Patellofemoral Pain syndrome and VMO exercises
Clinical Bottom Line(s): Vastus medialis oblique (VMO) specific exercises are not significantly
more effective than general quadriceps strengthening at improving sings/symptoms of patellofemoral
pain syndrome (PFPS). Both VMO specific and general quadriceps strengthening exercises however
are shown to improve PFPS compared to a control group.
Citation: Syme G, Rowe P, Martin D, Daly G. Disability in patients with chronic patellofemoral pain
syndrome: A randomized controlled trial of VMO selective training versus general quadriceps
strengthening. Manual Therapy. 2008; (article in press).
Clinical question: In the adult population with patellofemoral pain syndrome (PFPS) or anterior
knee pain (AKP); are exercises that strengthen muscle at the hip joint more effective at reducing pain
than exercises that strengthen the vastus medialis oblique (VMO) based on pain surveys taken by
each subject before and after treatment?
The study: This was a single blind randomized controlled study (RCT). The purpose of this study
was to see if VMO specific exercises were effective at treating patellofemoral pain syndrome (PFPS).
They judged effectiveness by comparing a VMO group to a general quadriceps strengthening group
and a control group.
The study patients: 69 subjects (41 female, 28 male) who all had PFPS were recruited from a
hospital orthopedic clinic. These subjects were randomly assigned into three equal groups according
to treatment condition. On average the subjects had been having pain for about 47 months.
Control Group: The control group (n=23) was evaluated at the beginning and the end of the study
period, but they received no physical therapy or treatment of any kind in the interim. They were
ignored until the end of the trial.
Experimental Group(s): The general quadriceps strengthening group (n=23) attended a supervised
training group twice a week to build quadriceps strength. Subjects in the VMO selective group
(n=23) were seen by PTs and given home exercises based on the McConnell technique for treating
The evidence: This study shows that quadriceps strengthening can improve PFPS by reducing pain
as measured by the McGill Pain Questionnaire (p=0.003) and improving functional abilities as
measured by the NRS 101 average pain intensity previous month (p<0.001) when compared to the
control group. It also shows that VMO specific exercises do not work to treat PFPS by reducing pain
better than general quadriceps strengthening (p=0.27), but they do help treat it compared to doing
Comments: The results in this study seem to have good external validity and should be repeatable
because they used general quadriceps strengthening exercises including open and closed chain
exercises. A future study of PFPS could look into general quadriceps weakness as a possible cause.
A limitation of this study is that the examiners ignored the control group, and did not monitor what
they were doing in the interim.
Appraised by: Matt Bugnet Date appraised: 8/05/2008