Scoring System Predicts Ability Of Orthotics to Ease Knee Pain

The success of orthotic devices for patellofemoral pain can be predicted by a patient's age, height, midfoot morphometry, and pain severity, according to a small, single-center Australian study.

The use of these predictor variables can help practitioners make better informed treatment decisions, wrote Bill Vicenzino, Ph.D., in an article published online (Br. J. Sports Med. 2008 [doi:10.1136/bjsm.2008.052613]).

The researchers performed a post hoc analysis of a randomized, single-blind clinical trial in 42 patients aged 18-40 years with patellofemoral pain (PFP) of nontraumatic origin who were given one of several treatments, including flat inserts, physical therapy, and foot orthoses. The latter consisted of four pairs of prefabricated ethylene-vinyl acetate foot orthoses with a 6-degree varus wedge and built-in arch support.

Patients given foot orthoses were followed for 12 weeks. During the first 6 weeks, patients attended six 30-minute physical therapy sessions in which they rated the comfort of the orthoses on a visual analog scale, with 0 mm indicating they were too uncomfortable to wear and 100 mm indicating no discomfort.

The severity of the worst and usual patellofemoral pain experienced during the previous week also was measured on a visual analog scale, with 0 mm representing no pain and 100 mm as the worst pain imaginable.

The orthoses were then modified, and patients were encouraged to wear them throughout the study, wrote Dr. Vicenzino, head of the division of physiotherapy at the School of Health and Rehabilitation Sciences, University of Queensland, Brisbane (Australia), and colleagues.

The outcome measure was the perceived effect of the orthoses as measured on a 5-point Likert scale, with options ranging from marked improvement to marked worsening. Only those who scored “marked improvement” were considered to have a successful outcome.

For the analysis of predictor variables, morphometric foot measurements and demographic data were recorded for the 42 participants at baseline and at the first intervention appointment. Morphometric characteristics included weight-bearing (taken when equal weight is on each foot) and non-weight-bearing measures of the midfoot; weight-bearing arch height; and midfoot width difference (the change in midfoot width from a non-weight-bearing to a weight-bearing position). Demographic data included age, sex, height, weight, and body mass index.

At 12 weeks, 17 (40%) of the patients had successful outcomes, on the basis of the Likert scale. Analysis showed that four of the predictor variables—age over 25 years, height less than 165 cm, worst pain less than 53 mm, and midfoot width difference greater than 11 mm—were significantly associated with a successful outcome. Compared with the pretest probability of success in all 42 patients of 40%, patients who had three of the four predictors had a post-test probability of success of 85%. For patients with two of the identified predictors, that probability was 61%, and for patients with one variable, it was 53%. No patients had all four predictors.

The study was funded primarily by the National Health and Medical Research Council of Australia.

The success of orthotic devices for patellofemoral pain can be predicted by a patient's age, height, midfoot morphometry, and pain severity, according to a small, single-center Australian study.

The use of these predictor variables can help practitioners make better informed treatment decisions, wrote Bill Vicenzino, Ph.D., in an article published online (Br. J. Sports Med. 2008 [doi:10.1136/bjsm.2008.052613]).

The researchers performed a post hoc analysis of a randomized, single-blind clinical trial in 42 patients aged 18-40 years with patellofemoral pain (PFP) of nontraumatic origin who were given one of several treatments, including flat inserts, physical therapy, and foot orthoses. The latter consisted of four pairs of prefabricated ethylene-vinyl acetate foot orthoses with a 6-degree varus wedge and built-in arch support.

Patients given foot orthoses were followed for 12 weeks. During the first 6 weeks, patients attended six 30-minute physical therapy sessions in which they rated the comfort of the orthoses on a visual analog scale, with 0 mm indicating they were too uncomfortable to wear and 100 mm indicating no discomfort.

The severity of the worst and usual patellofemoral pain experienced during the previous week also was measured on a visual analog scale, with 0 mm representing no pain and 100 mm as the worst pain imaginable.

