Abstract
This study sought to determine the following: (1) Does the external fixator compromise
quality of imaging obtained? (2) How do findings from the evaluation under anesthesia
at the time of external fixator removal compare with the initial magnetic resonance
imaging (MRI) findings? This was a retrospective study of a consecutive patient series
at an academic level 1 trauma center. There were 19 consecutive patients with traumatic
knee dislocations and spanning external fixator applied. Each patient had a knee MRI
with the external fixator in place and examination at the time of external fixator
removal. A review of knee stability at the time of external fixator removal with physical
examination and stress fluoroscopy were performed. Our study revealed only minor incidence
of poorly visualized structures. Clinical stability was present after fixator removal
in only 11 of 14 medial collateral ligament tears, 4 of 16 lateral collateral ligament
tears, 1 of 19 anterior cruciate ligament tears and 3 of 19 posterior cruciate ligament
tears. MRI is a useful imaging modality in the setting of knee dislocations placed
in spanning external fixators. Patients' knees largely remain unstable after external
fixator removal.
Keywords
knee dislocation - magnetic resonance imaging - external fixator
