Heel pad thickness--a contributing factor associated with plantar heel pain in young adults

Functional Morphologic Changes of the Heel Fat Pad and Plantar Fascia in Patients With Heel Pain During Weightbearing and Nonweightbearing

Background

This study aimed to investigate the thickness changes of the heel fat pad and the plantar fascia associated with loading and unloading in healthy individuals and patients with heel pain and reveal the differences between them.

Methods

The study included adult male participants with (n = 9) and without (n = 26) heel pain. The participants placed their right foot on an evaluation apparatus with a polymethylpentene resin board (PMP), while their left foot was positioned on a weighing scale used to adjust the loading weight. The heel fat pad was differentiated into superficial Microchamber and deep Macrochamber layers. These layers and plantar fascia thickness were measured using an ultrasonographic imaging device at loading phase ranging from 0% to 100% of their body weight and unloading phase from 100% to 0%. Additionally, the study examined the thickness change ratios of the superficial and deep heel fat pad layers when the load increased from 0% (unload) to 100% (full load).

Results

In healthy individuals and patients with heel pain, no significant thickness changes were observed in the Microchamber layer of the heel fat pad or the plantar fascia during loading and unloading evaluations. However, significant thickness changes were observed in the Macrochamber layer of the heel fat pad, and the pattern of change differed between the loading and unloading phases. Additionally, patients with heel pain showed differences in the thickness change and thickness change ratios of the microchamber and macrochamber layers of the heel fat pad during both loading and unloading phases. The thickness of the plantar fascia did not show significant differences between both groups.

Conclusion

Compared with healthy individuals, in our relatively small study, patients with heel pain had greater deep fat pad compression in loading and less recovery after load removal. This finding suggests that these patients have different intrinsic fat pad function and related morphology than those without heel pain.

Level of Evidence

Level III, retrospective cohort study.

Autologous Whole-Blood Versus Corticosteroid Local Injection in Treatment of Plantar Fasciitis: A Randomized Single Blind Placebo-Controlled Study

BACKGROUND

Autologous whole-blood intralesional injection has attracted interest as a possible means of treatment for chronic plantar fasciitis. We contrasted its effectiveness with that of corticosteroids, which have a longer history of success in treating tendinopathies such as plantar fasciitis. In order to monitor the disease's progress naturally, we also compared them with a placebo.

METHODS

Sixty clinically diagnosed patients were taken up for intralesional injection of autologous whole blood (AWB), corticosteroid, and normal saline as placebo mixed with 2 mL of lignocaine after dividing them into three groups. Two doses were given and followed up in the third, sixth, and 12th weeks. The evaluation was done according to the visual analog scale (VAS) and the number of tablets of paracetamol (PCM) 500 mg consumed for the following period.

RESULTS

When compared to the placebo group in the third, sixth, and 12th weeks, the corticosteroid group exhibited a significant improvement with a p<0.001 in the VAS score, whereas the autologous whole blood group showed no meaningful difference. When compared to the placebo group at the sixth and 12th weeks, the AWB group's VAS score showed a statistically significant difference with a p>0.001. At each follow-up, the placebo group consumed more analgesics than the corticosteroid group, with a p<0.001. Only in the third week of follow-up did AWB demonstrate a statistically significant difference in PCM consumption as compared to the corticosteroid group.

CONCLUSION

Statistically significant improvement was seen in both the AWB group and corticosteroid group as compared to the placebo group. The corticosteroid group achieved earlier and superior relief of pain while AWB had a longer lasting effect. Therefore, study results indicate almost similar results in short-term studies.

Ultrasonographic Assessment of Indian Patients With Plantar Fasciitis and Its Clinical Correlation: A Prospective Observational Study

INTRODUCTION

Plantar fasciitis is a debilitating clinical condition and is one of the most common causes of heel pain. The risk factors include frequent and prolonged running, obesity, a sedentary lifestyle, work-related weight bearing, and inappropriate footwear. Ultrasonography being a non-invasive, cost-effective, and easily available modality is a useful adjunct in the diagnosis.

