Iatrogenic Metacarpal Shaft Fracture Following Distal Radius External Fixator Removal in Clinic

External fixation remains an accepted option for certain unstable distal radius fractures, particularly when ligamentotaxis and percutaneous augmentation can restore and maintain alignment. Known complications include pin-tract infection, loss of reduction, nerve irritation, stiffness, and complex regional pain syndrome. Fracture through a metacarpal Schanz pin site during in-clinic removal has not, to our knowledge, been specifically described.

A 70-year-old right-hand-dominant female sustained a shortened, dorsally angulated, extra-articular fracture of the left distal radius after a fall from standing height. After persistent displacement following attempted closed reduction, operative options were discussed, including volar locked plating versus closed reduction with percutaneous pinning and wrist-spanning external fixation. The patient underwent closed reduction, percutaneous Kirschner-wire augmentation, and wrist-spanning external fixation using radial and second-metacarpal Schanz pins. At approximately 8 weeks, radiographs demonstrated distal radius healing and the patient elected in-clinic external fixator removal rather than removal in the operating room. During removal, the distal second-metacarpal 3.0-mm threaded/4.0-mm shaft Schanz pin was cut below the clamp with large pin cutters. The patient experienced immediate pain at the pin site, and postremoval radiographs demonstrated a nondisplaced second metacarpal shaft fracture through the distal pin tract. The fracture was treated nonoperatively and progressed to radiographic union.

This case highlights a potentially preventable complication of external fixator removal from small-diameter long bones. When removing wrist-spanning external fixators, particularly in older patients or those with decreased bone quality, clinicians should consider disassembling the construct and removing metacarpal pins intact rather than cutting pins under constraint. When pin cutting is unavoidable, support of the pin-bone interface and avoidance of torsional or recoil forces may reduce fracture risk.