Deformity Visualisation

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The ability to pre-contour a plate before surgery has several potential benefits including reduced surgical time, greater accuracy especially if complex contouring is necessary, and in some situations the ability to use the precontoured plate as a reduction guide. 

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This is commonly helpful during surgical management of comminuted long bone fractures, where achieving optimal relative alignment of the major proximal and distal segments of the fractured bone is essential. This can be particularly challenging in small patients, in humeral and especially femoral fractures, and when fractures are juxta-articular. Figure 1 shows a plate pre-contoured to a 3D-printed, mirrored, contralateral femur (the affected femur had a comminuted diaphyseal fracture). Appropriate alignment of the proximal and distal major fracture fragments resulted when the precontoured plate was applied in the same position.

In some non-comminuted fractures plate precontouring is helpful where complex plate contouring is necessary, especially if plate positioning is critical to adequately stabilise small fragments. Figure 2 shows plate pre-contouring prior to stabilisation of a feline humeral condylar Y-fracture.

Less commonly, a pre-contoured plate can act as a reduction guide in other situations such as open or closing wedge osteotomies for limb deformity, limb-spare surgery, and arthrodesis.

Figure 1 – For visualisation of antebrachial deformities is it useful to include the humerus, carpus and paw in the print. It is essential to remember that the printed model represents the alignment of the bones under non-loaded conditions in the CT scanner, and therefore that alteration in overall limb alignment may occur during loading. This is particularly relevant at the antebrachiocarpal joint which can develop laxity during chronic abnormal loading which can result is persistent carpal valgus despite appropriate bone deformity correction.

Figure 2 – Two distal femoral malunions. 

Figure 3 – A 3D-printed antebrachium of an eight year old greyhound with distal radial osteosarcoma. The model was used to plan osteotomy locations and to pre-contour plates.