Pedobarography

Number: 0294

Table Of Contents

Policy
Applicable CPT / HCPCS / ICD-10 Codes
Background
References

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Policy

Scope of Policy

This Clinical Policy Bulletin addresses pedobarography.

1. Experimental and Investigational

   Aetna considers pedobarography (foot pressure studies) experimental and investigational because there are no reliable evidence in the medical literature demonstrating the value of pedobarography in improving the diagnosis and management of foot conditions and improving health outcomes.

2. Related Policies

   • CPB 0263 - Gait Analysis and Electrodynogram

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Table:

CPT Codes / HCPCS Codes / ICD-10 Codes

Code	Code Description
Information in the [brackets] below has been added for clarification purposes.   Codes requiring a 7th character are represented by "+":
CPT codes not covered for indications listed in the CPB:
96001	Comprehensive computer-based motion analysis by video-taping and 3-D kinematics; with dynamic plantar pressure measurements during walking
Other CPT codes related to the CPB:
96000	Comprehensive computer-based motion analysis by video-taping and 3-D kinematics
96002	Dynamic surface electromyography, during walking or other functional activities, 1-12 muscles
96003	Dynamic fine wire electromyography, during walking or other functional activities, 1 muscle
96004	Review and interpretation by physician or other qualified health care professional of comprehensive computer-based motion analysis, dynamic plantar pressure measurements, dynamic surface electromyography during walking or other functional activities, and dynamic fine wire electromyography, with written report
Other HCPCS codes related to the CPB:
L1900 - L1990	Ankle-foot orthosis (AFO)
L3000 - L3649	Orthopedic shoes
ICD-10 codes not covered for indications listed in the CPB (not all inclusive):
E10.40 - E10.49	Type 1 diabetes mellitus with neurological complications
E11.40 - E11.49	Type 2 diabetes mellitus with neurological complications
E13.40 - E13.49	Other specified diabetes mellitus with neurological complications
G99.0	Autonomic neuropathy in diseases classified elsewhere
I83.001 - I83.029	Varicose veins of lower extremities with ulcer
I83.201- I83.229	Varicose veins of lower extremities with both ulcer and inflamation
L89.500 - L89.529	Pressure ulcer of ankle
L89.600 - L89.629	Pressure ulcer of heel
L89.890 - L89.899	Pressure ulcer of other site
M19.071 - M19.079	Primary osteoarthritis ankle and foot
M19.271 - M19.279	Secondary osteoarthritis, ankle and foot
M41.00 - M41.9	Scoliosis
Z46.89	Encounter for fitting and adjustment of other specified devices
Z47.81 - Z47.89	Encounter for other orthopedic aftercare

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Background

Pedobarography refers to dynamic measurements of the pressure distribution on the bottom of the foot through all stages of the gait cycle.  It has been used to study weight-bearing foot function both in health and disease.

The Podia-Scan system (Sensor Products Inc., East Hanover, NJ) has been used to measure static plantar foot pressure distribution, and create images of pressure distribution across the plantar surface.  It consists of a sensing mat, scanner and image analysis software.  The system produces a color representation of the sole of the foot.

According to the manufacturer, the Podia-Scan system can be used for a wide variety of indications, e.g., to identify areas of potential ulceration, aid in the prescription of foot orthoses, determine the degree of pronation and supination, screen patients with diabetic peripheral neuropathy and other neuropathies, evaluate patients before and after surgery, regulate weight bearing after surgery, monitor degenerative foot disorders, assess orthotic efficacy, and detect scoliosis.

There is, however, inadequate evidence in the peer-reviewed published medical literature demonstrating the value of pedobarography for each of these indications.

Tuna et al (2005) compared probable plantar pressure alterations in patients with rheumatoid arthritis (RA) with normal subjects and examined the relation between pressure distribution under the foot and radiological foot erosion score.  A total of 200 feet of 50 chronic RA patients and 50 healthy controls were evaluated.  Static and dynamic pedobarographical evaluations were used to define the plantar pressure distribution.  Furthermore, the modified Larsen scoring system was used to detect the staging of erosions on feet radiograms of patients with RA.  Static pedobarography revealed higher pressure and contact areas in the fore-foot.  All dynamic pedobarographical parameters except for plantar contact area were significantly different between patients with RA and control subjects.  Patients with high erosion scores had higher static fore-foot and dynamic phalanx peak pressure values.  These investigators concluded that pedobarographical examination can be useful to assess pressure distribution disorders in RA feet and may provide suitable guidelines for the design of various plantar supports.

