Effect of artificial surface shapes and their malpositioning on the mechanics of the replaced ankle joint for possible better prosthesis designs

2021 ◽  
Vol 90 ◽  
pp. 105489
Author(s):  
Daisy Ferraro ◽  
Sorin Siegler ◽  
Claudio Belvedere ◽  
Maria Ruiz ◽  
Alberto Leardini
Swiss Surgery ◽  
2003 ◽  
Vol 9 (6) ◽  
pp. 283-288
Author(s):  
Maurer ◽  
Stamenic ◽  
Stouthandel ◽  
Ackermann ◽  
Gonzenbach

Aim of study: To investigate the short- and long-term outcome of patients with isolated lateral malleolar fracture type B treated with a single hemicerclage out of metallic wire or PDS cord. Methods: Over an 8-year period 97 patients were treated with a single hemicerclage for lateral malleolar fracture type B and 89 were amenable to a follow-up after mean 39 months, including interview, clinical examination and X-ray controls. Results: The median operation time was 35 minutes (range 15-85 min). X-ray controls within the first two postoperative days revealed an anatomical restoration of the upper ankle joint in all but one patient. The complication rate was 8%: hematoma (2 patients), wound infection (2), Sudeck's dystrophy (2) and deep vein thrombosis (1). Full weight-bearing was tolerated at median 6.0 weeks (range 2-26 weeks). No secondary displacement, delayed union or consecutive arthrosis of the upper ankle joint was observed. All but one patient had restored symmetric joint mobility. Ninety-seven percent of patients were satisfied or very satisfied with the outcome. Following bone healing, hemicerclage removal was necessary in 19% of osteosyntheses with metallic wire and in none with PDS cord. Conclusion: The single hemicerclage is a novel, simple and reliable osteosynthesis technique for isolated lateral type B malleolar fractures and may be considered as an alternative to the osteosynthesis procedures currently in use.


BMJ ◽  
1951 ◽  
Vol 1 (4721) ◽  
pp. 1494-1494
Author(s):  
J. S. Batchelor
Keyword(s):  

2019 ◽  
Vol 19 (06) ◽  
pp. 1950050
Author(s):  
M. T. KARIMI ◽  
R. B. TAHMASEBI ◽  
B. SATVATI ◽  
F. FATOYE

Flat foot is the most common foot disorder that influences the alignment of the lower limb structure. It is controversial whether the use of foot insole influences kinetic and kinematic of the leg or not. Therefore, this study investigated the influence of foot insole on the gait performance in subjects with flat foot disorder. A group of flat foot subject was recruited into this study (the number of subjects was 15). The motion of the leg joints was determined using the Qualysis motion analysis system. Moreover, the force applied on the lower limb was recorded by a Kistler force plate. The range of motion of the lower limb joints, the moments applied on the lower limb joints and force transmitted through the leg were the parameters used in this study. The difference between these parameters during walking with and without insole was evaluated using the paired [Formula: see text]-test. Significant value was set at [Formula: see text]. There was no significant difference between the range of motion of ankle joint while walking with and without insole. However, the medial directed force applied on the leg decreased significantly [Formula: see text]. The use of foot insole did not influence the moments transmitted through the hip and knee joints. The walking speed of the subjects improved while walking with foot insole. Use of foot insole influenced the magnitude of the force applied on the leg and the adductor moment of ankle joint due to its influence on foot alignment. As the walking speed of the improved subjects follows the use of insole, it can be concluded that it may have a positive effects on the performance of flat foot subjects.


2021 ◽  
Vol 13 (sup1) ◽  
pp. S89-S91
Author(s):  
Sébastien Pavailler ◽  
Nicolas Masson ◽  
Nicolas Horvais
Keyword(s):  

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0025
Author(s):  
Zhao Hong-Mou

