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Pes cavus is a complicated, multiplanar deformity that requires a thorough understanding in order to provide the appropriate level of care. The foot and ankle surgeon should perform a comprehensive examination, including a neurologic evaluation, in the workup of this patient population. Understanding the cause of the patient's deformity is a critical step in predicting the disease course as well as the most acceptable form of treatment. The surgical correlation with the patient's pathologic anatomy requires an in-depth clinical evaluation, in addition to the radiographic findings, as the radiographic findings do not necessarily correlate with the patient's discomfort., Competing Interests: Disclosure Dr A.M. Jacobs has nothing to disclose regarding this topic., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Measurements of plantar loading reveal foot-to-floor interaction during activity, but information on bone architecture cannot be derived. Recently, cone-beam computer tomography (CBCT) has given visual access to skeletal structures in weight-bearing. The combination of the two measures has the potential to improve clinical understanding and prevention of diabetic foot ulcers. This study explores the correlations between static 3D bone alignment and dynamic plantar loading., Methods: Sixteen patients with diabetes were enrolled (group ALL): 15 type 1 with (N, 7) and without (D, 8) diabetic neuropathy, and 1 with latent autoimmune diabetes. CBCT foot scans were taken in single-leg upright posture. 3D bone models were obtained by image segmentation and aligned in a foot anatomical reference frame. Absolute inclination and relative orientation angles and heights of the bones were calculated. Pressure patterns were also acquired during barefoot level walking at self-selected speed, from which regional peak pressure and absolute and normalised pressure-time integral were worked out at hallux and at first, central and fifth metatarsals (LOAD variables) as averaged over five trials. Correlations with 3D alignments were searched also with arch index, contact time, age, BMI, years of disease and a neuropathy-related variable., Results: Lateral and 3D angles showed the highest percentage of significant (p < 0.05) correlations with LOAD. These were weak-to-moderate in the ALL group, moderate-to-strong in N and D. LOAD under the central metatarsals showed moderate-to-strong correlation with plantarflexion of the 2nd and 3rd phalanxes in ALL and N. LOAD at the hallux increased with plantarflexion at the 3rd phalanx in ALL, at 1st phalanx in N and at 5th phalanx in D. Arch index correlated with 1st phalanx plantarflexion in ALL and D; contact time showed strong correlation with 2nd and 3rd metatarsals and with 4th phalanx dorsiflexion in D., Conclusion: These preliminary original measures reveal that alteration of plantar dynamic loading patterns can be accounted for peculiar structural changes of foot bones. Load under the central metatarsal heads were correlated more with inclination of the corresponding phalanxes than metatarsals. Further analyses shall detect to which extent variables play a role in the many group-specific correlations.

Objectives: To investigate, in anti-cyclic citrullinated peptide antibody positive (CCP+) at-risk individuals without clinical synovitis, the prevalence and distribution of ultrasound (US) bone erosions (BE), their correlation with subclinical synovitis and their association with the development of inflammatory arthritis (IA)., Methods: Baseline US scans of 419 CCP+ at-risk individuals were analysed. BE were evaluated in the classical sites for rheumatoid arthritis damage: the second and fifth metacarpophalangeal (MCP2 and MCP5) joints, and the fifth metatarsophalangeal (MTP5) joints. US synovitis was defined as synovial hypertrophy (SH) ≥2 or SH ≥1+power Doppler signal ≥1. Subjects with ≥1 follow-up visit were included in the progression analysis (n=400)., Results: BE were found in ≥1 joint in 41/419 subjects (9.8%), and in 55/2514 joints (2.2%). The prevalence of BE was significantly higher in the MTP5 joints than in the MCP joints (p<0.01). A significant correlation between BE and US synovitis in the MTP5 joints was detected (Cramer's V=0.37, p<0.01). The OR for the development of IA (ever) was highest for the following: BE in >1 joint 10.6 (95% CI 1.9 to 60.4, p<0.01) and BE and synovitis in ≥1 MTP5 joint 5.1 (95% CI 1.4 to 18.9, p=0.02). In high titre CCP+ at-risk individuals, with positive rheumatoid factor and BE in ≥1 joint, the OR increased to 16.9 (95% CI 2.1-132.8, p<0.01)., Conclusions: In CCP+ at-risk individuals, BE in the feet appear to precede the onset of clinical synovitis. BE in >1 joint, and BE in combination with US synovitis in the MTP5 joints, are the most predictive for the development of clinical arthritis., Competing Interests: Competing interests: This study was conducted while ADM was an ARTICULUM Fellow. KM reports personal fees from AbbVie, UCB and Eli Lilly, outside the submitted work. RJW has received honoraria from AbbVie, Novartis and GE for ultrasound-related educational activities. PE reports consultant fees from BMS, AbbVie, MSD, Pfizer, Novartis and Roche, outside the submitted work. He also reports research grants from UCB, AbbVie, BMS, Pfizer, MSD and Roche, outside the submitted work., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: In planovalgus deformity with triceps contracture, a midfoot break happens, and ankle dorsiflexion (ADF) occurs at the mid-tarsal joint during gait. Results of standard 3D gait analysis may misinterpret the true ankle dorsiflexion because it recognizes the entire foot as a single rigid segment. We performed this study to investigate whether the severity of planovalgus deformity is associated with the discrepancy between the value of ADF evaluated by physical examination and 3-dimensional (3D) gait analysis. In addition, we aimed to identify the radiographic parameters associated with this discrepancy and their relationships., Methods: Consecutive 40 patients with 65 limbs (mean age, 11.7 ± 5.5 years) with planovalgus foot deformity and triceps surae contracture were included. All patients underwent 3D gait analysis, and weightbearing anteroposterior (AP) and lateral (LAT) foot radiographs. ADF with knee extension was measured using a goniometer with the patient's foot in an inverted position., Results: Twenty-one limbs underwent operation for planovalgus foot deformity, and 56 limbs underwent operation for equinus deformity. The difference between ADF on physical examination and ADF at initial contact on gait analysis was 17.5 ± 8.4°. Differences between ADF on physical examination and ADF at initial contact on gait analysis were significantly associated with the LAT talus-first metatarsal angle (p = 0.008) and calcaneal pitch angle (p = 0.006), but not associated with the AP talus-first metatarsal angle (p = 0.113), talonavicular coverage angle (p = 0.190), talocalcaneal angle (p = 0.946), and naviculocuboid overlap (p = 0.136)., Conclusion: The discrepancy between ADF on physical examination and 3D gait analysis was associated with the severity of planovalgus deformity, which was evaluated on weightbearing LAT foot radiographs. Therefore, physicians should be cautious about interpreting results from 3D gait analysis and perform a careful physical examination to assess the degree of equinus deformity in patients with planovalgus foot deformity.