METHODS

A prospective observational study was conducted among 30 patients with unilateral plantar fasciitis. The diagnosis was based on history and examination. Heel pad thickness and plantar fascia thickness were recorded using ultrasonography.

RESULTS

The ultrasonography results showed increased plantar fascia and heel pad thickness in the affected limb with plantar fasciitis than the normal one (p<0.001). The BMI was positively correlated with the heel pad thickness (p<0.05). The receiver operating characteristic (ROC) curve showed 90% sensitivity and 60% specificity for heel pad thickness (p<0.001).

CONCLUSIONS

Ultrasonography is a sensitive and specific tool to identify patients with plantar fasciitis.

Ultrasonic Evaluation of the Heel Fat Pad Under Loading Conditions Using a Polymethylpentene Resin Plate: Part 2. Reliability and Agreement Study

Previously, we developed an instrument to evaluate the heel fat pad (HFP) two-layer structure, under varying loading conditions, with ultrasonography from the plantar surface through a polymethylpentene resin plate; the measured values were equivalent to those obtained without this plate. The study described here aimed to determine the intra- and inter-examiner reliabilities of the HFP thickness measurements and the agreement between long- and short-axis measured values using this instrument. Two examiners successively recorded the HFPs of 40 healthy adults twice under the no loading and loading conditions on the long- and short-axis scans. The HFPs were classified into two layers, and their thicknesses were measured. Short-term intra- and inter-examiner reliabilities were determined using the intraclass correlation coefficients. Measurements were repeated 1 mo later to determine the long-term intra-examiner reliability. The agreement between the measured long- and short-axis values was investigated by calculating the minimal detectable changes. The determined short- and long-term intra-examiner reliabilities ranged from 0.750 to 0.999 and from 0.765 to 0.952, respectively. Inter-examiner reliability ranged from 0.765 to 0.997. Differences may occur between the values measured at different axes. The measurements using this evaluation instrument were reliable, and it is best to unify the measurement axis for quantitative research.

Effect of plantar fascia-specific stretching and Achilles tendon stretching on shear wave elasticity of the plantar fascia in healthy subjects

BACKGROUND

The effect of stretching on the mechanical properties of the plantar fascia (PF) remain unclear. This study was performed to determine the effect of PF-specific stretching (PFSS) and Achilles tendon stretching (ATS) on the viscoelastic properties of the PF with shear wave elastography (SWE).

METHODS

We recruited 14 participants (8 men, 6 women) with no history of PF disorders or painful episodes. The mean age of the participants was 30.9 ± 4.8 (range, 25-41) years. All participants performed sustained PFSS (sPFSS) on one foot and intermittent PFSS (iPFSS) on the other foot. Two weeks later, all participants performed sustained ATS (sATS) on one foot and intermittent ATS (iATS) on the other foot. SWE measurements were performed immediately after each stretching.

RESULTS

The PF elasticity immediately before stretching ranged from 133.8 kPa to 144.7 kPa. The PF elasticity after stretching ranged from 158.9 kPa to 215.8 kPa. There was a significant increase in PF elasticity after sPFSS, iPFSS, sATS, and iATS (P < .01). The elasticity after sATS was greater than that after iATS (P = .03). In contrast, there were no differences in PF elasticity after stretching between sPFSS and iPFSS (P = .13), sPFSS and sATS (P = .17), or iPFSS and iATS (P = .50).

CONCLUSIONS

PF elasticity increased after stretching regardless of the frequency and type of PFSS and ATS.

LEVEL OF EVIDENCE

Level II, prospective cohort study.

