Vasti Control of Patellofemoral Kinematics in Asymptomatic Volunteer
Condition: Abnormalities; Patellofemoral Pain Syndrome
MeSH terms: Patellofemoral Pain Syndrome
Study type: Observational

Summary: 
      Background:

        -  Patellofemoral pain syndrome is one of the most common knee problems. It is
           characterized by pain in the front of the knee that is aggravated by deep knee flexion,
           prolonged sitting, and repetitive movement. The most widely accepted theory regarding
           the source of this pain is that a force imbalance around the knee puts extra stress on
           the area, leading to pain.

        -  Researchers are interested in learning more about the muscle groups around the knee to
           better understand the causes of knee pain.

      Objectives:

      - To obtain more information on how muscles, tendons, and bones work together to cause motion
      in the knee, both in the normal state and after immobilizing certain muscles around the knee.

      Eligibility:

      - Healthy individuals between the ages of 18 and 55, who have no current or chronic muscle,
      bone, or joint problems and who have no implants or other problems that would prevent them
      from receiving a magnetic resonance imaging (MRI) scan.

      Design:

        -  This protocol will be carried out over two visits, both of which will involve using
           standard MRI sequences to look at the knee at rest and in motion.

        -  The first part will examine the knee under its natural state, with a standard MRI scan
           of the knee both at rest and in motion.

        -  The second part will involve temporarily reducing the force producing capabilities of
           one of the extensor muscles in the knee. To do so, study doctors will inject lidocaine
           into the muscle, which will temporarily (for approximately 2 hours) block the force
           producing capacity of this muscle, and then perform the MRI scan.
    

Detailed description: 
      Patellofemoral pain syndrome is one of the most common problems of the knee. It is
      characterized by anterior knee pain that is aggravated by deep knee flexion, prolonged
      sitting, and repetitive flexion/extension. The most widely accepted theory in regards to the
      source of this pain is that a force imbalance around the knee leads to static patellofemoral
      malalignment and dynamic patellofemoral maltracking. In turn, this malalignment and
      maltracking lead to elevated joint contact stresses, which ultimately leads to patellofemoral
      pain. Current understanding of patellofemroal maltracking is typically focused on static 2D
      alignment (lateral tilt and displacement). Yet, patellofemoreal pain is most often
      exacerbated during dynamic events and the patella has complete six degrees of freedom in its
      movement. More recent studies have been able to quantify patellofemoral kinematics during
      volitional dynamic tasks and demonstrate that the maltracking problem is more complex than
      originally postulated. Specifically, in patients with patellofemoral pain, altered kinematics
      are not limited to excessive patellar lateral translation and tilt, but include excessive
      patellar superior translation along with excessive flexion and varus rotation. Although these
      results are useful in demonstrating how specific maltracking patterns could lead to
      patellofemoral pain, they do not present any associations between a potentially altered force
      balance around the knee and the observed maltracking patterns. Therefore, the overall goal of
      this work is to determine the specific sources of maltracking patterns in patellofemoral
      pain. As part of this overall goal, the purpose of this study is to determine how the loss of
      force in the vasti medialis muscle alters the dynamic control of patellar kinematics.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Subjects for this study will be recruited through the Patient Recruitment and Public
        Liaison (PRPL) office. PRPL will respond to clinical research study inquiries, conduct
        preliminary screening for the protocol, and refer prospective patients to the Protocol
        Manager.
      
Keywords: Maltracking; Anterior Knee Pain; Knee; Natural History