A while back, I put a bit of a lengthy post on Instagram about the how the hip labrum contributes to hip stability. The reason I posted about it was because 50%-70% of hockey players have hip labrum tears (Kuhn et al., 2016, Epstein et al., 2012, Silivis et al., 2011). Although anatomically the hip is a very stable joint, I wanted to make sure people realize the importance of the labrum and other structures in stabilizing the hip for optimal function. So, read the rest of this article first to learn about the hip labrum and why it’s an integral structure for proper function of the hip, then go check out my Instagram post. And stay tuned for Parts II and III of this series to learn about the other stabilizers of the hip.
The hip labrum is a common cause of hip pain in hockey players and athletes in general. It can be torn, pinched and irritated. Lots of athletes have labrum repairs, especially in pivoting and rotational sports such as soccer and hockey. But what is the hip labrum, what does it do, and why is it so commonly an issue?
Labrum Anatomy
The hip labrum is a triangular shaped fibrocartilage that sits deep to all the muscle and ligaments in the hip and is attached to the perimeter of the acetabulum. The labrum attaches inferiorly to the transverse ligament, which completes the circular socket of the hip joint.
Limits anterior translation of the femur
The role of the hip labrum has been commonly studied. One of its roles is to limit anterior translation of the femoral head in the acetabulum (Myers et al., 2011). Anterior translation typically occurs with hip external rotation (Nho et al., 2015). In fact, some research (Dy et al., 2008) that suggests there is a substantial amount of strain on the anterior labrum with external rotation and abduction movements, both of which are repeated constantly as part of the skating stride (Upjohn et al., 2008, Stull et al, 2011). Thus, suggesting that every time a hockey player takes a stride, they are putting a substantial amount of strain on the anterior labrum. Therefore, the labrum can become a common cause of pain due to the amount of strain being placed on it when the player is in full stride. It can even reach a point where it can fray and eventually tear, leading to further issues that will be discussed next.
Suction seal limits hip distraction
Another role of the labrum is that it creates a suction seal for the hip joint (Philipon et al., 2014). This seal creates a negative pressure inside the joint, which is actually similar to sticking a Nerf bullet on the window. When the bullet sticks, it requires some force to pull it off. The same idea for the suction seal of the labrum to which makes it more difficult to distract from the joint. But when the labrum becomes torn, the suction seal is lost due to the loss of the negative pressure inside the joint. This makes it easier for the femur to be distracted from the acetabulum. The hip joint is surrounded by ligaments and muscles which are more than enough to avoid the hip to be completely dislocated, however, just having more freedom to move in the joint can lead to issues by irritating tissues such as the labrum and joint capsule/ligaments (Myers et al., 2011). Previous research has suggested that hockey players produce approximately 350N of lateral force during skating (Sim et al., 1978). According to Newtons second law, which states that for every action there is an equal and opposite reaction, there will have to be an equal force in order to stop the leg from being pulled off of the hip. The role of the suction seal of the labrum in skating is to stop the femur from separating from the acetabulum. Without the seal, other structures such as ligaments and muscle must do its job.
Thankfully, we can train the muscles to make up for the lack of suction seal and there are arthroscopic procedures that can repair the tear to restore the suction seal. The labrum is important for hip stability, but the issue is that a high percentage of hockey players have tears even though they may not be aware. These players start relying on other structures like the capsular ligaments to stabilize the hip, which we will discuss in Part 2. But it makes sense to me that we should be training the hip cuff muscles, discussed in part 3, as a prehab regiment to increase hip stability even in those that are asymptomatic.
Like this post? Want to learn more about hip pathology in hockey players? Be sure to check out my other posts www.be-elite.ca/blog and on Instagram @alwaysbeelite.
References
Dy, C. J., Thompson, M. T., Crawford, M. J., Alexander, J. W., McCarthy, J. C., & Noble, P. C. (2008). Tensile strain in the anterior part of the acetabular labrum during provocative maneuvering of the normal hip. JBJS, 90(7), 1464-1472.
Epstein, D. M., McHugh, M., Yorio, M., & Neri, B. (2013). Intra-articular hip injuries in National Hockey League players: a descriptive epidemiological study. The American journal of sports medicine, 41(2), 343-348.
Kuhn, A. W., Noonan, B. C., Kelly, B. T., Larson, C. M., & Bedi, A. (2016). The hip in ice hockey: A Current concepts review. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 32(9), 1928-1938.
Myers, C. A., Register, B. C., Lertwanich, P., Ejnisman, L., Pennington, W. W., Giphart, J. E., … & Philippon, M. J. (2011). Role of the acetabular labrum and the iliofemoral ligament in hip stability: an in vitro biplane fluoroscopy study. The American journal of sports medicine, 39(1_suppl), 85-91.
Nho, S. J., Leunig, M., Larson, C. M., Bedi, A., & Kelly, B. T. (Eds.). (2015). Hip arthroscopy and hip joint preservation surgery. Springer New York.
Upjohn, T., Turcotte, R., Pearsall, D. J., & Loh, J. (2008). Three-dimensional kinematics of the lower limbs during forward ice hockey skating. Sports biomechanics, 7(2), 206-221.
Stull, J. D., Philippon, M. J., & LaPrade, R. F. (2011). “At-risk” positioning and hip biomechanics of the Peewee ice hockey sprint start. The American journal of sports medicine, 39(1_suppl), 29-35.
Sim, F. H., & Chao, E. Y. (1978). Injury potential in modern ice hockey. The American journal of sports medicine, 6(6), 378-384.
Silvis, M. L., Mosher, T. J., Smetana, B. S., Chinchilli, V. M., Flemming, D. J., Walker, E. A., & Black, K. P. (2011). High prevalence of pelvic and hip magnetic resonance imaging findings in asymptomatic collegiate and professional hockey players. The American journal of sports medicine, 39(4), 715-721.