January 9, 2012

Collateral Damage

Rounding Up the Usual Suspects: Sports Hernia/Athletic Pubalgia

by Corey Dawkins and Ben Lindbergh

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Athletic pubalgia (more commonly called sports hernias) have been getting more attention in the last few years, but reports often mistake them for inguinal hernias or otherwise misrepresent what they are. Despite the hernia connotation, this injury does not involve any actual herniation, which is defined as the protrusion of an organ or other bodily structure through the wall that normally contains it. Therefore, “athletic pubalgia” is a more appropriate term and encompasses any number of variants, including chronic adductor strains.

Football, soccer, and ice hockey have traditionally seen the highest number of cases of athletic pubalgia, but in the last few years we have seen numerous baseball players undergo surgery, including Stephen Drew, Josh Hamilton, Hunter Pence, Nick Markakis, and Kevin Youkilis. In today’s column, we’re going to look primarily at athletic pubalgia, but we’ll also discuss how they differ from inguinal hernias.

Anatomy
The anatomy of athletic pubalgia and inguinal hernias is essentially the same. The pubic bones are located in the middle of the extreme end of the lower abdomen and form a joint between the two called the pubic symphysis. The rectus abdominis and transverse abdominis muscles combine to form a common tendon that attaches onto the pubic bone where the external oblique muscle also forms fascia that blends into the same area.

One of the groin muscles (adductor longus) originates from the same area but pulls in the opposite direction, as shown in the second illustration. The different tendons, along with several ligaments, form what is called the inguinal canal, which is the site of inguinal hernias. The combined tendons, ligaments, and connective tissue form part of the lower abdominal wall, where athletic pubalgia occur.

Source    Sprintforever.blogspot.com Normal Anatomy             Source Proscan.com                           

Mechanism of injury
There is still some debate about what forms athletic pubalgia, but generally it forms much the same way that you play king of the mountain: whoever is stronger generally wins out. The adductor longus is a large and strong muscle in the lower extremity that exerts force on the area with maneuvers common to baseball, such as cutting, pivoting, or twisting. The lower abdominal muscle fibers can be strong, but as the saying goes, you are only as strong as your weakest link.

You could have six- or eight-pack abs and extremely strong muscles, but often it is the connective tissues and tendons that are the weak point. Basically, a tug of war takes place between two or three muscles, with fascia overlaying it all. Microscopic tearing of the fascia, or tendon tissue, causes pain and inflammation. In acute episodes, true tearing can also occur. This is what athletic pubalgia is, except that the material underneath it can bulge in the weakened area without pushing through.

The tension placed on the muscle attachment area is magnified by abdominal extension and hyperabduction of the thigh. This stretches the abdominal muscles, adductor longus, and adductor brevis and can lead to fraying or tearing of the fascia. The tightness of the muscles of the hip, abdomen, and groin play a role in the development of athletic pubalgia.

Source Aidmygroin.com

Inguinal hernias are different and potentially much worse but not uncommon. One study by Kingworth and LeBlanc found that the lifetime risk for males to have an inguinal hernia stands at about 27 percent, but only 3 percent in females. Inguinal hernias occur when a portion of the abdominal contents—usually the intestines—protrude through the tear or opening.

Source: Drugs.com – Direct inguinal hernia

There are a multiple types of inguinal hernias: direct and indirect. Indirect hernias are more prevalent in males as a result of their larger superficial rings. The ring is larger in males as a result of allowing the testes to pass through the canal as an embryo, and is considered a congenital hernia.

The type of hernia that we traditionally think of is the direct inguinal hernia, which is an acquired hernia that stems from a tear in the posterior wall of the inguinal canal. Tearing is usually the result of general weakness followed by a significant force applied to the area.

Presentation
Inguinal hernias are easier to explain, so we will look at them first. Inguinal hernias present as a lump or bulging in the groin that often disappears in a prone position or when pressure is placed on the area. Pain and discomfort increases with activities, hence the occasional screaming from your father or uncle when he lifts something heavy. You can use this picture for a visual example, although some may find it too graphic due to partial male nudity. Occasionally, the herniated intestinal tissue become pinched off and begins dying in a process called strangulation. These cases require surgery because of the risk to the internal organs.

The physical examination for an inguinal hernia is not exactly fun. There is tenderness in the area, as well as a palpable protruding mass. In the wonderful “turn your head and cough test,” the doctor will almost always be able to feel the hernia. An MRI or CT can be ordered to get a better idea of the extent of the hernia.

Athletic pubalgia has a different presentation, which depends in part on the variant of athletic pubalgia present. In baseball players, specifically pitchers, the fascia of the adductors are often involved. A fair amount of pain is still present when it first develops, and it feels like a typical groin strain except in a slightly different spot. It can be extremely difficult to diagnose accurately at first because it presents like a groin strain but often persists like a mild chronic strain. A bulge is not visible, and the pain may dissipate with rest but comes back with twisting motions. Over time, the weakened area can progress into true tearing, much like the felt in the tug of war example given earlier.

Athletic pubalgia has associated tenderness, especially in the acute stage, but it doesn’t have any palpable hernia during the cough test. The doctor has the patient perform a sit-up against resistance, which can be painful. MRIs can also help assess the area, but at times it can be difficult to give a definitive diagnosis by MRI because of the different structural interactions of the tendons and fascia. Recent improvements in technique can more accurately assess the area for athletic pubalgia and are being adopted more readily among MRI centers. Other tests, such as bone scans, may be performed to rule out other injuries or non-athletic conditions.

Treatment
Traditional therapy involves several weeks of rest and strengthening of the area in addition to corticosteroid and/or PRP injection, but in active athletes that is not always enough. The healing tissue forms as scar tissue and has a different strength characteristic than the surrounding tissues, making it more prone to re-injury in the future. Therefore, athletes who want to remain active often need surgery to repair the area.

There are two types of surgery: open, or laparoscopic, in which a camera is used. Most surgeons prefer the open method in athletes because of the improved visibility and ability to address the multiple components of athletic pubalgia. Laparoscopic methods usually use a mesh to theoretically strengthen the area, which can be appropriate for patients who are not as active. In all, there are over 100 variants of surgery to treat athletic pubalgia. In addition to repairing any tears of the abdominal fascia, the fascia involving the adductor tendons are released to decrease the force that pulls on the newly repaired area.

Summary
Twisting, cutting, and pivoting are motions inherent to baseball, so athletic pubalgia will always be a potential pitfall of playing the game. Athletic pubalgia can be incredibly difficult to treat, in part because of the numerous variants present. In active athletes, non-surgical treatment almost always fails if the patient wants to continue to be active. Surgeons who specialize in treating athletic pubalgia in high-level athletes most often use the open technique in order to address any of the variants present, which may not always be apparent prior to surgery even after MRI and other scans. Surgery keeps the player out for some time, but there is no alternative, since conservative therapy almost always fails.

Corey Dawkins is an author of Baseball Prospectus. Follow @CoreyDawkinsBP
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Ben Lindbergh is an author of Baseball Prospectus. Follow @benlindbergh
Click here to see Ben's other articles. You can contact Ben by clicking here