High-velocity, low-amplitude manipulation (HVLA) does not alter three-dimensional position of sacroiliac joint in healthy men: a quasi-experimental study

Key points

1. 01HVLA manipulation of the ilium produced no statistically significant change in sacroiliac joint mobility before versus after treatment.
2. 02After manipulation there was a small, non-significant trend toward more movement on the treated (right) side and less on the opposite (left) side.
3. 03Findings echo earlier imaging work showing thrust manipulation does not alter the position relationship between the sacrum and ilium.
4. 04Only healthy men aged 18 to 35 were studied, with no pain and no true no-treatment control group.

How it was conducted

Design

Quasi-experimental study (non-randomized, convenience sample)

Participants

30 healthy men aged 18 to 35, recruited from 38 initially enrolled

Groups

Manipulation group (n=15) and placebo group (n=15) on alternate days

Intervention

Single HVLA thrust to the anterior right ilium; placebo group held in the same tension position without thrust

Primary outcome

Sacroiliac joint mobility (ilium displacement) measured by 3D motion analysis during 90-degree hip flexion, before and after

Analysis

Paired t-test for mobility and Fisher's exact test for associations, significance set at p<0.05

What they found

• Right (treated) sacroiliac joint, manipulation group: pre 39.98 mm +/- 10.82 (CI 29.16 to 50.8) versus post 42.85 mm +/- 27.17 (CI 15.68 to 70.02), p=0.61.
• Left (control side) sacroiliac joint, manipulation group: pre 41.73 mm +/- 15.34 (CI 10.89 to 82.99) versus post 39.97 mm +/- 14.70 (CI 24.67 to 54.07), p=0.39.
• No outcome reached statistical significance on either the treated (right) or control (left) side.
• Dividing subjects into most movable (n=15) and least movable (n=15) by the median and associating with the Gillet test gave a non-significant, weak, negative correlation.

Limitations

• Small sample of only healthy young men without pain, so results may not apply to symptomatic patients or women.
• Non-randomized convenience sampling and no blinded assessor, introducing possible selection bias.
• No true no-treatment control group; the placebo group was held in the manipulation tension position, which may itself be a confounder.
• No accepted gold-standard non-invasive tool to validate the mobility measurements.

Why it matters

For patients

If you receive an SIJ manipulation, any short-term relief may not be because the joint was physically repositioned.

For clinicians

This adds to evidence that HVLA does not measurably reposition or change SIJ mobility, so any benefit likely works through other mechanisms.

For readers

A small, exploratory study suggesting the long-assumed mechanical effect of SIJ manipulation is not detectable, pending larger trials in people with pain.