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Our Signature partners make their mark by helping us identify new and meaningful resources for people with arthritis. Our Supporting partners are active champions who provide encouragement and assistance to the arthritis community. Ankle Anatomy An inside look at the structure of the ankle. Although it is typically referred to as a single joint, the ankle is actually two joints: The true ankle joint , which is composed of three bones: the tibia , the larger and stronger of the two lower leg bones, which forms the inside part of the of the ankle the fibula , the smaller bone of the lower leg, which forms the outside part of the ankle the talus , a small bone between the tibia and fibula and the calcaneus, or heel bone.
The subtalar joint , which is composed of two bones: the talus the calcaneus The ends of the bones are covered by articular cartilage. They include the following: anterior tibiofibular ligament , which connects the tibia to the fibula. The major tendons include the following: Achilles tendon , which attaches the calf muscle and calcaneus.
These tendons pull the foot toward the body and help control their motion. Where it Hurts Shoulder Anatomy Find about the anatomy of the shoulder and how arthritis can effect it. Track Your Health Share your experience with arthritis to shape research and patient care for yourself and others. Stay in the Know. Live in the Yes. I Want to Contribute. Donate Every gift to the Arthritis Foundation will help people with arthritis across the U. It is irrational to build into a prosthesis the freedom to translate in the absence of the mechanism which controls that freedom.
Currently most of the TAR designs in clinical use have fully conforming mobile bearings [ 89 ], and only apparently these represent correct compromises between mobility and conformity. These are claimed to be anatomical, but all feature a flat shape of the tibial component, very unnatural, in addition to the natural anatomical talus. These must rely fully on ligaments for final joint stability, but unfortunately the functioning of the ligaments was not considered explicitly in the design.
In addition to replication of original joint function, i. The reliability and repeatability of the operative technique is considered by the surgeons as a fundamental characteristic for a TAR design. Relevant instrumentation must be robust and accurate enough for guaranteeing the correct position of the components with the minimum bone stock removal. Durability is also dependent on good fixation of the components, which would involve an appropriate load transfer to the bone and a minimum risk of loosening.
The current designs show a large variety of fixation elements. Pegs, long or short stems and cylindrical or rectangular bars have been used [ 92 ].
More recent designs use bone screws [ 93 , 94 ]. As far as the materials are discussed, moving from the original tibial components made in polyethylene, most of the recent two-part designs include a metal-backed tibial component.
The design of the elements used to limit the floating of the bearing core is then an additional critical issue. Entrapment of the meniscal bearing in some prostheses is enforced by sharp limiting interfaces, to prevent dislocation and separation.
Ribs and grooves, lugs and cutouts, and even systems of interlockable flanged grooves have been devised for this purpose [ 83 , 84 , 94 ]. These latter prostheses may be at high risk of polyethylene wear through contact at these interfaces.
From the numerous reviews of the current TAR designs [ 83 , 84 , 89 , 94 ], it emerges that only a few different conceptual approaches have been followed. Basically, in the two-part devices, the replication of the original anatomy was sought. On the other hand, in the three-part designs, the introduction of a non-anatomical meniscal bearing, flat above and nearly anatomical below, was assumed to achieve the necessary conformity.
The TAR design formulated by the present authors was the first in which the shapes of the articular surfaces in the sagittal plane were chosen to have a natural interaction with the retained ankle ligaments [ 78 , 79 , 86 ].
The design process followed investigations [ 17 , 21 , 22 ] which included measurements on cadaver specimens in virtually unloaded conditions and mathematical models. These have shown how the mutual action of the passive structures of the ankle control and limit joint motion, i.
Previous designs of TAR focused exclusively on the geometry of the prosthetic components in relation to the morphological features of the intact articular surface of the talus [ 92 , 95 , 96 ].
Our mathematical analysis Figure 10 showed that the fixed articular surfaces should both have anatomical shapes or should both be non-anatomical [ 78 ]. Current three-part prostheses [ 93 , 97 — ] use a more or less natural-like convex surface for the talar component and a non-anatomical flat surface for the tibial component. This combination of anatomical and non-anatomical surfaces cannot be compatible with the retained ligaments [ 78 ].
Early clinical results suggest that a ligament-compatible TAR design can achieve good clinical results [ 87 ], a low wear rate [ ] and a good recovery of function [ 57 ]. Direct comparisons with other TAR designs and longer term outcome studies are required to corroborate these short term observations. Recently, there has been renewed interest in ankle joint replacement likely because longer term outcome studies have become available, and because the FDA has approved a few more designs in the United States [ 83 , ], for the options for TAR surgeons being greatly expanded.
Most recent efforts in TAR development seem to be dedicated to two-part devices, apparently under the assumption that the failure of the original such designs was due only to the poor quality of the fixation elements and of the polyethylene inserts. Despite the general tendency in orthopaedic surgery to simpler and quicker surgical procedures, most recent designs seem to require long techniques and cumbersome apparatus [ 83 ].
In addition to optimal component design, there continues to be much debate within the surgeons interested in TAR as to indications, patient selection, and operative technique. The mobility and stability of the ankle joint have been investigated extensively, but many critically important issues still need to be elucidated. However, there seems to be a general agreement on several important observations. A more isometric pattern of rotation for fibres within the calcaneofibular and the tibiocalcaneal ligaments with respect to all the others has been shown.
Many recent studies have found changing positions of the instantaneous axis of rotation, suggesting that the hinge joint concept is an oversimplification for the ankle joint. A few recent works have also claimed anterior shift of the contact area at the tibial mortise during dorsiflexion, which would imply combined rolling and sliding motion at this joint.
