ACL Injuries in Female Soccer Players

Despite almost a decade of explosive growth in the interest and participation of women in soccer, this sport continues to be one of the fastest growing sports in the United States. Starting in preadolescence, extending through the teenage years and now into adulthood, more and more women are participating in soccer. Favorable Northern California weather, the recent addition of all-weather turf fields and the opportunities through club, high school and developmental programs, such as the Olympic Development Program, have allowed soccer to become a year round endeavor. It is not surprising, therefore, that primary care physicians, emergency rooms and orthopedic surgeons are seeing higher numbers of injuries associated with soccer. This trend should not be interpreted to mean that soccer is a particularly high-risk sport for injury. Rather, it is more a reflection of the number of individuals participating and the increasing hours spent on practice fields and in competition.

Those treating soccer injuries on a regular basis, have recognized the pattern of injuries evolve as the players mature. In the younger age groups, the most common injuries seen are bumps, bruises, sprains, and for the most part, relatively uncomplicated fractures involving both the lower and upper extremity. Some of these fractures, however, can be more complicated when the growth plate is involved. Most of those injuries are treated in a conservative fashion without surgical intervention. They also carry a much less risk of life-long disability or impairment of function.

However, as the players reach skeletal maturity, the severity of injuries and the areas involved begin to change. With their increased body mass and faster more aggressive style of play, the injuries one begins to see are more complicated fractures, the addition of head injuries, such as concussions, and more serious and complex injuries involving joints, especially the knee. One knee ligament injury in particular which is receiving increasing attention is that involving the anterior cruciate ligament (ACL), especially in female soccer players. Indeed, the incidence of this injury appears to be approaching epidemic levels.

Some studies have suggested that the incidence of ACL injuries in female soccer players occurs three to five times more frequently than similar injuries in male participants. There are several theories on why this may be occurring. These include differences in male and female anatomy as well as hormonal factors. However, the most widely accepted theory is that the difference in lower extremity muscle strength, particularly involving the muscles around the knee, contributes to a higher level of these injuries in the female athlete.

The anterior cruciate ligament resides deep in the center of the knee joint. It serves as a check reign for anterior displacement of the lower leg in relationship to the upper leg or thigh. Probably more importantly, it is involved in the rotational stability of the knee allowing the lower leg or tibia to move in a coordinated fashion with the upper leg or femur. As the ligament crosses an open space within the knee joint, tears of the anterior cruciate ligament are unable to heal in most cases to allow return of stability to the joint. While a torn ligament may scar into surrounding tissues and provide some stability to the knee, the normal strength and the function of the ligament rarely returns. Therefore injuries to this ligament place the player at an increased risk of additional episodes of buckling or giving way. These episodes are often accompanied by further damage to the knee, particularly meniscal and articular cartilages. Such repetitive injuries place the individual at significant risk for life-long disability with the development of degenerative arthritis in the knee as additional structures are injured or compromised.

While the mechanism of injury involving the anterior cruciate ligament is often thought of as a contact-type occurrence, such as in football, a significant proportion of these injuries occur in noncontact fashion. In sports such as soccer, with rapid acceleration, deceleration, and pivoting, the ACL can be torn in this fashion. Similarly, this type of noncontact injury is seen in other women’s sports such as basketball and volleyball, where the injury can also occur as the player comes down awkwardly from a jumping maneuver.

The history of an episode of buckling or giving way in the knee, often times accompanied by a “popping” sensation, is typical of an ACL injury. While most times this is accompanied by significant pain and almost immediate swelling, it is not uncommon that the amount of pain and swelling that occurs following these injuries is fairly minor. This can occur to the degree that the player is actually able to continue play that day or within a relatively short period of time, only to present after an additional episode of giving way results in more dramatic symptoms.

