Papers by Keyword: Arthroplasty

Abstract: This paper addresses to a research of a dynamic answer obtained through numerical simulations of a human ankle joint implant with finite element method. The research background consists of an inverse dynamic analysis based on Newton-Euler formalism completed with Lagrange’s multipliers method. Thus, a parameterized virtual model of a human ankle joint was elaborated and simulated together with the implant, in dynamic conditions similar with real ones in reality. A results numerical processing was obtained with the aid of MSC Nastran and important results were obtained for orthopedic implants design.

Abstract: The serious diseases and accidents are the leading causes for the surgeries/transplantation in human body. In present time, a large proportion of world population is facing arthritis problems that lead to partial/total knee arthroplasty and total hip arthroplasty. The implants used in the arthroplasty require high strength, high corrosion and wear resistance and longer life span in a working environment. The quality of fabricated implants significantly depends upon the manufacturing methods used to process the raw materials. In present time, various sintering techniques are popularly used to produced implants owing to improved product quality; however, artificial implant manufacturing industry is looking for more energy efficient, time saving and eco-friendly processing techniques which can offer implants at economical cost along with adequate quality. The present article reviews an overview of different sintering techniques used for producing biomedical implants have been presented. The limitations of these processes have been highlighted and the potential of microwave sintering to address these challenges has been identified. Advantages of using microwave sintering over conventional sintering are also discussed in terms of microstructures, mechanical properties and process efficiency. It has been realized that microwave sintering has potential to cater the needs of the industry for processing of biomaterials as a time saving, energy efficient and environment friendly sintering technique as compare to conventional sintering.

Abstract: This article aims to evaluate the results and outcomes of patients with highly comminuted radial head fractures, Mason III / IV type, treated surgically by arthroplasty with a cemented modular radial head prosthesis. A fracture of the radial head with a high degree of comminution left untreated can lead to complex functional impairment in which both elbow flexion and extension and also the pronation / supination of the forearm are limited, all of which will affect their daily activities. Management of radial head fractures should be based on both injury-specific factors and patient factors. Injury-specific factors include fracture size, displacement, rotation block, and associated injuries. Patient factors include age, associated injuries, bone quality, and activity level. Six patients underwent surgery for highly comminuted radial head fractures. All participants were followed up to 36 months postsurgery. A final review was carried out at 12-36 months after surgery when clinical, functional and imagistic assessment was performed. Functional results were very good; stability and ROM data obtained were within normal limits. Surgical treatment using modular radial head prosthesis offered excellent results, the elbow mobility being in the normal range and patients requiring a short period of recovery to achieve these parameters.

Abstract: Cervical disc herniations represent the most frequent cervical-level pathology in patients aged 40 and above. Symptoms usually include C6-C7 radiculopathy, which has a prevalence of 3.3/1000 individuals. There still is a debate on whether any gender is more frequently affected, as some authors report women are more frequently affected [2, 3] while others claim both genders are equally affected. Ever since the 1950s the standard treatment for such patients was represented by Anterior Cervical Discectomy and Fusion (ACDF), however, concern for the development of adjacent level degeneration after the fusion of mobile vertebral segments has increased the interest in developing new dynamic disc prostheses designed to mimic the functions and natural motion of the spine. The purpose of this paper is to summarize, in a comprehensive literature-review-type article, the existing data regarding the ProDisc-C spinal implant within the OVID, SCOPUS and MEDLINE databases while at the same time presenting the personal experience of the authors using the above-mentioned implant.

Abstract: The biomechanics of the glenohumeral joint depend on the interaction of both static and dynamic stabilizing structures. The combined effect of these stabilizers is to support the multiple degrees of motion within the glenohumeral joint. Total shoulder arthroplasty requires release of contracted tissues, repair of rotator cuff defects, reconstruction of normal skeletal anatomy with proper sizing, and positioning of components. Arthroplasty of the shoulder is unlike arthroplasty of the hinge joints when the collateral ligaments afford a high degree of stability and is even distinct from the hip when bony conformity is large and range of motion is less. The goal of this paper is biomechanical analyses of normal, injured and implanted shoulder joint.

Abstract: The resurfacing arthroplasty is a new method, superior techniques used in hip arthroplasty, through the immediate post-operative recovery and distance, followed by a complete reversal of limb function and a minimum rate of postoperative complications. Performance of this prosthesis is evident in well selected cases (young patients with physical activity) after a surgical indication correctly formulated. 39 patients with aseptic necrosis of the femoral head prosthesis underwent surgery with total hip resurfacing type in Clinical Orthopaedics-Traumatology, University Hospital Bucharest between 2005-2009. The diagnosis was established by X-ray and MRI examination. Sex ratio was: 22 men and 17 women. Age groups: 11 patients 20-30 years, 30-40 years 16 patients, 12 patients over 40 years... Approach was developed by postero-lateral joint capsule being maintained to preserve femoral vasculature. Recovery was fast in a short amount of time patients. All patients were reviewed clinically and radiographically at 4 weeks, 6 weeks, 3 months, 6 months, and 12 months, then annually. There were 5 cases of revision after resurfacing arthroplasty type of causes independent of design and composition of these prostheses. Revision surgeries of these prostheses have gone easier than in the case of conventional prostheses. Most times it is enough just replacing the stem, keeping torque meta-metal large head with all its benefits. The importance of this type of arthroplasty is that: are aimed at young people, preserves bone capital, maintain femoral vasculature, rapid, resumption of intense physical activity, complete recovery of movement in the hip joint, lack of formidable complications in hip arthroplasty dislocation represented.

