Anteromedial versus posterolateral hip musculature strengthening with dose-controlled in women with patellofemoral pain: a randomized controlled trial

Key points

1. 01Both groups improved significantly in pain intensity, function, and global perceived effect at six weeks and six months
2. 02No between-group difference was found for any primary or secondary clinical outcome
3. 03Posterolateral hip group gained more abductor strength; anteromedial group gained more adductor and internal rotator strength
4. 04Neither intervention changed dynamic knee valgus as measured by the frontal plane projection angle
5. 05These findings challenge the assumption that posterolateral hip strengthening is uniquely effective for patellofemoral pain

How it was conducted

Design

Randomized controlled trial, two-arm parallel group, blinded assessor

Participants

52 women with patellofemoral pain, aged 18-40 years, physically active at least 3 days per week

Groups

Posterolateral hip group (PLHG, n=26): abduction, clam, external rotation plus shared knee exercises; Anteromedial hip group (AMHG, n=26): adduction, flex-ring squeeze, internal rotation plus shared knee exercises

Dose

Twice weekly for 6 weeks (~12 sessions), approximately 60 minutes per session, supervised at a university physiotherapy clinic

Primary outcomes

Numeric pain rating scale (0-10) and Anterior Knee Pain Scale (0-100) at 6 weeks

Follow-up

6 weeks and 6 months

What they found

• Pain intensity (NPS): between-group difference at 6 weeks was 0.53 (95% CI -1.63 to 0.57, P=0.33); no significant difference at 6 months (difference 0.07, 95% CI not significant, P=0.89)
• Function (AKPS): between-group difference at 6 weeks was 0.34 (95% CI -1.11 to 0.89, P=0.89); no significant difference at 6 months (difference 1.61, P=0.55)
• Global perceived effect: no between-group difference at 6 weeks (difference -0.50, 95% CI -0.59 to 1.59, P=0.36) or 6 months (P=0.48)
• Hip abductor strength group-by-time interaction: significant in favor of PLHG (P=0.02); PLHG increased abductor strength ~24% versus ~9% in AMHG
• Hip adductor strength group-by-time interaction: significant in favor of AMHG (P value from within-group table: AMHG significant, PLHG not significant)
• Hip internal rotator strength group-by-time interaction: significant in favor of AMHG (P=0.01)
• Dynamic knee valgus (frontal plane projection angle): no significant between-group or within-group change in either group at 6 weeks (between-group difference 0.37, P=0.82)
• Treatment adherence was high and similar: PLHG averaged 10.3 sessions, AMHG averaged 10.2 sessions (mean difference 0.10, 95% CI -0.09 to 0.9)
• 46 of 52 participants (88.5%) completed assessments at both 6-week and 6-month follow-up

Limitations

• Only women were included, limiting generalizability to men
• Not all clinical outcomes were collected at the 6-month follow-up
• Exercise continuity between 6 weeks and 6 months was not monitored
• Intervention dose (twice weekly for 6 weeks) was lower than the average reported in prior PFP exercise studies

Why it matters

For patients

Women with patellofemoral pain can expect similar pain relief and functional improvement regardless of whether their hip strengthening program focuses on the outer hip or inner hip muscles, as long as it is combined with knee strengthening.

For clinicians

Clinicians do not need to restrict hip strengthening to the posterolateral musculature; anteromedial hip exercises produce equivalent clinical outcomes, which expands the exercise selection available for managing patellofemoral pain.

For readers

This trial provides the first direct head-to-head comparison of anteromedial versus posterolateral hip strengthening in patellofemoral pain, challenging the prevailing preference for posterolateral-only protocols.