Use of transilial pinning for the treatment of sacroiliac separation in 25 dogs and finite element analysis of repair methods.

A retrospective study of 25 cases of sacroiliac separation showed that transilial pinning is an effective method of repair for sacroiliac separations. Only 8% of cases of sacroiliac separation had transilial pinning as the sole surgical intervention as other concomitant minor injuries, such as fractured ischium or pubis, did not require surgery. Even though pin loosening and migration along with local soft tissue irritation occurred in all cases, 92% of the cases had 'good' or 'excellent' outcomes. Sacroiliac separation heals by fibrosis, not directly by bone healing, and therefore can heal sufficiently in four weeks to allow pain free weight bearing in four weeks. Additionally, finite element modelling was undertaken to analyse micro-movement of repaired sacroiliac separations. The micro-motion analysis showed that the lag screw fixation method was more stable than the transilial fixation method since the relative motion between the two indicated that the latter allowed more unsupported iliac movement.