Optimization Design of the Inner Structure for a Bioinspired Heel Pad with Distinct Cushioning Property

In the existing research on prosthetic footplates, rehabilitation insoles, and robot feet, the cushioning parts are basically based on simple mechanisms and elastic pads. Most of them are unable to provide adequate impact resistance especially during contact with the ground. This paper developed a bioinspired heel pad by optimizing the inner structures inspired from human heel pad which has great cushioning performance. The distinct structures of the human heel pad were determined through magnetic resonance imaging (MRI) technology and related literatures. Five-layer pads with and without inner structures by using two materials (soft rubber and resin) were obtained, resulting in four bionic heel pads. Three finite element simulations (static, impact, and walking) were conducted to compare the cushioning effects in terms of deformations, ground reactions, and principal stress. The optimal pad with bionic structures and soft rubber material reduced 28.0% peak vertical ground reaction force (GRF) during walking compared with the unstructured resin pad. Human walking tests by a healthy subject wearing the 3D printed bionic pads also showed similar findings, with an almost 20% decrease in peak vertical GRF at normal speed. The soft rubber heel pad with bionic structures has the best cushioning performance, while the unstructured resin pad depicts the poorest. This study proves that with proper design of the inner structures and materials, the bionic pads will demonstrate distinct cushioning properties, which could be applied to the engineering fields, including lower limb prosthesis, robotics, and rehabilitations.

Ultrasonic Evaluation of the Heel Fat Pad under Weight-Bearing Conditions Using a Polymethylpentene Resin Plate: Part 1

To evaluate the two-layer structure of the heel fat pad (HFP) from non-weight-bearing to full-weight-bearing conditions, we developed an instrument that assesses these changes from the sole through a polymethylpentene resin plate (PMP) with ultrasonography. For actual use, we investigated the influence on measured values and ultrasonogram appearance by interposing the PMP. Additionally, as the PMP may be bent under weight-bearing conditions, its influence on the measured values was investigated. First, two examiners measured the distances inside the phantom with and without a PMP. Second, ultrasonograms were obtained from 40 healthy adults with and without a PMP, and the thicknesses of the whole layer and the two layers of the HFP were measured using the same ultrasonogram. For each experiment, reproducibility was investigated. Third, the distances inside the phantom were measured and compared through the bent PMP, which models the weight-bearing condition, and the flat PMP. The reproducibility of the measurements was equivalent with and without the PMP interposed. Potential bias in measured values arising from deformation of PMP under weight-bearing conditions was not detected. Overall, the PMP's interposition and the bending of the PMP might not influence the measured values and reproducibility of the measurements.

Medical imaging for plantar heel pain: a systematic review and meta-analysis

Background

Medical imaging can be used to assist with the diagnosis of plantar heel pain. The aim of this study was to synthesise medical imaging features associated with plantar heel pain.

Methods

This systematic review and meta-analysis conducted searches in MEDLINE, CINAHL, SPORTDiscus, Embase and the Cochrane Library from inception to 12th February 2021. Peer-reviewed articles of cross-sectional observational studies written in English that compared medical imaging findings in adult participants with plantar heel pain to control participants without plantar heel pain were included. Study quality and risk of bias was assessed using the National Institutes of Health quality assessment tool for observational cohort and cross-sectional studies. Sensitivity analyses were conducted where appropriate to account for studies that used unblinded assessors.

Results

Forty-two studies (2928 participants) were identified and included in analyses. Only 21% of studies were rated ‘good’ on quality assessment. Imaging features associated with plantar heel pain included a thickened plantar fascia (on ultrasound and MRI), abnormalities of the plantar fascia (on ultrasound and MRI), abnormalities of adjacent tissue such as a thickened loaded plantar heel fat pad (on ultrasound), and a plantar calcaneal spur (on x-ray). In addition, there is some evidence from more than one study that there is increased hyperaemia within the fascia (on power Doppler ultrasound) and abnormalities of bone in the calcaneus (increased uptake on technetium-99 m bone scan and bone marrow oedema on MRI).

Conclusions

People with plantar heel pain are more likely to have a thickened plantar fascia, abnormal plantar fascia tissue, a thicker loaded plantar heel fat pad, and a plantar calcaneal spur. In addition, there is some evidence of hyperaemia within the plantar fascia and abnormalities of the calcaneus. Whilst these medical imaging features may aid with diagnosis, additional high-quality studies investigating medical imaging findings for some of these imaging features would be worthwhile to improve the precision of these findings and determine their clinical relevance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13047-021-00507-2.

The thickness of heel fat-pad in patients with plantar fasciitis

Objective

The aim of this study was to investigate the thickness of heel fat pad (THP) and to detect the relationship between the plantar fasciitis (PF) and age, occupation, BMI, longitudinal arch, the thickness of heel fat-pad in the patients with PF.

Methods

A total of 50 patients (29 women and 21 men; mean age: 46.5 years (range: 22–70)) that were diagnosed with PF were included to this study. Patients' affected side were compared with the healthy opposite side with the angle of medial arch (AMA) and first metatarsophalangeal angle (FMTPA) on the foot radiograms, and THP and thickness of first metatarsal fat pad (TFMFP) using ultrasonography (USG) of both feet.

Results

The mean AMAs of feet with pain and without pain were 122.56° and 120.60°, respectively. The mean FMTPAs of feet with pain and without pain were 14.72° and 14.40°, respectively. The mean THPs of feet with pain at the point of the medial calcaneal tubercle and the mean TFMFPs of the feet with pain at the point of the first metatarsal head were 19.45 mm and 6.75 mm, respectively. The mean THPs of feet without pain at the point of the medial calcaneal tubercle and the mean TFMFPs of the feet without pain at the point of the first metatarsal head were 19.94 mm and 6.75 mm, respectively. It was observed that the mean AMA in the heels with pain was significantly higher than that of the heel without pain (p < 0.05) and the mean THP in the heels with pain was significantly thinner than that of the heel without pain (p < 0.05).

Conclusion

The results indicate that USG is an accurate and reliable imaging technique for the measurement of THP in the diagnosis of plantar fasciitis and the heel pad was thinner in the painful heels of patients with plantar fasciitis.

Level of evidence

Level III, Diagnostic Study.

3D printing individualized heel cup for improving the self-reported pain of plantar fasciitis

BACKGROUND

To explore the therapeutic effect and the biomechanical mechanism of 3D printing individualized heel cup in treating of plantar heel pain.

METHODS

The clinical effect was evaluated by plantar pressure analysis and pain assessment in participants. Its biomechanical mechanism of protecting the plantar heel was explored using finite element simulation.

RESULTS

The individualized heel cup could support and protect the osseous structure and soft tissue of plantar heel while walking and jogging, as well as significantly reduce the self-reported pain after being worn for 4 weeks. The nylon heel cup could alter the load concentration of the heel as well as decrease the load affected on plantar fascia and calcaneus bone. It also provided an obvious support for heel pad.

CONCLUSION

To summarize, the 3D printed individualized heel cup can be used as an effective method for the treatment of plantar heel pain.

The effectiveness of raising the heel height of shoes to reduce heel pain in patients with calcaneal spurs

[Purpose] To investigate the effect of heel height on the distribution of plantar foot force and heel pain in patients with a heel spur. [Subjects and Methods] Plantar force was measured using 8 force sensors in 16 patients (3 men, 13 women), with symptomatic heel spur for 4 heel heights (0-4 cm). Sensors were located at the hallux (T1); medial to lateral metatarsals (M1 through M3), mid-foot (MF); and at the central, lateral, and medial heel (CH, LH, and MH). Pain was evaluated using the minimum compression force that caused pain and was measured using an algometer. [Results] Load bearing shifted from the heel (CH) to the mid-foot (MF) and hallux (T1) with increasing heel height. Raising the heel from 2 to 3 cm reduced the magnitude of load bearing, relative to the minimum compression force for pain, by 3.70% at the LH and 2.35% at the MH. Excellent clinical outcomes, defined by a 70-100% decrease in pain, were achieved in 10/16 participants with the use of a 2-cm and 3-cm heel height in men and women, respectively. [Conclusion] Increasing heel height effectively decreases the plantar force on the heel during weight-bearing activities.

Effects of Body Mass Index on Mechanical Properties of the Plantar Fascia and Heel Pad in Asymptomatic Participants

BACKGROUND

Musculoskeletal foot disorders have a high incidence among overweight and obese individuals. One of the important factors causing this high incidence may be plantar fascia and heel pad (HP)-related mechanical changes occurring in these individuals. The aim of the present study was to investigate the plantar fascia and HP stiffness and thickness parameters in overweight and obese individuals and compare these values with those of normal-weight individuals.