Background: Estimating muscle-tendon complex (MTC) lengths is important for planning of soft tissue surgery and evaluating outcomes, e.g. in children with cerebral palsy (CP). Conventional musculoskeletal models often represent the foot as one rigid segment, called a mono-segment foot model (mono-SFM). However, a multi-segment foot model (multi-SFM) might provide better estimates of triceps surae MTC lengths, especially in patients with foot deformities., Research Question: What is the effect of a mono- versus a multi-SFM on simulated ankle angles and triceps surae MTC lengths during gait in typically developing subjects and in children with CP with equinus, cavovarus or planovalgus foot deformities?, Methods: 50 subjects were included, 10 non-affected adults, 10 typically developing children, and 30 children with spastic CP and foot deformities. During walking trials, marker trajectories were collected for two marker models, including a mono- and multi-segment foot; respectively Newington gait model and Oxford foot model. Two musculoskeletal lower body models were constructed in OpenSim with either a mono- or multi-SFM based on the corresponding marker models. Normalized triceps surae MTC lengths (soleus, gastrocnemius medialis and lateralis) and ankle angles were calculated and compared between models using statistical parametric mapping RM-ANOVAs. Root mean square error values between simulated MTC lengths were compared using Wilcoxon signed-rank and rank-sum tests., Results: Mono-SFM simulated significantly more ankle dorsiflexion (7.5 ± 1.2°) and longer triceps surae lengths (difference; soleus:2.6 ± 0.29 %, gastrocnemius medialis:1.7 ± 0.2 %, gastrocnemius lateralis:1.8 ± 0.2%) than a multi-SFM. Differences between models were larger in children with CP compared to typically developing children and larger in the stance compared to the swing phase of gait. Largest differences were found in children with CP presenting with planovalgus (4.8 %) or cavovarus (3.8 %) foot deformities., Significance: It is advisable to use a multi-SFM in musculoskeletal models when simulating triceps surae MTC lengths, especially in individuals with planovalgus or cavovarus foot deformities., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Chronic non-bacterial osteomyelitis (CNO) is a group of immune-mediated diseases which appears in bone inflammation, destruction and some orthopaedic consequences, especially in the cases of spinal involvement. This study is to compare characteristics and treatment outcomes of CNO patients with spinal involvement. The retrospective cohort study included data from 91 pediatric patients with CNO. The diagnosis is based on Jannson's criteria with morphological confirmation (nonspecific chronic inflammation). Spine involvement detected by X-ray, computed tomography, magnetic resonance imaging, and bone scan in 29 (31.9%) patients. No differences in the family history, concomitant immune-mediated diseases between spinal (SpCNO) and peripheral (pCNO) forms of CNO have been revealed. Only 5 (10.2%) SpCNO patients (10.2%) had monofocal monovertebral involvement. The main risk factors of spinal involvement were female sex: RR = 2.0 (1.1; 3.9), sensitivity (Se) = 0.66, specificity (Sp) = 0.6; multifocal involvement: RR = 2.1 (0.9; 5.0), Se = 0.83, Sp = 0.37; no foot bones involvement: RR = 3.1 (1.3; 7.5), Se = 0.83, Sp = 0.5; sternum involvement RR = 2.3 (1.3; 4.1), Se = 0.24, Sp = 0.94. In the linear regression analysis only female sex (p = 0.005), multifocal involvement (p = 0.000001) and absence of foot bones involvement (p = 0.000001) were independent risk factors of spinal involvement (p = 0.000001). The response rate on bisphosphonates and tumor necrosis factor-a inhibitors was 90.9% and 66.7%, consequently. Only 4/29 (13.8%) SpCNO patients underwent surgery due to severe spinal instability or deformities. The spinal involvement is frequent in CNO and could be crucial for choosing a treatment strategy. Bisphosphonates and TNFa-inhibitors could be effective treatment options for severe SpCNO.

Background: The purpose of this study was to evaluate correlation between three-dimensional medial longitudinal arch joint complex mobility and medial arch angle in stage II posterior tibial tendon dysfunction flatfoot under loading., Methods: CT scans of 15 healthy feet and 15 feet with stage II posterior tibial tendon dysfunction flatfoot were taken both in non- and simulated weight-bearing condition. The CT images of the hindfoot and medial longitudinal arch bones were reconstructed into three-dimensional models with Mimics and Geomagic reverse engineering software. The three-dimensional complex mobility of each joint in the medial longitudinal arch and their correlation with the medial arch angle change were calculated., Results: From non- to simulated weight-bearing condition, the medial arch angle change and the medial longitudinal arch joints mobility were significant larger in stage II posterior tibial tendon dysfunction flatfoot (p<0.05). The eversion of the talocalcaneal joint, the proximal translation of the calcaneus relative to the talus, the dorsiflexion of the talonavicular joint, the dorsiflexion and abduction of the medial cuneonavicular joint, and the lateral translation of the medial cuneiform relative to the navicular, and the dorsiflexion of the first tarsometatarsal joint were all significantly correlated to the medial arch angle change in stage II posterior tibial tendon dysfunction flatfoot (all r>0.5, p<0.05)., Conclusions: There is increased mobility in the medial longitudinal arch joints in stage II posterior tibial tendon dysfunction flatfoot and the medial arch angle change under loading causes displacement not only at hindfoot joints but also involve midfoot and forefoot joint., (Copyright © 2018 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.)

Objective: To investigate the impact of subclinical synovitis detected by ultrasonography (US) on the ankles and feet of patients with rheumatoid arthritis., Methods: We retrospectively reviewed the data of patients (n = 59) who underwent US., Results: The functional ability and quality of life (QoL) of patients in the subclinical group were impaired. While the physician visual analog scale (VAS) scores significantly decreased in the subclinical group, patient and pain VAS scores significantly decreased only in patients without synovitis., Conclusion: US-detected subclinical foot and ankle synovitis considerably affected patient functional status and QoL; however, it was often unnoticed by physicians., (© 2018 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)

Inflammation-mediated foot osteopenia may play a pivotal role in the etiogenesis, pathogenesis, and therapeutic outcomes in individuals with diabetes mellitus (DM), peripheral neuropathy (PN), and Charcot neuroarthropathy (CN). Our objective was to establish a volumetric quantitative computed tomography-derived foot bone measurement as a candidate prognostic imaging marker to identify individuals with DMPN who were at risk of developing CN. We studied 3 groups: 16 young controls (27 ± 5 years), 20 with DMPN (57 ± 11 years), and 20 with DMPN and CN (55 ± 9 years). Computed tomography image analysis was used to measure metatarsal and tarsal bone mineral density in both feet. The mean of 12 right (7 tarsals and 5 metatarsals) and 12 left foot bone mineral densities, maximum percent difference in bone mineral density between paired bones of the right and the left feet, and the mean difference of the 12 right and the 12 left bone mineral density measurements were used as input variables in different classification analysis methods to determine the best classifier. Classification tree analysis produced no misclassification of the young controls and individuals with DMPN and CN. The tree classifier found 7 of 20 (35%) individuals with DMPN to be classified as CN (1 participant developed CN during follow-up) and 13 (65%) to be classified as healthy. These results indicate that a decision tree employing 3 measurements derived from volumetric quantitative computed tomography foot bone mineral density defines a candidate prognostic imaging marker to identify individuals with diabetes and PN who are at risk of developing CN., (Copyright © 2017 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.)