Kul-Panza and Berker (2006) assessed pedobarographical findings and balance in patients with knee osteoarthritis (OA).  A total of 48 patients with knee OA and 30 controls were included in this study.  Pedobarographical measures were obtained from all patients and controls.  Pain intensity of patients was measured using the visual analog scale (VAS).  The percentage of pressure on fore-foot and hind-foot was measured using static pedobarography, and the peak pressures at fore-foot, mid-foot, and hind-foot were measured using dynamic pedobarography.  The center-of-pressure sway length and width were measured for evaluation of balance.  The percentage of right hind-foot pressure (p < 0.05) and peak pressure of the right fore-foot during walking were lower in the OA group than in the control group (p < 0.05).  The sway width in the OA group was higher than in the control group (p < 0.05).  The VAS score at rest was negatively correlated with peak pressures of both right and left hind-feet in the OA group (p < 0.05).  The grade of OA was positively correlated with sway length and sway width (p < 0.05).  These authors concluded that pedobarography may become a useful technique to determine foot pressures that change because of disturbed weight-bearing and balance problems in patients with knee OA.

Schmiegel et al (2008) evaluated the use of pedobarographic measurements for detecting changes in plantar loading characteristics and their relationship to foot pain in patients with RA.  A total of 112 patients with RA (55.0 +/- 11.0 years of age) were divided into 3 groups according to their Health Assessment Questionnaire (HAQ) Score and compared to a control group of 20 healthy adults (CG).  Thirty-six patients with good physical capacity belonged to group 1 (RA1; HAQ-score: 0 - 1.0), 38 patients with moderate capacity to group 2 (RA2; score: 1.1 - 2.0) and 38 patients with low capacity to group 3 (RA3; score: 2.1 to 3.0).  Each patient's foot pain was clinically assessed.  Pedobarography was used to analyze foot loading parameters while walking barefoot.  In the forefoot, average pressures under the lateral forefoot were higher in RA1 patients than in RA2 patients and controls (p < 0.05) despite an inconspicuous clinical examination of the foot in RA1 patients.  RA1 patients also demonstrated higher plantar pressures than RA2 under the second metatarsal head (p < 0.05).  In contrast, no significant differences in maximum force could be demonstrated between patient groups.  Furthermore, in RA3 patients with lower physical capacity, foot pain was increased as compared to RA1 and RA2 patients.  The authors concluded that in RA patients, pedobarographic patterns show specific changes which characterize the level of functional capacity.  In patients with foot involvement, pedobarographic measurements can be useful during the earlier stages of the disease, when clinical examination does not yet indicate the need for more aggressive treatment or orthopedic interventions.  However, it has yet to be proven that pedobarographic measumrents would improve the management of patients with RA.

Charles et al (2001) examined if pedobarographic outcomes correlated with those post-operative results and if the dynamic pedobarography provided useful information in the functional evaluation of cavovarus feet.  A total of 16 patients with cavovarus foot deformity (mean age of 32.8 years, range of 17 to 56) with a total of 21 feet were examined before and after surgery.  The average follow-up time was 24 months (range of 6 to 50).  The study protocol included physical examination, angle measurements on weight-bearing radiographs and dynamic pedobarography.  Patients performed 5 trials at self-selected speed for each foot.  The amount of correlation was established between: plantar peak pressure pattern and patient's subjective functional result, the evidence of callosities and increased peak pressures in fore-foot and mid-foot regions of interest, the change of calcaneal pitch or Hibbs' angle (first metatarsal - calcaneal axis) and the mid-foot contact area.  The patient's functional opinion and pedobarographic improvement of peak pressures correlated in 7 feet, the patients estimated the result better in 13 feet and worse in 1 foot.  In 4 regions of interest, callosities and increased peak pressures occurred together in 69 % of the cases, in 15.5 % callosities were observed without augmented peak pressures and in 15.5 % increased peak pressures were measured without evidence of callosities.  No correlation was found between radiographical and pedobarographical parameters which describe a reduction of the cavus deformity: calcaneal pitch angle and mid-foot contact area (Pearson correlation coefficient, r = -0.36), Hibbs' angle and mid-foot contact area (r = 0.55), although all parameters changed significantly (p = 0.001).  The authors stated that pre- and post-operative assessment of the cavovarus foot is mainly based on static methods such as clinical and radiographical evaluation.  The results of this study demonstrated that the dynamic measurement of plantar peak pressures and contact area offers limited information about functional and anatomical improvement after surgery.  Patients with severe deformities and muscular discoordination have difficulties walking consistently on the platform at each trial and severe decrease of plantar contact area makes the exact positioning of the masks difficult, which leads to problems with standardized measurements.  In this context, the dynamic pedobarography can not be used as a profitable diagnostic tool that provides an objective measurement that can add a dynamic component to a clinical or radiographical examination.