METHODS

This study was carried out in 87 (52 female, 35 male) healthy sedentary individuals between the ages of 19 and 58 years (34 ± 11 years). Participants were subsequently categorized according to body mass index (BMI) as normal weight (18.5 kg/m² < BMI < 25 kg/m²) or overweight and obese (BMI ≥25 kg/m²). Plantar fascia and HP thickness and stiffness were measured with an ultrasonography device using a linear ultrasonography probe.

RESULTS

Overweight and obese individuals had higher HP thickness ( P < .001), plantar fascia thickness ( P = .001), heel pad microchamber layer (MIC) stiffness ( P < .001), and heel pad macrochamber layer (MAC) stiffness ( P < .001), whereas they had lower plantar fascia stiffness ( P < .001) compared with the individuals with normal weight. BMI had a moderate correlation with HP thickness ( P < .001, r = 0.500), plantar fascia thickness ( P = .001, r = 0.536), MIC stiffness ( P < .001, r = 0.496), and MAC stiffness ( P < .001, r = 0.425). A negative and moderate correlation was found between BMI and plantar fascia stiffness ( P < .001, r = -0.439).

CONCLUSION

Increased BMI causes a decrease in the stiffness of plantar fascia and an increase in the thickness of the plantar fascia as well as the thickness and stiffness of HP. Increased body mass could cause changes in the mechanical properties of HP and plantar fascia.

LEVEL OF EVIDENCE

Level 3, comparative study.

Heel Pad Stiffness in Plantar Heel Pain by Shear Wave Elastography

The goal of the study was to evaluate the reliability of supersonic shear wave elastography in measuring heel pad stiffness and the change in heel pad stiffness in patients with plantar heel pain. In the reliability test involving 12 normal participants, each heel pad was tested six times in succession, and adequate reliability was reflected in the intraclass correlation coefficients (0.95, 0.93 and 0.96 for the microchambers, macrochambers and bulk heel pad, respectively). In the clinical assessment involving 20 normal participants and 16 unilateral plantar heel pain patients, diseased heel pads (86.8 ± 22.9, 36.8 ± 7.7 and 46.6 ± 10.9 kPa for the microchambers, macrochambers and bulk heel pad, respectively) were significantly stiffer than unaffected heel pads (66.8 ± 14.1, 25.2 ± 5.7, 34.2 ± 6.6 kPa) and those of normal participants (60.9 ± 11.4, 26.3 ± 6.1, 31.8 ± 6.3 kPa), suggesting that the heel pad with plantar heel pain was associated with loss of elasticity.

Dynamic Patterns of Forces and Loading Rate in Runners with Unilateral Plantar Fasciitis: A Cross-Sectional Study

Aim/Hypothesis

The etiology of plantar fasciitis (PF) has been related to several risk factors, but the magnitude of the plantar load is the most commonly described factor. Although PF is the third most-common injury in runners, only two studies have investigated this factor in runners, and their results are still inconclusive regarding the injury stage.

Objective

Analyze and compare the plantar loads and vertical loading rate during running of runners in the acute stage of PF to those in the chronic stage of the injury in relation to healthy runners.

Methods

Forty-five runners with unilateral PF (30 acute and 15 chronic) and 30 healthy control runners were evaluated while running at 12 km/h for 40 meters wearing standardized running shoes and Pedar-X insoles. The contact area and time, maximum force, and force-time integral over the rearfoot, midfoot, and forefoot were recorded and the loading rate (20–80% of the first vertical peak) was calculated. Groups were compared by ANOVAs (p<0.05).

Results

Maximum force and force-time integral over the rearfoot and the loading rate was higher in runners with PF (acute and chronic) compared with controls (p<0.01). Runners with PF in the acute stage showed lower loading rate and maximum force over the rearfoot compared to runners in the chronic stage (p<0.01).

