The value of delayed MRI scans in the assessment of acute wrist injuries.

The aim of this study was to better quantify the role of delayed MRI scans in acute wrist injuries, and to assess the prevalence and distribution of multiple occult injuries of the wrist. A retrospective study was made of all patients who had been referred to the orthopaedic trauma clinic for a possible scaphoid fracture and with normal radiographs over a two year period. There were 110 patients. Patients were initially treated conservatively with a scaphoid cast or a futura splint for two weeks. This was then removed and the wrist examined and further radiographs taken. The patients with normal radiographs who had positive clinical findings for a scaphoid fracture at two weeks or persisting pain at six weeks had an MRI scan. MRI was performed with and without fat saturation sequences. A total of 110 wrists were analysed. Twenty-eight (25.4%) were reported as normal; 24 patients (21.8%) had occult bone fractures. Three (2.7%) had scaphoid fractures diagnosed by MRI scans. There were nine (8.1%) distal radius, two trapezium and five hook of hamate fractures. Bone bruising was seen in 12 (10.9%). Carpal degeneration was seen in ten and a TFC tear was noted in five (4.5%). Other findings were a ganglion in 14 (12.7%) and three (2.7%) had Kienbock's disease. The MRI scan is a useful tool in obtaining a definite diagnosis in acute wrist injuries. Among other findings, an occult scaphoid fracture was diagnosed on MRI in 2.7% of cases in this study. To conclude, in the majority of patients with persisting symptoms after two weeks following a wrist trauma, the cause of symptoms was pathology in other tissues in the wrist including soft tissues, other carpal bones and distal forearm.