Pantarsal Arthrodesis Using a Plantar Plate: Finite Element Analysis of Plate Position and Preliminary Results of Four Cases

A finite element analysis was carried out to determine the optimal plate placement for pantarsal arthodesis. Three different plate placement scenarios were considered: cranial, lateral, and caudal. Under similar loading conditions, the finite element results showed that the cranial and lateral plates experienced stresses surrounding the metatarsal screws which may indicate screw loosening or failure. High stress concentrations were also noticed in both plates at the tarsocrural joint. In comparison, the caudal placed plate showed much lower stress levels, which suggests that this is the optimal plate position. Four dogs weighing in excess of 25Kg subsequently underwent pantarsal arthrodesis using a caudal plating technique. Successful arthrodesis occurred in all cases. The results of this study suggest that a caudal plate position is the preferable option in pantarsal arthodesis and warrants further investigation. InTRoduCTIon The application of bone plates to the dorsal, medial, or lateral aspect of the tarsus has been reported for pantarsal arthrodesis 1-5. Pantarsal arthrodesis using a number of other techniques have been reported in the literature: pin and tension band wire 6, lag screws 7, and transarticular external fixation 8,9. Partial tarsal arthrodesis can be achieved using a plantar plating technique 10. Adjunctive stability using coaptation has been recommended following arthrodesis with internal fixation 1,5,11. Structural finite element analysis (FEA) has the potential to provide valuable information on bone-plate constructs and, in particular, can identify regions of high stress or strain and hence predict the likely locations of failure. The use of FEA to successfully model bone-plate constructs and identify regions where plate failure and/or screw pullout may occur has been proven in recent years 17-21. A significant advantage offered by FEA is the ability to carry out “virtual prototyping” of various designs via computational models before the designs are put into service. In the case of bone-plate Pantarsal Arthrodesis Using a Plantar Plate: Finite Element Analysis of Plate Position and Preliminary Results of Four Cases W McCartney MVB, Dipl ECVS, DSAS(Orth), PhD, MRCVS 1,2 B MacDonald BSc, MSc, PhD, CEng 2 D Comiskey B Eng, PhD 2 I Robertson MB, Bch. BAO 3 1Marie Louise Veterinary Hospital, 38 Warrenhouse Road, Baldoyle, Dublin 13 , Rep of Ireland. 2MDORC, School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin 9, Rep of Ireland 3Royal College of Surgeons of Ireland, 123 St Stephens Green, Dublin 2