Conclusion

Runners with PF showed different dynamic patterns of plantar loads during running over the rearfoot area depending on the injury stage (acute or chronic). In the acute stage of PF, runners presented lower loading rate and forces over the rearfoot, possibly due to dynamic mechanisms related to pain protection of the calcaneal area.

Plantar fasciopathy: revisiting the risk factors

BACKGROUND

Plantar fasciopathy is the most common cause of acquired sub-calcaneal heel pain in adults. To-date, research of this condition has mainly focused on management rather than causal mechanisms. The aetiology of plantar fasciopathy is likely to be multifactorial, as both intrinsic and extrinsic risk factors have been reported. The purpose of this review is to critically reevaluate risk factors for plantar fasciopathy.

METHODS

A detailed literature review was undertaken using English language medical databases.

RESULTS

No clear consensus exists as to the relative strength of the risk factors reported.

CONCLUSIONS

To-date numerous studies have examined various intrinsic and extrinsic risk factors implicated in the aetiology of plantar fasciopathy. How these factors interact may provide useful data to establish an individuals' risk profile for plantar fasciopathy and their potential for response to treatment. Further research is indicated to rank the relative significance of these risk factors.

The association between body mass index and musculoskeletal foot disorders: a systematic review

The primary aim of this systematic review was to investigate the relationship between body mass index (BMI) and foot disorders. The secondary aim was to investigate whether weight loss is effective for reducing foot pain. Five electronic databases (Ovid MEDLINE, Ovid EMBASE, Ovid AMED, CINAHL and The Cochrane Library) and reference lists from relevant papers were searched in April 2011. Twenty-five papers that reported on the association between BMI and musculoskeletal foot disorders met our inclusion criteria and were reviewed. The evidence indicates: (i) a strong association between increased BMI and non-specific foot pain; and (ii) a strong association between increased BMI and chronic plantar heel pain in a non-athletic population. The evidence is inconclusive regarding the relationship between BMI and the following specific disorders of the foot; hallux valgus, tendonitis, osteoarthritis and flat foot. With respect to our second aim, there were only two prospective cohort studies that reported a reduction in foot symptoms following weight loss surgery. In summary, increased BMI is strongly associated with non-specific foot pain in the general population and chronic plantar heel pain in a non-athletic population. However, there is currently limited evidence to support weight loss to reduce foot pain.

Radiological interventions for soft tissue injuries in sport

Injection therapy has played an integral role in the rehabilitation of sports injuries for many years. The athlete's primary goal is a rapid return to sporting activity. This may be achieved by a combination of either a temporary or permanent reduction in pain, and by a pharmacological or physiological effect that promotes or accelerates a healing response. A wide variety of pharmacological agents are used. However, there is often a lack of good evidence that quantifiable effects can be achieved. There are restrictions on the use of some pharmaceutical agents. This article reviews the various pharmacological agents and bioactive substrates that are available, and discusses the current evidence base of their use in common sports injuries.

Bulk compressive properties of the heel fat pad during walking: a pilot investigation in plantar heel pain

BACKGROUND

Altered mechanical properties of the heel pad have been implicated in the development of plantar heel pain. However, the in vivo properties of the heel pad during gait remain largely unexplored in this cohort. The aim of the current study was to characterise the bulk compressive properties of the heel pad in individuals with and without plantar heel pain while walking.

METHODS

The sagittal thickness and axial compressive strain of the heel pad were estimated in vivo from dynamic lateral foot radiographs acquired from nine subjects with unilateral plantar heel pain and an equivalent number of matched controls, while walking at their preferred speed. Compressive stress was derived from simultaneously acquired plantar pressure data. Principal viscoelastic parameters of the heel pad, including peak strain, secant modulus and energy dissipation (hysteresis), were estimated from subsequent stress-strain curves.

FINDINGS

There was no significant difference in loaded and unloaded heel pad thickness, peak stress, peak strain, or secant and tangent modulus in subjects with and without heel pain. However, the fat pad of symptomatic feet had a significantly lower energy dissipation ratio (0.55+/-0.17 vs. 0.69+/-0.08) when compared to asymptomatic feet (P<.05).