Introduction: Nonunion is a common complication (15%) of hindfoot and ankle arthrodesis. Autograft can improve the fusion rate because of its osteoconductive, osteoinductive and osteogenic properties. However, autograft harvesting is a source of morbidity. One alternative is to combine allograft with demineralized bone matrix (DBM) and iliac bone marrow aspirate (BMA). This combination graft has similar biological properties to healthy bone. When used alone, allograft has osteoconductive and sometimes structural properties. DBM provides osteoinduction and improves the osteconductivity. BMA adds cells and thereby osteogenic potential., Hypothesis: Given its intrinsic properties, allograft-DBM-BMA is as effective as autograft-DBM treatment while simplifying the clinical practice., Material and Methods: One hundred and fifteen cases of ankle and hindfoot arthrodesis were studied in 82 patients divided in two groups: autograft-DBM vs allograft-DBM-BMA. Treatment effectiveness was assessed using clinical (time to fusion, fusion rate) and radiological (trabecular bone bridge, disappearance of joint space) criteria. A CT scan was done in 60% of cases when fusion could not be confirmed using the clinical and radiological criteria., Results: There was no significant difference between the two groups in terms of fusion rate, time to fusion, number of heterotopic ossifications, revision rate and quantity of DBM used. The nonunion rate was 18% in the autograft group and 13% in the allograft group. The infection rate was 11% in the autograft and 4% in the allograft group., Discussion: Allograft-DBM-BMA is an alternative to autograft-DBM that provides similar effectiveness without increasing the number of nonunion or complications. Osteonecrosis and surgical revision are risk factors., Level of Evidence: III retrospective study., (Copyright © 2017. Published by Elsevier Masson SAS.)

Background: Although Lisfranc injuries are uncommon, representing approximately 0.2% of all fractures, they are complex and can result in persistent pain, degenerative arthritis, and loss of function. Both open reduction and internal fixation (ORIF) and primary fusion have been proposed as treatment options for these injuries, but debate remains as to which approach is better., Questions/purposes: We asked whether ORIF or primary fusion led to (1) fewer reoperations for hardware removal; (2) less frequent revision surgery; (3) higher patient outcome scores; and (4) more frequent anatomic reduction., Methods: A systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Three trials met the criteria for inclusion within the meta-analysis. Qualifying articles for the meta-analysis had data extracted independently by two authors (NS, AF). The quality of each study was assessed using the Center for Evidence Based Medicine's evaluation strategy; data were extracted from articles rated as good and fair: two and one article, respectively., Results: The risk ratio for hardware removal was 0.23 (95% confidence interval [CI], 0.11-0.45; p < 0.001) indicating more hardware removal for ORIF than fusion. For other revision surgery, the risk ratio for ORIF was 0.36 (95% CI, 0.08-1.59; p = 0.18) favoring neither. Similarly, neither was favored using patient-reported outcomes; the standard mean difference was calculated to be 0.50 (95% CI, -2.13 to 3.12; p = 0.71). When considering the risk of nonanatomic alignment, neither was favored (risk ratio, 1.48; 95% CI, 0.34-6.38; p = 0.60)., Conclusions: The surgeon should consider the increased risk of hardware removal along with its associated morbidity and discuss this with the patient preoperatively when considering ORIF of Lisfranc injuries. Because no new trials have been performed since 2012, further randomized controlled trials will be needed improve our understanding of these interventions., Level of Evidence: Level I, therapeutic study.

Background: Evaluation of the results of treatment for clubfoot by the Ponseti technique is based on clinical and functional parameters. There is a need to establish universally recognized quantitative measurements to compare, better understand, and more precisely evaluate therapeutic outcome., Methods: Nine angles were measured on standard radiographs of 145 children with idiopathic clubfeet treated between 2000 and 2010 with the Ponseti method. The average follow-up was 6.3 years. The need for additional surgery and the functional outcome was correlated to the radiologic measurements., Results: Three radiologic parameters were identified as having significant (P ≤ .001) predictive value. The lateral tibiocalcaneal angle with the ankle at maximal dorsiflexion measuring fixed equinus was larger in the preoperated group (77 ± 12 degrees) compared to the nonoperated group (67 ± 14 degrees). Functional outcome was better with smaller angles. The lateral talocalcaneal angle with the ankle at maximal dorsiflexion measuring hindfoot rigidity was smaller (29 ± 8 degrees) in the preoperated group compared to the nonoperated group (35 ± 9 degrees). Functional outcome was better with larger angles. The lateral talo-first metatarsal angle with the ankle at maximal plantarflexion measuring foot cavus was larger in the preoperated group (31 ± 10 degrees) compared to the nonoperated group (22 ± 11 degrees), whereas functional outcome did not correlate with this angle., Conclusions: The lateral view with the foot in maximal dorsiflexion was found to be the most significant and useful view to detect abnormality in Ponseti-treated clubfeet. In our practice now, we are using only this view in order to reduce the radiation exposure to the child., Level of Evidence: Level III, retrospective case series., (© The Author(s) 2015.)

pedCAT(®) (CurveBeam, Warrington, PA) is a technology for 3-dimensional (3D) imaging with full weightbearing that has been proved to exactly visualize the 3D bone position. For the present study, a customized pedography sensor (Pliance; Novel, Munich, Germany) was inserted into the pedCAT(®). The aim of our study was to analyze the correlation of the bone position and force/pressure distribution. A prospective consecutive study of 50 patients was performed, starting July 28, 2014. All patients underwent a pedCAT(®) scan and simultaneous pedography with full weightbearing in the standing position. The following parameters were measured on the pedCAT(®) image for the right foot by 3 different investigators 3 times: lateral talo-first metatarsal angle, calcaneal pitch angle, and minimum height of the fifth metatarsal base, second to fifth metatarsal heads, and medial sesamoid. From the pedography data, the following parameters were defined using the standardized software algorithm: midfoot contact area, maximum force of midfoot, maximum force of midfoot lateral, maximum force of entire foot, and maximum pressure of first to fifth metatarsal. The values of the corresponding pedCAT(®) and pedographic parameters were correlated (Pearson). The intra- and interobserver reliability of the pedCAT(®) measurements were sufficient (analysis of variance, p > .8 for each, power >0.8). No sufficient correlation was found between the pedCAT(®) and pedographic parameters (r < 0.05 or r > -0.38).3D bone position did not correlate with the force and pressure distribution under the foot sole during simultaneous pedCAT(®) scanning and pedography. Thus, the bone positions measured with pedCAT(®) do not allow conclusions about the force and pressure distribution. However, the static pedographic parameters also do not allow conclusions about the 3D bone position.one position and force/pressure distribution are important parameters for diagnostics, planning, and follow-up examinations in foot and ankle surgery., (Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

