Structures involved in posterior tibial tendon dysfunction

NewsBot · Dec 19, 2021

A Computational Model of Force within the Ligaments and Tendons in Progressive
Collapsing Foot Deformity
Hamed Malakoutikhah, Erdogan Madenci, L. Daniel Latt
University of Arizona, Tucson, AZ

Background: Progressive collapsing foot deformity results from degeneration of the ligaments and the
posterior tibial tendon (PTT). Our understanding of the relationship between the failures of them remains
incomplete. We sought to improve this understanding through computational modeling of force in these
soft tissues.
Methods: The impact of PTT and ligament tears on force changes in the remaining ligaments was
investigated by quantifying ligament force changes during simulated ligament and tendon cutting in a
previously validated finite element model of the foot. The ability of the PTT to restore foot alignment in
a collapsed foot was evaluated by increasing the PTT force in a foot with attenuated ligaments and
comparing the alignment angles to the intact foot.
Results: Rupture of any one of the ligaments led to overloading the remaining ligaments, except for the
plantar naviculocuneiform, first plantar tarsometatarsal, and spring ligaments, where removing one led to
unloading the other two. The attenuation of the plantar fascia, long plantar, short plantar, and spring
ligaments significantly overloaded the deltoid and talocalcaneal ligaments. Isolated PTT rupture had no
effect on foot alignment, but did increase the force in the deltoid and spring ligaments. Increasing the force
within the PTT to 30% of body weight was effective at restoring foot alignment during quiet stance,
primarily through reducing hindfoot valgus and forefoot abduction as opposed to improving arch height.
Conclusion: The attenuation of any one ligament often leads to overload of the remaining ligaments which
may lead to progressive degeneration. The PTT can maintain alignment in the collapsing foot, but at an
increased load which could lead to its injury. Early intervention, in the form of ligament repair or
reconstruction, might be used to prevent the progression of deformity. Moreover, strengthening the PTT
through therapeutic exercise might improve its ability to restore foot alignment.
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NewsBot · Dec 22, 2021

The role of medial ligaments and tibialis posterior in stabilising the medial longitudinal foot arch: a cadaveric gait simulator study
JorisRobberechta
Foot and Ankle Surgery; 21 December 2021

Background
Debate exists whether adult acquired flatfoot deformity develops secondary to tibialis posterior (TibPost) tendon insufficiency, failure of the ligamentous structures, or a combination of both.

Aim
The aim of this study is to determine the contribution of the different medial ligaments in the development of acquired flatfoot pathology. Also to standardise cadaveric flatfoot models for biomechanical research and orthopaedic training.

Methods
Five cadaveric feet were tested on a dynamic gait simulator. Following tests on the intact foot, the medial ligaments – fascia plantaris (FP), the spring ligament complex (SLC) and interosseous talocalcaneal ligament (ITCL) – were sectioned sequentially. Joint kinematics were analysed for each condition, with and without force applied to TibPost.

Results
Eliminating TibPost resulted in higher internal rotation of the calcaneus following the sectioning of FP and SLC (d>1.28, p=0.08), while sectioning ITCL resulted in higher external rotation without TibPost (d=1.24, p=0.07). Sequential ligament sectioning induced increased flattening of Meary’s angle.

Conclusion
Function of TibPost and medial ligaments is not mutually distinctive. The role of ITCL should not be neglected in flatfoot pathology; it is vital to section this ligament to develop flatfoot in cadaveric models.
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NewsBot · Dec 27, 2021

The role of medial ligaments and tibialis posterior in stabilising the medial longitudinal foot arch: a cadaveric gait simulator study
JorisRobberechta et al
Foot and Ankle Surgery; 21 December 2021

Background
Debate exists whether adult acquired flatfoot deformity develops secondary to tibialis posterior (TibPost) tendon insufficiency, failure of the ligamentous structures, or a combination of both.

Aim
The aim of this study is to determine the contribution of the different medial ligaments in the development of acquired flatfoot pathology. Also to standardise cadaveric flatfoot models for biomechanical research and orthopaedic training.

Methods
Five cadaveric feet were tested on a dynamic gait simulator. Following tests on the intact foot, the medial ligaments – fascia plantaris (FP), the spring ligament complex (SLC) and interosseous talocalcaneal ligament (ITCL) – were sectioned sequentially. Joint kinematics were analysed for each condition, with and without force applied to TibPost.

Results
Eliminating TibPost resulted in higher internal rotation of the calcaneus following the sectioning of FP and SLC (d>1.28, p = 0.08), while sectioning ITCL resulted in higher external rotation without TibPost (d = 1.24, p = 0.07). Sequential ligament sectioning induced increased flattening of Meary’s angle.

Conclusion
Function of TibPost and medial ligaments is not mutually distinctive. The role of ITCL should not be neglected in flatfoot pathology; it is vital to section this ligament to develop flatfoot in cadaveric models.
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NewsBot · Jan 8, 2022

The contribution of the ligaments in progressive collapsing foot deformity: A comprehensive computational study.
Malakoutikhah H, Madenci E, Latt LD
Journal of Orthopaedic Research : Official Publication of the Orthopaedic Research Society, 03 Jan 2022,

The contribution of each of the ligaments in preventing the arch loss, hindfoot valgus, and forefoot abduction seen in progressive collapsing foot deformity (PCFD) has not been well characterized. An improved understanding of the individual ligament contributions to the deformity would aid in selecting among available treatments, optimizing current surgical techniques, and developing new ones. In this study, we evaluated the contribution of each ligament to the maintenance of foot alignment using a finite element model of the foot reconstructed from computed tomography scan images. The collapsed foot was modeled by simulating the failure of all the ligaments involved in PCFD. The ligaments were removed one at a time to determine the impact of each ligament on foot alignment, and then restored one at a time to simulate isolated reconstruction. Our findings show that the failure of any one ligament did not immediately lead to deformity, but that combined failure of only a few (the plantar fascia, long plantar, short plantar, deltoid, and spring ligaments) could lead to significant deformity. The plantar fascia, deltoid, and spring ligaments were primarily responsible for the prevention of arch collapse, hindfoot valgus, and forefoot abduction, respectively. Moreover, to produce deformity, a considerable amount of attenuation in the spring, tibiocalcaneal, interosseous talocalcaneal, plantar naviculocuneiform, and first plantar tarsometatarsal ligaments, but only a small amount in the plantar fascia, long plantar, and short plantar ligaments was needed. The results of this study suggest that the ability of a ligament to prevent deformity may not correlate with its attenuation in a collapsed foot.
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NewsBot · Jan 20, 2022

The contribution of the ligaments in progressive collapsing foot deformity: A comprehensive computational study
Hamed Malakoutikhah et al
J Orthop Res. 2022 Jan 3

The contribution of each of the ligaments in preventing the arch loss, hindfoot valgus, and forefoot abduction seen in progressive collapsing foot deformity (PCFD) has not been well characterized. An improved understanding of the individual ligament contributions to the deformity would aid in selecting among available treatments, optimizing current surgical techniques, and developing new ones. In this study, we evaluated the contribution of each ligament to the maintenance of foot alignment using a finite element model of the foot reconstructed from computed tomography scan images. The collapsed foot was modeled by simulating the failure of all the ligaments involved in PCFD. The ligaments were removed one at a time to determine the impact of each ligament on foot alignment, and then restored one at a time to simulate isolated reconstruction. Our findings show that the failure of any one ligament did not immediately lead to deformity, but that combined failure of only a few (the plantar fascia, long plantar, short plantar, deltoid, and spring ligaments) could lead to significant deformity. The plantar fascia, deltoid, and spring ligaments were primarily responsible for the prevention of arch collapse, hindfoot valgus, and forefoot abduction, respectively. Moreover, to produce deformity, a considerable amount of attenuation in the spring, tibiocalcaneal, interosseous talocalcaneal, plantar naviculocuneiform, and first plantar tarsometatarsal ligaments, but only a small amount in the plantar fascia, long plantar, and short plantar ligaments was needed. The results of this study suggest that the ability of a ligament to prevent deformity may not correlate with its attenuation in a collapsed foot.
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NewsBot · Feb 3, 2022

Middle Facet Subluxation Correlation with Foot and Ankle Offset in the Assessment of Progressive Collapsing Foot Deformity
Connor Maly, Nacime S. Mansur, MD, Matthieu Lalevee, MD, ...
Foot & Ankle Orthopaedics January 21, 2022

Introduction/Purpose:
Identifying markers of severity and progression in Progressive Collapsing Foot Deformity (PCFD) provides surgeons with critical information, possibly aiding in the decision making along the treatment algorithm. Subtalar middle facet subluxation (MFS), the percent undercoverage of the talus in relation to its calcaneus counterpart, was recognized as a reliable marker in weight-bearing computerized tomography (WBCT) for PCFD diagnosis. The Foot and Ankle Offset (FAO), the relative position between the center of the ankle joint and the foot tripod, is a three-dimensional WBCT tool predictive of disease severity. Our objective is to assess the relationship between the amount of MFS and FAO in flexible PCFD patients. We hypothesize that MFS is a reliable assessment of disease severity and correlates with FAO.

