Knee Injury In Female Athletes

Dr. Anthony Luke, Director of UCSF Primary Care Sports Medicine, has been kind enough to share some of his expertise with us. He has agreed to join us for regular blogs on common sports related medical questions with a focus on prevention of injuries.

Do women get more knee injuries?

Unfortunately, women have higher rates of injury to the anterior cruciate ligament (ACL) in the knee. As early as the 1990’s, higher rates of injuries to the ACL in women versus men have been observed (6:1 in basketball and 2:1 in soccer). Researchers have speculated that the greater risk to women is due to various factors, since many reasons can lead to tearing the ligament when an athlete lands with an awkward twisting motion.

The leading reasons include hormonal causes, anatomical variations between men and women, and differences in neuromuscular control. Estrogen hormone receptors have been found on the surface of the ACL and researchers have tried to demonstrate whether the menstrual cycle can affect the laxity of one’s ligaments. So far, an effect has not been clearly shown. The differences in lower extremity alignment is another major area that has been suspected to play a role, particularly the greater angles at the knees due to the wider female pelvis compared to men as well as a smaller notch in the center of the knee where the ligament attaches. Again, no major significance has been noted so far. The most promising explanation for more common ACL tears in females seems to involve the athlete’s ability to balance (proprioception) and control the knee with one’s muscles (neuromuscular control). Because of anatomical and muscle strength differences between average men and women, females have less stability and upper body control which can lead to an awkward fall.

Careful work on co-ordination, balance and hamstring strength can help reduce one’s risk of an ACL tear especially for female athletes. Many professional, college and competitive high school athletes are participating in programs to prevent a season ending knee injury. Activities designed to restore both functional stability about the joint and enhance motor control skills can help prevent injury. Use of balance equipment such as wobble board and jumping exercises on one leg can improve dynamic stability.

In one study, female soccer players, ages 14 to 18, who underwent a neuromuscular training program (Preventative Injury and Enhancement Program (PEP) program) consisting of basic warm-up activities, stretching techniques for the trunk and lower extremity, strengthening exercises, plyometric activities and soccer-specific agility drills had 88% less ACL injuries in the first year and 74% less injuries in the second year. Referring the patient to a health professional familiar with similar proprioception programs may be the best measure to teach the athlete proactively reduce the chance of an ACL tear.

Anthony Luke MD, MPH Director, UCSF Primary Care Sports Medicine 1701 Divisadero St. #240 San Francisco, CA, 94115 415-353-7566

References

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Mandelbaum, B.R., Silvers, H.J., Watanabe, D.S., Knarr, J.F., Thomas, S.D., Griffin, L.Y., Kirkendall, D.T., Garrett, W. Jr. (2005) Effectiveness of a neuromuscular and proprioceptive training program in preventing anterior cruciate ligament injuries in female athletes: 2 year follow up. Am J Sport Med 33, 1003-1011.

Myklebust, G., Engebretsen, L., Braekken, I.H., Skulberg, A., Olsen, O.E., Bahr, R. (2003) Prevention of ACL injuries in female handball players: a prospective intervention study over 3 seasons. Clin J Sports Med. 13, 71-78.