INTERPRETATION

Plantar heel pain is characterised by reduced energy dissipation ratio of the heel pad when measured in vivo and under physiologically relevant strain rates.

Clinical findings in men with chronic pain after falanga torture

OBJECTIVES

To explore clinical findings in men with chronic pain after falanga torture as compared with controls, and to try to understand the nature of the pain mechanisms responsible.

METHODS

Eleven male torture victims from the Middle East with chronic pain after falanga, and 11 age, sex, and ethnically matched controls with no history of torture were recruited. All participants were interviewed regarding pain characteristics in the feet and lower legs at rest and when walking. Structural changes and motor and sensory function were clinically assessed according to a standardized protocol. The walking pattern was observed for compensatory gait patterns.

RESULTS

The torture victims had pain in their feet and lower legs and a compensated gait pattern, usually with severe pain during walking. Reduced light touch and thermal sensation, tactile dysesthesia, allodynia, and tenderness on palpation were common findings. Structural changes in the feet were found in more than half of the victims, but did not correlate with pain reports. These clinical findings were nonexistent or seen only rarely in controls.

DISCUSSION

We found clear clinical signs of nerve injury in the feet. The sensory findings indicated 2 neuropathic pain mechanisms, one dominated by a peripheral pain generator and other by irritative phenomena (dysesthesia, allodynia), indicating central sensitization. It is reasonable to assume that these changes are due to the falanga exposure. A nociceptive contribution cannot be excluded. It is important to perform an individual diagnostic analysis to facilitate adequate treatment.

Musculoskeletal disorders associated with obesity: a biomechanical perspective

Despite the multifactorial nature of musculoskeletal disease, obesity consistently emerges as a key and potentially modifiable risk factor in the onset and progression of musculoskeletal conditions of the hip, knee, ankle, foot and shoulder. To date, the majority of research has focused on the impact of obesity on bone and joint disorders, such as the risk of fracture and osteoarthritis. However, emerging evidence indicates that obesity may also have a profound effect on soft-tissue structures, such as tendon, fascia and cartilage. Although the mechanism remains unclear, the functional and structural limitations imposed by the additional loading of the locomotor system in obesity have been almost universally accepted to produce aberrant mechanics during locomotor tasks, thereby unduly raising stress within connective-tissue structures and the potential for musculoskeletal injury. While such mechanical theories abound, there is surprisingly little scientific evidence directly linking musculoskeletal injury to altered biomechanics in the obese. For the most part, even the biomechanical effects of obesity on the locomotor system remain unknown. Given the global increase in obesity and the rapid rise in musculoskeletal disorders, there is a need to determine the physical consequences of continued repetitive loading of major structures of the locomotor system in the obese and to establish how obesity may interact with other factors to potentially increase the risk of musculoskeletal disease.

Factors associated with chronic plantar heel pain: a systematic review

Chronic plantar heel pain (CPHP) is one of the most common soft tissue disorders of the foot, yet its aetiology is poorly understood. The purpose of this systematic review was to examine the association between CPHP and the various aetiological factors reported in the literature. Seven electronic databases and the reference lists of key articles were searched in August 2005. The resulting list of articles was assessed by two independent reviewers according to pre-determined selection criteria and a final list of articles for review was created. The methodological quality of the included articles was assessed and the evidence presented in each of the articles was descriptively analysed. From the 16 included articles, body mass index in a non-athletic population and the presence of calcaneal spur were the two factors found to have an association with CPHP. Increased weight in a non athletic population, increased age, decreased ankle dorsiflexion, decreased first metatarsophalangeal joint extension and prolonged standing all demonstrated some evidence of an association with CPHP. Evidence for static foot posture and dynamic foot motion was inconclusive and height, weight and BMI in an athletic population were not associated with CPHP. The findings of this review should be used to guide the focus of prospective cohort studies, the results of which would ultimately provide a list of risk factors for CPHP. Such a list is essential in the development of new and improved preventative and treatment strategies for CPHP.

