Can we predict the outcome for people with patellofemoral pain? A systematic review on prognostic factors and treatment effect modifiers.

BACKGROUND: Patellofemoral pain (PFP) is a multifactorial and often persistent knee condition. One strategy to enhance patient outcomes is using clinically assessable patient characteristics to predict the outcome and match a specific treatment to an individual. AIM: A systematic review was conducted to determine which baseline patient characteristics were (1) associated with patient outcome (prognosis); or (2) modified patient outcome from a specific treatment (treatment effect modifiers). METHODS: 6 electronic databases were searched (July 2016) for studies evaluating the association between those with PFP, their characteristics and outcome. All studies were appraised using the Epidemiological Appraisal Instrument. Studies that aimed to identify treatment effect modifiers underwent a checklist for methodological quality. RESULTS: The 24 included studies evaluated 180 participant characteristics. 12 studies investigated prognosis, and 12 studies investigated potential treatment effect modifiers. Important methodological limitations were identified. Some prognostic studies used a retrospective design. Studies aiming to identify treatment effect modifiers often analysed too many variables for the limiting sample size and typically failed to use a control or comparator treatment group. 16 factors were reported to be associated with a poor outcome, with longer duration of symptoms the most reported (>4 months). Preliminary evidence suggests increased midfoot mobility may predict those who have a successful outcome to foot orthoses. CONCLUSIONS: Current evidence can identify those with increased risk of a poor outcome, but methodological limitations make it difficult to predict the outcome after one specific treatment compared with another. Adequately designed randomised trials are needed to identify treatment effect modifiers.

Initial effects of anti-pronation tape on the medial longitudinal arch during walking and running.

OBJECTIVES: To investigate the effect of an augmented LowDye taping technique on the medial longitudinal arch of the foot during dynamic tasks such as walking and jogging, and to elucidate the relation between tape induced changes in static and dynamic foot posture. METHODS: Seventeen subjects (mean (SD) age 27 (5.8) years) who were asymptomatic and exhibited a navicular drop greater than 10 mm were studied. Medial longitudinal arch height standardised to foot length during standing and at mid-stance of walking and jogging was measured from digital video images taken before and after the application of an anti-pronation taping technique. A no tape control condition was also included. RESULTS: Compared with the no tape control condition, tape produced a significant mean (SD) increase in the medial longitudinal arch height index of 0.031 (0.015), 0.026 (0.014), and 0.016 (0.017) during standing, walking, and jogging respectively (p < 0.05). The relative increase in medial longitudinal arch height represents an anti-pronation effect. The tape induced changes in the medial longitudinal arch height measured during standing correlated strongly with those measured during walking and jogging (Pearson's r = 0.7 and 0.76 respectively). CONCLUSIONS: The augmented LowDye tape was effective in controlling pronation during both static and dynamic activity. Tape induced changes in static foot posture paralleled those during walking and jogging.

Symmetry of plantar pressures and vertical forces in healthy subjects during walking.

The purpose of this study was to determine the degree of symmetry for in-shoe plantar pressure and vertical force patterns between the left and right feet of healthy subjects during walking. Thirty subjects with a mean age of 29.6 years participated in the study. Each subject walked a distance of 8 m three times while in-shoe plantar pressure and vertical force data were collected. A total of 12 steps were analyzed for both feet, and maximum vertical force, peak pressure, and pressure-time integrals were calculated for four plantar regions of the foot. No differences in the three variables were noted between male and female subjects. Plantar pressure and vertical force patterns were found to be symmetrical between the left and right feet, except for two of the four plantar regions studied. Only the forefoot and rearfoot regions were found to show significant differences between the left and right feet for plantar pressure and vertical force, respectively. The degree of asymmetry for these two plantar regions in the same foot, however, was minimal.

The distribution of plantar pressures in American Indians with diabetes mellitus.