Methods:
In this retrospective IRB-approved comparative study, a total of 56 individuals with PCFD (74 feet) who underwent WBCT for baseline assessment were analyzed. Two blinded fellowship-trained foot and ankle surgeons performed the measurements. MFS was executed in the coronal-plane, at the midpoint (on sagittal-plane) of the middle facet (see attached figure). Dedicated software was utilized to perform the FAO, using the most plantar voxels of the first metatarsal, fifth metatarsal, calcaneal tuberosity and centre of the ankle. Interobserver agreement was quantified for MFS and FAO using intraclass correlation coefficient (ICC). Intermethod agreement between MFS and FAO was assessed by Spearman's correlation. Bivariate linear regression analysis was used to assess the relationship between MFS and FAO. A partition prediction model and multivariate analysis were utilized to assess influence of MFS measurements on FAO values and vice versa.

Results:
A total of 56 patients (74 feet) were included in the study. The ICCs for interobserver reliability was 0.87 for MFS and 0.95 for FAO. In a bivariate analysis, MFS and FAO were found to be significantly and linearly correlated (P< 0.0001, R2 0.26). Foot Angle Offset = 2.22 + 0.12*Medial Facet Subluxation (%). In multivariate analysis, FAO and body mass index (BMI) were significantly correlated with MFS (<0.001 and 0.02, respectively). The partition prediction model demonstrated that an MFS of 27.5% was an important threshold for increased FAO, with FAO of 3.4% +-2.4% when MFS was below threshold and 8.0% +-3.5% when above threshold.

Conclusion:
We found a positive linear correlation between MFS and FAO measurements. An MFS of 27.5% was an important threshold for higher FAO values, which corresponded to a worst overall alignment. Our results are consistent with the idea that MFS is a reliable marker for PCFD diagnoses and severity, correlating well with the FAO. This data may support clinical decisions in PCFD patients. Also, BMI was found to be positively correlated with MFS. Future prospective and longitudinal studies are needed to confirm the findings of this study
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NewsBot · Feb 13, 2022

Does tibialis posterior dysfunction correlate with a worse radiographic overall alignment in Progressive Collapsing Foot Deformity? A retrospective study
MatthieuLalevéeab et al
Foot and Ankle Surgery; 12 February 2022

Background
Posterior Tibial Tendon (PTT) dysfunction is considered to have an important role in Progressive Collapsing Foot Deformity (PCFD). The objective of our study was to assess the relationship between PTT status and three-dimensional foot deformity in PCFD.

Methods
Records from 25 patients with PCFD were included for analysis. The PTT was considered deficient in patients with a positive single heel rise test or a deficit in inversion strength. Three-dimensional foot deformity was assessed using the Foot and Ankle Offset (FAO) from Weight-Bearing-CT imaging. Hindfoot valgus, midfoot abduction and medial longitudinal arch collapse were assessed on X-Rays using hindfoot moment arm, talonavicular coverage angle and Meary’s angle respectively. Deland and Rosenberg MRI classifications were used to classify PTT degeneration.

Results
PCFD with PTT deficit (13/25) had a mean FAO of 7.75+/-3.8% whereas PCFD without PTT deficit had a mean FAO of 6.68+/-3.9% (p=0.49). No significant difference was found between these groups on the hindfoot moment arm and the talonavicular coverage angle (respectively p=0.54 and 0.32), whereas the Meary’s angle was significantly higher in case of PCFD with PTT deficit (p=0.037). No significant association was found between PTT degeneration on MRI and FAO.

Conclusion
PCFD associated three-dimensional deformity, hindfoot valgus and midfoot abduction were not associated with PTT dysfunction. PTT dysfunction was only associated with a worse medial longitudinal arch collapse in our study.

Considering our results, it does not appear that PTT is the main contributor to PCFD.
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NewsBot · Mar 28, 2022

The impact of ligament tears on joint contact mechanics in progressive collapsing foot deformity: A finite element study
Hamed Malakoutikhah et al
Clin Biomech (Bristol, Avon). 2022 Mar 18

Background: Patients with longstanding progressive collapsing foot deformity often develop osteoarthritis of the ankle, midfoot, or hindfoot joints, which can be symptomatic or lead to fixed deformities that complicate treatment. The development of deformity is likely caused by ligament degeneration and tears. However, the effect of individual ligament tears on changes in joint contact mechanics has not been investigated.

Methods: A validated finite element model of the foot was used to compare joint contact areas, forces, and pressures between the intact and collapsed foot, and to evaluate the effect of individual ligament tears on joint contact mechanics.

Findings: Collapsing the foot resulted in an increase in contact pressure in the subtalar, calcaneocuboid, tibiotalar, medial naviculocuneiform, and first tarsometatarsal joints but a decrease in contact pressure in the talonavicular joint. Rupture of the spring ligament was the main contributor to increased calcaneocuboid and subtalar joint contact pressures and decreased medial naviculocuneiform and first tarsometatarsal joint contact pressures, as well as talonavicular subluxation. Deltoid ligament rupture was the primary source of increased contact pressure in the medial naviculocuneiform, first tarsometatarsal, and tibiotalar joints.

Interpretation: Degenerative tearing of the ligaments in flatfoot deformity leads to increased joint contact pressures, primarily in the calcaneocuboid, subtalar, and tibiotalar joints, which has been implicated in the development of osteoarthritis in these joints. An improved understanding of the relationship between ligament tears and joint contact pressures could provide support for the use of ligament reconstructions to prevent the development of arthrosis.
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NewsBot · Apr 9, 2022

The impact of ligament tears on joint contact mechanics in progressive collapsing foot deformity: A finite element study
Hamed Malakoutikhah et al
March 18, 2022

Highlights
•Spring ligament rupture increases calcaneocuboid and subtalar joint contact pressures.
•A ruptured spring ligament reduces the load in the medial column.
•Deltoid ligament rupture increases ankle joint contact pressure.
•A ruptured deltoid ligament increases the load in the medial column.
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Background
Patients with longstanding progressive collapsing foot deformity often develop osteoarthritis of the ankle, midfoot, or hindfoot joints, which can be symptomatic or lead to fixed deformities that complicate treatment. The development of deformity is likely caused by ligament degeneration and tears. However, the effect of individual ligament tears on changes in joint contact mechanics has not been investigated.
Methods
A validated finite element model of the foot was used to compare joint contact areas, forces, and pressures between the intact and collapsed foot, and to evaluate the effect of individual ligament tears on joint contact mechanics.
Findings
Collapsing the foot resulted in an increase in contact pressure in the subtalar, calcaneocuboid, tibiotalar, medial naviculocuneiform, and first tarsometatarsal joints but a decrease in contact pressure in the talonavicular joint. Rupture of the spring ligament was the main contributor to increased calcaneocuboid and subtalar joint contact pressures and decreased medial naviculocuneiform and first tarsometatarsal joint contact pressures, as well as talonavicular subluxation. Deltoid ligament rupture was the primary source of increased contact pressure in the medial naviculocuneiform, first tarsometatarsal, and tibiotalar joints.
Interpretation
Degenerative tearing of the ligaments in flatfoot deformity leads to increased joint contact pressures, primarily in the calcaneocuboid, subtalar, and tibiotalar joints, which has been implicated in the development of osteoarthritis in these joints. An improved understanding of the relationship between ligament tears and joint contact pressures could provide support for the use of ligament reconstructions to prevent the development of arthrosis.
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NewsBot · Apr 14, 2022

