Wedged Orthoses and Knee Osteoarthritis

Introduction: In shoe wedged orthoses have been shown to be an effective conservative approach in reducing pain in patients with osteoarthritis (OA). The mechanism responsible for this pain reduction is not well-understood. It is not known whether placing a medial or lateral wedge in the shoe results in alterations in lower extremity alignment, knee joint moments or some combination of the two. The longterm effects of this intervention on OA patients' functional status as well the progression of their OA has not been studied. Therefore, the purpose of this study is to examine the effect of in-shoe wedged orthoses in patients with knee OA on the frontal plane knee joint moment. Methods: 38 patients between the ages of 40-70 yrs with knee OA (grades I-IV) will be recruited from within the medical community. Subjects with a diagnosis of unilateral knee OA of greater than 3 months duration, as defined by the American College of Rheumatology Guidelines, will be included. 19 subjects will be assigned to a treatment group and 19 subjects will be assigned to a control group. The treatment group will receive custom molded orthotics with a lateral wedge. Both the treatment and control groups will be tested initially and then again 1 year later. The dependent variable is peak knee adduction moment. Statistics: A two-way ANOVA will be used to test the hypothesis. This design will include 2 levels of group (control and treatment) and two levels of trial (pretest and 1 yr posttest). Significance will be determined at a level of p<.05.

Inclusion criteria

• Diagnosed unilateral knee osteoarthritis by a qualified physician
• Recent (within 3 months of entrance into the study) radiographic confirmation of OA grade (I-IV) as evidenced by joint space narrowing and the presence of osteophytes
• A score of 50-90 mm on a 100 mm visual analogue pain scale for walking
• Ability to walk independently without the use of assistive devices

Exclusion criteria

• History of lower extremity joint surgery or other lower extremity injury that would hinder ambulation
• Severe foot deformity that would prevent the accommodation of the wedged orthotic device
• Other disease process such as neurologic, cardiac, or oncologic, that would hinder one's ability to ambulate
• Any condition, such as diabetes, that results in loss of sensation in the lower extremities