Hybridized Circular External Skeletal Fixator Articulated Intramedullary Pin Constructs for Stabilization of Comminuted Femur Fractures in Three Cats

This case series describes the use of a hybridized circular external fixator applied in combination with an articulated intramedullary (IM) pin to stabilize comminuted diaphyseal femoral fractures, two that extended into the subtrochanteric region, in three cats operated at the University of Florida Small Animal Hospital between January 2017 and June 2024. The IM pin was placed initially to align the fracture through an open approach. The construct included a proximal partial ring arch with three half-pins and a distal stretch ring with opposing olive wires. Rings were articulated with a caudolateral threaded rod and diagonal strut. All fractures were acceptably reduced and aligned. The hybridized construct allowed functional limb use during the postoperative convalescent period and the fixators were removed 8, 15, and 16 weeks following surgery. In one cat, the IM pin was retained postfixator removal and articulated with a single remaining proximal half-pin for an additional 2 weeks. Analysis of the sagittal and frontal plane alignment on postfixator removal radiographs found a significant difference in the anatomical lateral proximal femoral angle, with consistent alignment, compared with the contralateral intact femur, in all other measurement indices. Owners perceived that their cat had nearly normal limb function when contacted 4, 24, and 92 months following surgery. The outcome of these cases validates the utility of the use of a hybridized circular external fixator construct in conjunction with an articulated IM pin to stabilize comminuted proximal femoral fractures in three cats, addressing anatomical challenges often encountered with traditional methods.

Acknowledgment

None.

 

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Publication History

Article published online:
15 July 2025