Does Tibialis Posterior Dysfunction Correlate with Overall Foot Deformity in Progressive Collapsing Foot Deformity?
Matthieu Lalevée, MD, Nacime S. Mansur, MD, Kepler Carvalho, MD, ...
Foot & Ankle Orthopaedics April 9, 2022

Introduction/Purpose:
Posterior Tibial Tendon (PTT) dysfunction is considered to play an important role in Adult Acquired Flatfoot Deformity recently renamed Progressive Collapsing Foot Deformity (PCFD). Previous flatfoot classifications are mainly based on a progressive mechanical failure of the PTT causing chronological appearance of deformities. A consensus of experts recently met and decided to remove the central place of the PTT dysfunction from the PCFD classification system. The primary objective of our study was to assess the relation between the PTT clinical status and the three-dimensional overall foot deformity. The secondary objective was to assess the relation between the degeneration of PTT at the MRI and the three- dimensional overall foot deformity. We hypothesized that the more damaged the PTT, the more severe the deformity of the foot.

Methods:
We retrospectively identified all symptomatic PCFD over 18 years old who consulted our center from 01/01/2019 to 12/31/2020. PCFD with concomitant (< 3 mois) clinical examination, Weight-Bearing CT (WBCT) and MRI were included. PCFD presenting with previous surgical intervention were excluded. Finally 25 PCFD were included in the analysis (19 Women, mean age 53.96+/-14.9 years, mean BMI 33.2+/-8.1 kg/m2A PCFD presenting either a deficit on the single heel rise test or a decrease in inversion strength (superior or equal to 3/5) was classified PTT deficient. The MRI of all these PCFD were analyzed, and PTT degeneration was classified according to Deland and Rosenberg classifications. The three-dimensional overall deformity of each PCFD was assessed on WBCT by the Foot and Ankle Offset (FAO). Normality of different variables were assessed using Shapiro- Wilk test. Comparisons were performed using Student's t-test or Anova for normal, and Mann-Whitney or Kruskal-Wallis's test for non-normal variables.

Results:
Patients with clinically deficient PTT (13/25 PCFD, 52%) had a mean FAO of 7.75+/-3.8% whereas patients without PTT deficit (12/25 PCFD, 48%) had a mean FAO of 6.68+/-3.9%, without significant difference between groups (p=0.49). According to Deland classification, 4/25 PTT (16%) were classified grade 0, 7/25 (28%) grade 1, 4/25 (16%) grade 2, 5/25 (20%) grade 3 and 5/25 (20%) grade 4 without any significant difference between groups (p=0.36).According to Rosenberg classification, 4/25 PTT (16%) were classified type 0, 15/25 (60%) type 1, 2/25 (8%) type 2 and 4/25(16%) type 3 without any significant difference between groups (p=0.79).Seven PCFD had a FAO>10%. Among them, 42.9% had a PTT without clinical deficit and 57.1% had a PTT with little or no damage on the MRI. Nine PCFD had a FAO<5%. Among them, 44.4% had a PTT clinically deficient and 22.2% had a PTT with important damage on the MRI.

Conclusion:
The importance of three-dimensional overall foot deformity in PCFD was neither correlated with the clinical presence or absence of PTT deficiency, nor with the PTT degeneration on MRI in our study. A patient with important deformity may have an intact PTT and a patient with small deformity can present a deficient PTT. Despite the obvious lack of power in this study, it does not appear that PTT plays a significant role in the PCFD overall deformity.
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NewsBot · May 18, 2022

A Computational Model of Force within the Ligaments and Tendons in Progressive Collapsing Foot Deformity
Hamed Malakoutikhah, Erdogan Madenci, L Daniel Latt
J Orthop Res. 2022 May 17

Progressive collapsing foot deformity results from degeneration of the ligaments and posterior tibial tendon (PTT). Our understanding of the relationship between their failures remains incomplete. We sought to improve this understanding through computational modeling of the forces in these soft tissues. The impact of PTT and ligament failures on force changes in the remaining ligaments was investigated by quantifying ligament force changes during simulated ligament and tendon cutting in a validated finite element model of the foot. The ability of the PTT to restore foot alignment was also evaluated by increasing the PTT force in a foot with attenuated ligaments and comparing the alignment angles to the intact foot. We found that failure of any one of the ligaments led to overloading the remaining ligaments, except for the plantar naviculocuneiform, first plantar tarsometatarsal, and spring ligaments, where removing one led to unloading the other two. The combined attenuation of the plantar fascia, long plantar, short plantar, and spring ligaments significantly overloaded the deltoid and talocalcaneal ligaments. Isolated PTT rupture had no effect on foot alignment but did increase the force in the deltoid and spring ligaments. Moreover, increasing the force within the PTT to 30% of body weight was effective at restoring foot alignment during quiet stance, primarily through reducing hindfoot valgus and forefoot abduction as opposed to improving arch collapse. Our findings suggest that early intervention might be used to prevent the progression of deformity. Moreover, strengthening the PTT through therapeutic exercise might improve its ability to restore foot alignment.
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NewsBot · May 30, 2022

Histologic grading correlates with inflammatory biomarkers in tibialis posterior tendon dysfunction
Richard M.DanilkowiczSelene G.ParekhDavid M.TainterNicholasAllenJeffreyO’DonnellAndrewHanselmanSamuel B.Adams
Foot and Ankle Surgery

Background
It has been theorized that tibialis posterior tendon dysfunction (TPTD) is a degenerative process unrelated to inflammation. The purpose of this study was to determine if inflammatory cytokines, matrix metalloproteases (MMPs), and glutamate were elevated in diseased tibialis posterior tendons (TPTs).

Methods
Matched diseased TPT, TPT insertion, and flexor digitorum longus (FDL) samples were collected from 21 patients. The samples were individually incubated in media, which was analyzed for inflammatory cytokines, MMPs, and glutamate. Histology and statistical analyses were performed.

Results
Diseased TPT and TPT insertion were significantly elevated compared to transferred FDL in eight inflammatory markers (p<0.005). Only the diseased TPT was significantly elevated compared to the transferred FDL tendons for glutamate (p<0.01). Histologic grading correlated with inflammatory cytokine levels.

Conclusion
Diseased TPT and TPT insertion demonstrated significantly elevated levels of inflammatory markers compared to the transferred tendons used as controls, suggesting a role for inflammation in the disease process. The amount of inflammation correlated with increased tendon degradation.
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NewsBot · May 31, 2022

ULTRASONOGRAPHIC CHANGES OF PLANTAR FASCIA IN PATIENTS WITH PLANTAR FASCIITIS DUE TO ACQUIRED FLAT FOOT
O. Turchin et al
Annals of the Rheumatic Diseases 2022;81:1795.

Background Plantar fasciitis is a chronic degenerative process of the plantar fascia enthesis. It manifests by pain, predisposition to prolonged course and treatment resistance. In many cases, plantar fasciitis develops in patients with acquired flat feet. Taken into consideration above mentioned, the study of the plantar fascia changes in patients with acquired flat feet by sonography is relevant.

Objectives To investigate the quantitative and qualitative sonographic changes of the plantar fascia in the case of plantar fasciitis in patients with acquired flat foot.

Methods 190 patients with plantar fasciitis on the basis of acquired flat feet (133 females and 57 males). The average age of patients was 48 ± 0.97 years (18-81years). Unilateral pathology was noted in 117 patients and bilateral – in 73 patients. The average body mass index was 27.68±0.3. The average duration of pain syndrome was 101 ± 6.0 days (7-390 days). The pain syndrome lasted up from 1 to 6 months – in 152 patients, and more than 6 months – in 38 patients. The control group included 15 healthy volunteers (30 feet). Clinical radiological, sonographic, and statistical methods were used.

Results The main sonographic features were significant reduction in echogenicity, erased or missing fibrous pattern, fuzzy contour of the aponeurosis; and modified contour of the calcaneus; small focal hyperechogenicity points in enthesis were detected. Loci of vascularization were detected using power Doppler sonography. The average thickness of plantar fascia in the study group was 6,14±1,5 mm (2,3-7,7 mm) and in control group – 3,5±0,1 mm (2,5-4,4 mm).

Conclusion Sonographic signs of plantar fasciitis on the basis of acquired flat feet were changes in echogenicity and structure, changes in the contours of the cortical layer of enthesis and plantar fascia, the thickening of the enthesis of the plantar fascia of more than 4 mm.
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NewsBot · Sep 6, 2022

BIOMECHANICAL STUDY OF ADULT ACQUIRED
FLATFOOT FOR INTERVENTION
PENG YINGHU
PHD Thesis

Adult-acquired flatfoot (AAF) is a common foot deformity characterized by medial
longitudinal arch collapse, excessive hindfoot eversion, and pain and intolerance, which
was associated with a variety of lower limb symptoms, such as patellofemoral pain, ankle
pain, plantar fasciitis, and lower back pain. AAF individuals lack a stable arch support that
attenuates shock absorption, gait efficiency and plantar foot fatigue. Posterior tibial tendon
dysfunction (PTTD) is the common cause of AAF. Understanding the compensatory
mechanism led by PTTD could provide guidance for conservative and surgical treatments.
Meanwhile, orthotic and surgical treatments are normally prescribed depending on the
AAF stages. Customized foot orthoses (i.e., arch support) have been used clinically to
provide stability and relieve pain in early-stage. In stages III and IV, mid/hindfoot
arthrodesis are recommended to treat severe foot deformity. These salvage treatments
unavoidably impair mid/hindfoot mobility and may lead to foot pain and joint
degeneration over time. Clinicians and researchers endeavor to optimize procedures to
correct the foot misalignment and alleviate pain, whilst the procedures are normally
empirical. Existing literature targeted on the muscle and joint biomechanics of AAF and
may not adequately address the internal loading distribution essential to understand and
improve the biomechanical performance of treatments with the existing foot models.
Therefore, the overall purposes of the study were to investigate the internal biomechanical
characteristics of the flatfoot and identify the effects of orthotic and surgical treatments
by adopting the musculoskeletal multibody and finite element foot models. The
biomechanical study evaluated the effects of tibialis posterior (TP) weakness and foot
orthosis on the lower limb mechanics of AAF. Subsequently, we investigated the
performance of customized foot orthosis (different arch support heights) and mid/hindfoot
arthrodesis.
The first study examined the impacts of TP weakness on lower limb mechanics in
individuals with foot orthosis via gait analysis and musculoskeletal modelling. The results
indicated that TP weakness increased the ankle joint force in the superior-inferior direction
but decreased in the anterior-posterior direction. The flexor hallucis longus and flexor
digitorum longus forces increased with the decreased TP strength. Foot orthosis
significantly reduced the second peak knee force, peak ankle force, and most muscle
forces. We believed that TP weakening might cause compensatory muscle activation and
attenuated joint load. The orthosis could correct aberrant muscle and joint mechanics in
flatfoot individuals with TP weakness.

The second study investigated the internal foot biomechanics by reconstructing a muscle
driven foot-orthosis finite element (FE) model from a volunteer with flexible AAF. The
model enabled a three-dimensional representation of the plantar fascia and its interactions
with surrounding osteotendinous structures. The volunteer walked in foot orthosis with
different arch heights (low, normal, and high). Muscle forces during stance were estimated
by the multibody model and then applied to drive a FE foot model. The foot FE model
was validated by comparing the predicted foot pressures with measurements. The results
indicated that peak foot pressures decreased as the arch support height increased. However,
peak pressures of midfoot increased during all simulated instants. Meanwhile, the plantar
fascia loading decreased by 5% to 15.4% in proximal regions but increased for foot
orthosis with high arch support in the middle and distal regions. Although arch support
could decrease the peak foot pressure and plantar fascia loading, the excessive arch height
may induce high midfoot pressure and loadings at the central portion of the plantar fascia.
The third study evaluated the influence of mid/hindfoot arthrodeses on the internal foot
loading with the developed foot FE. The severe flatfoot model was developed from the
flexible flatfoot through the attenuation of ligaments and the unloading of the posterior
tibial muscle. The simulations of five mid/hindfoot arthrodeses (subtalar, talonavicular,
calcaneocuboid, double, and triple arthrodeses) and a control condition (no arthrodesis)
were performed simultaneously in the detailed foot multibody dynamics model and FE
model. Muscle forces calculated by a detailed multi-segment foot model and ground
reaction force were used to drive the FE model of the foot. The internal foot loadings
among the control and those arthrodeses conditions were compared. The results indicated
that the navicular heights in double and triple arthrodeses were higher than that in other
procedures, while the subtalar arthrodesis had the smallest values. Compared to the control
condition, five mid/hindfoot arthrodeses reduced the peak plantar fascia stress. However,
double and triple arthrodeses increased the peak medial cuneo-navicular joint contact
pressures and peak foot pressures as well as the metatarsal bones stresses. The proposed
computational platform can predict the biomechanical factors that lead to the
postoperative symptoms in patients with flatfoot, thus assisting the optimization of the
surgical procedures.
In conclusion, this study adopted musculoskeletal multibody and FE models to investigate
the lower limb mechanics and internal foot mechanics of AFF. This study identified the
compensatory muscle activation and attenuation of the joint load caused by TP weakness
that might be restored by the orthosis. Meanwhile, a muscle-driven flatfoot FE model was
developed and validated. The proposed model was adopted to investigate the effects of
orthosis insoles and five mid/hindfoot arthrodeses on the internal foot mechanics of AAF.
The developed foot models could provide a simulation platform that can perform
pathomechanics analysis, orthotic insole optimization and preoperative analysis for
surgical treatment for the flatfoot
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NewsBot · Oct 14, 2022

Comparison of in vivo hindfoot joints motion changes during stance phase between non-flatfoot and stage II adult acquired flatfoot
Zhenhan Deng et al
J Foot Ankle Res. 2022 Oct 13;15(1):74

Background: To compare the kinematic characteristics of hindfoot joints in stage II adult acquired flatfoot deformity (AAFD) with those of non-flatfoot through the 3D-to-2D registration technology and single fluoroscopic imaging system.

Methods: Eight volunteers with stage II AAFD and seven volunteers without stage II AAFD were recruited and CT scans were performed bilateral for both groups in neutral positions. Their lateral dynamic X-ray data during the stance phase, including 14 non-flatfeet and 10 flatfeet, was collected. A computer-aided simulated light source for 3D CT model was applied to obtain the virtual images, which were matched with the dynamic X-ray images to register in the "Fluo" software, so that the spatial changes during the stance phase could be calculated.

Results: During the early-stance phase, the calcaneous was more dorsiflexed, everted, and externally-rotated relative to the talus in flatfoot compared with that in non-flatfoot (p < 0.05). During the mid-stance phase, the calcaneous was more dorsiflexed and everted relative to the talus in flatfoot compared with that in non-flatfoot (p < 0.05); however, the rotation did not differ significantly between the two groups (p > 0.05). During the late-stance phase, the calcaneous was more plantarflexed, but less inverted and internally-rotated, relative to the talus in flatfoot compared with that in non-flatfoot (p < 0.05). During the early- and mid-stance phase, the navicular was more dorsiflexed, everted, and externally-rotated relative to the talus in flatfoot compared with that in non-flatfoot (p < 0.05). During the late-stance phase, the navicular was more plantarflexed, but less inverted and internally-rotated, relative to the talus in flatfoot compared with that in non-flatfoot (p < 0.05). There was no difference in the motion of cuboid between the two groups during the whole stance phase (p > 0.05).

Conclusions: During the early- and mid-stance phase, excessive motion was observed in the subtalar and talonavicular joints in stage II AAFD. During the late-stance phase, the motion of subtalar and talonavicular joints appeared to be in the dysfunction state. The current study helps better understanding the biomechanics of the hindfoot during non-flatfoot and flatfoot condition which is critical to the intervention to the AAFD using conservative treatment such as insole or surgical treatment for joint hypermotion.
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NewsBot · Nov 14, 2022

Coverage maps demonstrate 3D Chopart joint subluxation in weightbearing CT of progressive collapsing foot deformity
Andrew Behrens et al
Sci Rep. 2022 Nov 12;12(1):19367

A key element of the peritalar subluxation (PTS) seen in progressive collapsing foot deformity (PCFD) occurs through the transverse tarsal joint complex. However, the normal and pathological relations of these joints are not well understood. The objective of this study to compare Chopart articular coverages between PCFD patients and controls using weight-bearing computed tomography (WBCT). In this retrospective case control study, 20 patients with PCFD and 20 matched controls were evaluated. Distance and coverage mapping techniques were used to evaluate the talonavicular and calcaneocuboid interfaces. Principal axes were used to divide the talar head into 6 regions (medial/central/lateral and plantar/dorsal) and the calcaneocuboid interface into 4 regions. Repeated selections were performed to evaluate reliability of joint interface identification. Surface selections had high reliability with an ICC > 0.99. Talar head coverage decreases in plantarmedial and dorsalmedial (- 79%, p = 0.003 and - 77%, p = 0.00004) regions were seen with corresponding increases in plantarlateral and dorsolateral regions (30%, p = 0.0003 and 21%, p = 0.002) in PCFD. Calcaneocuboid coverage decreased in plantar and medial regions (- 12%, p = 0.006 and - 9%, p = 0.037) and increased in the lateral region (13%, p = 0.002). Significant subluxation occurs across the medial regions of the talar head and the plantar medial regions of the calcaneocuboid joint. Coverage and distance mapping provide a baseline for understanding Chopart joint changes in PCFD under full weightbearing conditions.
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NewsBot · Nov 21, 2022

Computational Modeling of Peritalar Joint Contact Mechanics in Flexible Flatfoot Deformity
Hamed Malakoutikhah, PhD candidate, Erdogan Madenci, PhD, and L. Daniel Latt, MD, PhD
Source

Introduction/Purpose:
Patients with longstanding progressive collapsing foot deformity (PCFD) often develop osteoarthritis of the peritalar (tibiotalar, subtalar, and talonavicular) joints, which can be symptomatic or can lead to fixed deformities that further complicate the treatment of other sequalae of the deformity (Mann, 1992). Degeneration and subsequent tearing of the arch supporting ligaments leads to altered joint contact mechanics which is a likely causative factor in the development of arthrosis (Hauser and Dolan, 2011). However, the initial effect of ligament tears on changes in joint contact mechanics in the collapsing foot has not been well characterized. The goal of this work was to compare the joint contact mechanics between the neutrally aligned and the flexible flatfoot (collapsed foot).
Methods:
A validated finite element model of the foot (Malakoutikhah et al., 2022a) was used to compare joint contact pressures between the normally aligned and the collapsed foot. The model of the foot constructed from CT scan images of a female cadaveric foot weighing 60 kg included all 28 bones, 72 ligaments, cartilage, and an encapsulating soft tissue. The model was loaded with 0.5 body weight applied at the center of mass and 0.25 body weight applied to the Achilles tendon simulating quiet stance. The collapsed foot model was created by simulated transection of the plantar fascia, long plantar, short plantar, deltoid, and spring ligaments and unloading of the posterior tibial tendon (Malakoutikhah et al., 2022b). The joint contact pressure maps were determined for both the neutrally aligned and collapsed foot models. The average and peak contact pressures were compared.
Results:
The peak contact pressures were increased in the tibiotalar and subtalar joints, but paradoxically were decreased in the talonavicular joint in the collapsed as compared to the neutrally aligned foot (Figure 1). The center of pressure was markedly different in all three joints between the neutral and collapsed foot conditions. Specifically, collapsing the foot caused two centers of the talonavicular joint peak pressure to shift towards the central region of the navicular bone, which were evenly distributed in the lateral and medial regions in the neutrally aligned foot. In the subtalar joint, the peak pressure that was uniformly distributed in the lateral and medial regions of the posterior facet in the neutrally aligned foot shifted towards the lateral region in the collapsed foot. Similarly, the peak contact pressure across the tibiotalar joint moved from the center to the lateral region when the foot collapsed.
Conclusion:
Degenerative tearing of the arch supporting ligaments in PCFD leads to an increase and laterization of the contact pressure in the tibiotalar and subtalar joints with a decrease of the pressure in the talonavicular joint. The paradoxical unloading of the talonavicular joint may be a result of the inability of the malaligned medial column to transmit force from the hindfoot to the forefoot. One implication of this work is that future treatments of PCFD might be directed towards normalizing contact pressure within the peritalar joints to prevent the progression of disease and the development of arthrosis.
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NewsBot · Mar 7, 2023

Axial Plane Rotation of the Talus in Progressive Collapsing Foot Deformity: A Weightbearing Computed Tomography Analysis
Jaeyoung Kim et al
Foot Ankle Int. 2023 Mar 2

Background: Progressive collapsing foot deformity (PCFD) is recognized as a 3-dimensional deformity centered around the talus. Previous studies have described some features of talar motion in the ankle mortise in PCFD, such as sagging in the sagittal plane or valgus tilt in the coronal plane. However, axial plane alignment of the talus in the ankle mortise in PCFD has not been investigated extensively. The purpose of this study was to examine this axial plane alignment of PCFD vs controls using weightbearing computed tomography (WBCT) images and to determine if talar rotation in the axial plane is associated with increased abduction deformity, as well as to assess the medial ankle joint space narrowing in PCFD that may be associated with axial plane talar rotation.

Methods: Multiplanar reconstructed WBCT images of 79 patients with PCFD and 35 control patients (39 scans) were retrospectively analyzed. The PCFD group was divided into 2 subgroups depending on preoperative talonavicular coverage angle (TNC): moderate abduction (TNC 20-40 degrees, n=57) and severe abduction (TNC >40 degrees, n=22). Using the transmalleolar (TM) axis as a reference, the axial alignment of the talus (TM-Tal), calcaneus (TM-Calc), and second metatarsal (TM-2MT) were calculated. Difference between TM-Tal and TM-Calc was calculated to examine talocalcaneal subluxation. A second method to assess talar rotation within the mortise utilized an angle between the lateral malleolus and the talus (LM-Tal) in the axial slices of WBCT. In addition, the prevalence of medial tibiotalar joint space narrowing was assessed. These parameters were compared between the control and PCFD groups, and between moderate and severe abduction groups.

Results: The talus was significantly more internally rotated with respect to the ankle TM axis and the lateral malleolus in PCFD patients compared to controls, and in the severe abduction group compared with the moderate abduction group, using both measurement methods. Axial calcaneal orientation did not differ between groups. There was significantly greater axial talocalcaneal subluxation in the PCFD group, and this was also greater in the severe abduction group. The prevalence of medial joint space narrowing was higher in PCFD patients.