Chan et al (2007) used dynamic pedobarography to study pressure distribution patterns in the foot after surgical correction of cavovarus feet.  These researchers also assessed the influence of ankle power generation on pressure distribution in these feet.  A total of 9 children (14 feet) diagnosed with Charcot-Marie-Tooth disease who had undergone operative treatment with a combination of osteotomies and muscle transfers were the subjects of this study.  Pre- and post-operative pedobarographic measurements recorded included pressure over the medial fore-foot, lateral fore-foot, medial mid-foot (MMF), lateral mid-foot (LMF), and heel segments.  In 6 patients (9 feet) who had a complete gait analysis, the power generation of the ankle was also obtained both pre-operatively and post-operatively.  Lateral radiographical measurements included

1. the talus-first metatarsal angle,
2. the calcaneus-first metatarsal angle, and
3. the calcaneal pitch.

The radiographs showed significant improvements in all 3 angles.  Increased LMF and decreased fore-foot pressures were seen on pre-operative pedobarographic measures.  Post-operatively, improvement in pressure at the LMF was seen.  When post-operative measurements were compared with the normal values, only the LMF was similar; the other 4 segments showed decreased fore-foot and MMF pressures and increased heel pressures (p = 0.000 for the lateral fore-foot and MMF; p = 0.040 for the heel and medial fore-foot).  The heel pressures displayed an inverse relationship to ankle power generation.  The amount of correction achieved radiographically did not correlate with pedobarographic measurements.  The increased heel pressure that was noted was not addressed by treatment.  Normalization of pressure patterns should be the goal in treating children with symptomatic cavovarus feet.  Although the foot deformity is corrected completely in neuromuscular disorders, pressure distribution was not normalized, and therefore, symptoms might persist. Both patients and parents should be informed about this possible problem before surgical intervention.

Jameson et al (2008) stated that although pedobarography has been widely used in quantitative clinical gait analysis for children, the collection, processing, analysis, and interpretation of the data vary widely.  In most cases in children, foot dysfunction during gait is primarily a consequence of skeletal segmental mal-alignment, which can be characterized by the location and duration of the center of pressure progression (COPP) relative to the foot.  This study determined the validity and reliability of a technique using the COPP and established a normative database for the COPP in children.  Simultaneous pedobarograph and kinematic data collection was performed on 23 children (46 feet) who were neurologically healthy.  The validity of the COPP technique was determined by comparing the pedobarograph-based and kinematic-based determinations of the orientation of the longitudinal (or long) axis of the foot, an essential component of the COPP approach.  Intra-rater and inter-rater reliability for the pedobarograph-based technique were determined by comparing repeated measures of the long axis of the foot from 4 analysts.  Normative data for the location and duration of the COPP were generated from this cohort of neurologically healthy children.  The mean difference for the long axis of the foot between the pedobarograph-based and kinematic-based methods was 2.3 degrees (p < 0.001).  The mean difference between first and second determinations of the long axis of the foot by the same analyst was 1.0 degrees (p < 0.001; correlation coefficient, 0.975).  The mean difference between the 4 analysts' determinations of the long axis of the foot was 1.9 degrees (p < 0.001; correlation coefficient, 0.969).  The normal COPP is located under the heel segment for 23.7 % of stance, under the mid-foot segment for 28.7 % of stance, and under the fore-foot segment for 47.5 % of stance.  The authors concluded that this study established clinically acceptable validity and reliability for the pedobarograph COPP technique and determined the location and duration of the COPP in a cohort of neurologically healthy children.  This standardized approach to the determination of foot loading patterns, based upon normative data, should facilitate the characterization of abnormal foot loading patterns, clinical decision making, and the assessment of outcome after a variety of interventions.

Richter and Zecj (2009) evaluated the clinical use, and analyzed the potential clinical benefit of intraoperative pedography (IP) in a sufficient number of cases in comparison with cases treated without IP.  Patients (aged 18 years and older) who sustained an arthrodesis and/or correction of the foot and ankle were included.  A total of 100 cases were included (ankle correction arthrodesis, n = 12; subtalar joint correction arthrodesis, n = 14; arthrodesis without correction midfoot, n = 15; correction arthrodesis mid-foot, n = 26; correction fore-foot, n = 33).  Fifty-two patients were randomized for the use of IP.  In 24 of the 52 patients (46 %), the correction was modified after IP during the same operation.  The authors concluded that in 46 % of the cases a modification of the surgical correction was made after IP in the same surgical procedure.  The authors stated that Wwhether IP improve the plantar force distribution of the foot and the mid- or long-term clinical outcome has to be critically analyzed when longer follow-up is completed.