The primary purpose of this study was to determine the magnitude and duration of plantar pressures acting on the feet of American Indians with diabetes mellitus. A secondary purpose was to determine whether differences in the range of motion of the ankle and first metatarsophalangeal joints existed between American Indians with and without diabetes. Three groups of American Indian subjects were tested: a control group (n = 20); a group with diabetes but no peripheral neuropathy (n = 24); and a group with diabetes and peripheral neuropathy (n = 21). A floor-mounted pressure sensor platform was used to collect plantar pressure data while subjects walked barefoot. The results indicated that American Indians with diabetes have 1) a pattern of peak plantar pressure similar to patterns previously reported for non-American Indians with diabetes and 2) a reduction in ankle and first metatarsophalangeal joint range of motion in comparison with nondiabetic American Indians.

Athletic footwear: design, performance and selection issues.

The purpose of this paper is to assist the practitioner in understanding the various advantages and disadvantages associated with the use of athletic footwear. In addition, the various components of a typical athletic shoe are described, including the upper, the midsole/outsole, the last, as well as the lasting process. Since the various models of athletic shoes that are available to the consumer can change in a very rapid and unpredictable manner, it is extremely difficult for the clinician to maintain a database of current shoe models and features. This paper stresses the importance of the clinician providing the athlete a list of footwear features and components based on their particular foot classification or problem, rather than attempting to recommend a specific model of athletic shoe. A detailed explanation of these features is provided to assist the practitioner in helping the athlete select the most appropriate shoe.

Velocity of the center of pressure during walking.

The purpose of this study was to describe the velocity of the center of pressure during walking in a sample of young, healthy individuals. The velocity of the center of pressure was recorded in 60 subjects while they walked barefoot over a floor-mounted pressure platform. The results of this study indicate that the velocity of the center of pressure follows a predictable pattern during the stance phase of walking. Intraclass correlation coefficients calculated to measure between-trial reliability for specific parameters of the velocity of the center of pressure ranged from 0.361 to 0.912. These study results suggest that velocity of the center of pressure may be a useful measurement in future gait research.

The effect of foot orthoses on transverse tibial rotation during walking.

The purpose of this study was to determine the effectiveness of two types of foot orthoses in controlling the magnitude and rate of internal tibial rotation, measured by the tibial pointer device, during walking. Ten subjects between the ages of 23 and 43 years volunteered to participate in the study. Prior to data collection, each subject was issued two types of foot orthoses: a pair of rigid, plastic orthoses with posting in either the forefoot or the rearfoot, and a pair of soft, accommodative, premolded orthoses with no posting. All subjects wore standardized footwear. Following a controlled break-in period for both footwear and orthoses, each subject was asked to walk at a self-selected speed over a 12-m walkway while the movement of internal tibial rotation was recorded with a video camera during five trials. The results indicated that both the rigid plastic and the accommodative foot orthoses significantly reduced the magnitude and the rate of internal tibial rotation. No significant difference was noted between the soft and rigid foot orthoses conditions.

Plantar fasciitis: etiology and treatment.

Plantar fasciitis is a common pathological condition of the foot and can often be a challenge for clinicians to successfully treat. The purpose of this article is to present and discuss selected literature on the etiology and clinical outcome of treating plantar fasciitis. Surgical and nonsurgical techniques have been used in the treatment of plantar fasciitis. Nonsurgical management for the treatment of the symptoms and discomfort associated with plantar fasciitis can be classified into 3 broad categories: reducing pain and inflammation, reducing tissue stress to a tolerable level, and restoring muscle strength and flexibility of involved tissues. Each of these treatments has demonstrated some level of effectiveness in alleviating the symptoms of plantar fasciitis. Previous studies have grouped all forms of nonsurgical therapy together. It is, therefore, difficult to determine if one type of treatment is more effective compared with another. Until such research is available, the clinician would be wise to include treatments from all 3 categories.

Variability of plantar pressure data. A comparison of the two-step and midgait methods.

The number of trials required to obtain a reliable representation of the plantar pressure pattern is an important factor in the assessment of people with insensate feet or the use of plantar pressure data as a basis for fabrication of foot orthoses. Traditionally, the midgait method has been used for the collection of pressure data, but the large number of walking trials required by this method can increase the risk of injury to the plantar surface of the insensate foot. As a result, the two-step method of plantar pressure data collection has been advocated. The purpose of this investigation was to determine the degree of variability in regional plantar pressure measurements using the midgait and two-step methods of data collection. Plantar pressure data were collected from ten volunteers (five men and five women) between the ages of 20 and 35 years in 20 trials using both data-collection protocols. The results of the study indicate that three to five walking trials are needed to obtain reliable regional peak pressure and pressure-time integral values when the two-step data-collection protocol is used. Although either method can be used for pressure data collection, one method should be used consistently when repeated assessments are required.

