Oxidatively Degradable Poly(thioketal urethane)/Ceramic Composite Bone Cements with Bone-Like Strength

Current bone cements lack resorbability and integration with host bone. PMMA provides strength but does not degrade. Ceramic cements resemble bone chemistry but are brittle. This gap motivated the development of a new cement type. Prior research has shown that non-degradable cements can hinder long-term healing. No prior work had resolved the need for resorbable, strong cements. This paper's contribution introduces a novel polymeric system. The study addresses the challenge of weight-bearing applications in bone repair.

The aim was to develop a resorbable bone cement with mechanical strength. The specific problem is the lack of integration and degradation of current cements. The motivation is to improve bone regeneration outcomes. This study focuses on creating a polymer that degrades in oxidative environments. The cement must support bone growth and degrade at the right rate. The goal is to match the properties of natural bone. The study tests the material in a rabbit model. The results aim to guide future clinical applications.

A thioketal diol was synthesized and crosslinked with lysine triisocyanate. The resulting PTKUR was tested for hydrolytic and oxidative stability. Films were exposed to simulated bone defect conditions in vitro. Mechanical strength was measured against trabecular bone standards. Composite cements were made with ceramic particles. Working time was compared to calcium phosphate cements. Bone integration was assessed in rabbit femoral condyle defects. Histological analysis confirmed resorption by osteoclasts.

PTKUR films remained stable for six months under hydrolytic conditions. Degradation occurred within a week under oxidative conditions. Composite cements had working times similar to calcium phosphate cements. Their strength exceeded trabecular bone in compression tests. Bone growth was observed at the bone-cement interface at six and twelve weeks. Histology showed osteoclast activity at the interface. The cement supported appositional bone formation. These findings suggest the cement degrades selectively in bone remodeling.

The PTKUR/ceramic composite cements degrade in oxidative environments. They provide bone-like strength and support bone growth in vivo. The cement integrates with host bone at six and twelve weeks. Osteoclasts mediate resorption of the material. This represents an initial step toward resorbable bone cements. The findings suggest the material is suitable for weight-bearing applications. The authors propose that this system could replace non-degradable cements. Further testing in clinical models is recommended.