Conclusion: Our findings suggest that talar malrotation in the axial plane should be considered an underlying feature of abduction deformity in PCFD. The malrotation occurs in both the talonavicular and ankle joints. This rotational deformity should be corrected at the time of reconstructive surgery, especially in cases of severe abduction deformity. In addition, medial ankle joint narrowing was observed in PCFD patients, with a higher prevalence of medial ankle joint narrowing in those with severe abduction.
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NewsBot · Mar 7, 2023

Evaluation of the heel external rotation test in soft tissue deficiencies associated with adult acquired flatfoot deformity (AAFD). A cadaver sectioning analysis
Cavan West et al
Foot (Edinb). 2023 Feb 22;55:101984

Background: To date, evaluation of the heel external rotation test has not been taken with respect to AAFD. Traditional 'gold standard' tests do not account for the contribution of the midfoot ligaments towards instability. These tests would be flawed as any midfoot instability may produce a false positive result.

Aims: To evaluate the differential contribution of the spring, deltoid and other local ligaments in external rotation generated at the heel.

Methods: Serial ligament sectioning was performed on 16 cadaveric specimens, with a 40 N-external rotation force applied to the heel. These were divided into four groups with different sequences of ligament sectioning. Measurements of the total amount/range of external, tibiotalar and subtalar rotation were made.

Results: The deep component of the deltoid ligament (DD) was the main ligament influencing heel external rotation (P < 0.05, in all cases), and acted primarily at the tibiotalar joint (87.9 %). The spring ligament (SL) influenced heel external rotation predominantly (91.2 %) at the subtalar joint (STJ). Greater than 20 degrees external rotation could only be achieved with DD sectioning. The interosseous (IO) and cervical (CL) ligaments did not significantly contribute to external rotation at either joint (P > 0.05).

Conclusion: Clinically relevant external rotation (>20 degrees) is solely attributable to DD failure in the presence of intact lateral ligaments (LL). This test may improve detection of DD instability and allow clinicians to subclassify patients with Stage 2 AAFD into those where DD may or may not be compromised.
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NewsBot · Apr 14, 2023

Joint coverage analysis in progressive collapsing foot deformity
Kassidy Knutson et al
J Orthop Res. 2023 Mar 9

Progressive collapsing foot deformity (PCFD) is characterized by a progressive subluxation of the peritalar bones and respective joints. Two-dimensional conventional radiographs are limited in their ability to visualize the peritalar bones and joints with adequate detail to describe the complex three-dimensional deformity. An improved understanding of the relationship between joint coverage and deformity would allow clinicians to use coverage analysis to distinguish among the stages of PCFD. The aim of this study was to analyze the joint coverage of the six articular relationships within the talocrural, subtalar, and Chopart joints using weightbearing computed tomography (WBCT) scans. Ten individuals with a flexible hindfoot and ten individuals with a rigid hindfoot presentation of PCFD were compared to twenty-seven asymptomatic control individuals. The three most relevant findings are: (I) the anterior-medial facet of the subtalar joint contains the greatest reduction in coverage for patients with a rigid deformity, (II) an increase in talonavicular overlap (TNO) moderately correlated with a decreased coverage in the: tibiotalar, anterior-medial subtalar, talonavicular joints, and (III) the calcaneocuboid joint lacks radiographic values to adequately quantify alignment and coverage. To conclude, there were significant differences in coverage area of various articulating regions throughout the hind- and midfoot when comparing PCFD patients to asymptomatic control individuals. Relevant radiographic measures correlating to articular coverage areas of clinical interest were identified, possibly helping to better quantify PCFD in clinical practice.
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NewsBot · May 23, 2023

Quantifying increased lateral column instability in Adult Acquired Flatfoot Deformity (AAFD)
David Chrastek et al
The Foot; 16 May 2023, 102036

AAFD comprises ligamentous failure and tendon overload, mainly focused on the symptomatic posterior tibial tendon and the spring ligament. Increased lateral column (LC) instability arising in AAFD is not defined or quantified. This study aims to quantify the increased LC motion in unilateral symptomatic planus feet, using the contralateral unaffected asymptomatic foot as an internal control.

In this case matched analysis, 15 patients with unilateral stage 2 AAFD foot and an unaffected contralateral foot were included. Lateral foot translation was measured as a guide to spring ligament competency. Medial and LC dorsal sagittal instability were assessed by direct measurement of dorsal 1st and 4th/5th metatarsal head motion and further video analysis.

The mean increase in dorsal LC sagittal motion (between affected vs unaffected foot) was 5.6 mm (95% CI [4.63 to 6.55], p<0.001). The mean increase in the lateral translation score was 42.8 mm (95% CI [37.48 to 48.03], p<0.001). The mean increase in medial column dorsal sagittal motion was 6.8 mm (95% CI [5.7 to 7.8], p<0.001). Video analysis also showed a statistically significant increase in LC dorsal sagittal motion between affected and unaffected sides (p<0.001).

This is the first study that quantifies a statistically significant increased LC dorsal motion in feet with AAFD. Understanding its pathogenesis and its link to talonavicular/spring ligament laxity improves foot assessment and may allow the development of future preventative treatment strategies.
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NewsBot · Jun 5, 2023

Quantifying increased lateral column instability in Adult Acquired Flatfoot Deformity (AAFD)
David Chrastek et al
Foot (Edinb). 2023 May 16

AAFD comprises ligamentous failure and tendon overload, mainly focused on the symptomatic posterior tibial tendon and the spring ligament. Increased lateral column (LC) instability arising in AAFD is not defined or quantified. This study aims to quantify the increased LC motion in unilateral symptomatic planus feet, using the contralateral unaffected asymptomatic foot as an internal control. In this case matched analysis, 15 patients with unilateral stage 2 AAFD foot and an unaffected contralateral foot were included. Lateral foot translation was measured as a guide to spring ligament competency. Medial and LC dorsal sagittal instability were assessed by direct measurement of dorsal 1st and 4th/5th metatarsal head motion and further video analysis. The mean increase in dorsal LC sagittal motion (between affected vs unaffected foot) was 5.6 mm (95% CI [4.63-6.55], p < 0.001). The mean increase in the lateral translation score was 42.8 mm (95% CI [37.48-48.03], p < 0.001). The mean increase in medial column dorsal sagittal motion was 6.8 mm (95% CI [5.7-7.8], p < 0.001). Video analysis also showed a statistically significant increase in LC dorsal sagittal motion between affected and unaffected sides (p < 0.001). This is the first study that quantifies a statistically significant increased LC dorsal motion in feet with AAFD. Understanding its pathogenesis and its link to talonavicular/spring ligament laxity improves foot assessment and may allow the development of future preventative treatment strategies.
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NewsBot · Jun 6, 2023

Progressive flatfoot deformity accompanied with avulsion and dislocation of accessory navicular
Shinya Adachi MD et al
Foot & Ankle Surgery: Techniques, Reports & Cases
Volume 3, Issue 2, Summer 2023, 100297

The accessory navicular is one of the most common accessory bones in the foot, and it is mostly asymptomatic. Symptomatic cases largely belong to type 2, which is characterized by the presence of a 1-3 mm synchondrosis between the large accessory navicular and the native navicular. Chronic injury to the synchondrosis is considered to be a major cause of symptoms. In this case report, we describe an uncommon case of an avulsed type 2 accessory navicular, which was dislocated to the level of the medial malleolus. A plantar slip existed between the accessory and the native naviculars, which enabled the patient to perform an active inversion of the foot, but not a single heel raise. The collapse of the medial longitudinal arch progressed rapidly over 4 months prior to surgery, with an increased lateral hindfoot pain, suggesting an impingement due to the progression of hindfoot valgus. Surgical treatments, including plication of the ruptured spring ligament, excision of the accessory navicular, and transfer of the flexor digitorum longus tendon, were successful in improving the symptoms and flatfoot deformity. This case represents an uncommon subtype of symptomatic accessory navicular with complete avulsion and dislocation, presenting as a posterior tibial tendon dysfunction disorder and progressive flatfoot deformity.
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NewsBot · Jul 19, 2023

Increase in lateral contact force in the tibiotalar joint during walking in flatfoot patients with reduced stiffness of the spring ligament
Yooha Son et al
Journal of Biomechanics; Volume 157, August 2023, 111711

