Extended foot-ankle musculoskeletal models for application in movement analysis.

Multibody simulations of human motion require representative models of the anatomical structures. A model that captures the complexity of the foot is still lacking. In the present work, two detailed 3D multibody foot-ankle models generated based on CT scans using a semi-automatic tool are described.

Foot-ankle simulators: A tool to advance biomechanical understanding of a complex anatomical structure.

In vitro gait simulations have been available to researchers for more than two decades and have become an invaluable tool for understanding fundamental foot-ankle biomechanics. This has been realised through several incremental technological and methodological developments, such as the actuation of muscle tendons, the increase in controlled degrees of freedom and the use of advanced control schemes. Furthermore, in vitro experimentation enabled performing highly repeatable and controllable simulations of gait during simultaneous measurement of several biomechanical signals (e.

Insertion of a pressure sensing arrayminimally affects hindfoot bone kinematics.

Background: Understanding the development of ankle osteoarthritis (OA) is of high importance and interest; however its causality is poorly understood and several links to joint loading conditions have been made. One way of quantifying joint loading conditions is by measuring the intra-articular pressure distribution during gait simulations performed by in-vitro experimental set-ups. However the effect of inserting a pressure sensing array in the ankle joint could potentially disturb the proper kinematics and therefore the loading conditions.

Extrinsic Muscle Forces Affect Ankle Loading Before and After Total Ankle Arthroplasty.

Background: Joint loading conditions have an effect on the development and management of ankle osteoarthritis and on aseptic loosening after total ankle arthroplasty (TAA). Apart from body weight, compressive forces induced by muscle action may affect joint loading. However, few studies have evaluated the influence of individual muscles on the intraarticular pressure distribution in the ankle.

An in vitro approach to the evaluation of foot-ankle kinematics: performance evaluation of a custom-built gait simulator.

Despite their well-known limitations, in vitro experiments have several benefits over in vivo techniques when exploring foot biomechanics under conditions characteristic of gait. In this study, we present a new setup for dynamic in vitro gait simulation that integrates a numerical model for generating the tibial kinematics control input, and we present an innovative methodology to measure full three-dimensional joint kinematics during gait simulations. The gait simulator applies forces to the tendons.

Specimen-specific tibial kinematics model for in vitro gait simulations.

Until now, the methods used to set up in vitro gait simulations were not specimen specific, inflicting several problems when dealing with specimens of considerably different dimensions and requiring arbitrary parameter tuning of the control variables. We constructed a model that accounts for the geometric dimensions of the specimen and is able to predict the tibial kinematics during the stance phase. The model predicts tibial kinematics of in vivo subjects with very good accuracy.

In vitro analysis of muscle activity illustrates mediolateral decoupling of hind and mid foot bone motion.

Activity of the extrinsic ankle-foot muscles is typically described for the whole foot. This study determines if this muscle activity is also confirmed for individual foot segments defined in multi-segment foot models used for clinical gait analysis. Analysis of the individual bone motion can identify functional complexes within the foot and evaluates the influence of an altered foot position on muscle activity.

Alterated talar and navicular bone morphology is associated with pes planus deformity: a CT-scan study.

We compared bone and articular morphology of the talus and navicular in clinically diagnosed flatfeet and evaluated their potential contribution to talo-navicular joint instability. We used CT images to develop 3D models of talus and navicular bones of 10 clinically diagnosed flatfeet and 15 non-flatfeet. We quantified their global bone dimensions, inclination and dimensions of the articular surfaces and their curvatures.

The first metatarsophalangeal joint meniscus and its relation to hallux valgus deformity--an anatomical and clinical study.

Background: This study describes the anatomy and incidence of the metatarsophalangeal (MTP) joint meniscus, a structure not mentioned before in literature.

Methods: An anatomical cadaver study on 102 feet was performed with special attention to the first MTP joint anatomy. These results were compared with the per-operative findings in a clinical prospective study on 100 consecutive hallux valgus surgeries.