Rongies et al (2009) assessed the progress of a selected model of rehabilitation on the basis of subpedal pressure distribution and center of gravity sway in pedobarographic examination and evaluated changes in pain intensity in patients with a history of coxarthrosis.  The study included 21 patients with Altman grade 2 coxarthrosis.  A postural pedobarographic examination was performed immediately before and after a 15-day course of rehabilitation with a PEL 38 electronic pedobarograph and computer image analyser with TWINN 99 software, version 2.08.  Following the rehabilitation, the study group displayed a statistically significant reduction in pain intensity, improved balance between the average and maximum subpedal pressures of both feet as well as a decrease in the velocity of center of gravity sway.  The authors concluded that

1. a correlation between reduced pain intensity and improved balance of loads on both feet, as well as decreased velocity of center of gravity sway were observed in the study group after the rehabilitation,
2. the pedobarographic examination may become a new method of diagnosis and follow-up in rehabilitation,
3. pedobarography, owing to its ease of repeatability and non-invasiveness, may constitute a valuable attempt at objective monitoring of the progress of rehabilitation and its results, and
4. the study results encourage further research based on a larger cohort of patients and a control group with a multi-stage prospective design.

Sinclair et al (2009) noted that current methods of treating congenital clubfeet provide high rates of functional outcomes.  Despite the clinical outcomes, radiographical assessment suggests residual equinus deformity of the hindfoot.  It is unclear if these deformities result in abnormal foot-floor pressures and if they correlate with clinical outcome.  These researchers evaluated 28 feet in 20 patients following Ponseti treatment for clubfoot by clinical and pedobarographic examination a mean of 33 months after removal of the last cast.  The data were compared to age-matched and weight-matched normal subjects and to the unaffected foot in the unilaterally affected patients.  Despite ankle range of motion of 30 degrees and a physiological hind-foot valgus alignment in 19 cases, pedobarography suggested differences in maximum force, impulse, contact area, and peak pressure compared to normal subjects.  Compared to the unaffected foot the only difference was reduced peak pressure over the medial hind-foot and fore-foot with increased pressure over the lateral mid-foot.  Similar to radiographical abnormalities in studies on treated clubfeet with good functional outcome, pedobarographic analyses show differences compared to a control group.  The authors stated that the value of pedobarographic analysis for predicting successful treatment of congenital clubfoot is questionable since it does not correlate with the clinical outcome in patients treated with the Ponseti method.

Paul et al (2013) quantitatively characterized plantar pressure distribution in women affected by Ehlers-Danlos syndrome of the hypermobile type (EDS-HT) to verify the existence of peculiar patterns possibly related to postural anomalies or physical and functional lower limb impairments typical of this disease.  A sample of 26 women affected by EDS-HT (mean age of 36.8; SD 12.0) was tested using a pressure platform in 2 conditions:

1. static standing and
2. walking.

Raw data were processed to assess contact area and mean and peak pressure distribution in rear-foot, mid-foot and fore-foot.  Collected data were then compared with those obtained from an equally numbered control group of unaffected women matched for age and anthropometric features.  The results showed that, in both tested conditions, women with EDS-HT exhibited significantly smaller fore-foot contact areas and higher peak and mean pressure than the control group.  No differences in the analyzed parameters were found between right and left limb.  The authors concluded that the findings of the present study suggested that individuals with EDS-HT are characterized by specific plantar pressure patterns that are likely to be caused by the morphologic and functional foot modification associated with the syndrome.  They stated that the use of electronic pedobarography may provide physicians and rehabilitation therapists with information useful in monitoring the disease's progression and the effectiveness of orthotic treatments.  These preliminary findings from a small uncontrolled study need to be validated by well-designed studies.

Fang and colleagues (2013) examined the diagnostic significance of foot plantar pressure distribution abnormalities in patients with diabetic peripheral neuropathy (DPN).  A total of 107 patients were divided into 3 groups:

1. normal control (28 participants, 56 feet),
2. non-DPN (56 patients, 112 feet), and
3. DPN groups (23 patients, 46 feet).

