Detailed guides to painful problems, treatments & more

Vastus medialis 9% smaller in patients with patellofemoral pain

PainSci » bibliography » Pattyn et al 2011
Tags: etiology, biomechanics, patellar pain, running, anatomy, pro, arthritis, aging, pain problems, knee, leg, limbs, overuse injury, injury, exercise, self-treatment, treatment

One article on PainSci cites Pattyn 2011: The Complete Guide to Patellofemoral Pain Syndrome

PainSci notes on Pattyn 2011:

It is an article of faith for many professionals that the inner portion of the quadriceps muscle group (VMO) is weak and atrophied in patients with patellofemoral pain, “despite very little objective evidence” according to this paper. For the first time, researchers used MRI to measure the size of the vastus medialis obliquus muscle in patients with and without patellofemoral pain syndrome, and found that it was 9% smaller in PFPS patients. The results are just barely statistically significant, and of course it is “not clear whether this atrophy is a result or a cause of PFPS.” However, that wise disclaimer is contradicted by the following statement that VMO is a “contributing factor in PFPS” — a troubling inconsistency in the paper’s abstract.

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.

BACKGROUND: Quadriceps atrophy and in particular atrophy of the vastus medialis obliquus (VMO) muscle have been frequently related with patellofemoral pain syndrome (PFPS), despite very little objective evidence.

HYPOTHESIS: Patients with PFPS exhibit atrophy of the VMO in comparison with healthy controls.

STUDY DESIGN: Case-control study; Level of evidence, 3.

METHODS: Forty-six patients with PFPS and 30 healthy control persons with similar age, gender, body mass index, and activity index distributions underwent magnetic resonance imaging (MRI) of the quadriceps. The muscle size was determined by calculating the cross-sectional area of the total quadriceps and its components.

RESULTS: The cross-sectional area (CSA) of the VMO was significantly smaller in the PFPS group than in the control group (16.67 ± 4.97 cm(2) vs 18.36 ± 5.25 cm(2)) (P = .040). A tendency was noted for a smaller total quadriceps CSA for the PFPS patients at midthigh level (66.99 ± 15.06 cm(2) vs 70.83 ± 15.30 cm(2)) (P = .074).

CONCLUSION: This is the first study to examine VMO size in PFPS patients by MRI. Patients with patellofemoral problems exhibited atrophy of the VMO. Although it is not clear whether this atrophy is a result or a cause of PFPS, the results of this study do show that atrophy of the VMO is a contributing factor in PFPS. Longitudinal, prospective studies are needed to establish the cause-effect relation of VMO atrophy and PFPS.

related content

This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog. A few highlights: