Effects of simulated vastus medialis strength variation on patellofemoral joint biomechanics in human cadaver knees
PainSci summary of Lee 2002?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided at the bottom of the page, as often as possible. ★★☆☆☆?2-star ratings are for studies with flaws, bias, and/or conflict of interest; published in lesser journals. Ratings are a highly subjective opinion, and subject to revision at any time. If you think this paper has been incorrectly rated, please let me know.
From the abstract: “Treatment included iliotibial band stretching and patellar mobilizations that focused on stretching the lateral retinaculum. It may have been these latter treatments or strengthening of the quadriceps muscle as a whole that was responsible for the decrease in symptoms.” Indeed! This study suggests that vastus medialis muscle may have little effect on patellofemoral joint mechanism, although a study of living patients would be better than studying the dead knees of cadavers, as was done here.
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.
Selective strengthening of the vastus medialis (VM) muscle is a conservative treatment used to address some patellofemoral joint (PFJ) problems. The objective of this study was to examine the effects of varying VM strength on PFJ kinematics and contact pressures and areas. We tested five fresh-frozen cadaveric knees using a custom knee jig, which permits the simulation of physiologic quadriceps loading while also allowing the VM force to be varied. PFJ kinematics were measured with a magnetic tracking device. PFJ contact pressures and areas were measured with Fuji pressure-sensitive film. For PFJ kinematics, the change in the medial-lateral and superior-inferior translation was significant at 0% of VM strength and 150% of VM strength with respect to the 100% of VM strength condition (p 0.05). The functional range of VM strength is between 75% and 125% of total VM strength. The PFJ kinematics and contact pressures were not significantly influenced by VM strength except at extreme conditions (0% of VM strength or 150% of VM strength) in human cadaveric knees.
related content
- “The functional anatomy of the iliotibial band during flexion and extension of the knee: implications for understanding iliotibial band syndrome,” an article in Journal of Anatomy, 2006.
- “An anatomic study of the iliotibial tract,” an article in Arthroscopy, 2007.
- “Iliotibial band syndrome: an examination of the evidence behind a number of treatment options,” an article in Scandinavian Journal of Medicine & Science in Sports, 2010.
- “The deep layer of the tractus iliotibialis and its relevance when using the direct anterior approach in total hip arthroplasty: a cadaver study,” an article in Archives of Orthopaedic & Trauma Surgery, 2017.
These two articles on PainScience.com cite Lee 2002 as a source:
- PS Save Yourself from Patellofemoral Pain Syndrome! — Patellofemoral pain syndrome (aka runner’s knee) explained and discussed in great detail, including every imaginable self-treatment option and all the available scientific evidence
- PS Patellofemoral Pain & the Vastus Medialis Myth — Can just one quarter of the quadriceps be the key to anterior knee pain?
