Karl-Philipp Kienle, Presenter: Nothing to Disclose

Johannes Keck, Abstract Co-Author: Nothing to Disclose

Klaus A. Siebenrock MD, PhD, Abstract Co-Author: Nothing to Disclose

Stefan F. Werlen MD, Abstract Co-Author: Nothing to Disclose

Tallal Charles Mamisch MD, Abstract Co-Author: Consultant, Siemens AG

Aim in this prospective study was, to show the physiological changes of the hip during maturation using MRI, based on cross-sectional examination in asymptomatic hips from children and young adults aged between 9 and 16 years.

All 331 pupils from a primary- and high-school were asked to take part in this study. 64 pupils (127 asymptomatic hips) were willing to participate and obtained MRI on 3T machine at baseline and 1 year follow up. We analyzed on MR-images, the femoral morphology and epiphyseal changes and looked at the relation to age, status of the epiphyseal scar and location on the femur. We assessed on 7 radial positions around the femoral neck, rotating from anterior to posterior, (1) head-radius, (2) neck-radius, (3) tilt-angle, (4) epiphyseal-extension and the (5) alpha angle.

Looking at the influence of age, we saw that, as we expected, head and neck radius increased highly significant (p<0,001). The epiphyseal extension increased significantly (p<0,05), but it’s tilt showed no differences (p > 0,05). So doesn’t the alpha angle. Building groups by using the epiphyseal status (“open” = open epiphysis at first and second appointment; “open-closed” = open at first and closed at the second appointment; “closed” = closed epiphysis on both appointments), we found, that the epiphyseal extension has highest changes in the “open”- and nearly stops in the closed group. The tilt angle didn’t change significant at the different time points (p> 0,05).Significant smaller alpha-angles could be found in the “closed” group, however these are in a normal range in the “open” one. Correlated to the position, highest alpha-angle values are located in anterior-superior and superior-anterior position, which are the typical ones for femoroacetabular impingement.

We assessed pattern of changes for femoral hip morphology in asymptomatic volunteers, to create normative data. Within our data we saw most changes in epiphyseal extension versus minor changes in tilt. These data can be used as normative values, which can be compared to patients or cohorts with certain risk factor (e.g. professional athletes).

Classification of epiphyseal and femoral changes using MRI will offer the chance to detect and understand pathological changes for development of preserving strategies.

Kienle, K, Keck, J, Siebenrock, K, Werlen, S, Mamisch, T, Physiological Changes of the Hip during Maturation: MR Assessed Data in a 1 Year Follow-up on a Cross Sectional Asymptomatic Cohort from 9-16 Years.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9006983.html