Stress fractures of the foot and ankle may be more common among athletes than previously reported. A low threshold for investigation is warranted and further imaging may be appropriate if initial radiographs remain inconclusive. Most of these fractures can be treated conservatively with a period of non-weight-bearing mobilization followed by gradual return to activity. Early surgery augmented by bone graft may allow athletes to return to sports earlier. Risk of delayed union, nonunion, and recurrent fracture is high. Many of the patients may also have risk factors for injury that should be modified for a successful outcome., (Copyright © 2015 Elsevier Inc. All rights reserved.)

A cohort of adult acquired flatfoot deformity rigid-body models was developed to investigate the effects of isolated tendon transfer with successive levels of medializing calcaneal osteotomy (MCO). Following IRB approval, six diagnosed flatfoot sufferers were subjected to magnetic resonance imaging (MRI) and their scans used to derive patient-specific models. Single-leg stance was modeled, constrained solely through physiologic joint contact, passive soft-tissue tension, extrinsic muscle force, body weight, and without assumptions of idealized mechanical joints. Surgical effect was quantified using simulated mediolateral (ML) and anteroposterior (AP) X-rays, pedobarography, soft-tissue strains, and joint contact force. Radiographic changes varied across states with the largest average improvements for the tendon transfer (TT) + 10 mm MCO state evidenced through ML and AP talo-1st metatarsal angles. Interestingly, 12 of 14 measures showed increased deformity following TT-only, though all increases disappeared with inclusion of MCO. Plantar force distributions showed medial forefoot offloading concomitant with increases laterally such that the most corrected state had 9.0% greater lateral load. Predicted alterations in spring, deltoid, and plantar fascia soft-tissue strain agreed with prior cadaveric and computational works suggesting decreased strain medially with successive surgical repair. Finally, joint contact force demonstrated consistent medial offloading concomitant with variable increases laterally. Rigid-body modeling thus offers novel advantages for the investigation of foot/ankle biomechanics not easily measured in vivo.

Background and Purpose: Charcot neuropathy is characterized by bone destruction in a foot leading to deformity, instability, and risk of amputation. Little is known about the pathogenic mechanisms. We hypothesized that the bone-regulating Wnt/β-catenin and RANKL/OPG pathways have a role in Charcot arthropathy., Patients and Methods: 24 consecutive Charcot patients were treated by off-loading, and monitored for 2 years by repeated foot radiography, MRI, and circulating levels of sclerostin, dickkopf-1, Wnt inhibitory factor-1, Wnt ligand-1, OPG, and RANKL. 20 neuropathic diabetic controls and 20 healthy controls served as the reference., Results: Levels of sclerostin, Dkk-1 and Wnt-1, but not of Wif-1, were significantly lower in Charcot patients than in the diabetic controls at inclusion. Dkk-1 and Wnt-1 levels responded to off-loading by increasing. Sclerostin levels were significantly higher in the diabetic controls than in the other groups whereas Wif-1 levels were significantly higher in the healthy controls than in the other groups. OPG and RANKL levels were significantly higher in the Charcot patients than in the other groups at inclusion, but decreased to the levels in healthy controls at 2 years. OPG/RANKL ratio was balanced in all groups at inclusion, and it remained balanced in Charcot patients on repeated measurement throughout the study., Interpretation: High plasma RANKL and OPG levels at diagnosis of Charcot suggest that there is high bone remodeling activity before gradually normalizing after off-loading treatment. The consistently balanced OPG/RANKL ratio in Charcot patients suggests that there is low-key net bone building activity by this pathway following diagnosis and treatment. Inter-group differences at diagnosis and changes in Wnt signaling following off-loading treatment were sufficiently large to be reflected by systemic levels, indicating that this pathway has a role in bone remodeling and bone repair activity in Charcot patients. This is of particular clinical relevance considering the recent emergence of promising drugs that target this system.

Blount's disease, or tibia vara, is the most common cause of pathologic genu varum in children and adolescents. Changes in the loading of knee structures such as tibial articular cartilage, menisci and subcondral bone are well documented in case of genu varum. But the mechanical effects of this condition on foot bones are still questionable. In this study, the authors hypothesized that stress distributions on foot bones might increase in patients with tibia vara when compared with patients who had normal lower extremity mechanical axis. Three-dimensional (3D) finite element analyses of human lower limb were used to investigate and compare the loading on foot bones in normal population and patient with tibia vara. The segmentation software, MIMICS was used to generate the 3D images of the bony structures of normal and varus malalignment lower extremity. Except the spaces between the adjacent surface of the phalanges fused, metatarsals, cuneiforms, cuboid, navicular, talus and calcaneus bones were independently developed to form foot and ankle complex. Also femur, tibia and fibula were modeled utilizing mechanical axis. ANSYS version 14 was used for mechanical tests and maximum equivalent stresses (MES) were examined. As a result of the loading conditions, in varus model MES on talus, calcaneus and cuboid were found higher than in normal model. And stress distributions changed through laterally on middle and fore foot in varus deformity model.

The Charcot joint, or Charcot neuroarthropathy, is a syndrome that was described over 140 years ago but one with very little exposure in the neurologic literature. We present a case recently seen and then discuss the history, epidemiology, pathophysiology, clinical features, and diagnosis of acute and chronic Charcot joint disease with particular emphasis on the value and limitations of imaging. A diagnostic algorithm is proposed. We also review the therapeutic strategies available for acute and chronic Charcot joints with a treatment algorithm. This review is aimed at enhancing the awareness of neurologists regarding Charcot neuroarthropathy, because they are often the principal caregivers for patients with peripheral neuropathy. We hope to promote early detection of acute Charcot neuroarthropathy, thereby reducing or preventing the bony deformation of chronic Charcot neuroarthropathy.