Donor site morbidity after articular cartilage repair procedures: a review.

In order to perform an Osteochondral Autologous Transplantation (OAT) or an Autologous Chondrocyte Implantation (ACI), the integrity of healthy intact articular cartilage at a second location needs to be violated. This creates the possibility for donor site morbidity. Only recently have any publications addressed this issue.

Total ankle replacement. Design evolution and results.

The ankle joint has unique anatomical, biomechanical and cartilaginous structural characteristics that allow the joint to withstand the very high mechanical stresses and strains over years. Any minor changes to any of these features predispose the joint to osteoarthritis. Total ankle replacement (TAR) is evolving as an alternative to ankle arthrodesis for the treatment of end-stage ankle osteoarthritis.

High inter-specimen variability of baseline data for the tibio-talar contact area.

Background: The tibio-talar contact area has been widely investigated to monitor biomechanical changes due to articular incongruities or an altered loading. This study aims to investigate for the first time in a systematic way the extent of the inter-specimen variability of the tibio-talar contact area, and its repercussions when analyzing data concerning this parameter.

Methods: Ten specimens were loaded to record the tibio-talar contact characteristics by use of pressure sensitive film.

Risk of neurovascular injuries in flexor hallucis longus tendon transfers: an anatomic cadaver study.

Background: Flexor hallucis longus (FHL) tendon transfer is a frequently used treatment for both posterior tibial tendon insufficiency and chronic Achilles tendinopathy. We observed difficulties in harvesting the FHL tendon that may arise from cross-attachments with the flexor digitorum longus (FDL) tendon near the knot of Henry. The posterior tibial nerve is located nearby the decussation of these tendons.

Biphalangeal fifth toe.

Background: A biphalangeal fifth toe is a common variant in the European population. The frequency is higher in the Japanese population. It is considered an anatomical variant of the normal triphalangeal fifth toe.

Economic aspects of diabetic foot care in a multidisciplinary setting: a review.

Background: To evaluate the economic aspects of diabetic foot care in a multidisciplinary setting.

Method: A review of the English language literature, published from 1966 to November 2005.

Results: The results of available studies on the cost-of-illness of diabetic foot problems are difficult to compare.

The posteromedial rim of the talar dome as the site for harvesting cartilage in the ankle: an anatomic study.

Purpose: The goal of this study was to determine whether a biopsy specimen of a fixed size can be harvested reliably and consistently by arthroscopy at the posteromedial rim of the talar dome.

Methods: A cartilage biopsy specimen was taken post mortem arthroscopically from the posteromedial rim of the talar dome in 20 ankles. We aimed to take a full-thickness biopsy specimen of 10 x 5 mm in size.

The HINTEGRA ankle: rationale and short-term results of 122 consecutive ankles.

The HINTEGRA ankle was developed as an attempt to specifically address the needs of minimal bone resection, extended bone support, proper ligament balancing, and minimal contact stresses within and around the prosthesis. The purpose of this study was to determine the short-term results in a consecutive series of 116 patients (122 ankles). Preoperative diagnoses were posttraumatic osteoarthrosis in 91 ankles (75%), primary osteoarthrosis in 16 ankles (13%), and systemic arthritis in 15 ankles (12%).

Outcome and recurrence rate of diabetic foot ulcers treated by a total contact cast: short-term follow-up.

Foot ulcers in patients with diabetes present an increasing burden to healthcare. Total contact cast (TCC) is a well established treatment option for many of these ulcers, but little seems to be known about the final outcome once healing has been reached. The study examined healing and final outcome after TCC treatment among patients with diabetes.

Severe Lisfrancs injuries: primary arthrodesis or ORIF?

Twenty-eight patients, with severe, acute Lisfranc dislocations, requiring operative intervention, were treated between 1989 and 1992 in a level one Trauma Center. Different treatment protocols were used by the two senior staff surgeons. This allowed ORIF to be compared to complete arthrodesis and partial arthrodesis.