ABSTRACT
BACKGROUND:Polylactic acid and its copolymers have been widely used in biomedical fields because of their good biocompatibility and biodegradability, which have become a hotspot in the research of biomaterials. OBJECTIVE:To review the biocompatibility of fully degradable polylactic acid and its copolymers. METHODS:A computer-based online retrieval of PubMed and CNKI was performed to search relevant papers published from 2006 to 2016, with the key words of "polylactide, polylactic acid, copolymer, biodegradability, biocompatibility, animal" in English and Chinese, respectively. RESULTS AND CONCLUSION:Polylactic acid and its copolymers as polyester compounds are approved by the US Food and Drug Administration for use in the biomedical field because of their good biocompatibility mainly as drug delivery carriers and temporary implants. Moreover, their side effects in clinical application have attracted attentions. Polylactide copolymers can cause some adverse reactions when used in drug delivery systems, orthopedic and skin care, and other clinical medical fields. These copolymers are deemed to have no impact on the central nervous system, eyes, cardiovessels and other tissues and organs. They also have no virtually genotoxic and carcinogenic effects. Currently, the polylactide copolymer implant mainly results in local reactions in the surrounding tissues, and no systemic reactions have been found.
ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the treatment effect of three and four-part fractures of proximal humerus in elder patients using indirect reduction combined with locking proximal humeral plate (LPHP) fixation.</p><p><b>METHODS</b>From November 2004 to May 2008, 24 cases of proximal humeral three and four-part fracture were treated with percutaneous plate fixation using LPHP included 6 males and 18 females with an average age of 70 years old ranging from 55 to 88 years. The surgery was performed through antrolateral transdeoltoid approach. After extra articular capsule indirect reduction, the plate was inserted through the incision, and then an incision was made distal to previous incision to expose distal plate. The proximal fragments were fixed with 4 to 6 screws, and distal fragments were fixed with 3 screws. Shoulder exercises were performed at the 2nd to 3rd day after operation. Two weeks after operation, active shoulder exercise was done, which was gradually intensified 3 weeks after operation. The functional outcomes of the shoulder were assessed according to Constant score.</p><p><b>RESULTS</b>All the fractures united clinically and radiologically. The mean healing time was 10.5 weeks (8 to 21 weeks). The mean Constant score was 81.6 points (49 to 92 points). A total of 20 patients had excellent or satisfactory result, with only one scored as poor.</p><p><b>CONCLUSION</b>The technique of extra articular capsule indirect reduction combined LPHP internal fixation has the advantages of stable, easy to operate, less vascular damage and so on. It can effectively treat the proximal humerus three-and four-part fractures, especially to elder patients.</p>