The orthoses were then modified, and patients were encouraged to wear them throughout the study, wrote Dr. Vicenzino, head of the division of physiotherapy at the School of Health and Rehabilitation Sciences, University of Queensland, Brisbane (Australia), and colleagues.

The outcome measure was the perceived effect of the orthoses as measured on a 5-point Likert scale, with options ranging from marked improvement to marked worsening. Only those who scored “marked improvement” were considered to have a successful outcome.

For the analysis of predictor variables, morphometric foot measurements and demographic data were recorded for the 42 participants at baseline and at the first intervention appointment. Morphometric characteristics included weight-bearing (taken when equal weight is on each foot) and non-weight-bearing measures of the midfoot; weight-bearing arch height; and midfoot width difference (the change in midfoot width from a non-weight-bearing to a weight-bearing position). Demographic data included age, sex, height, weight, and body mass index.

At 12 weeks, 17 (40%) of the patients had successful outcomes, on the basis of the Likert scale. Analysis showed that four of the predictor variables—age over 25 years, height less than 165 cm, worst pain less than 53 mm, and midfoot width difference greater than 11 mm—were significantly associated with a successful outcome. Compared with the pretest probability of success in all 42 patients of 40%, patients who had three of the four predictors had a post-test probability of success of 85%. For patients with two of the identified predictors, that probability was 61%, and for patients with one variable, it was 53%. No patients had all four predictors.

The study was funded primarily by the National Health and Medical Research Council of Australia.

The success of orthotic devices for patellofemoral pain can be predicted by a patient's age, height, midfoot morphometry, and pain severity, according to a small, single-center Australian study.

The use of these predictor variables can help practitioners make better informed treatment decisions, wrote Bill Vicenzino, Ph.D., in an article published online (Br. J. Sports Med. 2008 [doi:10.1136/bjsm.2008.052613]).

The researchers performed a post hoc analysis of a randomized, single-blind clinical trial in 42 patients aged 18-40 years with patellofemoral pain (PFP) of nontraumatic origin who were given one of several treatments, including flat inserts, physical therapy, and foot orthoses. The latter consisted of four pairs of prefabricated ethylene-vinyl acetate foot orthoses with a 6-degree varus wedge and built-in arch support.

Patients given foot orthoses were followed for 12 weeks. During the first 6 weeks, patients attended six 30-minute physical therapy sessions in which they rated the comfort of the orthoses on a visual analog scale, with 0 mm indicating they were too uncomfortable to wear and 100 mm indicating no discomfort.

The severity of the worst and usual patellofemoral pain experienced during the previous week also was measured on a visual analog scale, with 0 mm representing no pain and 100 mm as the worst pain imaginable.

The orthoses were then modified, and patients were encouraged to wear them throughout the study, wrote Dr. Vicenzino, head of the division of physiotherapy at the School of Health and Rehabilitation Sciences, University of Queensland, Brisbane (Australia), and colleagues.

The outcome measure was the perceived effect of the orthoses as measured on a 5-point Likert scale, with options ranging from marked improvement to marked worsening. Only those who scored “marked improvement” were considered to have a successful outcome.

For the analysis of predictor variables, morphometric foot measurements and demographic data were recorded for the 42 participants at baseline and at the first intervention appointment. Morphometric characteristics included weight-bearing (taken when equal weight is on each foot) and non-weight-bearing measures of the midfoot; weight-bearing arch height; and midfoot width difference (the change in midfoot width from a non-weight-bearing to a weight-bearing position). Demographic data included age, sex, height, weight, and body mass index.

At 12 weeks, 17 (40%) of the patients had successful outcomes, on the basis of the Likert scale. Analysis showed that four of the predictor variables—age over 25 years, height less than 165 cm, worst pain less than 53 mm, and midfoot width difference greater than 11 mm—were significantly associated with a successful outcome. Compared with the pretest probability of success in all 42 patients of 40%, patients who had three of the four predictors had a post-test probability of success of 85%. For patients with two of the identified predictors, that probability was 61%, and for patients with one variable, it was 53%. No patients had all four predictors.

The study was funded primarily by the National Health and Medical Research Council of Australia.