Block timing did not change delirium after hip fracture

Design

Single-blind randomised controlled trial (timing comparison)

Population

76 adults aged 65 or older with hip fracture having arthroplasty under spinal anaesthesia

Primary outcome

Postoperative delirium within 7 days

Effect

8.1% vs 12.8% (risk difference -4.7%, 95% CI -18.4% to 9.0%, P=0.71)

Regional analgesia is used to reduce pain and opioid exposure in older hip-fracture patients, where postoperative delirium is common. This randomised trial asked a narrower question: does the timing of an anterior iliopsoas muscle space block, a day before versus an hour before surgery, affect delirium.

Among 76 patients aged 65 or older having hip arthroplasty under spinal anaesthesia, postoperative delirium within 7 days was 8.1% with the block the day before and 12.8% an hour before, a non-significant difference (risk difference -4.7%, 95% CI -18.4% to 9.0%, P=0.71). Early resting and movement pain were lower in the day-before group at 6 hours, but these differences did not survive correction for multiple comparisons.

The practical message is that within this window, when you place the block is not a lever for delirium, so timing can be chosen on logistics and pain control rather than cognitive protection. The study was small, so it cannot exclude a modest effect.

• Randomised trial in 76 hip-fracture patients aged 65 or older under spinal anaesthesia.
• Delirium within 7 days was 8.1% (block day before) vs 12.8% (block one hour before), not significant.
• Early pain was lower in the day-before group but did not survive multiple-comparison correction.
• Choose block timing on logistics and analgesia, not on delirium prevention.
• The trial was small and cannot exclude a modest effect either way.

Why it matters

It tells teams not to reorganise block scheduling in the hope of preventing delirium, as the timing did not matter here.

Don't overread it

This small single-blind trial compared timing, not block versus no block, and the early pain benefit did not survive correction for multiple comparisons.

The statistics, in plain English

The delirium confidence interval runs from -18% to +9%, so it includes a meaningful benefit and a meaningful harm; a 76-patient trial simply cannot settle a difference this size, which is why the null result is not proof of no effect.

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