The Outcome Effect of Shoe Lift for Individuals With Low Back Pain and Pronated Foot Due to Anatomical Leg Length Discrepancy
Condition: Low Back Pain; Flatfoot; Leg Length Inequality
MeSH terms: Flatfoot; Leg Length Inequality; Back Pain; Low Back Pain
Study type: Interventional

Summary: 
      People with anatomical leg length discrepancy (LLD) commonly presented excessive subtalar
      pronation of the long leg compared to their short leg in order to equalize leg length.
      Although such compensation may decrease the stress in the pelvis and/or low back region, the
      pronated foot may lead to excessive stress loading onto the ankle or foot, resulting in
      musculoskeletal injuries. Clinically, the pronated foot has been effectively controlled using
      functional orthoses with proper posting by adjusting the subtalar joint in the neutral
      position. But for people with compensatory pronated foot resulted from anatomical LLD, to
      control excessive pronation of the long leg would exaggerate their asymmetry in leg length.
      Instead, the pronated foot can be controlled simply by adjusting the length of the short leg.
      However, there is limited evidence of such intervention in previous literature. The purpose
      of this research project is going to determine the effect of leg length adjustment on
      pronation control in people with anatomical LLD. According to this purpose, 5 study
      objectives will be developed: 1) to examine the validity and reliability of LLD measurement
      using a hand-held laser distance meter, 2) to compare the foot types before and after leg
      length adjustment, 3) to compare the kinetic variables before and after leg length adjustment
      during quiet stance, 4) to compare the kinetic variables before and after leg length
      adjustment during level walking, and 5) to compare symptoms and functional levels related to
      low back pain (LBP) before and after leg length adjustment.

      The present research project will be designed as a convenience sampling, prospective,
      quasi-experimental, and pretest/posttest design. There will be 2 parts in this research: 1)
      validity and reliability test of laser measure for leg length and 2) foot morphology and
      kinetic analysis before and after leg length adjustment. For the first part of this research,
      10 male adults and 20 adults will be recruited for the validity and reliability tests
      respectively. Anthropometric measurements, including body height, body weight, foot length,
      foot width, and heel-ball distance, will be measured after a consent form is signed.
      Participants of the validity test will receive standing pelvic radiography and laser measure
      to measure their leg length. Each participant of the reliability test will receive 2 sessions
      of laser measure using a hand-held laser-distance meter. For the first session, all laser
      measurements will be employed twice by 2 raters with a rest interval of more than 5 min. One
      week later, another session of laser measure will be given again by one of these 2 raters.
      Intraclass correlation coefficient (ICC) will be used to test the interrater reliability,
      intrarater reliability, and validity of the laser measure method. Standard error of
      measurement (SEM), and small real difference (SRD) will be calculated to represented
      intrarater reliability also. For the second part of the research, another thirty adults with
      compensatory pronated foot resulted from LLD will be included in the research project but the
      sample size will be adjusted to the appropriate number according to power analysis. Each
      participant will be asked to fill out the visual analog scale (VAS) and the Oswestry
      Disability Index (ODI) and receive tests containing foot type examination, quiet stance with
      eye opening, quiet stance with eye closed, and level walking. All tests will be performed
      before and after leg length adjustment. The experiment will be completed after collecting 3
      successful trials for each test. All procedures will be done one month later. ANOVA with
      repeated measures will be calculated to compare the differences in these variables among
      before, immediately after, and 1 month following leg length adjustment when the data fit the
      assumptions of normal distribution. Discrete variables or variables with non-normal
      distribution were tested using the Friedman test. All statistical analyses will be calculated
      using SAS 9.1.3. The significant level was set at α = 0.05 while the power was at 0.8.

      Five possible results may be expected from conducting this research project: 1) there will be
      good validity and reliability of the laser distance meter to measure LLD, 2) there will be
      significant differences in measurements of foot type before and after leg length adjustment,
      3) there will be significant differences in kinetic data during quiet stance before and after
      leg length adjustment, 4) there will be significant differences in kinetic data during level
      walking before and after leg length adjustment, and 5) symptom and functional level related
      to LBP will improve after leg length adjustment. Completion of this research project will be
      projected to provide solid and objective evidences for leg length adjustment through views of
      morphology and kinetics in people with pronated foot due to anatomical LLD.
    


Intervention name(s): shoe lift
Intervention type(s): Other
Intervention description(s): shoe lift for balancing the heights of bilateral pelvis of participants with leg length discrepancy during standing
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment