Characteristics of Biodegradable Implants

Abstract

The development of synthetic biomaterials for bone fixations has greatly enhanced orthopedic surgery efficiency over the last two decades. With the advancement in medical technology, several materials such as metals, ceramics, polymers and composites have been considered over the years for possible implantation into the body. These materials however, must have the following required properties that will qualify them as potential medical devices: biocompatibility, mechanical properties, corrosion resistance, creep resistance, etc. The quest in making up for the disadvantages of metallic fixations has culminated in a paradigm shift to the use of biodegradable polymers. Biodegradable polymers are lightweight materials with low elastic moduli between 0.4-7 GPa. These materials can be engineered to degrade at rates that will slowly transfer load to the bone. In addition, complications like corrosion, release of metal ions and stress shielding associated with metal implants are eliminated. This review considers studies carried out on most commonly investigated and widely used synthetic biodegradable polymers, their successes and limitations. It also provides process for efficient utilization of these polymers as bone fixtures without inflammation and stress shielding.

Poly(lactic acid) blends in biomedical applications

“…PLA and its blends have been used for implants for over 3 decades [10,[151][152][153][154]. For instance, ocular implants were developed using PLA/polyvinyl pyrrolidone (PVP) for fluorometholone (FLM) delivery in which release rate increased with increase in PVP and followed first order kinetics.…”

The Role of Two-Step Blending in the Properties of Starch/Chitin/Polylactic Acid Biodegradable Composites for Biomedical Applications

“…Chitin and starch are abundantly available for use [16,17]. They are natural polymers with excellent biodegradable properties and have been used as implants [17][18][19]. Chitin is hydrophobic, while starch, a polysaccharide with a hydrophilic nature, is biocompatible and an absorbable natural polymer.…”

Preparation of Chitin-PLA laminated composite for implantable application

“…But the problem arose firstly, due to the mismatch in elastic moduli between the bone and metallic implants for bone healing And secondly the risk of forming corrosion products by the metal alloy which in turn causes inflammation and infection in the body tissue [5] . By using biodegradable polymer based materials, complications like mismatch of elastic moduli, corrosion, release of metal ions and stress shielding associated with metal implants can be eliminated [6] , [7] , [8] . Moreover, these biodegradable materials make it highly attractive for biological and medical applications as well as it can be broken down into smaller fractions in physiological environments by aerobic or anaerobic microorganisms, or biologically active processes (e.g.…”

“…enzyme reactions) or passive hydrolytic cleavage [9] , [10] , [11] , [12] . The most commonly investigated and widely used synthetic biodegradable polymers are polyglycolide/glycolic acid (PGA), polylactide/lactic acid (PLA), poly-ε-caprolactone (PCL), chitin, chitosan, gelatin etc [6] , [7] , [8] .…”