Introduction

Feline pelvic fractures are common accounting for 20-22% of fractures, with ilial involvement in 50% of cases. Ilial fractures are usually repaired with a lateral bone plate. It was hypothesised that application of a dorsal plate (DP) would reduce the complications of screw loosening and pelvic canal collapse seen with lateral plate (LP) fixation.

Materials and Methods

Sequential feline iliac fractures were stabilised with dorsal bone plates and screws. Data was retrieved from case notes and by telephone interview. Percentage pelvic canal narrowing and screw purchase was determined from immediate post operative and 4-6 week follow up radiographs. Data was compared to that from a previous study investigating complications associated with lateral plate fixation.

Results

Ten cats were recruited. All fractures were stabilised with 2.0 dynamic compression plates (DCP). Mean total screw purchase was 89mm. Mean number of screws per repair was 5.3. Pelvic collapse was 8.9% post-operatively and 10.9% at 4-6 weeks. Only one screw in one cat backed out by 10mm representing a 10% loss of total screw purchase. Plate bending was seen in one cat. None of the cats had obstipation or constipation with a mean follow up of 13.9 months.

Discussion

Total screw purchase was significantly greater with the DP over LP (89mm compared to 28mm). DP allowed a significant increase in screw purchase over the LP of 1.3 screws, almost exclusively in the caudal fracture fragment. Pelvic collapse immediately post-operatively after DP and LP was similar (8.9% and 9.6%). However, there was a significant decrease in pelvic collapse at follow-up radiography, (DP: 10.9%, LP: 21.3%) and screw loosening (LP 62% cases, DP 10% (1 cat)). Pelvic canal narrowing of over 45% was associated with constipation and obstipation in 29% of LP cases. The bent plate was a 1.0mm thick 2.0mm DCP, in all other cats the 1.5mm thick 2.0mm DCP was used and the authors would now always recommend using the thicker 2.0mm DCPs. The direction of bending may suggest that the tension side of the feline pelvis is dorsal, whereas it has been shown to be ventromedial in canines. DP results in increased screw purchase, reduced screw loosening and decreased pelvic canal narrowing compared to LP. Reduction in pelvic canal narrowing may reduce complications such as constipation, obstipation and megacolon.