In addition to the classic history, physical examination is often times definitive in making the diagnosis of a torn ACL. This is especially true when the player is examined shortly after their injury. Sometimes when the player presents later with significant swelling, pain and loss of motion in the knee, the examination can be compromised. Additional testing, such as an MRI scan, can help establish the diagnosis. Contrary to what many people believe, MRI scans are not 100% accurate in diagnosing this injury. There are a certain percentage of both false negative and false positive results. However, when a suggestive MRI scan is combined with a classic history and reliable physical examination the degree of accuracy of diagnosis is usually fairly high.

With regards to treatment, there are some individuals who because of the overall stability of their knee, age, or willingness to give up high risk sports, may be able to function following conservative treatment including muscle strengthening and bracing. In the case of the young competitive soccer player this is usually not the case. Surgical intervention is usually required in these individuals. Treatment choices are limited further by regulations restricting use of braces.

Surgical treatment of ACL injuries usually involves a reconstruction procedure where grafting of the torn ACL is carried out. This can be accomplished using the patient’s own tissues, such as a portion of the patellar tendon or hamstring tendons in what is referred to as autografting. Reconstruction can also be accomplished using allografts where tissues are obtained from a tissue bank. There are certain risks and benefits associated with either choice of graft material. The use of the patient’s own substitute tissues usually involves a somewhat more involved surgical procedure and a potential compromise in strength. Grafts obtained from a tissue bank run a greater risk of both bacterial and viral infections and they have a longer healing time prior to attaining their full strength. Other considerations include a greater cost and availability of grafting materials. Long-term results appear to be fairly similar between these groups. Often times, the decision of which graft material will be utilized are determined by surgeon and patient preference.

While the grafts are positioned in the knee in an arthroscopically assisted fashion, the recovery period following ACL reconstructive surgery is considerable in terms of time and rehabilitation. In recent years, rehabilitation following reconstructive surgery has become more aggressive promoting a rapid increase in return of motion to the knee joint and early strengthening. These are now usually begun immediately following the surgical procedure. Return to sports has become a somewhat controversial issue of late. Based on measurements of graft strength, traditionally athletes have been precluded from returning to their high-risk sports for a period of 9-12 months. More recently, there has been a movement to allow these patients, once they have completed a successful rehabilitation program involving motion and strength, to return to their sports 4-6 months following their surgery. This does, however, carry an increased risk of reinjury to the grafted anterior cruciate ligament, particularly in sports such as soccer where protective bracing is prohibited. These risks need to be recognized and the decision as to when to return to sports needs to be discussed between the surgeon, patient and her family.

In summary, the greater interest and participation in women’s soccer has resulted in a near epidemic of serious knee ligament injuries particularly involving the anterior cruciate ligament. Accurate diagnosis and proper treatment is important to the athlete to prevent the risk of life-long disability involving the knee joint. Any athlete who has sustained a twisting-type injury to the knee accompanied by a popping sensation, swelling and pain requires evaluation and treatment by individuals familiar with anterior cruciate ligament injuries. Hopefully advances in surgical treatment and preventive measures will improve the outcome in these athletes. However, it is unlikely that the preventive measures in themselves will eliminate the incidence of these injuries.

As the recognition of the number of ACL injuries being sustained by female athletes have increased, so have endeavors to initiate programs to attempt to, decrease their occurrence. Most recently, supervised and highly developed strengthening programs have been initiated. Some early studies had suggested that in fact these have led to a decrease in the number of ACL injuries. At the same time, however, as the popularity of artificial turf fields has increased, there are early concerns that these may contribute somewhat more to knee ligament injuries. Research in the area of optimal boot and cleat design is ongoing.

Additional information can be found on Dr. Batten’s web site at orthodoc.aaos.org/georgebattenmd.

George B. Batten, M.D. is a board certified orthopedic surgeon who has practiced in the Tri-Valley area for the past 17 years. He has a particular interest in the treatment of sport injuries in the youth athlete, and in particular those involving female soccer players. This has evolved as a consequence of his daughters’ involvement in local soccer programs over the past eleven years.