Manual lymphatic drainage before and after total knee arthroplasty: a randomized controlled trial

Key points

1. 01MLD is widely used after knee replacement to reduce swelling, but high-quality evidence for it has been sparse.
2. 02112 patients were split into three groups: MLD before and after surgery, MLD only after surgery, and no MLD at all.
3. 03There was no statistically significant difference between the groups on any outcome (function, swelling, range of motion, or pain).
4. 04Swelling, pain, and function all improved over time in every group, including the no-treatment control.
5. 05This was the largest randomized trial of MLD in orthopaedic surgery to date, and the first to test MLD given before surgery.

How it was conducted

Design

Single-centre randomized, controlled, observer-blinded trial (Therapeutic Level II), conducted March 2021 to July 2022

Participants

112 patients with knee osteoarthritis scheduled for primary total knee arthroplasty; mean age 69.4 years

Groups

Group 1 (n=37) MLD before and after TKA, Group 2 (n=36) MLD only after TKA, control (n=39) no MLD; MLD was 30 minutes daily for five consecutive days

Primary outcome

WOMAC score (0 best to 100 worst), assessed before surgery and 5 days after

Secondary outcomes

Pain (0 to 10 visual analogue scale), leg swelling volume in litres, and active and passive range of motion at multiple timepoints up to 6 weeks

Analysis

One-way ANOVA and chi-square tests, significance set at p < 0.05; intention-to-treat analysis used for missing data

What they found

• There was no statistically significant difference between the groups on any outcome measure.
• WOMAC scores improved from 51.3 (SD = 21.6) before surgery to 29.9 (SD = 14.9) at 5 days after surgery, with no significant difference between groups.
• Pain improved from 5.3 (SD = 2.4) before surgery to 3.1 (SD = 2.3) on postoperative day 5 and to 2.5 (SD = 2.2) at 6 weeks.
• Leg volume around the knee rose from about 3.45 L before surgery to 4.17 L at day 2 and 4.24 L at day 5, then returned to near-normal at 6 weeks (3.57 L versus 3.45 L).
• Baseline groups were well matched, including age (p = 0.393), height (p = 0.435), weight (p = 0.838) and BMI (p = 0.637).
• Baseline secondary outcomes were similar across groups: volume p = 0.925, flexion p = 0.862, pain p = 0.714.

Limitations

• The study was slightly under-powered because many patients were lost to six-week follow-up during the COVID-19 pandemic, and follow-up fell below 80 percent.
• The control group was not blinded and received no placebo or sham treatment, so a placebo effect could not be ruled out.
• Follow-up was limited to six weeks, so any longer-term effects were not assessed.
• No funding was available, so no study nurse could check the gathered data for completeness, and about one third of measurements could not be carried out.

Why it matters

For patients

If you are having a knee replacement, routine manual lymphatic drainage before or in the first days after surgery is unlikely to speed your recovery or reduce swelling beyond normal healing.

For clinicians

This trial argues against routinely prescribing MLD in the early peri-operative period for TKA, though its under-powering and short follow-up leave room for benefit in select cases.

For readers

A well-designed randomized trial found no meaningful benefit from a popular hands-on swelling therapy after knee replacement, a useful reminder that common treatments are not always backed by evidence.