Foot plantar pressure was measured while patients walked at a constant speed over a flat floor using F-Scan pressure insoles.  Recordings of 6 middle strides were averaged to evaluate the characteristics of foot plantar pressure distribution.  Compared with the normal group, the time of contact (TOC) was longer in non-DPN (p < 0.05) and DPN groups (p < 0.01).  The foot-to-floor force-time integral (FTI) was increased in DPN group (p < 0.01).  The fore-foot plantar force ratio increased in non-DPN and DPN patients (p < 0.05).  Moreover, in DPN patients, the ratio of lateral foot plantar force increased (p < 0.05).  The examination of the correlations between biomechanical parameters of the foot plantar and electrophysiological parameters of the lower limbs showed foot plantar biomechanical abnormalities correlated with abnormal sensory conduction of the sural nerve and motor conduction of the common peroneal nerve.  Receiver operating characteristic (ROC) analysis showed the area under FTI curve was 0.714 (p < 0.001).  The authors concluded that the plantar pressure was shifted towards the side of the fore-foot in DPN patients.  The foot plantar biomechanical changes were closely correlated with lower limb paresthesia and contraction abnormalities of lower-limb extensor muscles.  They stated that foot plantar pressure measurement might be used as a screening tool for early diagnosis of DPN.  These findings need to be validated by well-designed studies.

In a systematic review and meta-analysis, Fernando et al (2013) examined the effect of DPN on gait, dynamic electromyography and dynamic plantar pressures.  Electronic databases were searched systematically for articles reporting the effect of DPN on gait, dynamic electromyography and plantar pressures.  Searches were restricted to articles published between January 2000 and April 2012.  Outcome measures assessed included spatiotemporal parameters, lower limb kinematics, kinetics, muscle activation and plantar pressure.  Meta-analyses were carried out on all outcome measures reported by greater than or equal to 3 studies.  A total of 16 studies were included consisting of 382 neuropathy participants, 216 diabetes controls without neuropathy and 207 healthy controls.  Meta-analysis was performed on 11 gait variables.  A high level of heterogeneity was noted between studies.  Meta-analysis results suggested a longer stance time and moderately higher plantar pressures in DPN patients at the rear-foot, mid-foot and fore-foot compared to controls.  Systematic review of studies suggested potential differences in the biomechanical characteristics (kinematics, kinetics, EMG) of diabetic neuropathy patients.  However these findings were inconsistent and limited by small sample sizes.  The authors concluded that current evidence suggested that patients with DPN have elevated plantar pressures and occupy a longer duration of time in the stance-phase during gait.  Moreover, they stated that firm conclusions are hampered by the heterogeneity and small sample sizes of available studies.

Kluger et al (2014) introduced a so-called "neutral shoe" as a tool to assess reference values for dynamic pedobarographic investigations.  A total of 12 healthy volunteers were asked to participate.  During the first trial the participants were asked to walk with a neutral shoe (Breidbach, Germany).  The second trial was performed with the running shoe "Faas 500" (Puma SE, Germany).  Peak plantar pressure values were analyzed from 9 foot regions using the Pedar^® X system (Novel Inc., Munich, Germany).  The mean peak pressure reduction for the total foot was 36 % under the left (non-preferred) foot and 32 % for the right (preferred) foot.  A statistically significant reduction of peak pressure was observed for 8 regions, from a mean 14 % peak pressure reduction under the right metatarsal head 1 up to a 41 % peak pressure reduction under the right big toe.  The authors concluded that the neutral shoe is a feasible tool to assess reference values for dynamic pedobarography.  They stated that such a reference tool may help to standardize several steps in the development and construction of shoes and orthotic devices.

Choi et al (2014) noted that pedobarography can quantify static and dynamic foot pressure.  Despite an increase in the clinical use of pedobarography, the results and the clinical diagnosis do not always correlate, leading to confusion and misdiagnosis.  These investigators evaluated the potential of pedobarography to diagnose several diseases associated with abnormal pressure across the plantar surface.  The study included 72 patients (96 cases) between January 2009 and August 2012 with symptoms of excessive plantar pressure.  The average age was 50.9 years (range of 18 to 92).  Patients had the lesion for an average of 17 months (range of 8 to 29).  Pedobarographic measurements were used to evaluate the compatibility between the highest pressure on pedobarography and the clinical peak pressure with plantar ulcers or calluses.  Maximal peak pressure was evaluated by static and dynamic measurements using numeric and graphic measurements in pedobarography.  The diagnostic validity of pedobarography was analyzed by comparing clinical peak pressure and pedobarographic measurements.  The diagnostic validity of pedobarography was 17.7 % to 51 % for static measurement and 13.5 % to 49 % for dynamic measurement.  The diagnostic validity of pedobarography was low for intractable plantar keratosis and metatarsal head callus associated with metatarso-phalangeal dislocation in rheumatoid arthritis.  However, it was 57 % to 100 % for Charcot arthropathy with mid-foot ulcers.  When used to compare numeric pressure and graphic peak pressure for each part of the foot, pedobarography showed low diagnostic correlation.  The authors concluded that based on these findings, the diagnostic validity of pedobarography is low.

