Clinical applications 1 fixation

PMMA is also injected into vertebral bodies for fixation of fragility fractures of the spine, injected into screw holes to augment internal fixation in osteopenic bone, and injected into stmctural voids following resection of benign tumors to control dead space and support the surrounding bone. In many of these applications antimicrobial powder can be added to the PMMA for drug delivery when local delivery of antimicrobials is needed. 

Other materials used to achieve implant fixation such as porous metal and calcium ceramics are commercially bonded to implant surfaces, not injected. With better understanding of bioactive peptides, the future may bring the use of signaling molecules to augment biologic implant fixation. Bioactive peptides could be commercially bonded to the substrate surface or injected in liquid or gel form at the time of implantation. 

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PDS demonstrated no acute or toxic effects on implantation, and thus has been used in a number of clinical applications ranging from suture materials to bone fixation devices. Johnson and Johnson Orthopedics provides an absorbable pin for fracture fixation, and bone pins have been introduced into the market under the names OrthoSorb and Ethipin, respectively, in the USA and Europe. In craniofacial applications, the structure of PDS has been examined clinically in cranial vault procedures with promising results. Advantages include the absence of observed intracranial translocation, acceptable aesthetic outcomes and low complication rates. Nevertheless,... 

Biodegradable synthetic polymers such as poly(glycolic acid), poly(lactic acid) and their copolymers, and copolymers of trimethylene carbonate and glycolide have been used in a number of clinical applications [26-30]. The major applications include resorbable sutures, drug delivery systems and orthopaedic fixation devices such as pins, rods and screws [31, 32]. 

Abstract Polymers have been used as biomaterials in Orthopaedic Surgery for decades. Despite reports of complications with some polymeric materials, most are biocompatible and have been used successfully in total joint replacements, for soft tissue reconstruction, for joint fusion, and as fracture fixation devices. In this chapter we wiU describe the types of polymers used in connnercially-available orthopaedic implants, and then give a breakdown by clinical application. 

Biodegradable internal fixation devices such as screws, pins, and plates are already nsed in clinical applications such as orthopaedic surgery. The advantage of using biodegradable fixation devices instead of metallic counterparts in bone orthopaedic snrgery is obvions - the device simply disappears after the bone heals. Loads... 

Aliphatic polyesters are generally sensitive to hydrolysis and are biodegradable (Gross and Bhanu, 2002). They are formed by the polycondensation reaction of an aliphatic glycol with an aliphatic dicarboxylic acid. Among the aliphatic polyesters there is a family of polymers, the poly(a-hydroxy acids) such as polyglycolic acid (PGA), polylactic acid (PLA), and some of their copolymers, which have been used in a number of clinical applications sutures, plates and fixtures for fracture fixation devices and scaffolds for cell transplantation. 

The state of the art in ligament replacement remains the application of allografts. The use of artificial materials in this application is in its relative adolescence compared with fracture fixation and total-joint replacement While artificial structures for total-ligament replacement or graft augmentation have not been fully optimized to date, they have proven to be effective in secondary repair situations—where a primary gi has failed—or cases of chronic instability. Future developments in materials, particularly composites, may produce a structure that can meet the mechanical and fixation requirements for ligament replacement with improved clinical outcomes. 

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