EXAMINING THE USE OF ORTHOTICS IN THE MANAGEMENT OF PATELLOFEMORAL PAIN

 

            Traditionally, most interventions for patellofemoral pain are directed toward the patellofemoral joint itself, through strengthening the vastus medialis oblique, stretching, soft tissue mobilization, knee bracing, and patellar mobilization.⁴   Current research^2,5,6 indicates that the patellofemoral joint is affected by lower extremity joints proximal and distal to the knee. This means that intervention might not be directed to the area of pain, but rather directed to other joints in the lower extremity.⁴   For example, a close biomechanical relationship exists between the tibial axial rotation and the subtalar joint. Excessive pronation at the subtalar joint, defined as either too much motion or incorrect timing, internally rotates the tibia, and results in increased rotational strain on soft tissues in the lower extremity. Failure of the foot to resupinate in the stance phase would result in a compensatory internal rotation of the femur to achieve knee extension in midstance.⁷   Internal rotation of the femur would create a change in the line of pull of the quadriceps, and change the dynamics of the patellofemoral joint. ⁴

            Multiple studies^2,6,8 have investigated the connection between tibial internal rotation and excessive pronation. A study by Nawoczenski et al⁶ was one of the first to examine the effect of foot orthoses on three-dimensional motion of the lower leg and rearfoot during running. The researchers hypothesized that foot orthoses would affect subtalar and talocrural joint axial rotation, as studies up until that point had focused mainly on frontal plane movement analysis. Twenty-two subjects, with patellofemoral pain greater than one-month duration, were recruited.⁶   The subjects ran on a treadmill for two minutes with and without orthotics, and measurements were obtained from images collected during each trial. The researchers found significant differences (p<0.05) in tibial axial internal rotation in early stance phases, and concluded that prolonged or excessive tibial internal rotation delays the necessary external rotation of the tibia at midstance, and can be a precipitating factor in patellofemoral pain. They concluded that orthotics may be most effective for individuals with gait deviations during the first 50% of the stance phase.⁶ 

Way² hypothesized that correcting mild forefoot varus through thermoplastic foot orthoses would decrease accumulation of abnormal forces on the patellofemoral joint. He also proposed that controlling excessive tibial internal rotation in stance would control subsequent internal rotation of the femur, thus maintaining a more optimal quadriceps angle. The single-subject design study consisted of one 19 year-old female presenting with left sided patellofemoral pain and with a mild forefoot varus bilaterally. The researcher strengthened the study by employing an A-B-A-B design. The four phases included taking baseline measurements, providing intervention, mandating a withdrawal phase to determine if changes were due to maturation or treatment, and finally a second intervention phase to reaffirm a positive orthotic effect. Statistical analysis showed significant differences (p<0.05) between each phase of the study in the visual analog scale (VAS) for pain, and in 7 of 9 phases of a functional index questionnaire. Way² concluded that thermoplastic foot orthoses may be an effective treatment for individuals presenting with patellofemoral pain and mild forefoot varus, and felt that additional research is needed to determine the effect of orthoses on more severe forefoot deviations or rearfoot pronation.

Klingman et al⁸ investigated the impact of excessive rearfoot pronation on translation of the patella on the femur in the frontal plane. The researchers hypothesized that excessive subtalar joint pronation would increase internal rotation of the tibia, which would increase lateral displacement of the patella. Twelve females, ages 20 to 28 years, with greater than 6 degrees of calcaneal valgus, were X-rayed with and without foot orthoses while weightbearing in 45 degrees of knee flexion.⁸   The researchers measured patellar position using the medial patellar border and medial point of medial femoral condyle, and found that there was a statistically significant difference (p<0.05) in patellar alignment when correcting excessive rearfoot pronation with foot orthoses. They concluded that a relative medial glide occurs when controlling pronation, due to a decrease in amount of tibial internal rotation.⁸

A study performed by Sutlive et al³ examined 45 active-duty Army subjects aged 18-40, and identified characteristics of those most likely to benefit from over-the-counter foot orthoses and activity modification. The researchers took various lower extremity measurements in sitting, prone, standing, and supine at the initial visit. Pre-fabricated orthotics and activity modification were provided as the intervention, and then subjects completed the VAS for rating pain level. After 21 days, subjects completed another VAS and a Global Rating of Change (GRC) questionnaire to assess change of status in knee pain. The researchers determined that a 50% reduction in VAS scores would be considered successful, and found that subjects with a forefoot valgus of greater than or equal to 2 degrees, great toe extension of less than 78 degrees, and a navicular drop of less than or equal to 3 millimeters were most likely to respond favorably to intervention with prefabricated foot orthoses and activity modification. ³

A study by Johnston and Gross⁵ investigated the effect of custom-fit foot orthoses on quality of life, as determined by pain, stiffness, and physical function in individuals with patellofemoral pain. Sixteen subjects with knee pain, ages 14 to 50 years, with excessive pronation indicated by greater than 9 degrees calcaneal valgus in weightbearing, were recruited. ⁵   On the first encounter, the subjects were measured for orthotics and completed the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC). On the second encounter two weeks later, the subjects completed the WOMAC again to assure that the condition had not changed, and were given their orthotics. The subjects then completed the WOMAC two weeks after the second encounter, and again three months after the third encounter. Statistical analysis revealed a significant difference (p<0.05) in pain and stiffness in the two weeks after orthotics were issued, and a significant difference (p<0.05) in physical function after three additional months. ⁵   They found no significant change in WOMAC scores from the initial assessment to when the subjects received the orthotics. The researchers felt strongly that the results were due to the orthotic effect because they did not restrict footwear choices by the subjects during the study.⁵