A Cam Deformity Is Gradually Acquired During Skeletal Maturation in Adolescent and Young Male Soccer Players: A Prospective Study With Minimum 2-Year Follow-up.
Agricola R, Heijboer MP, Ginai AZ, Roels P, Zadpoor AA, Verhaar JA, Weinans H, & Waarsing JH. Am J Sports Med. 2014 Published Online First Feburary 28, 2014: doi: 10.1177/0363546514524364
Take Home Message: Cam deformities develop over time in skeletally immature elite soccer athletes.
A cam deformity may increase a person’s risk for chondral or labral hip injuries, and ultimately hip osteoarthritis (OA). Athletes in high-impact sports are more likely to have of cam deformities compared with nonathletes (see related posts below). Cam deformities may develop in response to high-impact sports during growth but it remains unclear as to how these deformities progress among athletes during and after skeletal maturity. Therefore, the authors of this study primarily assessed how a cam deformity develops among adolescents and if the formation of this deformity is primarily before skeletal maturity. Sixty-three elite adolescent soccer athletes (12 to 19 years of age) received bilateral hip x-rays at baseline and at a 2 year follow up. Skeletally immature athletes were more likely to develop a cam deformity or progress than older athletes. Among the 22 younger aged soccer players (12 or 13 years, 44 hips) the number of normal radiographic hips decreased from 84% at baseline to 43% at follow-up. In comparison, among the 24 athletes, who were between 14 and 15 years of age, 31% of hips had normal hip radiographs at baseline but only 17% did at follow-up. Among the 17 athletes over 16 years of age 35% had normal hip radiographs at baseline and follow-up. When the authors examined the 96 hips with open growth plates, 57% had normal radiographs at baseline but only 31% were still normal two years later. In contrast, among the 30 hips with closed growth plates 30% had normal hip radiographs at baseline and follow-up. Limited hip internal rotation as well as small neck shaft angle may be predictive of cam deformity formation.
This is one of the first studies to look over time at cam deformity formation and progression within an at-risk population of elite soccer players. The study supports previous claims that athletes in high-impact sports and who are still growing may be at risk for cam deformities. There are a few key clinical factors that we may be able to focus on such as internal rotation deficits to help aid in the prevention of cam deformity formation. Internal rotation deficits are focused on tremendously within the shoulder, and these findings support that we may need to investigate this clinical measure within the hip joint. Unfortunately, we do not know what caused the hip internal rotation deficits (i.e., bony vs. soft tissue) nor do we know if an intervention like stretching would be successful in improving range of motion. While these findings are interesting, we need to investigate whether these results would be similar among non-elite athletes who participate in the same at-risk sport. Without this additional information we do not know if we can apply these findings to non-elite athletes. This is an important question because cam deformities with internal rotation deficits are strongly associated with hip OA. Early intervention may be key because once radiographic changes start to occur in OA there is little that we can do to reverse the degenerative changes. As clinicians we may be able to start to investigate activity modification during vulnerable skeletal maturity times as well as emphasize clinical factors that we can modify (i.e., hip internal rotation deficits) to try to help prevent cam deformity development. However, if the internal rotation deficit is a result of bony adaptation, we may need to look even earlier in the process. These findings identify prospects for future research and may help in the early prevention of hip OA development.
Questions for Discussion: Do you think that activity modification for the hip is a reasonable recommendation among skeletally immature athletes? If yes, what modifications might you recommend? What have you seen clinically that aids with generalized hip pain or hip internal rotation deficits? Have you noticed hip internal rotation deficits among young athletes?
Written by: Nicole Cattano
Reviewed by: Jeffrey Driban