Scaphoid fracture nonunion: correlation of radiographic imaging, proximal fragment histologic viability evaluation, and estimation of viability at surgery: diagnosis of scaphoid pseudarthrosis.
OBJECTIVE
The purpose of this study was to correlate the pre-operative imaging, vascularity of the proximal pole, and histology of the proximal pole bone of established scaphoid fracture non-union.


METHODS
This was a prospective non-controlled experimental study. Patients were evaluated pre-operatively for necrosis of the proximal scaphoid fragment by radiography, computed tomography (CT) and magnetic resonance imaging (MRI). Vascular status of the proximal scaphoid was determined intra-operatively, demonstrating the presence or absence of puncate bone bleeding. Samples were harvested from the proximal scaphoid fragment and sent for pathological examination. We determined the association between the imaging and intra-operative examination and histological findings.


RESULTS
We evaluated 19 male patients diagnosed with scaphoid nonunion. CT evaluation showed no correlation to scaphoid proximal fragment necrosis. MRI showed marked low signal intensity on T1-weighted images that confirmed the histological diagnosis of necrosis in the proximal scaphoid fragment in all patients. Intra-operative assessment showed that 90% of bones had absence of intra-operative puncate bone bleeding, which was confirmed necrosis by microscopic examination.


CONCLUSIONS
In scaphoid nonunion MRI images with marked low signal intensity on T1-weighted images and the absence of intra-operative puncate bone bleeding are strong indicatives of osteonecrosis of the proximal fragment.
Department of Orthopaedics and Traumatology, University of Campinas - UNICAMP, Rua Tessália Vieira de Camargo, 126, Campinas, SP, 13083-970, Brazil, mbervian@hotmail.com.
Michel Roberto
MR
Bervian
Samuel
S
Ribak
Bruno
B
Livani
D000328:Adult; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D010020:Osteonecrosis / Q000175:diagnosis; D011446:Prospective Studies; D011542:Pseudarthrosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D021361:Scaphoid Bone / Q000098:blood supply / Q000293:injuries* / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed; D014954:Wrist Injuries / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery