Background There is controversy regarding the relationship between patellofemoral pain syndrome (PFPS) and insufficiency of the vastus medialis obliquus (VMO). The conventional clinical practice of VMO strengthening for PFPS has been challenged for lack of evidence. The purpose of this study was to observe the difference in sonographic findings of the VMO between patients with PFPS and healthy adults. Hypothesis The morphological characteristics of the VMO are different between patients with PFPS and healthy adults. Study Design Case-control study; Level of evidence, 3. Methods Fifty-four patients with PFPS and 54 age-, gender-, body height—, and body weight—matched healthy adults as controls were enrolled in the study to measure by sonography the insertion level, fiber angle, and volume of the VMO at its insertional portion to detect differences between patients with PFPS and healthy controls. Results The insertion level, fiber angle, and VMO volume were all significantly smaller in the PFPS group than in the control group (P < .05). Multivariate analysis of variance has revealed a Wilks λ value of .845 and an F value of 5.640 (P = .001). Conclusion There was a significant difference in the 3 VMO measures between patients with PFPS and the healthy controls. Individuals might be predisposed to PFPS by different VMO characteristics, including insertion level and fiber angle. The current study cannot determine whether the observed morphological differences were the results of atrophy in response to pain or if they represent dysplasia that was predisposed to pain development. The clinical manifestations of VMO characteristics should be thoroughly investigated in other populations. Clinical Relevance The function of the VMO is important to consider in the rehabilitation of patients with PFPS.
Reflex Response Times of Vastus Medialis Oblique and Vastus Lateralis in Normal Subjects and in Subjects With Patellofemoral Pain Syndrome