Relative movement of the navicular bone during normal walking.

The purpose of this study was to determine the pattern and magnitude of navicular bone (NB) movement during walking as well as the relationship between dynamic NB and rearfoot movement. The angle of rearfoot and displacement of the NB was recorded in 106 subjects using the 6D Research electromagnetic tracking system. The relative change in the height of the NB between foot flat and heel-off was 7.9 mm. The NB seems to undergo significant vertical as well as medial displacement during the stance phase of normal walking. This motion is also correlated with rearfoot motion during walking.

Effect of ankle dorsiflexion range of motion on rearfoot motion during walking.

The purpose of this study was to investigate whether the amount of ankle passive dorsiflexion range of motion influences the pattern of frontal plane rearfoot motion during walking. Three-dimensional motion of the rearfoot was measured in two groups of subjects, those with ankle passive dorsiflexion range of motion less than or equal to 10 degrees, and those with ankle passive dorsiflexion range of motion greater than 15 degrees, while they walked along a 6.1-m walkway. The results indicated that the only statistically significant differences between the two groups were in the time to reinversion of the rearfoot and the time to heel-off. Slight-to-moderate limitation of ankle passive dorsiflexion range of motion significantly alters the timing, but not the magnitude, of frontal plane rearfoot motion during walking.

Three-dimensional movement of the foot during the stance phase of walking.

This study presents research on typical movement of the rearfoot during walking. The data demonstrate the global nature of foot pronation and supination during gait. Study participants (N = 153) walked along a walkway while the angular displacement of the calcaneus, navicular, and first metatarsal relative to the tibia was measured; three-dimensional movement patterns for all three bones were very similar. This study provides additional information on how the foot functions during walking. This information should help to define and refine clinical management strategies for treating foot dysfunction.

Variability of the center of pressure pattern integral during walking.

The objective of this study was to measure the between-trial variability of the center of pressure pattern integral (COPPI) at the shoe-floor interface and within the shoe. Ten trials of the COPPI were recorded simultaneously at the shoe-floor interface and within the shoe as ten subjects walked over ground in standardized footwear and with two types of foot orthoses. While the results showed that the within-shoe shoe-only and soft orthoses conditions caused the greatest decrease in the COPPI, it was extremely inconsistent-between trials, whether measured at the shoe-floor interface or within the shoe. This suggests that the COPPI is not an acceptable method of assessing the effectiveness of foot orthoses.

A comparison of two motion analysis systems for the measurement of two-dimensional rearfoot motion during walking.

The purpose of this study was to compare two-dimensional rearfoot motion during walking measured by a traditional video-based motion analysis system to that of an electromagnetic analysis system. Twenty-five individuals (15 men, 10 women) with a mean age of 29.8 years served as subjects for this study. The results of the study showed that there was a high correlation (r = 0.945) between the mean motion paths produced by the two systems, indicating that they were very similar. The electromagnetic motion analysis system was able to produce these similar results in a fraction of the time required by the video-based system.

The relationship between static lower extremity measurements and rearfoot motion during walking.

Despite the fact that clinicians regularly perform static lower extremity measurements on their patients, to date, little research has been published supporting their ability to predict dynamic rearfoot motion. The abilities of static measurements to predict dynamic foot motion could have important implications considering the fact that excessive rearfoot motion has been associated with various injuries of the lower extremity. The purpose of this study, therefore, was to determine if static lower extremity measurements could be used to predict the magnitude of rearfoot motion during walking. Rearfoot motion of each lower extremity was measured from videotape in 27 healthy young adult subjects with a mean age of 26.1 years. In addition, 17 static measurements were measured and recorded bilaterally for each subject. The results of a multiple regression analysis indicated that the only variable that was able to predict maximum rearfoot pronation was the "difference in navicular height" (r2 = .17). None of the 17 measurements were found to predict time to maximum pronation. These results indicate that static measurements of the lower extremity and foot are poor predictors of dynamic rearfoot motion as measured by maximum pronation or time to maximum pronation in healthy individuals without severe foot deformities.

