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  • Noteworthy Injuries

James Carpenter


Seattle Seahawks offensive linemen James Carpenter suffered an Anterior Cruciate Ligament (ACL) injury during a pass rush drill in practice this week. He was carted off and then taken for an MRI. Carpenter will likely have surgery by Dr. Khalfayan as soon as swelling decreases and till be likely on a timetable that will put him safely into camp in a modified fashinon by early May. He likely will not be ready for contact until July and the start of formal training camp. The typical rehabilitation begins right after surgery and will continue for likely 9 months with the greatest outcomes and performance usually coming at 10-12 months.


Carpenter's injury came on the heels of John Moffitt being lost for the season with a pair of torn ligaments in his right knee.


What is an ACL injury?

Where is the ACL?

The word "cruciate" loosely defined, means "crossed", referring to the fact that there are two cruciate ligaments, the ACL (a broad ligament) crosses from front to back and the PCL (Posterior Cruciate Ligament) crossing from the back to the front. The ACL begins from the anterior portion of the intercondylar area of the tibia (shin bone), just behind the attachment of the medial mensicus. The ACL courses upwardly and backwards and attaches to the lateral condyle of the femur (thigh bone). The ACL is slack when the knee is flexed (bent as it is at your desk) and taut when fully extended (knee is straight as in standing).

What is the function of the ACL?

The main function of the ACL is to stabilize the joint. It prevents displacement (movement) and rotation of the femur on the tibia. The easiest application of this phenomenon is when going down the stairs or playing sports with a torn ACL. This is noticeably more difficult as a descent down stairs feels unstable to the lower leg.

Causes of ACL Injury?

Injuries to the ACL are among the most common of all sports-related knee injuries. It's estimated that each year in the United States between 95,000 and 250,000 people sustain a torn or ruptured ACL. The most common cause of ACL rupture is a traumatic force being applied to the knee in a twisting movement. This can occur with either a direct or an indirect force. Typically ACL tears happen when you slow down suddenly or cut or pivot with your foot firmly planted, twisting or overextending the knee. This type of stress in the knee can stretch the ACL beyond its normal elastic range for it's fibers and subsequently tear. Once the ligament tears, it doesn't heal — it remains loose. In our practice, about half of the cases of ACL rupture occur without contact, i.e., while side-stepping, pivoting or landing from a jump. The other half are associated with some type of contact, whether it be on the football field, on the snow fields or in a motor vehicle accident. Skiing injuries usually occur during a fall in the inexperienced skier, on rented skis when the bindings do not release. Women have ACL injuries more often than men do. The exact reason for this isn't clear. It is likely due to differences in anatomy, hormones, strength or conditioning.

What are the symptoms of an ACL tear?

When you tear your ACL, you may feel or hear a pop in the knee, experience significant pain in the knee, and have immediate swelling. When you try to stand and put weight on the injured leg, the knee may give way and feel unstable. In most cases, you must stop physical activity due to pain or because the knee is no longer able to support your weight.


Treatment Options:

There are both conservative (Non-Operative) and operative options. Some patients are able to rehabilitate their knee with a comprehensive physical therapy program and utilization of a brace for activities at risk. Patients involved in a sport that includes a jump, cut, or pivot; often opt for a surgery to reconstruct the torn ACL. The goal of the surgery is to restore the stability of the joint. This is accomplished by placing a graft in the knee to replace the native ACL.


After Surgery:

Your surgeon will instruct you on your allowed activities during the post-operative period. It is important that the surgeon understands your goals and when you would like to return to sport/activities. A supervised physical therapy is often prescribed after surgery. The goal of PT is to restore normal function in your knee and strengthen the surrounding and biomechanically important muscle groups.



The Sports Medicine Clinic

Chris Peterson, DO

Lake Washington Physical Therapy

Benjamin Wobker, PT, DPT


Other Injuries:

(click here)



Larry Maurer, DPM



Orthopedic Physical Assessment, 4th Edition. David J. Magee, 2006. Physical Rehabilitation: Assessment and Treatment, 4th Edition. Susan B. O’Sullivan and Thomas J. Schmitz, 2001.



ACL Anatomy

ACL Tear



ACL tear

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