Category: Ankle; Basic Sciences/Biologics Introduction/Purpose: To study the effect of different degrees of distal tibial varus and valgus deformities on the tibiotalar joint contact, and to understand the role of fibular osteotomy. Methods: Eight cadaveric lower legs were used for biomechanical study. Nine conditions were included: normal ankle joint (group A), 10° varus (group B), 5° varus (group C), 5° valgus (group D), 10° valgus (group E) with fibular preserved, and 10° varus (group F), 5° varus (group G), 5° valgus (group H), and 10° valgus (group I) after fibular osteotomy. The joint contact area, contact pressure, and peak pressure were tested; and the translation of contact force center was observed. Results: The joint contact area, contact pressure, and peak pressure had no significant difference between group A and groups B to E (P>0.05). After fibular osteotomy, the contact area decreased significantly in groups F and I when compared with group A (P<0.05); the contact pressure increased significantly in groups F, H, and I when compared with group A (P<0.05); the peak pressure increased significantly in groups F and I when compared with group A (P<0.05). There were two main anterior-lateral and anterior-medial contact centers in normal tibiotalar joint, respectively; and the force center was in anterior-lateral part, just near the center of tibiotalar joint. While the fibula was preserved, the force center transferred laterally with increased varus angles; and the force center transferred medially with increased valgus angles. However, the force center transferred oppositely to the medial part with increased varus angles, and laterally with increased valgus angles after fibular osteotomy. Conclusion: Fibular osteotomy facilitates the tibiotalar contact pressure translation, and is helpful for ankle joint realignment in suitable cases.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Patrick Fuerst ◽  
Albert Gollhofer ◽  
Markus Wenning ◽  
Dominic Gehring

Abstract Background The application of ankle braces is an effective method for the prevention of recurrent ankle sprains. It has been proposed that the reduction of injury rates is based on the mechanical stiffness of the brace and on beneficial effects on proprioception and neuromuscular activation. Yet, how the neuromuscular system responds to the application of various types of ankle braces during highly dynamic injury-relevant movements is not well understood. Enhanced stability of the ankle joint seems especially important for people with chronic ankle instability. We therefore aimed to analyse the effects of a soft and a semi-rigid ankle brace on the execution of highly dynamic 180° turning movements in participants with and without chronic ankle instability. Methods Fifteen participants with functional ankle instability, 15 participants with functional and mechanical ankle instability and 15 healthy controls performed 180° turning movements in reaction to light signals in a cross-sectional descriptive laboratory study. Ankle joint kinematics and kinetics as well as neuromuscular activation of muscles surrounding the ankle joint were determined. Two-way repeated measures analyses of variance and post-hoc t-tests were calculated. Results Maximum ankle inversion angles and velocities were significantly reduced with the semi-rigid brace in comparison to the conditions without a brace and with the soft brace (p ≤ 0.006, d ≥ 0.303). Effect sizes of these reductions were larger in participants with chronic ankle instability than in healthy controls. Furthermore, peroneal activation levels decreased significantly with the semi-rigid brace in the 100 ms before and after ground contact. No statistically significant brace by group effects were found. Conclusions Based on these findings, we argue that people with ankle instability in particular seem to benefit from a semi-rigid ankle brace, which allows them to keep ankle inversion angles in a range that is comparable to values of healthy people. Lower ankle inversion angles and velocities with a semi-rigid brace may explain reduced injury incidences with brace application. The lack of effect of the soft brace indicates that the primary mechanism behind the reduction of inversion angles and velocities is the mechanical resistance of the brace in the frontal plane.


1998 ◽  
Vol 1 (1) ◽  
pp. 23-39
Author(s):  
Carter J. Kerk ◽  
Don B. Chaffin ◽  
W. Monroe Keyserling

The stability constraints of a two-dimensional static human force exertion capability model (2DHFEC) were evaluated with subjects of varying anthropometry and strength capabilities performing manual exertions. The biomechanical model comprehensively estimated human force exertion capability under sagittally symmetric static conditions using constraints from three classes: stability, joint muscle strength, and coefficient of friction. Experimental results showed the concept of stability must be considered with joint muscle strength capability and coefficient of friction in predicting hand force exertion capability. Information was gained concerning foot modeling parameters as they affect whole-body stability. Findings indicated that stability limits should be placed approximately 37 % the ankle joint center to the posterior-most point of the foot and 130 % the distance from the ankle joint center to the maximal medial protuberance (the ball of the foot). 2DHFEC provided improvements over existing models, especially where horizontal push/pull forces create balance concerns.


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