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X-Ray versus CT to confirm diagnosis of triplane fracture

Three Part Question

[Children attending A&E with suspected ankle fracture] is [x-ray sensitive and specific compared to CT scan being gold standard] to [confirm diagnosis of triplane fracture]

Clinical Scenario

A 12 year old girl who has been brought with inversion injury to the left ankle while playing football. She was unable to bear weight. On examination there was swelling and tenderness over the lateral malleolus and anterior joint line. Left ankle X-ray showed Salter Harris Type 3 fracture of the distal tibia. You discussed with the orthopedic Specialty registrar on call; who was very kind to accept the patient and requested to carry out CT scan of the left ankle in order to rule out Triplane fracture. You wonder what is the sensitivity and specificity of x-ray to rule out Triplane fractures against CT scan being the gold standard.

Search Strategy

1 - OVID Medline 1946 - Week 4 2014
2 - Cochrane database - “X-Ray” “CT Scan” “triplane”
3 - Google search - “X-Ray” “CT Scan” “triplane”

[ exp Ankle Fractures/OR exp Tibial Fractures/OR exp Fibula/OR exp Ankle Injuries/ OR Malleolar fracture$.mp.OR Bimalleolar fracture$.mp.OR Trimalleolar fracture$.mp. OR Triplane fracture$.mp. OR Salter Harris fracture$.mp. OR exp Epiphyses/ OR Epiphyseal fracture$.mp. OR exp Fractures, Closed/ OR Lower OR Tillaux fracture$.mp] AND [exp Child/ OR Children$.mp. OR exp Pediatrics/ OR exp Child, Preschool/ OR exp Infant/ OR exp Adolescent/ OR Pediatric$.mp. OR Infant$.mp. OR Adolescent$.mp. OR Toddler$.mp. OR] AND [exp Radiography/ OR exp X-Rays/ OR Plain OR Radiograph$.mp. OR Xray$.mp. OR X-ray$.mp. OR OR Roentgenograph$.mp. OR Plain] AND [exp Tomography, X-Ray Computed/ OR X-Ray OR CT scan$.mp. OR OR Tomography$.mp] LIMIT TO Humans and English

Search Outcome

Medline - 450 papers found - 2 relevant
Cochrane - no relevant articles
Google scholar - no relevant articles

Two relevant papers have been critically appraised

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Stefan P. Lemburg et al
33 Patients aged 9-18 years were retrospectively identified between August 2001 to December 2006 with growth plate injuries to distal tibia with complete pre-therapeutic imaging including plain radiograph in anterior-posterior and lateral views and CT in sagittal, transverse and coronal plains obtained during 24 hours after trauma. The patients with incomplete image material were excluded. Level 2, Retrospective, single blinded randomized study, with gold standard CT as reference standard applied to all patients Accuracy of Plain radiography against CT scan to diagnose and classify ankle fractures in children.CT vs X-ray showed fewer tibial fragments, confidence interval (1.39 ± 0.75 vs. 1.61 ± 1.25, p = 0.023). Fracture involvement of metaphysic: Sensitivity 78% Specificity 90 %, Fracture involvement of epiphysis: Sensitivity 100% Specificity 75 %, Fracture involvement of growth plate: Sensitivity 96% Specificity 60 %, Fracture involvement of articular surface: Sensitivity 96% Specificity 75 %,Small sample size
Liporace FA et al
24 cases with plain radiographs and CT scans between January 2001 and January ‘2003 with diagnosis of paediatric Tillaux or triplane fractures were included. Six blinded third party orthopaedic surgeons who were not involved in the treatment were assigned in a randomised fashion to evaluate plain radiographs and ct scans on two separate occasions with a six month interval in between. On first occasion plain radiographs were assessed and on second occasion plain radiographs plus CT scans were assessed totalling 144 evaluations Cases without CT scans and those cases which were taken to the operating theatre immediately were excluded. Level 2, retrospective, single blinded third party evaluative test/retest study design Following first assessment a questionnaire was completed to determine Diagnosis, Amount of displacement and treatment plan. Following second assessment another questionnaire was completed to determine changes in diagnosis, perceived displacement and treatment plan.In 7 (4.8%) of 144 evaluations, CT scan changed the original diagnosis of fracture type from Tillaux to Triplane• No Demographics data was given. • Small sample size and sample size calculation, no details given regarding randomization. Ethical approval not mentioned


There are numerous factors that support preference of plain radiographs over CT scan for diagnostic imaging of musculoskeletal injury in children.In most ED departments plain radiography is assessable 24 hours.Majority of the ED doctors are confident in interpreting the plain radiographs.Radiographers are also available for hot reporting.Plain radiography is more cost effective as compared to CT scan.Finally, race against time – it is desirable to ensure comfort and short stay of the paediatric patients in the ED. Any reduction in unnecessary radiation is welcome. The two papers I have appraised have some similarities in study design. They are retrospective comparing accuracy of plain radiography against a gold standard of CT. They both are small sample size. In the first study the overall accuracy of plain radiograph is <90% for diagnosis of complex ankle fracture. The plain radiograph evaluation showed differing Salter-Harris classification in CT scans with the highest misclassification rates in type-III Salter-Harris fracture. No misclassification occurred in types I and II Salter-Harris fractures.It is interesting to know that plain radiograph either misclassified or did not detect Triplane fracture in 71%. These findings are not correlated to possible changes in therapeutic approach as the author admitted that this was beyond the scope of the article. In brief plain radiography of distal tibial growth plate fractures compared to CT showed a low overall accuracy. The second study outlines the influence of adding CT to plain radiographs compared with radiographs alone in the diagnosis, decision making process, and treatment of Tillaux and Triplane ankle fractures and showed no significant change in the diagnosis of fracture type from Tillaux to Triplane fractures. Although both the studies used similar framework but presented opposite conclusions

Clinical Bottom Line

The clinical bottom line was that there is not enough evidence at present to advocate high accuracy of plain radiography for diagnosis and classification of complex paediatric ankle fractures like Triplane fractures. CT is a necessary adjunct to offer insight into significant change from a non-operative to operative treatment plan. Furthermore CT helps to avoid the risk of future complications. In conclusion, radiography remains the primary imaging technique in evaluation of patients with Triplane fractures. In patients with multiple injuries due to high energy trauma and in patients with complex fractures the sensitivity of conventional radiography is moderate to poor.

Level of Evidence

Level 2 - Studies considered were neither 1 or 3.


  1. Lemburg SP, Lilienthal E, Heyer CM Growth plate fractures of the distal tibia: is CT imaging necessary? Archives of Orthopaedic and Trauma Surgery 2010 Nov;130(11):1411-7
  2. Liporace FA. Yoon RS. Kubiak EN. Parisi DM. Koval KJ. Feldman DS. Egol KA Does adding computed tomography change the diagnosis and treatment of Tillaux and triplane pediatric ankle fractures? ORTHOPEDICS 2012 Feb; 35(2):e208-12