Introduction Complex periarticular fractures of the long bones are difficult to treat. Classic intramedullary osteosynthesis do not provide a stable fixation Wiss et al.
This avoided the risks of surgery; however, closed reduction and prolonged immobilization often led to joint stiffness, malunion, and impairment from disuse. The subsequent development of safer surgical practices led to increased operative management of fractures which initially called for anatomic reduction and rigid fixation to achieve primary cortical healing.
An initial inflammatory stage, soft callus stage, hard callus stage, and remodeling. The inflammatory stage involves hematoma formation allowing inflammatory cells to infiltrate and debride the fracture site and recruit cells necessary for bone repair. A soft callus stage composed of cartilage is formed next as these progenitor cells differentiate to form osteoblasts and chondrocytes.
Chondrocytes then undergo maturation and the extracellular matrix is calcified. This is followed by removal of the calcified cartilage by osteoclasts and invasion by endothelial cells.
The hard callus is formed, as bone is laid down behind the infiltrating vasculature. The newly formed bone is then remodeled until morphologically and mechanically similar to its preinjury state. Each of these phases of bone repair has been well studied in murine models 141516 and 17 and is explained in greater detail below.
At the time of fracture, torn periosteum, exposed bone marrow, and injured soft tissues bleed and create the fracture hematoma. Stem cells differentiate into chondrocytes or osteoblasts depending on the mechanical environment.
Relative instability favors chondrocyte differentiation and endochondral ossification Fig. Operative fracture fixation uses the entire spectrum from absolute rigid internal fixation to relative stability. During this early period of fracture healing, the main extracellular components are type II collagen and proteoglycans.
The proteoglycans inhibit mineralization of the mass until enough cartilage has been formed. Hypertrophic chondrocytes begin releasing vesicles containing calcium and proteolytic enzymes that release phosphate ions from the surrounding matrix and degrade proteoglycans. Through the precipitation of calcium and phosphate and the decreasing concentration of neighboring proteoglycans, the callus begins to mineralize.
Between 2 and 3 weeks, chondroclasts remove the calcified cartilage as well as chondrocytes that have undergone apoptosis, 24 and gradually osteoblasts convert the soft callus to the hard callus by laying down woven bone that is identical to secondary spongiosa from the growth plate.
This replacement process generally is completed by 3 to 4 weeks at which point the fracture is united. Osteoclasts then begin the remodeling process and the woven bone is converted to lamellar bone. A By day 4, radiographs show misaligned bone segments due to the lack of stabilization following fracture.
Osteocalcin oc expression reveals a small amount of new bone forming along the periosteum.Baumgaertel F, Buhl M, Rahn BA.
Fracture healing in biological plate osteosynthesis. Injury ;29 Suppl 3:C3–C6. In order to gain a better understanding of the healing processes after plate fixation and indirect reduction, Baumgaertel designed a reproducible fracture model for the sheep femur in so that the differences between anatomical (rigid) and biological (bridging) fixation could be investigated.
Biological Osteosynthesis Ross H. Palmer, DVM, MS * From the Mobile Veterinary Surgical Group, Aptos, California Mobile Veterinary Surgical Group Aptos California * Mobile Veterinary Surgical Group, Jennifer Drive, Aptos, CA Methods of fracture treatment must strike a balance between fracture stability and soft tissue integrity.
Compared to traditionally lateral single plate, double plating provided stronger fixation which could accelerate fracture healing, prevent hardware failure, and improve knee function for patients with medial-instable DFFs.
With the better understanding of fracture healing biology and biomechanics of fracture fixation and healing, the trend of treatment is towards biological fixation, which can be accomplished by Minimally Invasive Percutaneous Plating Osteosynthesis (MIPPO) technique.
Treatment distal tibia fracture; Plate osteosynthesis; MIPO distal tibia. Introduction. Biological fixation has drastically modified orthopedic trauma surgery. The understanding that minor surgical trauma with less secondary vascular damage and preservation of the periosteum around the fracture zone maintains local healing properties has been essential in the evolution.