Objective: To study the clinical results of surgical treatment for Lisfranc fracture-dislocation., Methods: From January 2003 to September 2009, 57 patients with Lisfranc injuries were treated by surgical operation included 41 males and 16 females with an average age of 33.8 years old ranging from 20 to 64 years. According to Myerson's classification, there were 31 cases of middle column injuries, 15 cases of medial-middle column injuries and 11 cases of three-column injuries. Among them, 25 patients accepted the emergency operation (<24 hours) and 32 patients were treated in average 7 days (3 to 11 days) after injury., Results: All the wounds were healed primarily with a mean operative time of 50 min (30 to 70 min). All patients were followed up for 4 to 70 months (averaged 35 months). The total AOFAS scores (American Orthopaedic Foot and Ankle Society) was in averaged of(84.73 +/- 14.26). All the patients returned to normal daily life after a mean time of 5.1 months (3 to 12 months). The average AOFAS scores of 52 anatomical reduction cases was (87.63 +/- 13.71), 5 non-anatomical reduction cases was (74.31 +/- 21.96), 26 multiple column trauma cases was (76.58 +/- 11.51). Complications of osteoarthritis occurred in 8 cases, confirming it was the main complication of these injuries., Conclusion: Lisfranc injuries can be surgically treated well. Reduction of the middle column is the key to reestablishment the stability of the tarsometatarsal joint complex. The quality of the reduction correlated with treatment outcome.

Background: The prevalence of diabetes mellitus has reached epidemic proportions, this condition may result in multiple and chronic invalidating long term complications. Among these, the diabetic foot, is determined by the simultaneous presence of both peripheral neuropathy and vasculopathy that alter the biomechanics of the foot with the formation of callosity and ulcerations. To diagnose and treat the diabetic foot is crucial to understand the foot complex kinematics. Most of gait analysis protocols represent the entire foot as a rigid body connected to the shank. Nevertheless the existing multisegment models cannot completely decipher the impairments associated with the diabetic foot., Methods: A four segment foot and ankle model for assessing the kinematics of the diabetic foot was developed. Ten normal subjects and 10 diabetics gait patterns were collected and major sources of variability were tested. Repeatability analysis was performed both on a normal and on a diabetic subject. Direct skin marker placement was chosen in correspondence of 13 anatomical landmarks and an optoelectronic system was used to collect the data., Results: Joint rotation normative bands (mean plus/minus one standard deviation) were generated using the data of the control group. Three representative strides per subject were selected. The repeatability analysis on normal and pathological subjects results have been compared with literature and found comparable. Normal and pathological gait have been compared and showed major statistically significant differences in the forefoot and midfoot dorsi-plantarflexion., Conclusion: Even though various biomechanical models have been developed so far to study the properties and behaviour of the foot, the present study focuses on developing a methodology for the functional assessment of the foot-ankle complex and for the definition of a functional model of the diabetic neuropathic foot. It is, of course, important to evaluate the major sources of variation (true variation in the subject's gait and artefacts from the measurement procedure). The repeatability of the protocol was therefore examined, and results showed the suitability of this method both on normal and pathological subjects. Comparison between normal and pathological kinematics analysis confirmed the validity of a similar approach in order to assess neuropathics biomechanics impairment.

Study Design: Systematic review of case control studies., Objectives: To identify and analyze demographic and structural factors associated with hallux limitus/rigidus., Methods: A literature search was conducted across several electronic databases (Medline, EMBASE, CINAHL, and PubMed) using the following terms: hallux limitus, hallux rigidus, metatarsophalangeal joint, and big toe. Methodological quality of included studies was evaluated using the Quality Index. To evaluate the magnitude of differences between cases and controls, odds ratios were calculated for dichotomous variables and effect sizes (Cohen d) were calculated for continuous variables., Results: The methodological quality of the 7 included studies was moderate, with Quality Index scores ranging from 6 to 11 out of a possible score of 14. The overall mean age for the case group was 44.8 years (mean range, 23.4-54.9 years) and for the control group was 39.6 years (mean range, 23.4-58.8 years). There was a similar distribution of males and females across case and control groups. All studies used plain film radiography to assess foot structure. Cases were found to have a dorsiflexed first metatarsal relative to the second metatarsal, a plantar flexed forefoot on the rearfoot, reduced first metatarsophalangeal joint range of motion, a longer proximal phalanx, distal phalanx, medial sesamoid, and lateral sesamoid, and a wider first metatarsal and proximal phalanx. Measures of foot posture and arch height were not found to substantially differ between cases and controls., Conclusions: This review of case control studies indicates that several variables pertaining to the structure of the first metatarsophalangeal joint may be associated with hallux limitus/rigidus. These findings have implications for the conservative and surgical treatment of the condition.

Background: Changes in foot orientation due to orthoses and the relationship with perceived comfort are still unclear in pes cavus. The purpose of this study was to determine the acute changes of fore-foot angles due to the use of custom-made orthoses and their relationship with perceived comfort during standing., Methods: Two photographs were taken using a color-coded camera-based system from the posterior and medial views of 20 subjects with bilateral pes cavus under barefoot and with orthoses conditions during standing. Djian-Annonier, calcaneal inclination, 1st metatarsal declination and rearfoot angles were measured and perceived comfort in the forefoot, midfoot and rearfoot was estimated using an adapted Visual Analogue Scale-type questionnaire., Results: In comparison with the barefoot condition, orthoses increased significantly the 1st metatarsal declination angle by 1.9 degrees (p<0.01), and the Djian-Annonier angle by 1.1 degrees (p=0.02). The calcaneal inclination angle decreased significantly by an average of 3.0 degrees (p<0.01). Wearing orthoses significantly improved perceived comfort in forefoot, midfoot and rearfoot when compared to barefoot condition (p<0.01). A significant correlation was observed between variation of calcaneal inclination angle and the perceived comfort at the midfoot (r=-0.44; p=0.04)., Conclusion: Flattening of foot arch and improvement of midfoot perceived comfort in pes cavus could be attributed to the reduction of the calcaneal inclination angle in the sagittal plane by using orthoses during standing.

We describe the clinical presentation and diagnostic tests of a patient with regional transient osteoporosis (RTO) of the foot. This patient presented with a 4-month history of left-foot pain, nonpitting edema, and brownish discolorations of both feet. He had a history of tobacco abuse, alcohol abuse, and malnutrition. Radiological studies revealed severe osteopenia in the feet, and a MRI revealed bone marrow edema. The bone biopsy was consistent with RTO. This patient also had vitamin C deficiency. This case suggests a link between vitamin C deficiency and RTO, a hypothesis supported by our review of relevant literature on osteoporosis and vitamin C.

