Abstract
The objective of this study was to delineate the usefulness of clinical examination
and magnetic resonance imaging (MRI) in acute knee injuries. We aim to establish whether
the time period post acute knee injury is related to the diagnostic accuracy of clinical
examination and to investigate the strength of specific clinical examination findings
in predicting a clinically relevant MRI abnormality. Seventy patients were referred
to fracture clinic with an acute knee injury who subsequently went on to be investigated
with MRI over 12 months. These patients were retrospectively analyzed looking at the
time period they were reviewed, the components that were assessed at physical examination,
and the results of their eventual MRI scan looking for any correlation. A greater
proportion of patients who were examined at 2 weeks had relevant positive findings
on MRI scan, p = 0.03. Range of movement and lateral joint line tenderness were not associated with
a positive MRI scan at any period after injury. The presence of a moderate to large
effusion was not associated with an MRI abnormality if the examination was within
2 weeks of injury but was if present 2 weeks after injury, p = 0.0001. Range of movement should not form part of the decision making on whether
an injury should be investigated with MRI. Joint effusion in isolation within 2 weeks
after injury should not be an indication for MRI but a repeat clinical examination
in 2 weeks, where if still present, should be investigated with MRI.
Keywords
acute knee injury - MRI - clinical examination
