Paediatric Elbow - Overview
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On the lateral view the anterior humeral line goes through the capitelum, because the distal humerus angulates forward (Shaft condylar angle 40 degrees). Elevation of the fat pads signifies an effusion. An anterior fat pad may be normal. The posterior fat pad in the presence of trauma predicts an occult fracture in (76%) (Skaggs) of cases. (see below) On all views the radius should point to the capitelum (looking for radial head dislocation). |
Ossification around the elbow
The secondary ossification centres around the elbow present diagnostic problems. The most commonly used mnemonic for the sequence of ossification around the elbow is CRITOE or CRITOL (mean ossification times)
- C- Capitulum, (3 months)
- R- Radial head, (5 years)
- I- Internal (medial) epicondyle, (7 years)
- T- Trochlea, (9 years)
- O- Olecranon, (11 years)
- E- External or Lateral epicondyle, (13 years)
Lateral epicondyle appears at 13 and disappears at 15
The above was based on studies in the 1950 and 1960s on white populations.
A recent study on Chinese children showed the pattern of ossification differs from previously quoted figures: the ossification of the olecranon appeared earlier than that of the trochlea in both sexes. The timing was also different, with a slower ossification at mid childhood followed by a more rapid catching up in later childhood near the adolescent period. (time ossification present in 50% of girls)
- C- Capitulum, (1 year)
- R- Radial head, (5 years)
- I- Internal (medial) epicondyle), (5 years)
- O- Olecranon, (9 years)
- T- Trochlea, (9years)
- E- External or lateral epicondyle, (10years)
- In boys, with the exception of the capitulum, an average delay of 2 years was found in each of the ossification centers, although the sequence remained similar.
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As a rule of thumb a more convenient way to remember it is that they appear roughly every two years, slightly earlier in girls than boys |
Fat pads
Fat pads signify an effusion in the elbow. Anterior fat pads may be normal.
According to Skaggs et al a posterior fat pad signifies an intra capsular fracture of the elbow in 76% of cases.
They obtained repeat radiographs of the elbow in children with elevated fat pads at a mean of 3 weeks (range 8/7 to 37/7), out of plaster, any evidence of new bone formation they diagnosed as a fracture.
They found:
76% had evidence of fracture at follow up radiograph.
53% supracondylar
26% proximal ulna
12% lateral condyle
9% radial neck
They concluded an occult fracture was present in 76% of children. If a fat pad was present they treated the patients symptomatically in a splint non operatively for around 3 weeks, on removal of the splint they repeated radiographs, of note no fractures displaced.
They commented additional oblique X-Rays can improve diagnostic accuracy, but question the value of further radiographs as no fractures displaced.
The Posterior Fat Pad Sign in Association with Occult Fracture of the Elbow in Children - J BJS (A) 1999 81: 1429-33. - DAVID L. SKAGGS and RAFFY MIRZAYAN
Cheng, Jack C. Y; Wing-Man, Ko; Shen, W. Y; Yurianto, Henry; Xia, Guo; Lau, Joseph T. F; Cheung, Albert Y. K; - A New Look at the Sequential Development of Elbow-Ossification Centers in Children. Journal of Pediatric Orthopedics. 18(2):161-167, March/April 1998.