canine dorsal pantarsal arthrodesis plates

The concept of a dorsal plate is not new. Contoured DCPs have been used with success for pantarsal arthrodesis for some time. However, there is a fundamental problem with the use of DCPs. The plate loading takes place across the weakest plane of the plate on the compression side of the joint resulting in a relatively weak construct which leads to cycling and plate failure usually at the hole closest to the bend. In addition use of the same diameter screw in both metatarsals and the tibia can result in a mismatch. A large screw in the distal metatarsal makes the metatarsal involved very vulnerable to fracture. Although requiring more initial dissection than the medial approach, the dorsal plate makes alignment easier and does not involve screwing metatarsals to each other. Stability across the talocrural joint is achieved by a screw which passes through the plate and crosses the joint into the calcaneus. Noel Fitzpatrick and VI have revisited the dorsal plate and developed a range of plates which allow the surgeon to benefit from the advantages of dorsal plating whilst minimising the risks of failure. The Plates are hybrid in nature and taper distally to reduce the stress riser at the end of the plate. The vulnerable area on either side of the bend is substantially thicker and stronger than the plate proximally and distally to reduce stress at the joint. For maximum stability it is essential that a screw is placed across the talocrural joint. To facilitate this the holes on either side of the bend are extended into slots to increase the range of screw angles possible. The shape of the cranial plate lends itself to being placed by minimally invasive plate osteosynthesis (MIPO) to preserve as much soft tissue as possible. The Canine Dorsal Pantarsal Range developed by Noel Fitzpatrick currently comprises two hybrid plates which covers the typical patient range. Each plate has the following features: • Plate is much stronger around the bend to transfer stress away from vulnerable areas. • Plate tapers distally to minimise stress riser on metatarsal at the end of the plate. • Full hybrid. Metatarsal holes smaller than tibia holes. • Slots above and below the bend to maximise screw angle options. During MIPO application the distal end of the plate is fed from the joint down through the distal keyhole. The proximal half of the plate is pushed through and retrograded back up the tibia. All screw holes may be accessed through keyholes.