If the IOM is torn, the radius (the bone on the thumb side of your arm) becomes unstable. The "joystick" name comes from how the surgeon handles the bone: they grasp the neck of the radius and attempt to move it, much like a pilot or gamer would move a joystick, to see if it shifts abnormally. Why It’s Performed
While the joystick test is a standout, it is often part of a broader diagnostic "battery" for forearm injuries: Primary Focus Positive Indication Transverse stability Lateral translation of the radial neck. Radius Pull Test Longitudinal stability Proximal migration of the radius >3is greater than 3 Ulnar Variance Wrist alignment Shortening of the radius relative to the ulna on X-ray. joystick test
Research published in the Journal of Bone and Joint Surgery suggests that the joystick test is a highly sensitive and reproducible way to diagnose complete IOM disruptions. In clinical studies, it consistently showed negative results in healthy specimens and positive results in those with severed membranes, helping to avoid "false positives" that could lead to unnecessary surgery. Summary of Forearm Stability Tests If the IOM is torn, the radius (the
The test is typically performed in an operating room while the patient is under anesthesia, often using fluoroscopy (real-time X-ray) to see the bone movement clearly. Summary of Forearm Stability Tests The test is