Skopljak et al (2014) noted that pedobarography as a new diagnostic tool enables measuring the pressure between the foot and the floor during dynamic loading.  Dynamic analysis of the foot shows advantage over static analysis due to its capabilities for detecting high load points in certain diseases and in certain phases of walking.  Pedobarography as a new method in the context of rehabilitation include wide range of clinical entities.  In a prospective study, these researchers showed the advantages of pedobarography as new diagnostic and rehabilitation method in prevention programs.  This trial included 100 patients with type 2 diabetes mellitus (T2DM).  Research was carried out in the Primary Health Care Center of the Sarajevo Canton and the Center for Physical Medicine and Rehabilitation.  The test parameters were: Test of balance -- symmetric load for the test, the number of co-morbidities, clinical examination of foot deformity, test with 10-g monofilament, HbA1c.  From the total sample 45 patients (Group I) were selected, aged 50 to 65 years, who underwent pedobarography (on the appliance Novel Inc., Munich with EMED™ platform) and robotic fabrication of individual orthopedic insoles, followed by control pedobarography.  Plantar pressure was determined using standard pedobarography, computer recorded parameters: peak pressure (kPa), force (Ns), area (cm).  The average age of the respondents was 59.4 ± 11.38 years; altered results on the balance test were present in 34 % of patients; 61 % of respondents had less than or equal to 2 co-morbidities.  In the total sample, the average number of foot deformity was 2.84; 66 % of respondents had flat feet, and 57 % had valgus position.  The average HbA1c values were 7.783 ± 1.58 % (minimum of 5 to maximum of 15.0). All subjects (n = 45) after the 1st, and after the 2nd measurement of peak pressure, had values above 200 kPa, or were in the designated zone of peak pressure that needs to be corrected.  The authors concluded that new diagnostic technology, pedobarography and manufacturing of orthopedic insoles allowed the prevention and reduction of symptoms, reducing load on the foot, and are of great importance for the patient suffering from diabetes in prevention programs.  This was a relatively small (n = 45) study in a specific population (patients with T2DM aged between 50 and 65 years); its findings need to be validated by well-designed studies.

Erickson and colleagues (2015) describe their radiographic and pedobarographic outcomes of surgical treatment of cavovarus foot deformity in children with Charcot-Marie-Tooth disease; 19 patients (30 feet) were included.  Pre-operative and post-operative dynamic pedobarographic measurements were made and analyzed using the 5-mask technique.  Pedobarographic measures showed statistical significance for increased contact area and decreased peak forces in most mask areas after surgical treatment.  Peak pressure and re-distribution of varus pressure patterns trended toward improvement.  The authors found pedobarographic studies helpful; however, pedobarographic data are somewhat difficult to interpret and should be used in addition to clinical and radiographic examination.

Genc and associates (2016) evaluated the benefits and importance of pedobarography in the diagnosis and treatment of plantar pressure changes in the post-operative follow-up of calcaneus fractures treated with open reduction and internal fixation.  The 28 patients included 23 males (82 %) and 5 females (18 %).  The clinical evaluation was performed using the American Orthopaedic Foot and Ankle Society hind-foot scoring system.  The Bohler and Gissane angles were measured on the pre-operative and post-operative radiographs.  In the post-operative follow-up period (mean ± standard deviation 22.25 ± 10.8 months), all the patients underwent analysis with a dynamic pedobarogram.  Because the arch index of the operated feet was 29.73 % and that of the non-operated feet was 28.94 %, a similar slightly low arch was seen in both feet (p = 0.078).  When the plantar surface maximum pressures were evaluated, a significant reduction was seen in the operated feet in the second, third, fourth, and fifth metatarsals and the medial hind-foot (p < 0.05).  Displaced intra-articular calcaneus fractures resulted in a significant reduction in maximum pressure of the second, third, fourth, and fifth metatarsals and the medial hind-foot.  Also, the hind-foot pressure was lateralized.  The authors concluded that pedobarography is a simple and useful method for the diagnosis of plantar pressure changes occurring post-operatively.  These preliminary findings need to be validated by well-designed studies.

