Nerve block a day before hip fracture surgery did not reduce delirium compared with an hour before

Design

Prospective, single-blind, randomised trial

Population

79 patients aged 65 or older having hip arthroplasty for fracture 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%)

This single-blind randomised trial enrolled 79 patients aged 65 or older having hip arthroplasty for fracture under spinal anaesthesia. An anterior iliopsoas muscle space block was given either the day before surgery or an hour before.

Delirium within seven days occurred in 3 of 37 (8.1%) in the earlier group and 5 of 39 (12.8%) in the later group (risk difference -4.7%, 95% CI -18.4% to 9.0%). Pain scores at six hours were lower with the earlier block, but this did not survive correction for multiple comparisons.

The trial was small, and the interval is wide enough to include a meaningful benefit or harm. It does not answer whether the block reduces delirium compared with no block.

• Do not expect earlier timing of this block to prevent delirium on this evidence.
• Keep delirium screening and prevention measures in place regardless of analgesic strategy.
• Treat the early pain difference as unproven; it did not hold after adjustment.
• Await larger trials before changing block timing.

Why it matters

It is a reminder that analgesic timing has not been shown to reduce the main driver of poor recovery in older hip fracture patients.

Don't overread it

Seventy-six patients completed the trial; it was underpowered and had no no-block comparison.

The statistics, in plain English

A risk difference of -4.7% with an interval from -18.4% to 9.0% means the trial was too small to tell. Pain results that disappear after correction for multiple comparisons are usually chance findings.

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