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Randomized trial · measured the question itself

14-day trial in 128 adults after knee replacement: no clear sleep difference with melatonin

Haider and colleagues · The Journal of arthroplasty · 2024

Original title: Does Melatonin Improve Sleep Following Primary Total Knee Arthroplasty? A Randomized, Double-Blind, Placebo-Controlled Trial.

Under review. A person has not yet checked this summary against the paper. It is written from the PubMed abstract. Until a person checks it, search engines are asked not to list this page.

What the study found

No difference

Melatonin patients slept a bit more on days 2 and 3 (placebo: 5.0 ± 2.4, melatonin: 5.8 ± 2.0, P = .084), but differences were not significant. Sleep disturbance scores were similar in both groups.

The study at a glance

Type of study
Randomized trial
Who or what was studied
128 people · adults after knee replacement surgery
What was tested
Melatonin 5 mg each night vs placebo for 14 days
What it measured
The question itself: sleep, and safety with long-term use
Daily amount
5 mg a day
How long
2 weeks
Trial registration
NCT04795336
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
The Journal of arthroplasty, 2024
Source
PubMed record 38401621. This page is based on the abstract only.

How much this study counts

  • ✓Randomized: people were put into groups by chance, so the groups start out alike.
  • ✓Compared with a placebo, a dummy treatment.
  • •Medium size: 128 people.
  • –Short: 2 weeks. Longer-term effects are unknown.
  • ✓Measured the question itself: sleep, and safety with long-term use.
  • •The PubMed record has no conflict-of-interest statement.
  • •Summarized from the PubMed abstract only. The full paper may hold details the abstract leaves out.

✓ Strength– Limit• Note

These points come from fixed rules about the type of study, its size and length, what it measured, and who has a stake. Every study on Digestery gets the same rules.

Where this study sits

Each dot is one on-topic paper on this question. Steps near the top answer the question more directly.

↑ Stronger evidence

  1. Trials in people: sleep onset and sleep quality

    8

    2 benefit, 2 mixed, 4 no difference

    ↑ This study is the ringed dot

  2. Trials in people: other measures

    2

    1 benefit, 1 no difference

  3. Trials in people: lab tests or safety

    0

    None among the papers we read.

  4. Population studies

    0

    None among the papers we read.

  5. Blood levels and genes

    0

    None among the papers we read.

↓ Weaker evidence

  • Points to benefit
  • Mixed
  • No difference
  • No direction
  • Points to harm

How it fits with the other research

The short answer to “Does melatonin help you sleep?”

A small effect, clearer in children.

Confidence: low. Based on 20 on-topic papers.

Read the full answer

Of the other 7 papers on the same step: 2 benefit, 2 mixed, 3 no difference. This one found no difference.

Other papers on the same step

See all 20 studies on this question

How this page was made

Label

First read of the abstract
Claude Sonnet
Independent second read
Claude Haiku
Differences settled
The two reads agreed on every checked field. Claude Opus 5.5.
Headline
Claude Sonnet, from the checked study record. A script checked its numbers and wording.
Numbers
Checked against the abstract by a script
“How much this study counts”
Fixed rules, the same for every study
Source check by a person
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