Gurney and colleagues (2017) noted that the peripheral complications of diabetes mellitus remain a significant risk to lower-limb morbidity.  In New Zealand, risk of diabetes, co-morbidity and lower-limb amputation are highly-differential between demographic groups, particularly ethnicity.  There is growing and convincing evidence that the use of pedobarography can usefully inform diabetic foot care, particularly with respect to the prevention of re-ulceration among high-risk patients.  For the current feasibility study, these researchers embedded pedobarographic measurements into 3 unique diabetic foot clinic settings in the New Zealand context, and collected pedobarographic data from 38 patients with diabetes using a platform-based (Novel Emed) and/or in-shoe-based system (Novel Pedar).  Their objective was  to evaluate the feasibility of incorporating pedobarographic testing into the clinical care of diabetic feet in New Zealand.  These investigators observed a high response rate and positive self-reported experience from participants.  As part of their engagement with participants, these researchers observed a high degree of lower-limb morbidity, including current ulceration and chronic foot deformities.  The median time for pedobarographic testing (including study introduction and consenting) was 25 mins.  Despite working with a high-risk population, there were no adverse events (AEs) in this study.  In terms of application of pedobarography as a clinical tool in the New Zealand context, the current feasibility study led these researchers to believe that there are 2 avenues that deserve further investigation: First, the use of pedobarography to inform the design and effectiveness of off-loading devices among high-risk diabetic patients; and secondly, the use of pedobarography as a means to increase off-loading footwear and/or orthoses compliance among high-risk diabetic patients.  Both of these objectives deserve further examination in New Zealand via clinical trial.

The drawbacks of this feasibility study included: First, the accuracy of the response rate achieved in this study relied on self-report from the referring clinicians, who were asked to report to the research team when patients declined to participate.  It is feasible that, amidst a busy clinical environment, some clinicians did not report some declines – in which case, the high response rate gained in the current feasibility study may be an exaggeration.  On the other hand, given that the main reason patients gave for declining was time restriction (e.g., needing to leave immediately following the appointment to return to their job), it was possible that the response rate would have been higher than observed had patients been warned about the study in advance.  On balance, the authors believed that the response rate achieved was a relatively accurate reflection of the popularity of the pedobarographic test, and reflected the likely response rate that might be achieved in a full clinical trial.  Second, the questions asked of participants regarding their experience during data collection were not based on any previously validated questionnaires, and largely involved dichotomous (yes/no) responses (rather than Likert scales).  This was because these researchers were unable to find a validated questionnaire that addressed the relevant topics.

Sanders and associates (2020) stated that displaced intra-articular calcaneal fractures often result in permanent disability, reduced quality of life (QOL) and high socio-economic costs.  Since they often result in a change in geometry of the foot, pedobarography may be useful in predicting outcome at an early stage.  In a systematic review, these researchers examined if a correlation exists between pedobarography and functional outcomes in patients with a displaced intra-articular fracture.  Studies were included when they examined the correlation between pedobarography and functional outcome in displaced intra-articular calcaneal fractures.  Excluded were studies on less than 10 patients or on animals/cadavers.  Collected were baseline patient/treatment characteristics, pedobarographic data (peak pressures, maximum force and center of pressure) and functional outcome scores.  Out of 153 abstracts, 40 remained for full text screening and 9 were included.  Pedobarographic measurements (pressure plate or insoles) showed a lateralization of center of pressure, decreased pressures underneath the hind-foot, first and second toe and increased pressure underneath the mid-foot and fore-foot.  Correlations with functional outcome were found in some combined pedobarographic results (entire foot/multiple measurements), but hardly in pressures underneath specific foot areas.  The authors concluded that even though increased or decreased pressures in specific areas of the foot may not be directly related to functional outcome, combined scores often did.  These researchers stated that for pedobarography to serve as a prediction tool, it should be more standardized.

Fenwick and colleagues (2020) noted that fractures of the talus often lead to permanent restrictions of the affected limb.  Possible alterations after these fractures in gait have not been evaluated yet.  In a retrospective, single-center study, these researchers examined possible alterations of gait by pedybarography after talar fractures.  A total of 20 patients with operatively treated talar fractures were followed-up.  Objective and subjective function of the ankle was measured using range of motion (ROM), clinical scores and dynamic pedobarography.  There were 11 talar neck and 9 talar body fractures.  All patients received screw fixation.  There was a significant reduction in ROM.  The outcome was moderate to satisfying and the severity of the injury correlated with the clinical outcome and the ROM.  The presence of post-traumatic arthritis and joint incongruity led to a decreased function of ankle and subtalar joint and resulted in a worse clinical outcome.  Avascular necrosis (AVN) rate was associated to initial displacement; and dynamic pedobarography showed no significant changes in gait pattern.  The authors concluded that fractures of the talus led to dissatisfaction, pain and malfunction.  However, a change in gait pattern could not be proved.