Foot deformities in patients with flexible flatfeet, such as the flattened medial arch and hindfoot valgus, affect the force distribution around the tibiotalar joint during walking and increase the risk of secondary injuries. In this study, we developed a multi-segment foot model that could calculate the dynamics around the tibiotalar joint and investigated the difference in the kinetics between normal feet and feet with flatfoot. Ten participants with normal feet and ten with flexible flatfoot were enrolled in the study. The body kinematics, ground reaction force, and foot pressure of the participants were recorded during walking. A five-segment foot model was developed to calculate contact forces in the tibiotalar joint. A flatfoot model was developed by modifying the stiffness of the spring ligaments of a normal foot model. Ground reaction force was applied to the plantar surface of the foot models. The foot models were attached to a full-body musculoskeletal model to conduct inverse dynamic simulations of walking. Participants with flatfoot had significantly greater lateral contact force (1.19 BW vs. 0.80 BW) and more posteriorly located center of pressure (33.7 % vs. 46.6 %) in the tibiotalar joint than those with normal feet (p < 0.05). The average and peak posterior tibialis muscle forces were significantly larger in participants with flatfoot than in those with normal feet (3.06 BW vs. 2.22 BW; 4.52 BW vs. 3.33 BW). The altered mechanics may influence the risk of arthritis.
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NewsBot · Sep 27, 2023

Cervical Ligament Insufficiency in Progressive Collapsing Foot Deformity: It May Be More Important Than We Know
Jaeyoung Kim et al
Foot Ankle Int. 2023 Sep 22

Background: Subluxation at the subtalar joint is one of the major radiographic features that characterize progressive collapsing foot deformity (PCFD). Although it is recognized that the cervical ligament plays an important function in maintaining the subtalar joint's stability, its role and involvement in PCFD is largely unknown. The purpose of this study was to assess the prevalence of cervical ligament insufficiency in patients with PCFD and to establish if the degree of its pathology changes with increasing axial plane deformity.

Methods: This study retrospectively reviewed magnetic resonance imaging (MRI) of 78 PCFD patients and age- and gender-matched controls. The structures evaluated were the cervical, spring, and talocalcaneal interosseous ligaments. Structural derangement was graded on a 5-part scale (0-4), with grade 0 being normal and grade 4 indicating a tear of greater than 50% of the cross-sectional area. Plain radiographic parameters (talonavicular coverage angle [TNC], lateral talo-first metatarsal [Meary] angle, calcaneal pitch, and hindfoot moment arm) as well as axial plane orientation of the talus (TM-Tal) and calcaneus (TM-Calc) relative to the transmalleolar axis and talocalcaneal subluxation (Diff Calc-Tal) were correlated with the cervical ligament MRI grading system.

Results: The overall distribution of the degree of cervical ligament involvement was significantly different between the PCFD and control groups (P < .001). MRI evidence of a tear in the cervical ligament was identified in 47 of 78 (60.3%) feet in the PCFD group, which was significantly higher than the control group (10.9%) and comparable to that of superomedial spring (43.6%) and talocalcaneal interosseous (44.9%) ligaments. Univariate ordinal logistic regression modeling demonstrated a predictive ability of TM-Calc (odds ratio [OR] 1.17, 95% CI 1.06-1.30, P = .004), Diff Calc-Tal (OR 1.15, 95% CI 1.06-1.26, P = .002), TNC (OR 1.08, 95% CI 1.03-1.13, P = .003), and Meary angle (OR 1.05, 95% CI 1.02-1.10, P = .006) in determining higher cervical ligament grade on MRI.

Conclusion: This study found that cervical ligament insufficiency is more often than not associated with PCFD, and that an increasing axial plane deformity appears to be associated with a greater degree of insufficiency.
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NewsBot · Sep 29, 2023

Is a Keystone Bone Anomaly The Main Cause of Pes
Planus?
Ahmet Payas et al
Source

Background
In flexible pes planus, the height of the arcus pedis longitudinalis medialis (APLM) collapses during
weight bearing. We think that this may be caused by anomalies in the bones that support the arches
against the compression load. For this purpose, the volume (cm3
) and superficial area (cm2
) ratios of the
foot bones were calculated using foot computed tomography (CT) images of individuals with pes planus
and compared with healthy individuals
Methods
Fifteen pes planus patients diagnosed with pes planus in our clinic and with an APLM angle greater than
145 degrees and 15 healthy male participants were included. The foot computed tomography (CT)
images of the participants were taken with a General Electric brand IQ model 32 detector CT device in
accordance with the bone protocol, with a section thickness of 0.625 mm. Foot bones were segmented
from the obtained CT images with the help of the 3D Slicer program.
Results
The os cuneiforme mediale and os cuneiforme intermedium volume and superficial area ratios of the pes
planus group were significantly lower than the control group (p < 0.05). There was no difference between
the groups in the volume and superficial area ratios of the other foot bones (p > 0.05).
Conclusion
We think that pes planus is primarily caused by os cuniforme mediale and os cuneiforme intermedium
developmental anomalies, which act as a keystone in the formation of arches.
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NewsBot · Oct 12, 2023

Foot length - A reliable predictor of posterior tibial tendon thickness: A cadaveric study
Shiv Manik Ajoy et al
J Clin Orthop Trauma. 2023 Sep 22:44

Background: Tibialis posterior tendon, deltoid ligament and spring ligament are the three most important structures on the medial aspect of the foot. They contribute to the stability of the foot and ankle and also to the maintenance of the arches of the foot. These structures get affected and dimensions get disrupted in various traumatic and degenerative conditions. Normal range of dimensions of these structures has not been studied in an Indian population. Our objective is to define the normal thicknesses of these structures using a cadaveric model. We also hypothesize that longer the foot, higher stresses on these structures and hence thicker they will be. We aim to assess this hypothesis as well.

Methods: Dissection of the medial aspect of the foot was done on twenty cadaveric below knee specimens. Tibialis posterior tendon was identified and its thickness was measured. Deltoid and plantar calcaneonavicular ligaments were identified. Their lengths and thicknesses were measured. Length of the feet was also measured prior to dissection. Statistical analysis was done using the data obtained.

Results: Mean tibialis posterior thickness was 7.0165 ± 0.387 mm. Mean deltoid thickness was 5.124 ± 0.28 mm. Its mean length was 21.328 ± 2.22 mm. Mean plantarcalcaneonavicular ligament thickness was 2.491 ± 1.120 mm. Thicknesses of the tibialis posterior tendon and plantarcalcaneonavicular ligament correlated significantly with the length of the foot.

Conclusion: The thicknesses of the tibialis posterior tendon and plantar calcaneonavicular ligament are shown to be a function of and significantly proportional to the length of the foot. This helps the surgeon to estimate the thicknesses which the structures had prior to the pathology, in order to recreate the non-pathological anatomy after a tendon transfer or a reconstruction procedure. The normal thicknesses of tibialis posterior, deltoid and plantar calcaneonavicular ligaments are described for an Indian setting and deviations can be used to assess various pathologies of the foot and ankle affecting these structures.
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NewsBot · Oct 31, 2023

Decreased Peritalar Subluxation in Progressive Collapsing Foot Deformity with Ankle Valgus Tilting
Nacime Salomao Barbachan Mansur et al
JB JS Open Access. 2023 Oct 27;8(4):e23.00025

Background: Middle facet subluxation (MFS) has been established as an early indicator of peritalar subluxation. However, when progressive collapsing foot deformity (PCFD) affects the ankle leading to a valgus talar tilt (Class E), structures and anatomic relationships distal to the ankle joint may be affected. Therefore, this study aimed to assess radiographic parameters of peritalar subluxation in patients with PCFD who either did or did not have a valgus ankle. Our hypothesis was that these parameters would differ in Class E patients, upsetting their capability to quantify deformity.