The aim of the paper was to compare primary biomechanical stability of different arthrodesis screws (7.3 mm AO screw with and without washer, 6.5 mm Herbert screw and 6.5 mm Ideal Compression Screw (I.CO.S)). The work necessary to achieve an adequate compressive force with them was compared to the measurement with the AO screw with washer, because this method is for the time being the most commonly used one and is called the golden standard. Compressive force was measured indirectly, via screw tension measurement, with strain gauges method. From the measurements we calculated the work to reach a limit of 60 N and the ratios corresponding to the value of the golden standard: I.CO.S (35.2%), Herbert (89.0%), AO-screw without washer (116%). The I.CO.S showed superior results. Only in the case of extremely poor bone quality, a clear advantage of I.CO.S could be expected in practice.

Stress fractures of the foot and ankle are common in the athletic population. Because this population is especially eager to return to activity, such fractures can be challenging to treat. If the biomechanical faults are not addressed or gradual return to activity is not monitored appropriately, fractures occasionally recur. A retrospective analysis was conducted of 96 athletes who presented to a podiatric sports medicine practice over the course of 10 years with stress fractures confirmed by radiograph or bone scan. The most common type of fracture sustained by this population was tibial stress fracture, followed by second metatarsal fracture. Marathon training was the most common pre-injury activity overall, although fitness walking was the most common activity among those with metatarsal fractures. This study relates the most common types of stress fractures of the foot, ankle, and leg to certain athletic activities and correlates duration of symptoms before presentation with return-to-activity time.

The author presents an alternative approach to the pediatric flexible pes planovalgus patient. Hopefully, this algorithm can serve as a guide and not as a rule. It is meant to serve the foot and ankle surgeon as a means of eliminating the arbitrary assignment of a flatfoot to procedures. Instead, the algorithm assigns procedures to a type of flatfoot. The specific procedures listed are a guide to reduce our failures while continually improving our successes.

Aim: This study evaluates the pressure distribution, the radiological and clinical results in patients before surgery and 6 months after scarf osteotomy for hallux valgus., Methods: 29 patients were examined before surgery and 6 months after surgery for symptomatic hallux valgus. Pedographic analysis was performed by dividing the footprint of the patients into 8 regions of interest. For each region the maximum mean pressure and the peak pressure were evaluated. Moreover, clinicofunctional results (AOFAS score) and radiological results were evaluated., Results: 6 months postoperatively, maximum mean pressure increased significantly under the medial forefoot where as the peak pressure in this region revealed indifferent results. Significant improvement of clinicofunctional results and a significant reduction of the intermetatarsal and metatarsophalangeal angle could be seen., Conclusion: These results confirm the clinical and radiological findings of other studies, but this study shows for the first time an increase of pressure under the first ray of the foot after hallux valgus surgery and an adaptation to the pressure distribution of normal feet.

This study introduces a new technique to measure bone size and shape. A three-dimensional laser scan was taken of the talus, navicular, medial cuneiform, and first metatarsal from 107 skeletons of known age and sex. The bones were analyzed for differences in bone morphology between the sexes and the ability of each bone to contribute to the adducted position of the first metatarsal. Linear measurements showed that male bones were larger than female bones. Measurements of articular surfaces suggested that female bones had the potential for more movement to occur in the direction of adduction, possibly resulting in the female first metatarsal being more adducted than that in the male skeleton. Such differences may underlie the predisposition of the female foot to develop hallux valgus deformity.

Background: Limited joint mobility in diabetic patients has been identified as a risk factor in the development of plantar ulcers. We examined dorsal mobility and passive first ray stiffness in patients with diabetes and investigated the relationship between first ray mobility and ankle joint dorsiflexion., Methods: Forty individuals were studied: 20 with diabetes (mean estimated duration of 16 +/- 10 years) and 20 matched controls. Dorsal first ray mobility was measured using a mechanical device. Force-vs-dorsal mobility displacement values were collected at 10 N increments to a load limit of 55 N. Ankle joint dorsiflexion motion was measured with a goniometer. The "prayer sign," a clinical indicator of limited joint mobility, was evaluated in each patient. Subjects were separated into the two groups for data analysis., Results: Patients in the diabetic group had more stiffness and less dorsal first ray mobility than the control group (p <.05). In particular, patients with a positive prayer sign had significant first ray stiffness (p <.05). Patients with diabetes also had less ankle dorsiflexion (p <.05)., Conclusion: Patients with diabetes have more stiffness and less first ray mobility and less ankle dorsiflexion than those without diabetes. The presence of a positive prayer sign correlates with stiffness and loss of first ray mobility. Soft-tissue stiffness may contribute to the development of foot ulcers in diabetic patients with neuropathy.

Background: Several studies have demonstrated that patients with hallux valgus (HV) deformities have increased first ray sagittal mobility. However, the change in mobility that occurs after surgical correction of HV deformities has not been extensively evaluated. This study was done to determine if surgical realignment of the first ray in cadaver specimens with a proximal crescentic osteotomy and distal soft tissue reconstruction (DSTR) would reduce the first ray sagittal motion as measured with an external-type micrometer (the Klaue device)., Methods: Twelve fresh-frozen below-knee cadaver specimens with an HV deformity (HV angle > 15 degrees, 1-2 IM angle > 9 degrees) were used for the study. Standardized simulated weightbearing radiographs were obtained before and after the surgical correction of the deformity. The first ray sagittal motion was measured with an external micrometer (Klaue device) before correction of the HV deformity and after the procedure. All specimens had correction of the hallux valgus deformity with a DSTR and proximal crescentic osteotomy. Internal fixation was applied to secure the osteotomy site., Results: The HV angle was corrected from a mean of 28.6 degrees to a mean of 11.0 degrees. The 1-2 IM angle was corrected from a mean of 12.9 degrees to a mean of 6.8 degrees. The average preoperative first ray sagittal motion was 11.0 mm (range, 8.5 mm to 13.5 mm). After the surgical repair, the mean sagittal first ray motion was significantly decreased (p <.0005) to a mean of 5.2 mm (range, 3.5 mm to 7.5 mm)., Conclusion: After correction of HV deformities with a DSTR and a proximal crescentic osteotomy, first ray mobility in cadaver specimens was significantly reduced. The stabilization of first ray mobility that occurred immediately after surgical correction despite leaving the capsule of the first metatarsocuneiform (MC) joint undisturbed suggests that extrinsic anatomic features may play a role in first ray mobility. Additionally, stability of the first ray may be restored with a bunion procedure that does not sacrifice the first MC joint.

