SPR Unknown # 101 -- FINAL

Mark E. Bittman, MD

Cohen Children’s Hospital of New York, North Shore-LIJ Health System


Publication Date: 2013-12-15

History

Elbow pain and stiffness and remote history of trauma.

Findings

Figure 1 a-c: Radiographs of the elbow demonstrate a concave contour abnormality of the distal humerus with absence of the trochlear ossification center. Findings are characteristic of a fishtail deformity.

Figure 2 a-b: Coronal and sagittal proton density MRI images of the left elbow shows deficient development of the radial aspect of the trochlea, likely related to premature physeal arrest from prior fracture, with resulting fishtail deformity.

Figure 3: A lateral radiograph of the left elbow three years ago shows a dorsally angulated and posteriorly displaced supracondylar fracture.

Diagnosis

Fishtail deformity

Discussion

A fishtail deformity is characterized by resorption or failure of formation of the trochlear ossification center of the distal humerus. It is a rare complication of pediatric elbow fractures and the proposed mechanism is osteonecrosis of the trochlea or partial growth arrest. In a recent study of 15 patients, the average time interval between injury and presentation of the fishtail deformity was 4.7 years [1]. Patients typically present with pain and stiffness and history of a remote elbow fracture. Fishtail deformity has been described in all types of elbow fractures. The patient in this case sustained a Gartland type 3 supracondylar fracture three years prior prior. Treatment is often surgical debridement.

On plain radiographs, there is abnormal morphology of the distal humerus characterized by a concave contour abnormality of the lateral aspect of the distal humerus.

MRI can be used to further characterize the deformity. As in this example, MRI may depict the physeal growth arrest. Other findings on MRI include, intra-articular loose bodies, premature osteoarthritis and better evaluation of the cartilage especially in patients with an unossified or partially ossified trochlea.

Files

References

  1. Glotzbecker MP, Bae DS, Links AC, Waters PM. Fishtail deformity of the distal humerus: a report of 15 cases. J Pediatr Orthop. 2013 Sep;33(6):592-7.
  2. Hayter CL, Giuffre BM, Hughes JS. Pictorial review: 'fishtail deformity' of the elbow. J Med Imaging Radiat Oncol. 2010 Oct;54(5):450-6.

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