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Pop on Hop

An unfortunately large segment of the skiing community can relate quite well to the following story. Cruising down a run towards the end of the day. Not a great day, not a bad day, just a good day to be out on one of Montana’s fine slopes. Up ahead, a small riser, the kind you have been getting air on all season. A quick check to make sure the zone is clear, then hit it, nice hop. Nothing flashy but then the landing, flat. POP. One knee doesn’t feel quite right but not horrible, Skis put back on, time to cruise down, meet up with the family. First turn to the left, OK. Next turn to the right, wipeout. Next try, same result. 15 minutes later, an evaluation, followed by a toboggan ride down by ski patrol. By the time you are in the first aid room, that knee looks remarkably like the basketball you saw on TV the night before and you are struggling to walk. Not good, you have just popped your ACL.

Across the US, thousands of skiers and a lesser number of boarders tear their ACLs (anterior cruciate ligament) on the slopes. It is such a common occurrence that on a recent work trip to Beaver Creek, I heard the patrollers refer to it as AFK (another F knee). The classic story is a missed jump or turn, a crash and a pop. Typically the skier is unable to continue and has significant swelling inside the knee joint with the first 24 hours. These injuries often occur later in the day when legs are tired and muscles are no longer in a good position to pick up the slack. The question is, what happens next.

The first step in treatment is diagnosis. Sometimes the knee will hurt enough that care is sought in the Emergency department of a hospital or in one of the area urgent cares. In such settings more significant injuries (fractures, multiple ligament injuries) can be ruled out and the diagnosis of an ACL injury may be made. Often evaluation is deferred until an appointment with an orthopedic surgeon can be made. In clinic, the diagnosis of an ACL injury is usually pretty straight forward and can be made based on history, negative radiographs (x-rays) and a careful exam. MRI can be helpful for difficult exams or in the case of multiple ligaments being injured.

Once the diagnosis is made, treatment can begin. For all comers, initial treatment is ice, rest and regain motion. Neither operative nor non-operative treatments are likely to be successful until motion is symmetric with the other knee, a process that often takes 1-2 weeks. This process can often be facilitated by working with an experienced physical therapist. When symmetric motion has been obtained, the patient is then faced with the first big question, operative or non-operative management.

ACL reconstructions have not been shown to prevent arthritis, so the best argument for surgery is that with a good result, a patient will be more likely to get back to their previous level of activity. With non-operative care, a patient tries to strengthen their leg muscles to compensate for the missing ACL, sometimes in conjunction with an ACL brace. Successful non-operative patients often restrict their activities and avoid high risk sports (football, soccer, basketball and aggressive skiing). The advantage of non-operative care is an earlier return to some activities, avoiding potential surgical complications and the cost of surgery. Although there is certainly a meaningful up front cost to ACL reconstruction, a recent analysis showed the lifetime cost of ACL reconstruction of $38,121 versus $88,538 for lifetime costs associated with non-operative treatment of ACL injuries. Often, an orthopedic surgeon can help determine if operative or non-operative treatment is best for you. One of my favorite patients was a man in his late 30’s who popped his ACL skiing for the very first time. His stated goal was to be able to sit on a bar stool, drink beer and watch golf on TV. Despite the long odds, we were able to get him back without surgical intervention.

If a surgical option is chosen, the next decision point is timing. Once symmetric motion has been achieved, surgery is more of an elective issue. Although prolonged non-operative care may result in further damage to the knee (typically cartilage and meniscal injuries), there is no medical rush to proceed with surgery. The typical return to all activities after ACL reconstruction is 6-9 months so rarely does a week or three delay make a large difference. In general, it is reasonable to wait until a convenient time (school breaks, slow work times, after the honeymoon) to proceed with surgery.

Unfortunately, it is typically not possible to repair the native ACL and thus a reconstruction is the treatment of choice. This involves using some other tissue to reconstruct the ACL. Although in Europe an artificial ligament (LARS) may be used, it is not currently approved for use in the US. Similarly while quad tendon grafts are often used in Europe, they are decidedly uncommon in the US for primary reconstructions. In the US, reconstructions are done using autograft (patient’s own tissue) or allograft (cadaver or donor tissue)

The gold standard for ACL reconstructions in the US has long been the patella tendon autograft. This involves harvesting the central 1/3 of the patella tendon along with bone plugs from the patella (knee cap) and tibia (shin bone) and using this tissue to make a new ACL. This technique has the lowest failure rate but is accompanied by a higher rate of anterior knee pain with kneeling. In addition, this technique is more technically demanding and the post-operative therapy is even more essential than usual to reduce long term complications. If the decision is made to use a patella tendon autograft, using an experienced surgeon and therapy team is important.

Hamstring autograft has become one of the most common ways to reconstruct the ACL in the US. It involves harvesting 2 of the hamstring tendons and using them to make a new ACL. Although historically this has shown a higher failure rate than patella tendon grafts, more current studies suggest the failure rate may be about the same. Drawbacks of this graft type include permanent hamstring weakness (3-33% depending on the study) and inconsistency on graft size (tendon size varies and may be too small for a good ACL result).

The final way to reconstruct the ACL in the US is with allograft. This option can be quite attractive in that there is no harm to the patient from taking tissue. There are several studies however that suggest a higher failure rate in allograft reconstructions in patients younger than 30 or 40. For that reason, in uncomplicated cases, allograft is probably best suited to older patients desiring ACL reconstruction.

This article is meant to provide an overview of ACL treatment and should in no way take the place of a meaningful discussion between the patient with an ACL tear and their orthopedic surgeon. Treatment is typically individualized to the situation and your surgeon can best guide you through the decision making of operative versus non-operative treatment, timing of possible surgery and graft choice.

Alex B. Legrand, M.D.

Dr. Alex Legrand is a board certified orthopedic surgeon specializing in sports medicine.
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Dr. Alex Legrand is a board certified orthopedic surgeon specializing in sports medicine.
Learn more about this author

Dr. Alex Legrand is a board certified orthopedic surgeon specializing in sports medicine.
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Dr. Alex Legrand is a board certified orthopedic surgeon specializing in sports medicine.
Learn more about this author