- Design
- Single-blind randomised controlled trial
- Population
- 79 adults aged 65 or over having hip replacement for fracture
- Primary outcome
- Postoperative delirium within 7 days
- Effect
- 8.1% vs 12.8%; risk difference -4.7% (-18.4% to 9.0%)
This single-blind trial randomised 79 adults aged 65 or over having total hip replacement for hip fracture under spinal anaesthesia. They received an anterior iliopsoas muscle space block either the day before surgery or one hour before.
Delirium within seven days occurred in 8.1% of the early-block group and 12.8% of the late-block group (risk difference -4.7%, 95% CI -18.4% to 9.0%; P = 0.71). Pain at six hours was slightly lower with the early block, but this did not survive correction for multiple comparisons.
The trial was too small to exclude a meaningful benefit. Early analgesia after hip fracture is good practice anyway: uncontrolled pain contributes to delirium, and many units give a fascia iliaca or similar block in the emergency department. This trial does not change that; it only shows that moving one specific block earlier has not yet been proven to reduce delirium.
- Give effective analgesia early after hip fracture, including a regional block where trained staff are available.
- Do not expect block timing alone to prevent delirium; combine with a multicomponent bundle.
- Screen for delirium daily after surgery with a validated tool such as the 4AT.
- Avoid opioid excess and anticholinergic drugs in older patients with fractures.
Why it matters
It tempers the hope that block timing alone is a delirium intervention.
Don't overread it
With 76 analysed patients, the trial could not detect a moderate difference in delirium.
The statistics, in plain English
The risk difference interval from -18.4% to +9.0% is very wide: the data fit a large benefit, no effect, or harm. A non-significant result in a small trial is not evidence of no effect.
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