Relationship between three static angles of the rearfoot and the pattern of rearfoot motion during walking.

The purpose of this study was to determine the relationship of the static angle of the rearfoot during single leg standing, relaxed standing foot posture, and subtalar joint neutral position with the pattern of rearfoot motion during walking. The authors felt that this study was important to gain a better understanding of the relationship between dynamic rearfoot motion and three static rearfoot angles which are often included in foot examination procedures. The pattern of rearfoot motion was assessed using two-dimensional video recordings for each lower extremity of 31 healthy young adult subjects with a mean age of 25.2 years. The mean path of rearfoot motion during walking crossed relaxed standing foot posture but did not cross single leg standing or subtalar neutral position. These findings suggest that the mean path of rearfoot motion during the first 60% of the walking cycle occurs between the static angles of relaxed standing foot posture and single leg standing. In addition, the static angle of the rearfoot in single leg standing may serve as a clinical indicator of the degree of maximum rearfoot eversion occurring during the walking cycle.

Variations in foot volume before and after exercise.

Foot volume measurements were taken on 12 feet of nine female intercollegiate volleyball players (mean age of 20 years) before and after a 2-hr rigorous practice session. No significant difference was found between foot volume before and after exercise. A slight reduction in the foot volume after exercise was noted in comparison with the foot volume before exercise. These findings suggest that fitting footwear with extra space in front of the longest toe to accommodate changes in foot length associated with foot volume increases following exercise is not necessary. However, providing extra space in front of the longest toe during shoe fitting should still be considered in order to accommodate anterior sliding of the foot during athletic activities.

A comparison of the dynamic pedobarograph and EMED systems for measuring dynamic foot pressures.

The purpose of this study was to compare the peak pressure and peak force values obtained from two pressure assessment systems, the Dynamic Pedobarograph and the EMED SF. Twenty-one individuals with a mean age of 31.6 years walked barefoot over both systems using a two-step data collection protocol. Peak plantar pressures and peak vertical force values were measured under the heel, central forefoot, hallux, and entire foot for both systems. The results of this study demonstrated that the EMED SF system produced larger peak pressures under the central forefoot and hallux. The Pedobarograph, on the other hand, produced greater pressures under the heel and entire foot. With respect to peak vertical forces, the Pedobarograph showed significantly greater values under the heel and central forefoot compared with the EMED SF, but were significantly lower under the hallux and entire foot.

Footwear and foot orthotic effectiveness research: a new approach.

Measurement of calcaneal inversion and eversion during walking is limited when subjects wear shoes. The authors of this study propose the use of transverse tibial rotation as a viable alternative measurement when barefoot assessment is not possible. The purpose of this study, therefore, was to: 1) determine the relationship between transverse tibial rotation and rearfoot motion during the stance phase of normal walking and 2) demonstrate the usefulness of measuring transverse tibial rotation when evaluating the effect of footwear and insole foot orthotic devices. Part 1 consisted of eight volunteers (five women, three men) whose rearfoot and transverse tibial motion was videotaped while they walked along a 12-m walkway. The results of this study showed that although absolute values were not comparable, the two motion patterns are related to each other. The correlation between the mean rearfoot and tibial motion patterns of all 16 feet was r = .953. Part 2 investigated the effect of footwear and orthotics on transverse tibial rotation using two case presentations. A video camera was positioned in front of each subject as they walked at a self-selected speed under various footwear or orthotic conditions. The results of the case studies revealed that footwear or foot orthotics decrease maximum tibial internal rotation compared with barefoot walking. In addition, internal tibial rotation velocity and acceleration were decreased by the use of shoes, an accommodative orthosis, and an inflatable medial longitudinal arch support. A rigid orthotic produced a slight increase in transverse tibial rotation and a dramatic increase in transverse tibial acceleration.(ABSTRACT TRUNCATED AT 250 WORDS)