Background: Confusion occurs in up to 60% of patients following neck of femur fracture, delaying hospital discharge. We investigated venous – arterial circulation shunts (v-aCS) and the influence of cerebral embolism before and during surgery on subsequent cognitive function.

Methods: Cerebral emboli were counted in 16 patients with an inter-trochanteric or Garden III/IV fracture by transcranial Doppler (TCD) monitoring over 1 hour pre-operatively and intra-operatively. A v-aCS was diagnosed when 1 or more microbubbles were detected in the middle cerebral artery by TCD following intravenous injection of a microbubble emulsion. Cognitive function was investigated by a battery of computerised tests preoperatively and at 5 days postoperatively.

Results: Cerebral emboli were detected in 9 of 16 patients preoperatively (median 2, range 1–23) and in 10 patients during surgery (median 10, range 4 – 617). A v-aCS was associated with preoperative emboli in 9 patients (p=0.036, Fisher’s Exact) and intraoperative emboli in 10 patients (p=0.011, Fisher’s Exact). Cognitive function deteriorated following surgery only in patients with emboli, with the median (range) overall reaction times increasing from 3220ms (1926–5868) to 7493ms (4690–15992) [p=0.008]. The overall accuracy deteriorated from 2.57 to 2.37 (NS).

Conclusion: Cerebral embolism is common following femoral neck fracture in patients with a v-aCS and was associated with a deterioration in cognitive function.