Abstract
Patellofemoral pain (PFP) is one of the most common knee pathologies in active individuals. Interventions on PFP have shown positive short-term outcomes, but long-term outcomes are less compelling. We do not have a complete understanding of the underlying factors contributing to the development of PFP. Research on risk factors for PFP is vast and has identified many factors, most of them stemming from impairments at the hip. However, it has been hypothesized that there are factors more distally that may also be affecting control of the knee during functional tasks. There is a need to evaluate the foot and ankle to understand the morphological characteristics in individuals with PFP, and to evaluate how measures at the foot and ankle may be contributing to lower extremity movement patterns. These factors may aid in the construction of more comprehensive intervention studies to better the clinical management and outcomes of this condition. Therefore, the purpose of this study is to gain an understanding of the role the intrinsic foot muscles play in individuals with PFP, and how clinical measures (strength, range of motion, and alignment) at the hip, knee, foot, and ankle are related to clinically evaluated functional movements that are typically aberrant and cause pain in those with PFP.
We identified that the cross-sectional area of the abductor hallucis was smaller when individuals with PFP and healthy controls were compared. However, no difference in size or quality of the flexor digitorum brevis or quadratus plantae, as well as no difference in foot postures were identified between groups. While weight bearing on a single limb, the PFP pathologic group presented with a smaller IFM that provides eccentric control of the medial longitudinal arch, which may have implications up the chain during weight bearing functional tasks. Upon evaluation of dynamic balance, individuals with PFP performed with poor dynamic balance on a novel balance task; the dynamic leap and balance test (DLBT), compared to the healthy group. However, healthy individuals and individuals with PFP performed similarly on the common start excursion balance test (SEBT). DLBT should be evaluated, in conjunction with the SEBT, in individuals with PFP. If there are balance deficits present, evaluation of the mass, hip external rotation rom, hip flexion strength, and size of the abductor hallucis muscle may help guide clinical intervention. During a single leg squat, individuals with PFP did not have the same dysfunctions causing aberrant frontal plane knee motions. Implementing a contraction of the intrinsic foot muscles and a contraction of the gluteal muscles provides valuable information for clinical evaluation and intervention, and may be helpful in treating patients with PFP. We identified that a thorough clinical evaluation of the full lower extremity in those with PFP can give clinicians and researchers useful information to design more effective impairment-based rehabilitation programs.
