Rack-and-Pinion Displacement of an Intramedullary Pin During Minimally Invasive Plate-Rod Osteosynthesis of the Canine Femur-A Case Report.

ABSTRACT: We present a case of unexpected proximal displacement of an intramedullary pin (IMP) during plate-rod repair of a femoral fracture caused by minimally invasive plate osteosynthesis (MIPO), requiring immediate revision. Implant retrieval analysis and ex vivo modelling were performed to characterise the technique failure mode. The case details are reported. Implant retrieval analysis consisted of stereo zoom microscopic examination of the retrieved IMP. Wear patterns formed by conflict with a 2.8 mm, two-fluted surgical drill bit and a 3.5 mm AO locking screw were replicated using a simple paper impression model. The mechanism of pin movement was replicated in a benchtop laminated polyurethane foam block model, and wear patterns produced during drilling and screw insertion were characterised

SUBMITTER: Wills DJ 

PROVIDER: S-EPMC12523537 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature