Numerical Assessment of the Structural Effects of Relative Sliding between Tissues in a Finite Element Model of the Foot

Penetration and shared nodes between muscles, tendons and the plantar aponeurosis mesh elements in finite element models of the foot may cause inappropriate structural behavior of the tissues. Penetration between tissues caused using separate mesh without motion constraints or contacts can change the loading direction because of an inadequate mesh displacement. Shared nodes between mesh elements create bonded areas in the model, causing progressive or complete loss of load transmitted by tissue. This paper compares by the finite element method the structural behavior of the foot model in cases where a shared mesh has been used versus a separated mesh with sliding contacts between some important tissues. A very detailed finite element model of the foot and ankle that simulates the muscles, tendons and plantar aponeurosis with real geometry has been used for the research. The analysis showed that the use of a separate mesh with sliding contacts and a better characterization of the mechanical behavior of the soft tissues increased the mean of the absolute values of stress by 83.3% and displacement by 17.4% compared with a shared mesh. These increases mean an improvement of muscle and tendon behavior in the foot model. Additionally, a better quantitative and qualitative distribution of plantar pressure was also observed.

HUBUNGAN PENURUNAN LINGKUP GERAK SENDI DORSOFLEKSI ANKLE TERHADAP PLANTAR FASCIITIS PADA SALES PROMOTION GIRLS DI RAMAYANA

Plantar fasciitis adalah kondisi inflamasi lokal pada plantar aponeurosis di kaki yang dilaporkan merupakan penyebab utama dari nyeri pada tumit bawah. Pasien dengan plantar fasciitis melaporkan nyeri pada insersio plantar aponeurosis pada tuberkulum medial dari calcaneus. Ada beberapa faktor yang menjadi penyebab munculnya plantar fasciitis. Beberapa peneilitian menduga adanya hubungan antara penurunan lingkup gerak sendi dorsofleksi ankle dan nyeri pada tumit yang meningkat. Tujuan pada penelitian ini yaitu untuk mengetahui hubungan antara lingkup gerak sendi dorsofleksi ankle dengan risiko terjadinya plantar fasciitis. Metode penelitian yang digunakan yaitu metode observasional analitik cross sectional dengan teknik purposive sampling dengan jumlah sampel sebanyak 82 orang. Sampel pada penelitian ini adalah sales promotion girl di Ramayana yang telah memenuhi kriteria inklusi dan eksklusi. Uji korelasi Spearman digunakan pada penelitian ini untuk menganalisis hubungan penurunan lingkup gerak sendi dorsofleksi ankle dengan risiko terjadinya plantar fasciitis. Berdasarkan hasil uji korelasi Spearman dipeloreh nilai p = 0,321 (p> 0,05) sehingga Ha ditolak dan Ho diterima yang artinya tidak terdapat hubungan antara penurunan lingkup gerak sendi dorsofleksi ankle dengan risiko terjadinya plantar fasciitis. Serta nilai correlation coefficient didapatkan hasil -0,111 yang berarti adanya hubungan antara penurunan lingkup gerak sendi dorsofleksi ankle dengan plantar fasciitis berbanding terbalik dan kekuatan hubungan sangat lemah. Sehingga dapat disimpulkan bahwa penurunan lingkup gerak sendi dorsofleksi ankle tidak meningkatkan risiko terjadinya plantar fasciitis. Kata kunci: lingkup gerak sendi dorsofleksi ankle, plantar fasciitis, SPG

Staging of Plantar Fasciitis According to Ultrasonography

Objective. Analysis of sonographic examination of plantar aponeurosis in norm and in plantar fasciitis, determination of the staging of plantar fasciitis depending on the duration of the pain syndrome and sonographic changes in plantar aponeurosis. Materials and Methods. 193 patients (272 cases) with plantar fasciitis (131 females and 62 males). The average age of patients was 47.69±0.97 years (18-81 years). Unilateral pathology was noted in 114 patients (114 cases) and bilateral – in 79 patients (158 cases). The average body mass index was 26.68±0.24. The average duration of pain syndrome was 101.12±5.83 days (7-390 days). The pain syndrome lasted up to 1 month in 26 patients (37 cases), from 1 to 6 months – in 126 patients (181 cases), and more than 6 months – in 41 patients (54 cases). The control group included 20 healthy volunteers (40 feet). Clinical radiological, sonographic, and statistical methods were used. Results. The average thickness of plantar aponeurosis in the study group was 6.14±1.49 mm (2.3-7.7 mm) and in control group – 3.5±0.1 mm (2.5-4.4 mm). There were three stages of the plantar fasciitis. Stage I was characterized by the absence of thickening of the plantar aponeurosis and structural changes, and by signs of local perifocal edema in the subcutaneous fat of the area adjacent to the aponeurosis, which are manifested by a zone of heterogeneous echogenicity. Stage II was characterized by a spindle-shaped form of aponeurosis, a thickening of enthesis more than 4 mm, significant reduction in echogenicity, erased or missing fibrous pattern, fuzzy contour of the aponeurosis, and modified contour of the calcaneus. At stage III, inequality of the cortical calcaneal contour and small focal hyperechogenicity points in enthesis were detected. Distal free part of the aponeurosis also changed. Loci of vascularization were detected using power Doppler sonography. Conclusions. A quantitative sonographic sign of plantar fasciitis is the thickening of the enthesis of the plantar aponeurosis of more than 4 mm. Qualitative signs were changes in echogenicity and structure, changes in the contours of the cortical layer of enthesis and plantar aponeurosis, and distribution of echographic changes distally to the free part of the aponeurosis. The described signs, when compared with the duration of the pain syndrome, determine the stage of plantar fasciitis.

AB0171 ACHILLES ENTHESITIS AND PLANTAR FASCIITIS IN RHEUMATOID ARTHRITIS PATIENTS: IMPACT OF BODY MASS INDEX

Background:Enthesitis is known as a hallmark of spondyloarthitis. However, the growing use of ultrasonography (US) increased our opportunity to encounter enthesitis in rheumatoid arthritis (RA). The involvement of Achilles tendon and the plantar fascia is not rare in RA patients.Objectives:The aims of this study were to determine the prevalence of Achilles enthesitis and plantar fasciitis in RA patients, and to identify association with clinical data.Methods:We conducted a cross-sectional study including patients with RA (ACR/EULAR 2010). Demographic and clinical data were collected. Three groups were defined according to the BMI: normal (BMI<25kg/m2), overweight (BMI≥25kg/m2) and obese (BMI≥30kg/m2). US examination of Achilles tendon and plantar aponeurosis was performed by a blinded radiologist experienced in musculoskeletal US using a Philips HD11 device with a high-frequency linear transducer. Enthesitis was defined as hypoechoic and/or thickened insertion of the tendon close to the bone (within 2 mm from the bony cortex) which exhibits Doppler signal if active and that may show erosions, enthesophytes or calcifications as sign of structural damage. A p-value <0.05 was considered significant.Results:Sixty-two feet were examined in 31 RA patients (25 women and six men) with a mean age of 54.8±10.8 years old [32-70]. The mean disease duration was 8.5±7.2 years [1-37]. Rheumatoid Factor (RF) and Anti-Citrullinated Peptides Antibodies (ACPA) were positive in 61.3% and 83.8% of cases. The mean DAS28 ESR was 3.8±1.5 [0.6-7].The mean BMI was 27.7±5.4 kg/m2 [18.3-45.8]. Obesity was noted in 22.7 % of patients and overweight in 45.5% of patients. Clinical examination revealed pes planus valgus (PPV) in 55.6% of cases and pes cavus varus (PCV) in 18.5% of cases.Heel US revealed Achilles enthesitis in 79.6% of cases. The following elementary lesions were noted in the enthesis: thickness (24.1%), hypoechogenicity (37%), erosions (9.3%), enthésophytes (75.9%), and Doppler signal (3.7%). Plantar fasciitis was noted in 81.5% of cases. The following elementary lesions were found in the insertion of plantar aponeurosis: thickness (75.9%), hypoechogenicity (77.8%), erosions (16.7%), enthesophytes (13%), calcifications (1.9%), and Doppler signal (1.9%).An association was noted between BMI and Achilles enthesitis (p=0.002). This association was not found with plantar fasciitis (p=0.224).Achilles enthesitis was also associated with PCV (p=0.007) while plantar fasciitis was associated with PPV (p=0.039).Conclusion:Achilles enthesitis and plantar fasciitis are common in RA patients. These lesions seem to be associated with BMI and foot deformities rather than the inflammatory process.Disclosure of Interests:None declared

THE USE OF ALLOTRANSPLANT FROM THE SUBCUTANEOUS FAT WITH PLANTAR APONEUROSIS FOR THE MUSCULOSKELETAL STUMP FORMATION DURING ENUCLEATION

Objective. To develop a method for the formation of a musculoskeletal stump for an ocular prosthesis during enucleation using an allograft from subcutaneous fat with a plantar aponeurosis was developed Methods. The study included patients with the diagnosed choroid melanoma (n=15), and retinoblastoma (n=2). The orbital cavity was replenished with the section of subcutaneous adipose tissue with the sole aponeurosis, preserved by cryopreservation. The orbital cavity was filled with a section of subcutaneous adipose tissue with plantar aponeurosis, preserved by cryopreservation. The immediate effect was assessed 3 and 6 months after the treatment according to the following criteria: the presence of the orbital tissues edema, the mobility of the supporting stump with the prosthesis, the position of the stump with the prosthesis in the orbit, and the position of the upper eyelid. Results. In all cases, a positive result was obtained: after 3 months, the orbital tissue edema was absent in 7 patients, in 7 - it was mild, in 3 - it was moderately pronounced. After 6 months, the orbital tissue edema was absent in all patients. After 3 months the mobility of the supporting stump was moderately marked in 10 patients, and in 7 - it was feeble marked. After 6 months, the mobility of the stump was marked moderately in all patients. After 3 months in 7 patients, the position of the stump with the prosthesis had a symmetrical position; there was hypereffect in 10 patients. By 6 months, all patients had a symmetrical arrangement of the healthy eye and prosthesis. Conclusion. The designed method for the formation of the functional stump for an ocular prosthesis during enucleation using the allograft from subcutaneous fat with the plantar aponeurosis makes it possible to obtain good anatomical, cosmetic and functional results of the operation due to the achievement of a sufficient rangeofprosthetic movement of the ocular prosthesis. The introduction of the designed method of the functional stump formation into clinical practice increases the medical, social, economic efficiency of the rehabilitation of patients with malignant neoplasms of the eyeball membranes. What this paper adds For the first time, a method for the formation of a musculoskeletal stump for an ocular prosthesis during enucleation using an allograft from subcutaneous fat with a plantar aponeurosis was developed. It is shown that the allograft application makes it possible to obtain a good anatomical, cosmetic and functional result by achieving a sufficient rangeofprosthetic movement of the eye prosthesis.

The rise of the longitudinal arch when sitting, standing, and walking: Contributions of the windlass mechanism

The original windlass mechanism describes a one-to-one coupling between metatarsal joint dorsiflexion and medial longitudinal arch rise. The description assumes a sufficiently stiff plantar aponeurosis and absence of foot muscle activity. However, recent research calls for a broader interpretation of the windlass mechanism that accounts for an extensible plantar aponeurosis and active foot muscles. In this study, we investigate the rise of the arch in response to toe dorsiflexion when sitting, standing, and walking to discuss the windlass mechanism’s contributions in static and dynamic load scenarios. 3D motion analysis allowed a kinematic investigation of the rise and drop of the arch relative to the extent of toe dorsiflexion. The results suggest that static windlass effects poorly predict the relationship between arch dynamics and metatarsophalangeal joint motion during dynamic load scenarios, such as walking. We were able to show that toe dorsiflexion resulted in an immediate rise of the longitudinal arch during sitting and standing. In contrast, a decrease in arch height was observed during walking, despite toe dorsiflexion at the beginning of the push-off phase. Further, the longitudinal arch rose almost linearly with toe dorsiflexion in the static loading scenarios, while the dynamic load scenario revealed an exponential rise of the arch. In addition to that, the rate of change in arch height relative to toe motion was significantly lower when sitting and standing compared to walking. Finally, and most surprisingly, arch rise was found to correlate with toe dorsiflexion only in the dynamic loading scenario. These results challenge the traditional perspective of the windlass mechanism as the dominating source of foot rigidity for push-off against the ground during bipedal walking. It seems plausible that other mechanisms besides the windlass act to raise the foot arch.

Role of plantar aponeurosis in the formation of cavus component in recurrent congenital equinocavovarus deformity

Background. Congenital equinocavovarus deformity (CECVD) is the second most frequent among all congenital disorders of the musculoskeletal system in children, and one of the most common causes of childhood disability in Ukraine. The incidence of CECVD reaches 1–3 cases per 1,000 newborns (35–40 % of all foot deformities). According to some authors, plantar fasciotomy can improve the shape and function of support and walking in these patients. The purpose was to determine the role of plantar aponeurosis in the formation of the cavus component in cases of recurrent CECVD in children. Material and methods. Mathematical researches were carried out using the graph-analytical method. Results. To reduce the arch height when correcting pes cavus, it is necessary to increase significantly the length of the aponeurosis (up to 25 % of its initial length). To perform this task, a significant tensile force must be applied to the aponeurosis, the value of which depends on the magnitude of a decrease in the arch height. So, to reduce the arch height by 10 mm, it is necessary to lengthen the aponeurosis by 12 mm, for which a constant force of 932 N must be applied to it. To reduce the arch height by 20 mm, the magnitude of the tensile force applied to the aponeurosis must be increased to 1,438 N, which is almost impossible. Therefore, the presence of a shortened aponeurosis is a significant obstacle for the effective correction of pes cavus. Conclusions. Correction of pes cavus requires a significant decrease in the height of its longitudinal arch, which leads to a significant lengthening of the aponeurosis, up to 25 % of its initial length. To ensure an increase in the length of the aponeurosis, the presence of a significant constant tensile force that exceeds 1000 N is necessary. Plantar aponeurosis plays a direct role in supporting the longitudinal arch of the foot, and is one of the causes for the persistence of pes cavus in patients with recurrent CECVD, which does not respond to conservative treatment. To correct cavus foot, in the failure of conservative treatment, it is necessary to lengthen it by surgical intervention (intersection). The value of the angle of the longitudinal arch of the foot of 110° can be chosen as a criterion for choosing a decision in favor of preserving or resection of the aponeurosis.

No Association of Plantar Aponeurosis Stiffness with Medial Longitudinal Arch Stiffness

Lower stiffness of the medial longitudinal arch is reportedly a risk factor for lower leg disorders. The plantar aponeurosis is considered essential to maintaining the medial longitudinal arch. It is therefore expected that medial longitudinal arch stiffness is influenced by plantar aponeurosis stiffness. However, this has not been experimentally demonstrated. We examined the relationship between the plantar aponeurosis stiffness and medial longitudinal arch stiffness in humans in vivo. Thirty young subjects participated in this study. The navicular height and shear wave velocity (an index of stiffness) of the plantar aponeurosis were measured in supine and single-leg standing positions, using B-mode ultrasonography and shear wave elastography, respectively. The medial longitudinal arch stiffness was calculated based on body weight, foot length, and the difference in navicular height between the supine and single-leg standing conditions (i. e., navicular drop). Shear wave velocity of the plantar aponeurosis in the supine and single-leg standing positions was not significantly correlated to medial longitudinal arch stiffness (spine: r=−0.14, P=0.45 standing: r=−0.16, P=0.41). The findings suggest that the medial longitudinal arch stiffness would be strongly influenced by the stiffness of foot structures other than the plantar aponeurosis.