Imaging in index finger radial collateral ligament injury: attention to detail really pays...

Radial collateral ligament of the index finger is a rare ligament to rupture. X-ray is generally normal, except for subtle findings of soft tissue swelling and occasionally a small fracture. With continuous advances in imaging, ultrasound and high quality MRI allow clear depiction of small structures including joint capsule and collateral ligaments of even the small joints. This helps in definitive diagnosis and determines the extent of injury, which may affect the treatment options and final outcome. We report a rare case of index finger metacarpo-phalangeal joint radial collateral ligament tear. The subtle X-ray abnormality was chased on ultrasound and the diagnosis was proposed on ultrasound and later confirmed on MRI. We also discuss the imaging findings of this rare entity.