"Understanding ACL Injuries "

Chris Reed MPT, OCS, ATC

ACL Injuries

With the football season winding down and basketball season heating up, let’s discuss an injury that is common in both sports. Nearly 200,000 Americans sustain a tear of the Anterior Cruciate Ligament (ACL) annually. Female athletes are 3-4 times more likely to suffer from an ACL injury than male athletes, with a majority occurring in females between the ages of 15-25. Let’s examine the anatomy, mechanism of injury, signs and symptoms, non-surgical vs. surgical treatments, and the rehabilitation process.

Anatomy:
The ACL is one of the primary stabilizers in the knee. It runs diagonally through the middle of the knee originating from the anterior medial aspect of the tibial plateau and inserting into the posterior medial aspect of the lateral femoral condyle. Two bundles are braided together throughout the length of the ligament. It acts as the primary restraint against anterior tibial translation on the femur.

Mechanism of Injury:
There are two common ways the ACL is torn. The most common mechanism is from a hyperextension of the knee, usually as a result of landing on a straight leg. The other mechanism is during deceleration combined with a rotational movement, such as cutting. About half of ACL injuries are combined with damage to other structures in the knee, most commonly the medial meniscus and/or medial collateral ligament.

Signs and Symptoms:
Commonly the athlete will feel and hear a loud pop in the knee. There is usually an initial sharp pain, that resolves relatively quickly. There will be a large amount of swelling that develops over the next 15-20 minutes. The knee will feel loose and unstable in weight bearing and with ligamentous testing. The knee will become stiff to movement due to the swelling. It may be warm to the touch. The athlete will often require crutches and a knee immobilizer for the next several days to weeks. Initial treatment should include resting, icing 20 minutes at least 4 times per day, keeping the leg elevated as much as possible, and working to regain control of the quadriceps by trying to tighten the thigh and straighten the knee.

Non-Surgical Treatment:
In the majority of cases it is advisable to have the torn ACL surgically repaired. However, for the athlete that plays non-contact sports that do not require a lot of cutting, twisting, or change of directions, a course of physical therapy may be all that is required. The initial care in the surgical and non-surgical case is essentially the same. The initial goals are to eliminate the swelling, regain full extension range of motion, and restore voluntary quadriceps control. Once the athlete has achieved these goals, then a progressive strengthening program will be instituted to regain strength and coordination in the injured extremity. The athlete can expect this process to take between 6 and 9 months before feeling ready to return to athletic competitions.


Surgical Repair:
There are a variety of surgical options to choose from. The first decision to be made is whether to use a graft from your own body (autograft) or from a cadaver (allograft). Most of the time this will be based on the recommendation of your surgeon. If the autograft procedure is chosen, the graft will be harvested from either the central third of your patellar tendon or from one of your medial hamstring tendons. Less often, the graft is harvested from the quadriceps tendon above the patella. In the greater San Francisco Bay Area, most of the surgeons prefer to use the allograft procedure because there is less secondary tissue damage since there is no graft being harvested from your body. This allows for a less painful and quicker initial recovery.

Rehabilitation:
The initial phase of rehabilitation will focus on the same things discussed in the non-surgical section. The first one-two weeks are non-weight bearing and often a continuous passive motion machine will be used at home for several hours every day. The first 6 weeks will focus on regaining the ROM and voluntary control of the quadriceps muscles. Normalizing the gait pattern will also be of primary concern. The six to eight week mark after surgery is very critical. This is when the athlete is starting to feel pretty good and the new ACL is at its weakest. Once the athlete has regained full range of motion, the focus will shift to restoring full strength, coordination, and balance in the surgically repaired lower extremity. The athlete can expect it to take 9-12 months to return to athletic competition following ACL reconstruction.

I hope this article has provided you with a better understanding of ACL injuries and the recovery process following an injury. Please feel free send me any question relating to ACL injuries and/or rehabilitation at chris@agilept.com.

References:

1. Anterior Cruciate Ligament Injury. Available from URL: http://www.emedicine.com/pmr/byname/
anterior-cruciate-ligament-injury.htm (Accessed December 2006).
2. ACL Reconstruction. Available from URL: http://orthoinfo.aaos.org/
fact/thr_report.cfm?Thread_ID=216 (Accessed December 2006).
3. ACL Injury: Should it be fixed? Available from URL: http://orthoinfo.aaos.org/
indepth/thr_report.cfm?Thread_ID=14&topcategory=Knee (Accessed December 2006).
4. Women and ACL Injuries. Available from URL: http://orthoinfo.aaos.org/fact/thr_report.cfm?
thread_id=85&topcategory=Sports%20/%20Exercise (Accessed December 2006).