Many findings from the literature support the view of a close interaction between the geometry of the ligaments and the shapes of the articular surfaces in guiding and stabilising motion at the ankle joint.
Any design of joint replacement or ligament and articular surface reconstructions must take into consideration these important findings. Hamblen DL: Can the ankle joint be replaced?. J Bone Joint Surg Br. Comput Methods Biomech Biomed Engin. PubMed Google Scholar. Katcherian DA: Treatment of ankle arthrosis. Clin Orthop Relat Res. A systematic review of the literature. J Bone Joint Surg Am. Foot Ankle Int. Clin Biomech Bristol, Avon. Google Scholar. Gait Posture. Bull Pros Res.
Inman VT: The joints of the ankle. J Biomed Eng. Foot Ankle. Siegler S, Chen J, Schneck CD: The three-dimensional kinematics and flexibility characteristics of the human ankle and subiaiar jomnts. Part 2: Kinematics. J Biomch Engng. CAS Google Scholar. J Biomech. Med Biol Eng Comput.
A cadaveric study of lateral ligament injuries of the ankle. Acta Orthop Scand. Knee Surg Sports Traumatol Arthrosc. J Biomech Eng. J Bone Jt Surg [Am]. Theologis T, Stebbins J: The use of gait analysis in the treatment of pediatric foot and ankle disorders. Foot Ankle Clin. Hum Mov Sci. Crit Rev Biomed Eng. Bishop C, Paul G, Thewlis D: The reliability, accuracy and minimal detectable difference of a multi-segment kinematic model of the foot-shoe complex.
Woodburn J, Helliwell PS, Barker S: Three-dimensional kinematics at the ankle joint complex in rheumatoid arthritis patients with painful valgus deformity of the rearfoot. Rheumatology Oxford. Rouhani H, Favre J, Aminian K, Crevoisier X: Multi-segment foot kinematics after total ankle replacement and ankle arthrodesis during relatively long-distance gait.
Med Sci Sports Exerc. Powers CM: The influence of altered lower-extremity kinematics on patellofemoral joint dysfunction: a theoretical perspective. J Orthop Sports Phys Ther. J Orthop Res. Turner DE, Woodburn J: Characterising the clinical and biomechanical features of severely deformed feet in rheumatoid arthritis.
Gait and Posture. Clin Podiatr Med Surg. J Am Podiatr Med Assoc. Med Biol Eng Comp. Leardini A, Moschella D: Dynamic simulation of the natural and replaced human ankle joint. Stengel D, Bauwens K, Ekkernkamp A, Cramer J: Efficacy of total ankle replacement with meniscal-bearing devices: a systematic review and meta-analysis. Arch Orthop Trauma Surg. J Am Acad Orthop Surg. Instr Course Lect.
J Mech Behav Biomed Mat. Eng Med. Med Eng Phys. Clin Orthop. Foot Ankle Surg. Br Med Bull. Clin Orthop Rel Res. J Bone Joint Surg [Br]. Download references. The authors acknowledge the contribution of Andy Goldberg to the initial overall plan for this review paper.
You can also search for this author in PubMed Google Scholar. Correspondence to Alberto Leardini. AL carried out most of literature review work, and drafted the manuscript. JJOC contributed to the original organisation of the manuscript and edited its final versions. SG participated in the discussions about the anatomical, surgical and clinical issues, and contributed to the right interpretation of the clinical studies from the literature.
All authors read and approved the final version of the manuscript. This article is published under license to BioMed Central Ltd. Reprints and Permissions. Leardini, A. Biomechanics of the natural, arthritic, and replaced human ankle joint. J Foot Ankle Res 7, 8 Download citation. Received : 16 May Accepted : 03 February Published : 06 February Anyone you share the following link with will be able to read this content:.
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Skip to main content. Search all BMC articles Search. Download PDF. Abstract The human ankle joint complex plays a fundamental role in gait and other activities of daily living. Background The human shank and foot complex is an intricate, multi-joint mechanism, which is fundamental for the interaction between the lower limb and ground during locomotion. Figure 1. Full size image. Mobility and stability at the human normal and arthritic ankle joint Joint replacement is necessary in severely arthritic ankles to reduce pain, to restore joint stability, and to restore joint mobility.
Joint mobility in the normal ankle Motion at the ankle joint complex has been divided into that at the ankle and at the subtalar joints [ 7 , 8 ]. Experimental observations in-vitro Experimental in-vitro work was performed by the present authors explicitly to investigate whether or not a preferred path of joint motion is prescribed by the passive joint structures alone during dorsi- plantar-flexion in virtually unloaded conditions [ 17 ]. Corresponding mathematical models in the sagittal plane Computer-based geometrical models [ 21 ] elucidated this mechanism, initially in the sagittal plane Figure 2 , where most of the passive motion was shown to occur.
Figure 2. The subtalar joint allows side-to-side motion of the foot. The ends of the bones in these joints are covered by articular cartilage 1. The major ligaments of the ankle are: the anterior tibiofibular ligament 2 , which connects the tibia to the fibula; the lateral collateral ligaments 3 , which attach the fibula to the calcaneus and gives the ankle lateral stability; and, on the medial side of the ankle, the deltoid ligaments 4 , which connect the tibia to the talus and calcaneus and provide medial stability.
These components of your ankle, along with the muscles and tendons of your lower leg, work together to handle the stress your ankle endures as you walk, run, and jump. Skip to main content.
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