When the foot works properly it is an amazing, adaptive, powerful aid during walking, running, jumping, and in locomotion up or down hill and over uneven ground. Dysfunction of the foot can often arise from the foot losing its normal structural support, thus altering is shape. An imbalance in the forces that tend to flatten the arch and those that support the arch can lead to loss of the medial longitudinal arch. An increase in the arch-flattening effects of the triceps surae or an increase in the weight of the body will tend to flatten the arch. Weakness of the muscular, ligamentous, or bony arch supporting structures will lead to collapse of the arch. The main factors that contribute to an acquired flat foot deformity are excessive tension in the triceps surae, obesity, PTT dysfunction, or ligamentous laxity in the spring ligament, plantar fascia, or other supporting plantar ligaments. Too little support for the arch or too much arch flattening effect will lead to collapse of the arch. Acquired flat foot most often arises from a combination of too much force flattening the arch in the face of too little support for the arch. Treatment of the adult acquired flat foot is often difficult. The clinician should remember the biomechanics of the normal arch and respond with a treatment that strengthens the supporting structures of the arch or weakens the arch-flattening effects on the arch. After osteotomies or certain hindfoot fusions, the role of the supporting muscles of the arch, in particular the PTT, play less of a role in supporting the arch. Rebalancing the forces that act on the arch can improve function and lessen the chance for further or subsequent development of deformity.

Purpose: To determine the 1st ray mobility following a distal soft-tissue procedure with proximal osteotomy (DSTP-PMO) and any associated factors., Methods: A retrospective study of 30 men (35 feet) was performed. First ray mobility, ankle dorsiflexion, pes planus, and metatarsus adductus were evaluated at the final follow-up. All internal fixation was routinely removed at six to eight weeks postoperatively. Standard radiographs were evaluated and angular measurements were calculated on all feet., Results: The mean follow-up was 78 months. No cases of degenerative arthritis of the 1st MTC joint were noted on follow-up radiographs. DSTP-PMO resulted in a mean postoperative 1st ray mobility of 4.9 mm (range, 2.5 to 8). In those feet evaluated following bunion correction, there was no correlation with pes planus, limited ankle dorsiflexion or metatarsus adductus. The preoperative hallux valgus angle and 1-2 intermetatarsal angle correlated with toe pronation and a positive family history. Twenty-two patients had an AOFAS score of 90-100, seven of 80-89 and one less than 69., Conclusion: Hallux valgus in this group of male patients was not associated with limited ankle dorsiflexion or pes planus. Men with toe pronation and a positive family history had a greater hallux valgus deformity than those without after a distal soft tissue repair with proximal first metatarsal osteotomy. There was no evidence of first ray hypermobility after a DSTP-PMO.

Plantar fasciitis or heel spur syndrome usually resolves with conservative management, but for patients with continued pain, surgical intervention is often pursued. In some cases, plantar fasciitis is relieved, but pain in the lateral column area appears postoperatively. This lateral column pain may be debilitating for the patient and often overlooked by the foot and ankle surgeon. The goal of the study was to identify the maximum amount of plantar fascia that can be surgically released to treat recalcitrant heel pain effectively while preventing the development of lateral column symptoms. All patients undergoing plantar fasciotomy after failing conservative treatment were eligible to participate. Patients rated their pain with an 11-point (0-10) visual analog scale (VAS) and described its location prior to and at monthly intervals after their surgery. Surgeons recorded whether 25, 50, or 66% of the plantar fascia was released during surgery. Open procedures were performed 72% of the time, and endoscopically in 28% of the patients. Key outcome variables included degree of fascial release and foot structure. Patients (n = 47) with lateral column pain after surgery (n = 15 feet) had a mean +/- S.E. of 60.6 +/- 3.0% of their plantar fascia released while those without pain (n = 35 feet) had only 48.7 +/- 1.9% of this fascia released during surgery (ANOVA, p = .019). Age, weight, body mass index, gender, smoking status, comorbidities, general health, surgical procedure, postoperative care, calcaneal inclination angle, and talar declination angle did not differ for these groups (p > .146). For this patient population, regardless of surgical technique (endoscopic or open release), lateral column symptoms were more likely to result when more than 50% of the plantar fascia was released. The report proposes that a maximum of 50% of the plantar fascia be released during surgery.

The Maxwell-Brancheau arthroereisis (MBA) implant is currently used in treating flexible flatfoot deformities in children and adults. However, no guidelines have been established to determine the degree of correction with the five different MBA implant sizes (6-, 8-, 9-, 10-, and 12-mm diameters). A biomechanical analysis of these implants was performed in fresh-frozen cadaver limbs to quantitate the effects on subtalar joint (STJ) motion restriction and radiographic angles. This study found a restriction of subtalar joint range of motion that ranged from 32.0 +/- 5.4%, 44.8 +/- 7.7%, 59.0 +/- 7.2%, 65.5 +/- 8.7%, and 76.8 +/- 7.6% restriction with successively larger sized implants respectively (p < .001). Repeated measures analysis of variance (ANOVA) revealed alterations in the first intermetatarsal, lateral talo-first metatarsal, talar declination, calcaneal inclination, and first metatarsal declination angles with successively larger implant use. Analysis of the dorsal talo-first metatarsal, talo-second metatarsal, lateral talocalcaneal angles, and first to fifth metatarsal head splay showed no changes as implant size was altered. The study also attempted to assess the effects on the tendo Achillis when the subtalar joint was changed from a pronated to a supinated position. The observations showed a 6.33 +/- 1.40% (p = .001) increase in tendon length which suggests increased tension to the tendon. These findings can aid the surgeon in selection of the MBA implant size based on the desired amount of subtalar joint motion restriction. In turn, this may reduce errors in the correction of flexible flatfoot with the MBA implant.

This biomechanical study investigated the functional role of the posterior tibial tendon (PTT) in acquired flatfoot mechanics. Acquired flatfoot deformity has been attributed to PTT dysfunction; however, the progression from acute dysfunction to end-stage deformity has not been fully demonstrated. Eight human cadaver lower leg and foot specimens were used in two phases of experimental testing. In Phase 1, intact (normal) specimens were loaded to simulate (a) heel strike, (b) stance, and (c) heel rise both with and without PTT function. Then, each specimen was subjected to a procedure designed to create a simulated flatfoot deformity. The resulting flattened feet were used in Phase 2 to examine the effect of restoring PTT function to a flatfoot model. During both phases of testing, the 3-D kinematic orientation of the hindfoot complex was recorded. Small but statistically significant changes in the angular orientation of the hindfoot complex were observed, during both Phase 1 and 2 testing, when comparing the effects of a functional and dysfunctional PTT. The greatest angular changes were recorded during heel rise. For the normal foot, the small changes observed in the orientation of the hindfoot complex following release of the PTT load suggest that the intact osteo-ligamentous structure of the hindfoot is initially able to maintain normal alignment following acute PTT dysfunction. Once the soft tissues have been weakened, as in our flatfoot model, the PTT had little effect in overcoming the soft tissue laxity to correct the position of the foot.

