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Quadriceps or hip exercises for patellofemoral pain? A randomised controlled equivalence trial

PainSci » bibliography » Hansen et al 2023
Tags: treatment, patellar pain, exercise, strength, arthritis, aging, pain problems, knee, leg, limbs, overuse injury, injury, running, self-treatment

One article on PainSci cites Hansen 2023: The Complete Guide to Patellofemoral Pain Syndrome

PainSci notes on Hansen 2023:

This big British Journal of Sports Medicine trial tested the efficacy of both quads and hip strengthening as a treatment for patellofemoral pain: twelve weeks of either one or the other, in 200 people with aching kneecaps (a substantial sample size for once). There were no meaningful differences between the two groups. And then there was this:

“…neither programme surpassed the minimal clinically important change threshold.”

Both kinds of rehab were ineffective. Both of them were distinctly underwhelming, in this large test with no obvious flaws.

See a blog post that explores the implications a bit.

Details about the strength training

What exactly were these study subjects were doing to strengthen their hips and knees? What did the researchers ask them to do? Was it lame? Was it incompetent? Was it pathetically generic, one-size-fits-all? Surely only a poor quality exercise prescription could produce such mediocre results!

No, the intervention did not suck. If anything, I was pleasantly surprised with how thoughtfully thoughtfully conceived and diligently reported it all was. My interpretation of the results and their implications did not change when I double-checked. But for the sake of thoroughness, here is what they did…

The knee and hip strength training tested in this trial was reported in detail, and had no obvious major limitations: it was the kind of therapeutic prescription actual patients could expect to get from competent physical therapists in the community. Regardless of the how, strength actually improved by 10% in both groups. The specific prescription was “inspired by previous research and followed recommended prescribing guidelines.” Intriguingly, the authors cite one of their own previous papers which is actually about the failure to describe exercises tested in 38 other trials: “the level of exercise prescription detail was low,” they report. Hansen et al. seemed keen not to make that mistake in this trial; they obviously made a substantial effort to ensure that they were testing a good quality intervention, and to fully “show their work.”

The subjects did twelve weeks of home-based workouts, consisting of 3 sets of 8-12 repetitions. They were trained at an initial session with an “experienced” physiotherapist, and they were directed to adjust their repetitions to their ability; there were also monthly follow-up visits with review and emphasis of progression principles. The knee exercises were sitting knee extension, squat, and forward lunge. The hip exercises were hip external rotation (clam shell), side-lying/standing hip abduction, and prone/standing hip extension.

This was not intended to be a test of the best conceivable exercise prescription (such trials are almost never done, for good reasons). The intervention was intended to reflect the clinical reality for patients with access to good help. The only obvious way to improve on the prescription would be greater “customization,” and the authors address that:

“… although personalisation of exercise interventions to individual patients or subgroup of patients may be a useful strategy that can ultimately lead to improved outcomes for patients, such strategy remains to be supported by research evidence—preferably from prospective randomised trials.”

original abstract Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

OBJECTIVE: To assess effectiveness equivalence between two commonly prescribed 12-week exercise programmes targeting either the quadriceps or the hip muscles in patients with patellofemoral pain (PFP).

METHODS: This randomised controlled equivalence trial included patients with a clinical diagnosis of PFP. Participants were randomly assigned to either a 12-week quadriceps-focused exercise (QE) or a hip-focused exercise (HE) programme. The primary outcome was the change in Anterior Knee Pain Scale (AKPS) (0-100) from baseline to 12-week follow-up. Prespecified equivalence margins of ±8 points on the AKPS were chosen to demonstrate comparable effectiveness. Key secondary outcomes were the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire pain, physical function and knee-related quality of life subscales.

RESULTS: 200 participants underwent randomisation; 100 assigned to QE and 100 to HE (mean age 27.2 years (SD 6.4); 69% women). The least squares mean changes in AKPS (primary outcome) were 7.6 for QE and 7.0 for HE (difference 0.6 points, 95% CI -2.0 to 3.2; test for equivalence p<0.0001), although neither programme surpassed the minimal clinically important change threshold. None of the group differences in key secondary outcomes exceeded predefined equivalence margins.

CONCLUSION: The 12-week QE and HE protocols provided equivalent improvements in symptoms and function for patients with PFP.

related content

Specifically regarding Hansen 2023:

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