Upon Further Review: ACL Tear Management

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Instant replayNathan Swan, DPT

While watching football the other day it occurred to me that the process officials use when confirming or changing a call with instant replay is much like the scientific method in medicine. Let me explain. As with officiating football, in medicine some things are very obvious and clear, while other times the picture is a little clouded and you just have to form a decision or treatment using your best judgment. When it is not so clear, scientific studies (or instant replay in the case of football) are completed to get a better picture. The judgment either stands or changes upon further review.

In the orthopedic world this happens all the time. Unlike football, however, the review process is ongoing and always advancing, sometimes without our knowledge. In order to keep you up to date with some “calls” that may be changing in orthopedics this will be the first article in a series entitled “Upon Further Review.” First up is the management of ACL injuries. We’re going to take a further look at three aspects of ACL management – whether surgery is necessary, what to do before surgery, and key components of the rehab process.

ACLRecently, several articles have been published questioning the necessity of surgery following ACL rupture. One study found that about half of the people who try physical therapy before surgery elect not to have surgery. An article recently published in the British Medical Journal stated that whether people have surgery right away, decide to have surgery later, or choose not to have surgery, all groups have the same outcome after 2 and 5 years, even those who returned to participating in the active things they previously enjoyed.1 It would seem that there is minimal risk in trying physical therapy before surgery. There is a fair chance you can avoid surgery with therapy, but you can always elect to have surgery later without any detrimental ramifications while you wait. A systematic review published this year on the topic concluded “…Based on the current findings, people following ACL rupture should be trialed with non-operative intervention, but with a lower threshold for reconstruction for younger and physically active people.”2 In other words it is wise to try to non-operative treatment first; however, if you are younger and physically active you should lean towards surgery. Typically on-going instability or episodes of the knee giving way during functional activities is the best reason to go ahead with ACL reconstruction.

Physical Therapy for ACL tear

For the many people who do choose surgery, physical therapy is not only important after surgery but before as well. What happens before surgery plays an important role in the outcome of surgery. For example, it has been shown that the degree of quadriceps atrophy (muscle loss) before surgery is related to less strength and function following surgery. Loss of motion before surgery compared to your other knee also does not bode well for outcomes.3 Before undergoing surgery for a torn ACL you should have minimal pain and swelling, nearly full motion, and minimal strength loss. Reducing the swelling quickly is a key component since it limits your motion and reflexively inhibits your quadriceps, which leads to weakness and atrophy. Your physical therapist can help you achieve these goals before surgery and also train you on the care of your knee in the days immediately following surgery so feel confident and prepared on your surgery day.

Now let’s get to the rehab of the knee after surgery. The rehab process after ACL surgery is being refined, which has led to quicker and improved outcomes. I want to point out two specific components of rehab that have been improved through the years. The first is strength training. Of utmost importance is that your reconstructed ACL has adequate healing time and the surgical site is protected. The problem is that the quadriceps (one of the main muscle group that becomes weak) pulls the tibia forward, which places stress on the ACL. We now know which quadriceps strengthening exercises can be performed early on that place minimal stress on the ACL, and the exercises that should be delayed due to risk of ACL tear. This is very important because it has been shown that early overload strength training of the quadriceps and gluteals lead to better outcomes.4,5

The second component of rehab that has changed is the emphasis on avoiding another ACL injury (and I don’t just mean the one that was torn originally). After you tear an ACL you have increased likelihood of subsequently tearing the reconstructed ACL and the ACL on the opposite knee.6 You will remain at high risk for another tear until the modifiable factors that lead to the first ACL tear are changed. This will involve not only looking at the knees but how the whole body moves. According to extensive research, the majority of ACL injuries are non-contact injuries that occur primarily due to faulty movement patterns which should be thoroughly addressed before dynamic activities and sports are safely re-introduced.

1. Frobell, Richard B., et al. "Treatment for acute anterior cruciate ligament tear: five year outcome of randomised trial." BMJ: British Medical Journal 346 (2013): f232.

2. Smith, T. O., et al. "Is reconstruction the best management strategy for anterior cruciate ligament rupture? A systematic review and meta-analysis comparing anterior cruciate ligament reconstruction versus non-operative treatment." The Knee 21.2 (2014): 462-470.

3. De Valk, Eduard J., et al. "Preoperative patient and Injury factors of successful rehabilitation after anterior cruciate ligament reconstruction with single-bundle techniques." Arthroscopy: The Journal of Arthroscopic & Related Surgery 29.11 (2013): 1879-1895.

4. Escamilla, Rafael F., et al. "ACL strain and tensile forces for weight bearing and non-weight-bearing exercises after ACL reconstruction: A guide to exercise selection." Journal of Orthopaedic & Sports Physical Therapy 42.3 (2012): 208-220.

5. Lepley, Lindsey K., and Riann M. Palmieri-Smith. "Effect of eccentric strengthening after anterior cruciate ligament reconstruction on quadriceps strength." J Sport Rehabil 22.2 (2013): 150-156.

6. Salmon, Lucy, et al. "Incidence and risk factors for graft rupture and contralateral rupture after anterior cruciate ligament reconstruction." Arthroscopy: The Journal of Arthroscopic & Related Surgery 21.8 (2005): 948-957.