Abstract
Background
The pattern of appearance of secondary ossification centers in the elbow has been based on historical studies and is popularly referred to with the mnemonic CRITOL. However the six secondary ossification centers can be variable in their presentation and pose a challenge in assessment of children with elbow injuries. Furthermore limited studies available in the current literature have reported an aberration to the sequence of appearance especially with the ossification centers of trochlea and olecranon.
Aims
The aim of the study was to evaluate the relative sequence of appearance of secondary ossification centers for the trochlea and olecranon.
Methods
Children between 8 and 10 years of age who had radiographs of elbow following trivial trauma between July 2013 and Feb 2015 were identified using the hospital PACS database. Cases with radiographic markers of significant trauma ie. fat pad sign, displaced fracture were excluded. Anteroposterior and lateral views of elbow were reviewed for the presence of the six ossification centers.
Results
A total of 114 radiographs were reviewed of which 51 were boys and 63 were girls with a mean age of 9.03 years (±0.59). 60 radiographs were of right elbow and 54 were of the left elbow. The capitulum, radial head and medial epicondyle ossification centers were present in all patients. Both trochlea and olecranon ossification centers were noted in 51/114 (44.7%) children. 12/114 (10.5%) of the children were noted to have trochlea ossification center with no olecranon ossification center. Of these 12 children 7 were boys and 5 were girls. On the other hand 19/114 (16.7%) of the children had an olecranon ossification center but without a trochlea ossification center. Amongst these 7 were boys and 12 were girls.
Discussion and Conclusions
The results of this limited cross sectional study demonstrate that the CRITOL sequence may not followed in 16.7% of cases and more so in girls. Historical studies were based on conventional radiographs. However the current digital radiographs with image enhancement tools help in accurate identification of relatively small ossification centers which may not be apparent on conventional radiographs. The current study has helped to quantify the violators to CRITOL sequence.
Level of Evidence
Level III (Cross-sectional study among non-consecutive patients)
