@article{ref1,
title="A cam morphology develops in the early phase of the final growth spurt in adolescent ice hockey players: results of a prospective MRI-based study",
journal="Clinical orthopaedics and related research",
year="2020",
author="Siebenrock, Klaus A. and Werlen, Stefan F. and Reichenbach, Stephan and Steppacher, Simon D. and Schmaranzer, Florian and Hanke, Markus S.",
volume="ePub",
number="ePub",
pages="ePub-ePub",
abstract="BACKGROUND: Cam morphologies seem to develop with an increased prevalence in adolescent boys performing high-impact sports. The crucial question is at what age  the cam morphology actually develops and whether there is an association with an  aberration of the shape of the growth plate at the cam morphology site. QUESTIONS/PURPOSES: (1) What is the frequency of cam morphologies in adolescent ice  hockey players, and when do they appear? (2) Is there an association between an  extension of the physeal growth plate and the development of a cam morphology? (3)  How often do these players demonstrate clinical findings like pain and lack of  internal rotation? METHODS: A prospective, longitudinal MRI study was done to  monitor the proximal femoral development and to define the appearance of cam  morphologies in adolescent ice hockey players during the final growth spurt. Young  ice hockey players from the local boys' league up to the age of 13 years (mean age  12 ± 0.5 years) were invited to participate. From 35 players performing on the  highest national level, 25 boys and their parents consented to participate. None of  these 25 players had to be excluded for known disease or previous surgery or hip  trauma. At baseline examination as well as 1.5 and 3 years later, we performed a  prospective noncontrast MRI scan and a clinical examination. The three-dimensional  morphology of the proximal femur was assessed by one of the authors using radial  images of the hip in a clockwise manner. The two validated parameters were: (1) the  alpha angle for head asphericity (abnormal > 60°) and (2) the epiphyseal extension  for detecting an abnormality in the shape of the capital physis and a potential  correlation at the site of the cam morphology. The clinical examination was  performed by one of the authors evaluating (1) internal rotation in 90° of hip and  knee flexion and (2) hip pain during the anterior impingement test. <br><br>RESULTS: Cam  morphologies were most apparent at the 1.5-year follow-up interval (10 of 25;  baseline versus 1.5-year follow-up: p = 0.007) and a few more occurred between 1.5  and 3 years (12 of 23; 1.5-year versus 3-year follow-up: p = 0.14). At 3-year  follow-up, there was a positive correlation between increased epiphyseal extension  and a high alpha angle at the anterosuperior quadrant (1 o'clock to 3 o'clock)  (Spearman correlation coefficient = 0.341; p < 0.003). The prevalence of pain on the  impingement test and/or restricted internal rotation less than 20° increased most  between 1.5-year (1 of 25) and the 3-year follow-up (6 of 22; 1.5-year versus 3-year  follow-up: p = 0.02). <br><br>CONCLUSION: Our data suggest that a cam morphology develops  early during the final growth spurt of the femoral head in adolescent ice hockey  players predominantly between 13 to 16 years of age. A correlation between an  increased extension of the growth plate and an increased alpha angle at the site of  the cam morphology suggests a potential underlying growth disturbance. This should  be further followed by high-resolution or biochemical MRI methods. Considering the  high number of cam morphologies that correlated with abnormal clinical findings, we  propose that adolescents performing high-impact sports should be screened for signs  of cam impingement, such as by asking about hip pain and/or examining the patient  for limited internal hip rotation. LEVEL OF EVIDENCE: Level I, prognostic study.<p /> <p>Language: en</p>",
language="en",
issn="0009-921X",
doi="10.1097/CORR.0000000000001603",
url="http://dx.doi.org/10.1097/CORR.0000000000001603"
}