Tissue restoration after resorption of polyglycolide and poly-laevo-lactic acid screws

Abstract

Despite worldwide clinical use of bio-absorbable devices for internal fixation in orthopaedic surgery, the degradation behaviour and tissue replacement of these implants are not fully understood. In a long-term experimental study, we have determined the patterns of tissue restoration 36 and 54 months after implantation of polyglycolic acid and poly-laevo-lactic acid screws in the distal femur of the rabbit. After 36 months in the polyglycolic acid group the specimens showed no remaining polymer and loose connective tissue occupied 80% of the screw track. Tissue restoration remained poor at 54 months, the amounts of trabecular bone and haematopoietic elements being significantly lower than those in the intact control group. The amount of trabecular bone within the screw track at 54 months in the polyglycolic acid group was less than in the empty drill holes (p = 0.04). In the poly-laevo-lactic acid group, polymeric material was present in abundance after 54 months, occupying 60% of the cross-section of the core area of the screw track. When using absorbable internal fixation implants we should recognise that the degradation of the devices will probably not be accompanied by the restoration of normal trabecular bone.

The use of silk-based devices for fracture fixation

“…These potential benefits have been supported by reports demonstrating favourable results in treating fractures with these resorbable systems 4,[10][11][12][13][14][15] . However, conventional resorbable materials are associated with inflammatory reaction, can generate sterile sinus formation, result in incomplete remodelling of the bone and exhibit improper dynamics between device strength retention and wound healing 11,12,16 . They are primarily limited to specific applications such as paediatric craniofacial reconstruction 10 , fixation of metacarpal fractures [13][14][15] and long-term soft-tissue moudling 17 due to their lower strength and stiffness.…”

In Vitro Elution Characteristics of Vancomycin in a Composite Calcium Phosphate/Calcium Sulfate Bone Substitute

“…Previous works have noted the poor elution levels particular to this drug in comparison to other antibiotics such as tobramycin. Calcium phosphate products are advocated as carriers for targeted delivery of antibiotics in acute infection, yet, studies have alluded to the poor prolonged release of clinically effective concentrations of vancomycin [3], in combination with a poor resorption profile. We sought to investigate the elutive properties of a CaP/CaS composite, as well as review the materials resorptive profile.…”

Estudo do processo de reparação óssea em defeitos na calvária de ratos utilizando sinvastatina associada a um polímero de poli (ácido láctico-co-glicólico)

“…Dentre os materiais de enxerto de natureza orgânica, os polímeros têm como vantagens a processabilidade e flexibilidade de formulação, excelentes propriedades estruturais, ausência de emissão de irritantes ou vapores tóxicos, além da biocompatibilidade e biodegradabilidade (Bostman et al, 2005Piattelli et al, 1996. Henning et al em (1989) (Bostman et al, 2005).…”

“…Henning et al em (1989) (Bostman et al, 2005). Sua degradação primária é por meio de reações químicas como hidrólise e também por vias enzimáticas e celulares.…”

“…Avaliando-se a reparação após 36 meses, os espécimes que receberam ácido poli-ácido láctico não apresentam polímero residual na área observada, mas um tecido conjuntivo frouxo em volta do parafuso. Foi constatado que apesar da completa degradação do material, os defeitos não apresentavam osso trabecular após 54 meses (Bostman et al, 2005).…”