Electromechanical Delay of the Vastus Medialis Obliquus and Vastus Lateralis in Individuals With Patellofemoral Pain Syndrome
Journal of Orthopaedic & Sports Physical Therapy, 08/03/2012
Chen HY et al. – The mechanical properties of the vastus medialis obliquus (VMO) and vastus lateralis (VL) may be altered in patients with patellofemoral pain syndrome (PFPS).Methods
- Twenty–six individuals with PFPS and 26 healthy volunteers were studied.
- The VMO and VL were electrically stimulated to evoke muscle twitches.
- Ultrasound was used to assess patellar movement elicited by the muscle twitch.
- The time period from the onset of electrical stimulation to the onset of patellar movement was measured as the EMD.
- The EMDs of the VMO and VL were compared between groups using a mixed model ANOVA.
- Subsequent to a significant interaction (P<.001), post–hoc analysis indicated that EMD of the VMO was longer (PFPS, 37.3 ± 0.7; control, 25.9 ± 0.7; P<.001) and EMD of the VL was shorter (PFPS, 18.4 ± 0.5; control, 25.1 ± 0.5; P<.001) in the PFPS group.
- Therefore, for the individuals with PFPS, the EMD for the VMO was significantly longer than for the VL (P<.001) which was not the case for the control group (P=.20).