Methods: We performed a prospective comparative study utilizing weight-bearing computed tomography (WBCT) images of 21 feet with PCFD and with valgus of the ankle and 64 with flexible PCFD without ankle involvement. Parameters including MFS, the medial cuneiform-to-floor distance, the forefoot arch angle, the talonavicular coverage angle, the hindfoot moment arm (HMA), the foot-ankle offset (FAO), and the talar tilt angle (TTA) were measured and compared. Variables that influence the presence of ankle valgus and overall alignment were assessed by multivariable regression models.

Results: Patients with PCFD and ankle valgus demonstrated a higher mean HMA (20.79 mm [95% confidence interval (CI), 17.56 to 24.02 mm] versus 8.94 mm [95% CI, 7.09 to 10.79 mm]), FAO (14.89% [95% CI, 12.51% to 17.26%] versus 6.32% [95% CI, 4.96% to 7.68%]) and TTA (95% CI, 17.10° [14.75° to 19.46°] versus 2.30° [95% CI, 0.94° to 3.65°]) and lower mean MFS (21.84% [95% CI, 15.04% to 28.63%] versus 38.45% [95% CI, 34.55% to 42.34%]) compared with the group without ankle valgus (p < 0.0001 for all). The FAO was influenced by MFS in the group without ankle valgus (p <0.0001) but not in the group with ankle valgus (p = 0.9161). FAO values of ≥12.14% were a strong predictor (79.2%) of ankle valgus deformity.

Conclusions: Subluxation of the middle facet was not as severe and did not influence the overall alignment in patients with PCFD who had valgus of the ankle (Class E). These findings suggest a distal peritalar reduction in the presence of a proximal deformity, making MFS an imprecise disease parameter in this scenario. An FAO value of ≥12.14% was a strong indicator of ankle deformity in patients with PCFD.
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NewsBot · Oct 31, 2023

The Role of the Transverse Arch in Progressive Collapsing Foot Deformity
Eli Schmidt et al
Foot Ankle Int. 2023 Oct 30

Background: The transverse arch (TA) has recently been shown to significantly increase the intrinsic stiffness of the midfoot when coupled with the medial longitudinal arch (MLA). Progressive collapsing foot deformity (PCFD) is a complex deformity that ultimately results in a loss of stiffness and collapse of the MLA. The role of the TA has not been investigated in patients diagnosed with this disorder using weightbearing CT (WBCT).Therefore, this study aims to answer the following questions: (1) Is the curvature of the TA decreased in PCFD? (2) Where within the midfoot does TA curvature flattening happen in PCFD?

Methods: A retrospective review of weightbearing CT images was conducted for 32 PCFD and 32 control feet. The TA curvature was assessed both indirectly using previously described methods and directly using a novel measurement termed the transverse arch plantar (TAP) angle that assesses the angle formed between the first, second, and fifth metatarsals in the coronal plane. Location of TA collapse was also assessed in the coronal plane.

Results: The TAP angle was significantly higher in PCFD (mean 115.2 degrees, SD 10.7) than in the control group (mean 100.8 degrees, SD 7.9) (P < .001). No difference was found using the calculated normalized TA curvature between PCFD (mean 17.1, SD 4.8) and controls (mean 18.3, SD 4.0) (P = .266). Location of collapse along the TA in PCFD was most significant at the second metatarsal and medial cuneiform.

Conclusion: The TA is more collapsed in PCFD compared to controls. This collapse was most substantial between the plantar medial cuneiform and the plantar second metatarsal. This may represent a location of uncoupling of the TA and MLA.
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NewsBot · Feb 3, 2024

An Emphasis on the Role of Peroneus Brevis to Peroneus Longus Transfer in Progressive Collapsing Flatfoot Deformity
Maher, Moustafa Alaa et al
Techniques in Foot & Ankle Surgery ():10.1097/BTF.0000000000000415, January 15, 2024.

The role of the peroneal tendons in progressive collapsing flatfoot deformity (PCFD), also traditionally known as posterior tibial tendon dysfunction, is likely overlooked and almost certainly understudied. We explored the impact of peroneus brevis (PB) to peroneus longus (PL) transfer in the adult population with flexible PCFD deformities class A1 (flexible hindfoot valgus), B1 (flexible midfoot abduction), and C1 (flexible forefoot varus) as an augmentative measure combined with various bony procedures with proper assessment functionally, clinically, and radiologically. PB to PL tendon transfer poses a simple procedure dealing with muscle imbalance between the medial and lateral columns of the foot. It deals with the new understanding of the PCFD complex as a three-dimensional deformity. It works mainly on the axial plane to limit midfoot abduction and strongly augments the PL acting on the sagittal plane to address the forefoot varus. Finally, to a lesser extent, it deals with the coronal plane of hindfoot valgus, eliminating the primary evertor of the foot (PB) while simultaneously strengthening the PL, which contributes to the medial longitudinal and transverse arches of the foot, therefore decreasing the possibility of lateral column overload commonly caused by the Evans osteotomy through reducing pressure across the calcaneocuboid joint. This procedure is preferably indicated for flexible PCFD deformities class (A1, B1, and C1), yet is contraindicated in neuromuscular deformities with peroneal nerve palsy.
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NewsBot · Mar 6, 2024

Association Between Weightbearing CT and MRI Findings in Progressive Collapsing Foot Deformity
Lynn Andres et al
Source

Background:
Weightbearing computed tomography (WBCT) scans allow for a better understanding of foot alignment in patients suffering from progressive collapsing foot deformity (PCFD). However, soft tissue integrity (eg, spring ligament complex or tibialis posterior tendon) cannot be easily assessed via WBCT. As performing both WBCT and magnetic resonance imaging (MRI) might not be cost effective, we aimed to assess whether there is an association between osseous and soft tissue findings in WBCT and MRI.
Methods:
In this observational study, a consecutive cohort of 24 patients of various stages of PCFD (mean age 51 ± 18 years) underwent WBCT scans and MRI. Twenty-four healthy individuals of similar age, body mass index (BMI), and sex with WBCT scans were used as a control group. In addition to of osseous sinus tarsi impingement, 4 commonly used 3-dimensional (3D) measurements (talocalcaneal overlap [TCO], talonavicular coverage [TNC], Meary angle [MA], axial/lateral) were obtained using a dedicated postprocessing software (DISIOR 2.1, Finland) on the WBCT data sets. Sinus tarsi obliteration, spring ligament complex, tibiospring ligament integrity, as well as tibialis posterior tendon degeneration were evaluated with MRI. Statistical analysis was performed for significant (P < .05) correlation between findings.
Results:
None of the assessed 3D measurements correlated with either spring ligament complex or tibiospring ligament tears. BMI and TCO were found to be associated with tibialis posterior tendon tears. Seventy-five percent of patients with osseous sinus tarsi impingement on WBCT also showed signs of sinus tarsi obliteration on MRI.
Conclusion:
Although WBCT reflects foot alignment and can reveal osseous sinus tarsi impingement in PCFD patients, the association between WBCT-based 3D measurements and ligament or tendon tears assessed via MRI is limited. WBCT appears complimentary to MRI regarding its diagnostic value. Both imaging options add important information and may impact decision making in the treatment of PCFD patients.
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Structures involved in posterior tibial tendon dysfunction

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Personality Traits linked to Foot Structures

"Haleem’s Hen"; A mnemonic for the anatomy of hindfoot structures

A New Classification of Foot Structures Based on Foot Embryology is proposed

Palpation Skills in Foot and Ankle Anatomic Structures

A New Classification of Foot Structures Based on Foot Embryogenesis

which structures are in dysfunctions in LAS or CAI?

A comparison of foot kinetic parameters between pronated and normal foot structures during forward j

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Structures involved in posterior tibial tendon dysfunction

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Personality Traits linked to Foot Structures

"Haleem’s Hen"; A mnemonic for the anatomy of hindfoot structures

A New Classification of Foot Structures Based on Foot Embryology is proposed

Palpation Skills in Foot and Ankle Anatomic Structures

A New Classification of Foot Structures Based on Foot Embryogenesis

which structures are in dysfunctions in LAS or CAI?

A comparison of foot kinetic parameters between pronated and normal foot structures during forward j

Share This Page

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