Does adding hip exercises to quadriceps exercises result in superior outcomes in pain, function and quality of life for people with knee osteoarthritis? A systematic review and meta-analysis

Key points

1. 01Across 8 RCTs (341 participants), adding any hip exercise to quadriceps work improved walking function but not pooled pain or patient-reported function.
2. 02Resistance hip exercises (high or low intensity) consistently outperformed quadriceps alone for pain and function, while functional neuromuscular and multimodal hip exercises did not improve patient-reported outcomes.
3. 03People with medial-compartment knee osteoarthritis showed greater patient-reported function gains when hip and quadriceps exercises were combined.
4. 04The overall body of evidence was graded very low certainty, with all follow-up at 3 months or less and most trials low quality (mean PEDro 6).
5. 05Effects may be mediated by gains in hip abduction strength, which influence pelvic control and medial knee load during walking.

How it was conducted

Design

Systematic review with random-effects meta-analysis of RCTs (PROSPERO CRD42017057857)

Search

Medline, Embase, Cochrane, CINAHL, SportDiscus from inception to January 2018; 8 RCTs included

Participants

341 adults with symptomatic radiographically confirmed knee osteoarthritis (34% male)

Intervention

Hip strengthening (resistance, functional neuromuscular, or multimodal) added to quadriceps exercise, vs quadriceps exercise alone

Outcomes

Pain, patient-reported function, OARSI performance-based tests, quality of life; all follow-up 3 months or less

Analysis

Standardised mean differences with 95% CI; risk of bias by PEDro; certainty by modified GRADE

What they found

• Walking function: combined hip and quadriceps favoured over quadriceps alone, SMD -1.06 (95% CI -2.01 to -0.12), a large effect.
• Pain: no pooled difference between groups, SMD -0.09 (95% CI -0.96 to 0.79).
• Patient-reported function: no significant pooled difference overall, SMD -0.74 (95% CI -1.56 to 0.08); but in medial knee osteoarthritis, SMD -0.73 (95% CI -1.91 to -0.21) favoured combined exercise.
• Subgroup tests showed hip resistance exercises were superior to functional neuromuscular exercises for pain (p<0.0001) and patient-reported function (p<0.0001).
• Multimodal hip exercise added no benefit over quadriceps alone for pain (0.13, 95% CI -0.31 to 0.56), function (-0.15, 95% CI -0.58 to 0.29), or stair function (0.13, 95% CI -0.30 to 0.57).
• Overall meta-analysis combining all hip exercise types was graded very low certainty (GRADE) for all outcomes.

Limitations

• Only single studies were available for most hip-exercise subtypes, so most comparisons could not be meta-analysed.
• All follow-up was 3 months or less, leaving long-term effects in this chronic condition unknown.
• Most trials were low quality (6 of 8 low PEDro), and sensitivity analysis with only high-quality studies removed the apparent benefits.
• Findings apply mainly to mild-to-moderate radiographic disease, as only about 10% of participants had severe knee osteoarthritis.

Why it matters

For patients

If you have knee osteoarthritis, adding hip exercises (especially resistance work for the hip muscles) to your knee programme may help your pain, function, and walking, but the evidence is still weak.

For clinicians

Consider the type of hip exercise prescribed: resistance hip work appears more beneficial than functional neuromuscular or multimodal work, particularly for medial-compartment knee osteoarthritis.

For readers

Adding hip exercise to quadriceps work is not automatically better, the specific exercise type drives whether there is added benefit.