The hypermobile first ray has been implicated as contributing to the cause and progression of hallux valgus deformity. Deformity of the hallux is often accompanied by an enlarged first intermetatarsal (IM 1-2) angle. It has been hypothesized that subjects having an abnormally large IM 1-2 angle have laxity of the first ray. Objectives of this study were to compare dorsal mobility of the first ray in subjects with hallux valgus to asymptomatic controls, and to investigate the relationship between dorsal mobility and the IM 1-2 angle. Fourteen subjects (age 23-81) with hallux valgus were matched by gender and age to control subjects. The IM 1-2 angle was measured from radiographs. A load-cell device measured dorsal mobility of the first ray under a standard load of 55 N. Pearson's correlation coefficient identified a marginal correlation (r = .51) between IM 1-2 angle and dorsal mobility. An independent t-test showed a statistically (P < 0.01) larger amount of dorsal mobility in the group of subjects having hallux valgus. Mobility of the first ray was increased in subjects with hallux valgus and a large IM 1-2 angle may be an indicator of increased dorsal mobility.

Hallux valgus (HV) deformity is not always accompanied by pain. We compared roentgenograms of 32 feet of people with HV deformity and pain to roentgenograms of 22 feet of people with painless HV deformity. Twenty-three feet without HV deformity or pain were used as controls. Weightbearing and nonweightbearing roentgenograms of the lateral talar-first metatarsal angle showed a statistically significant difference between feet with deformity and pain compared with feet with painless HV, or compared with normal feet. Changes in the angles of HV between weightbearing and nonweight-bearing situations showed significant differences between HV feet and normal feet, whether or not they had pain. In HV patients, increased mobility in the sagittal plane may play a considerable role in the development of pain.

The Lapidus arthrodesis was originally described for the surgical correction of hallux valgus associated with metatasus primus adductus. It was popularized on the adult patient with moderate to severe hallux valgus deformity. However, the authors present a retrospective review of 23 adolescents between the ages of 13 and 20 who underwent the procedures. Characteristics of adolescent hallux valgus include a smaller dorsal medial eminence, less valgus rotation of the hallux, and certain mechanical influences. These influences may include a generalized increase in motion at the first metatarsocuneiform joint. The modified Lapidus arthrodesis eliminates motion at the first metatarsocuneiform joint and therefore directly addresses an etiology of the deformity. Both preoperative and postoperative radiographs were evaluated for reduction in the 1-2 intermetatarsal angle. Patients were evaluated through either chart review or telephone interview for present activity level, comfortable footgear, and overall satisfaction of the procedure. Twenty-seven out of 30 feet (90%) had either a good or excellent result with only three complications and two recurrences over a mean follow-up of 61 months.

A biomechanical model was used to calculate the mechanical properties of the foot at a load of 683 newtons, while changing arch height with and without the plantar fascia. An increase in arch height from 20 mm to 60 mm decreased predicted vertical displacement of the foot from 11.8 mm to 5.5 mm with the plantar fascia intact and from 13.5 mm to 7.5 mm without the plantar fascia. The amount of horizontal elongation decreased from 8.6 mm to 8.4 mm with the plantar fascia and increased from 9.8 mm to 11.7 mm without. A 60-mm arch height yielded a 40% increase in horizontal elongation and a 36% increase in vertical displacement when the plantar fascia was cut, whereas a 20-mm arch height yielded a 13% increase in horizontal elongation and a 14% increase in vertical displacement. A change in arch height from 20 mm to 60 mm increased stiffness of the foot with and without the plantar fascia.

Eleven fresh-frozen cadaver foot specimens were tested to define changes in tarsal alignment associated with flatfoot, or pes planus, a common clinical problem. The three-dimensional position of four bones (talus, calcaneus, navicular, and first metatarsal) relative to the fixed tibia was determined with a magnetic tracking system in the intact foot and flatfoot conditions. In the flatfoot, the average metatarsal-to-talar position difference was 11.7 degrees +/-4.4 degrees in abduction (P < 0.0001), 10.4 degrees +/-3.6 degrees in dorsiflexion (P < 0.0001), and 10.9 degrees +/-6.0 degrees in eversion (P < 0.0001) compared with the intact foot. The average calcaneal-to-talar position difference was 2.2 degrees +/-2.6 degrees in abduction (P=0.0171) and 2.7 degrees+/-2.0 degrees in eversion (P=0.0012) compared with the intact foot. The average navicular-to-talar position difference was 13.6 degrees +/-5.0 degrees in abduction (P < 0.0001), 10.5 degrees +/-6.6 degrees in dorsiflexion (P=0.0004), and 8.1 degrees +/-3.8 degrees in eversion (P < 0.0001) compared with normal. The average talar-to-tibial position difference was -8.2 degrees +/-3.2 degrees in dorsiflexion (P < 0.001) compared with the intact foot. The average arch height difference was 6.0+/-2.7 mm (P < 0.0001) less than the normal condition. The deformity associated with flatfoot is complex and occurs in multiple joints and in all three planes. An understanding of the normal and pathologic (flatfoot) conditions is necessary to surgically restore appropriate alignment and function in hindfoot reconstruction operations.

Intrinsic material properties and histomorphometry of freshly frozen, human cadaveric cartilage from the second metatarsal intermediate cuneiform (SMIC) articulation were obtained to provide biomechanical mapping of the surfaces. The biphasic creep indentation methodology and an automated creep indentation apparatus were used to measure aggregate modulus, Poisson's ratio, permeability, shear modulus, and thickness. Biomechanical experiments were performed on four sites of the SMIC joint in 14 specimens (seven pairs): two sites in the second metatarsal base and two sites in the intermediate cuneiform head. Results of the study indicate that no significant variations exist in the biomechanical comparisons between specific articulations, gross articulations, and left and right joints. For example, cartilage from the second metatarsal base and intermediate cuneiform head had an aggregate modulus of 0.99 MPa and 1.05 MPa, respectively. The Poisson's ratio and permeability of all test sites grouped together were found to be 0.08 and 3.05 x 10(-15) m4/N.s, respectively. Cartilage thickness was measured at 0.61 mm. This biomechanical study suggests that similarities in cartilage properties may be beneficial in preventing the human SMIC articulation from developing early degenerative changes. Histological evaluation demonstrated that SMIC cartilage exhibits structural characteristics (such as the absence of chondrocyte columnar arrangement in the deep zone) which may be typical of cartilage that does not experience habitually high compressive stresses. This knowledge could aid surgeons in generating a deeper perspective of the relationship between clinical pathologies of articular cartilage and intrinsic biomechanical etiologies of degenerative joint diseases.