Chatrenet and associates (2021) stated that peripheral neuropathy (PN) in patients with diabetes can lead to changes in the distribution of plantar pressure during walking, which can be recorded with pedobarography.  Compared to traditional spatial data reduction analysis, the pedobarographic Statistical Parametric Mapping (pSPM) allows comparison of the footprints with the advantage that sub-regions do not need to be defined a priori.  In a pilot study, these researchers examined the potential of pSPM in identifying specific distribution of spatial pressure in different stages of PN, which was defined according to usual tools (i.e., tendon reflexes and sensory tests).  Four groups were compared: patients with diabetes without PN (n = 24; 239 steps); with signs of mild PN (n = 12; 117 steps); with signs of severe PN (n = 6; 52 steps) and a control group without diabetes (n = 12; 124 steps).  Traditional spatial data reduction and pSPM were carried out to compare plantar pressures in the different groups.  In patients with PN, traditional spatial data reduction analysis showed lower plantar pressures with PN severity.  pSPM analysis was able to better define the initial changes: mild PN patients presented higher pressures on the anterior side of the metatarsal heads compared to patients without neuropathy.  Patients with severe PN were characterized by higher pressures under the medial foot arch compared to other groups.  The authors concluded that pSPM may identify specific features of plantar pressure distribution during walking in patients with mild PN and may become a useful screening tool for a timely identification of this complication.

de Castro and colleagues (2023) noted that areas of the foot with diabetic ulcers have been observed to have greater plantar pressures compared to non-ulcerated.  Pressures play an essential role in the mechanism of lesion, and their reduction is effective in prevention.  In a systematic review, these investigators examined pedobarography as a predictive tool for ulcer development, since there is still no consensus on this aspect.  They searched PubMed (Medline), Embase, Scopus, Web of Science, CINAHL and Scielo for cohort studies that measured plantar pressure at baseline and verified ulcer development on follow-up.  Pooled effects of accuracy, sensitivity, specificity and relative risk (RR) were calculated using the inverse variance method.  Risk of bias was evaluated using the QUADAS-2 tool.  A total of 3 studies (n = 2,000) had enough information on accuracy to be included into a meta-analysis, and 4 (n = 2,651) were analyzed using qualitative methods.  Pooled sensitivity and specificity were found to be 0.63 (confidence Interval [CI]: 0.58 to 0.68) and 0.42 (CI: 0.27 to 0.58), respectively.  Pooled relative risk was 1.95 (CI: 1.09 to 3.51).  Risk of bias was low-to-uncertain.  The authors concluded that pedobarography appeared to have low accuracy in evaluating risk of ulceration.  Several methodological heterogeneities were found, and the most optimal cut-off value has yet to be determined.

Ehrnthaller et al (2023) noted that orthoses are designed to achieve immobilization or off-loading of certain regions of the foot; however, their off-loading capacity for the specific regions has not yet been studied.  These researchers analyzed the plantar pressure distribution of 5 commonly applied orthoses for foot and ankle in a healthy population.  A total of 5 orthoses (post-operative shoe, forefoot relief shoe, short walker boot, high walker boot, and calcaneus fracture orthosis) were compared pedobarographically using insoles on a treadmill to a ready-made running shoe in 11 healthy subjects (median age of 29 years).  Peak pressure, maximum force, force-time integral, contact time, and contact area were evaluated separately for the forefoot, midfoot, and hindfoot.  The forefoot relief shoe, the short walker boot as well as the high walker boot significantly reduced the peak pressure at the forefoot with no significant differences between these orthoses.  None of the 5 orthoses off-loaded the midfoot; however, the calcaneus fracture orthosis and the short walker boot instead increased midfoot load.  For the hindfoot, the calcaneus fracture orthosis was the only device to significantly reduce the peak pressure.  The authors concluded that this was the 1st study to examine the specific off-loading capacities of different orthoses for specific foot regions in a healthy collective.  The knowledge of absolute and relative load shifts for the different orthoses is of fundamental interest for targeted clinical decision-making of physicians.  Moreover, these researchers stated that these findings need to be validated in larger healthy and patient cohorts.

The authors stated that 1 drawback of this trial was that only the orthosis-specific plantar pressure distribution was assessed, but not the ability of immobilization.  Some orthoses, especially the high walker boot, have fields of application due to their ability to immobilize the hind- and midfoot, that go beyond the plantar off-loading.  This aspect was not addressed in the present study.  In addition, these investigators retained the same sequence in testing the orthoses for each subject.  This held a potential bias.  Another drawback was the rather small sample size (n = 11) and the focus on healthy individuals.  Patients suffering from pain and/or gait insecurity might exhibit considerably different patterns of plantar pressure distribution; thus, it remained unclear, whether the present observations could be generalized to a clinical setting.

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