s not a surprise.
I wanted to briefly contrast injured ACLs from torn Achilles tendons. Torn Achilles tendons are much less common in the NFL. One study from Thomas Jefferson Hospital evaluated 406 cases over ten years, while there are 200,000 ACL injuries per year in the United States. Less common injuries mean fewer cases for surgeons and that will slow down progress in the field. A torn Achilles tendon usually occurs when the lower leg is extended, and the foot is dorsiflexed (the heel is flat on the ground, while the toes and arch of the foot are pointed upwards). This position stretches the tendon too much, and it can tear, particularly with sudden force and rapid changes in position. There is an excellent study from Duke, published in 2009, that describes recovery rates for NFL players with a torn Achilles tendon between 1997 to 2002. In total, 31 NFL players were evaluated and 36% were unable to return to play at all after surgery. The remaining players had a substantial reduction in performance, measured by variables such as receiving yards, passing yards, rushing and receiving touchdowns. The average reduction in production, and therefore fantasy football points, was 50%. Running backs and wide receivers had up to an 83 to 88% drop in production in this study. NFL players also missed more games, as these players averaged 12 games per year before surgery, and six games per year after surgery. Worse yet, their post-surgery performance got worse over the following three years. Sorry Kendall Hunter owners (that includes me). Surgery to repair Achilles tendons can be challenging, as the tendon is about six inches long, and the surgeon must repair it in a way that maintains the exact tension necessary for each patient. If the tendon is too loose, calf muscles will stretch it over time, the tendon is elongated, and this reduces power to push off. This complication impacted Dan Marino’s recovery from a torn Achilles. The other issue with Achilles tendon injuries is a more conservative rehabilitation process. Athletes are placed in a cast, and are non-weight bearing for six to eight weeks or longer. Again, this makes recovery of strength in lower leg muscles a more laborious process. There is a trend, however, to advance mobility and exercise for athletes recovering from surgery for a torn Achilles tendon, so in time this might improve the outlook for athletes with reconstructed Achilles tendons.
The moral of the story for dynasty owners? ACL injuries are not as bad as once feared, whereas a torn Achilles tendon is still a very bad thing for a dynasty player and owner. Owners of Broyles can sleep well tonight. But, for owners of Mikel Leshoure and Hunter, it is more like a nightmare.
1. Parekh SG, Wray WH 3rd, Brimmo O, Sennett BJ, Wapner KL. Epidemiology and Outcomes of Achilles Tendon Ruptures in the National Football League. Foot & Ankle Specialist, 2009 Dec; 2(6): 283-6.