Disruption of the interosseous membrane is easily
missed in patients with Essex-Lopresti syndrome. None of the imaging
techniques available for diagnosing disruption of the interosseous
membrane are completely dependable. We undertook an investigation to identify whether a simple intra-operative
test could be used to diagnose disruption of the interosseous membrane
during surgery for fracture of the radial head and to see if the
test was reproducible. We studied 20 cadaveric forearms after excision of the radial
head, ten with and ten without disruption of the interosseous membrane.
On each forearm, we performed the radius joystick test: moderate
lateral traction was applied to the radial neck with the forearm
in maximal pronation, to look for lateral displacement of the proximal radius
indicating that the interosseous membrane had been disrupted. Each
of six surgeons (three junior and three senior) performed the test
on two consecutive days. Intra-observer agreement was 77% (95% confidence interval (CI)
67 to 85) and interobserver agreement was 97% (95% CI 92 to 100).
Sensitivity was 100% (95% CI 97 to 100), specificity 88% (95% CI
81 to 93), positive predictive value 90% (95% CI 83 to 94), and
negative predictive value 100%). This cadaveric study suggests that the radius joystick test may
be useful for detecting disruption of the interosseous membrane
in patients undergoing open surgery for fracture of the radial head
and is reproducible. A confirmatory study