The Pathomechanics of Plantar Fasciitis

Plantar fasciitis is a musculoskeletal disorder primarily affecting the fascial enthesis. Although poorly understood, the development of plantar fasciitis is thought to have a mechanical origin. In particular, pes planus foot types and lower-limb biomechanics that result in a lowered medial longitudinal arch are thought to create excessive tensile strain within the fascia, producing microscopic tears and chronic inflammation. However, contrary to clinical doctrine, histological evidence does not support this concept, with inflammation rarely observed in chronic plantar fasciitis. Similarly, scientific support for the role of arch mechanics in the development of plantar fasciitis is equivocal, despite an abundance of anecdotal evidence indicating a causal link between arch function and heel pain. This may, in part, reflect the difficulty in measuring arch mechanics in vivo. However, it may also indicate that tensile failure is not a predominant feature in the pathomechanics of plantar fasciitis. Alternative mechanisms including 'stress-shielding', vascular and metabolic disturbances, the formation of free radicals, hyperthermia and genetic factors have also been linked to degenerative change in connective tissues. Further research is needed to ascertain the importance of such factors in the development of plantar fasciitis.

Analysis of variance (ANOVA) models in lower extremity wounds

Consider a study in which 2 new treatments are being compared with a control group. One way to compare outcomes would simply be to compare the 2 treatments with the control and the 2 treatments against each using 3 Student t tests (t test). If we were to compare 4 treatment groups, then we would need to use 6 t tests. The difficulty with using multiple t tests is that as the number of groups increases, so will the likelihood of finding a difference between any pair of groups simply by change when no real difference exists by definition a Type I error. If we were to perform 3 separate t tests each at alpha = .05, the experimental error rate increases to .14. As the number of multiple t tests increases, the experiment-wise error rate increases rather rapidly. The solution to the experimental error rate problem is to use analysis of variance (ANOVA) methods. Three basic ANOVA designs are reviewed that give hypothetical examples drawn from the literature to illustrate single-factor ANOVA, repeated measures ANOVA, and randomized block ANOVA. "No frills" SPSS or SAS code for each of these designs and examples used are available from the author on request.

Bilateral chronic proximal plantar fasciopathy: treatment with electrohydraulic orthotripsy

BACKGROUND

Patients presenting for treatment of chronic plantar fasciopathy often have bilateral involvement. When various nonoperative treatments fail, subsequent intervention may be problematic, especially since bilateral surgery (bilateral fascial release) may not be realistic because of variable, frequently restrictive postoperative weightbearing limitations.

METHODS

Twenty-three patients (46 heels) were treated with electrohydraulic high-energy orthotripsy to the plantar entheses of both feet while under the same anesthesia (conscious sedation). Following orthotripsy, all patients immediately were fully weightbearing and resumed normal activities of daily living and work, usually within 24 hours. Progressive return to athletic activities was allowed. Patients were assessed by three outcome parameters: (1) pain measured objectively by a dolorimeter combined with the patient's subjective evaluation of the level of pain; (2) pain after 5 minutes of walking upon arising; and (3) pain with daily activities. All pain measurements were done by the visual analog scale.

RESULTS

Patients initially experienced varied pain relief responses. This included earlier pain relief in one heel compared to the other, as well as better pain relief in one heel than the other at the 6- and 12-week evaluations, but with much less variance at the 1-year evaluation. By 3 months following orthotripsy, 28 heels (61%) had good or excellent results. These results were maintained or improved at 1 year. In 18 heels (39%), the outcome was fair or poor. Nineteen heels received a second orthotripsy application; one patient requested a second orthotripsy treatment of only one heel, while nine patients requested a second treatment of both heels. The outcome showed further improvement following the second application of orthotripsy. At 1 year after one or two orthotripsy applications, 19 patients (38 heels) were satisfied with the results in both heels (83%), while four patients (eight heels) still had an unsatisfactory outcome (17%).

CONCLUSION

Electrohydraulic high-energy orthotripsy is a reasonable nonincisional method for treating patients with bilateral chronic proximal plantar fasciopathy under a single anesthetic without the prolonged nonweightbearing status often recommended for patients following unilateral open or endoscopic fascial release.