Two artificial bone graft substitutes

Bone grafting substitutes is a variety of surgical methods to add or stimulate the formation of new bone wherever it is needed and is a common surgical procedure in orthopedic surgery. Next to blood, bone is the second most common tissue transplanted, with more than 2 million graft procedures performed worldwide each year. It is important to develop an artificial osteoconductive matrix of collagen bone graft substitutes using biological porous material as an alternative.

Commonly used artificial bone graft substitutes include calcium phosphate (CaP) and calcium sulfate (CaS) compounds.

Here is the content:

• CaP ceramics

• CaS compounds

  
  

  
  

CaP ceramics

CaP ceramics and bone cement are osteoconductive materials with crystal structure-dependent resorption rates. In general, CaP ceramics are brittle and have low tensile strength. They are mainly transmitted in the form of compressive strength - part of the structural support. However, their advantage lies mainly in their osteoconductive properties. Cap ceramics act as a kind of collagen bone graft substitute block and promote bone formation by promoting the formation of new bone from host osteoprogenitor cells in the presence of local osteoinductive growth factors. A commonly used CaP compound is tricalcium phosphate (TCP). Bone cement preparations of CaP are prepared by dissolving calcium in a water-soluble solvent. As the bone cement hardens, a precipitation reaction occurs in the body while the CaP crystals expand. This CaP bone cement preparation has advantages over block, granular and powderedbone graft substitutes because it can be filled using pressure depending on the shape and size of the bone defect.

However, care must be taken when using it to avoid extrusion of the cement outside the bone defect causing damage to the surrounding tissue. In addition, many prospective clinical trials have shown that TCP bone cement injections are safe and effective in the treatment of distal radius fractures with percutaneous kerf pins, as well as in the treatment of tibial plateau fractures with ORIF.

CaS compounds

CaS compound is another fully resorbable osteoconductivebone graft substitute. This material is available in cemented and spherical form, and once attached by osteoblasts, this material usually dissolves in vivo within 30-60 days. CaS compounds are effective in filling bone defects, for example in post-traumatic bone defects and bone defects at the stem end after fracture repositioning.

However, CaS is usually associated with persistent wound plasma exudate, a complication that results from the inflammatory response when the CaS complex is resorbed. The likelihood of exudation is reported to be higher in 4-51% of cases with extensive use of CaS bone grafting in bone with thin subcutaneous tissue (tibia, ulna). So, surgeons should use caution when there is concern about the development of infection.

Over the past few decades, the development of bone grafts substitutes has influenced the treatment of fractures, bone defects, and non-healing fractures after trauma. However, with a variety of bone grafts available, surgeons can be confused in their application. To clarify the best treatment option for patients requiring bone grafting, high-level evidence-based medical evidence and prospective randomized trials are needed to compare the available bone grafts. Until then, surgeons must evaluate each patient and disease condition and define the county goals they wish to achieve.