Abstract: The resurfacing arthroplasty is a new method, superior techniques used in hip arthroplasty, through the immediate post-operative recovery and distance, followed by a complete reversal of limb function and a minimum rate of postoperative complications. Performance of this prosthesis is evident in well selected cases (young patients with physical activity) after a surgical indication correctly formulated. 39 patients with aseptic necrosis of the femoral head prosthesis underwent surgery with total hip resurfacing type in Clinical Orthopaedics-Traumatology, University Hospital Bucharest between 2005-2009. The diagnosis was established by X-ray and MRI examination. Sex ratio was: 22 men and 17 women. Age groups: 11 patients 20-30 years, 30-40 years 16 patients, 12 patients over 40 years... Approach was developed by postero-lateral joint capsule being maintained to preserve femoral vasculature. Recovery was fast in a short amount of time patients. All patients were reviewed clinically and radiographically at 4 weeks, 6 weeks, 3 months, 6 months, and 12 months, then annually. There were 5 cases of revision after resurfacing arthroplasty type of causes independent of design and composition of these prostheses. Revision surgeries of these prostheses have gone easier than in the case of conventional prostheses. Most times it is enough just replacing the stem, keeping torque meta-metal large head with all its benefits. The importance of this type of arthroplasty is that: are aimed at young people, preserves bone capital, maintain femoral vasculature, rapid, resumption of intense physical activity, complete recovery of movement in the hip joint, lack of formidable complications in hip arthroplasty dislocation represented.

Abstract: An elastomeric spinal disk prosthesis design (BioFI™) with vertebral interlocking anchors has been modified using an embedded TiNi wire array. Bioinert styrenic block copolymer (Kraton®) and polycarbonate urethane (Bionate®) thermoplastic elastomer (TPE) matrices were utilized. Fatigue resistant NiTi wire was pretreated to induce superelastic martensitic microstructure. Stent-like helical structures were produced for incorporation within homogenous TPE matrix. Composite prototypes were fabricated in a vacuum hot press using transfer moulding techniques. Implant prototypes were subject to axial compression using a BOSE ® ELF3400. The NiTi reinforced implants exhibited reduction in axial strain, compliance, and creep compared to TPE controls. The axial properties of the NiTi reinforced Bionate® BioFI™ implant best approximated those of a spinal disk followed by Kraton®-NiTi, Bionate® and Kraton® prototypes. An ovine lumbar segment biomechanical model was used to characterize the disk prosthesis prototypes. Specimens were subject to 7.5Nm pure moments in axial rotation, flexion-extension and lateral bending with a custom jig mounted on an Instron® 8874. The motion preserving ligamentous nature of this arthroplasty prototype was not inhibited by NiTi reinforcement. Joint stiffness for all prototypes was significantly less than the intact and discectomy controls. This was due to lack of vertebral anchor rigidity rather than BioFI™ motion segment matrix type or reinforcement. Implant stress profiles for axial compression and axial torsion conditions were obtained using finite element methods. The biomechanical testing and finite element modelling both support existing BioFI™ design specifications for higher modulus vertebral anchors, endplates and motion segment periphery with gradation to a low modulus core within the motion segment. This closer approximation of the native spinal disk form translates to improvements in prosthesis biomechanical fidelity and longevity. Axial compressive strain induced within a TiNi reinforced Kraton® BioFI™ was found to be linearly proportional to the NiTi helical coil electrical resistance. This neural network capability delivers opportunities to monitor and telemeterize in situ multiaxis joint structural performance and in vivo spine biomechanics.

Abstract: To augment cement-bone bonding, hydroxyapatite (HA) granules were interposed at cement-bone interface (IBBC technique). HA granules were smeared on the bone surface just before cementing components. Porous HA granules of 300 to 500μm in diameter and 100 to 300μm in diameter were used from 1986 to 1988(first generation) and 1989 to 1991(second generation), respectively. 222 hips of 151 patients in the first generation and 252 hips of 170 patients in second generation could be followed. After 16 to 21 year follow up, radiolucent line (space), less than 1mm, was observed in 4 hips(1.8%) in the first generation and in 15 hips(6.2%) in the second generation(p<0.01). osteolysis was observed in 1 hip(0.5%) and 6 hips (1.6%), respectively. Loosening (separation) was observed only 2 cups (0.8%) in the second generation.