Bone Healing and Inflammation: Principles of Fracture and Repair

Bones comprise a significant percentage of human weight and have important physiologic and structural roles. Bone remodeling occurs when healthy bone is renewed to maintain bone strength and maintain calcium and phosphate homeostasis. It proceeds through four phases: (1) cell activation, (2) resorption, (3) reversal, and (4) bone formation. Bone healing, on the other hand, involves rebuilding bone following a fracture. There are two main types of bone healing, primary and secondary. Inflammation plays an integral role in both bone remodeling and healing. Therefore, a tightly regulated inflammatory response helps achieve these two processes, and levels of inflammation can have detrimental effects on bone healing. Other factors that significantly affect bone healing are inadequate blood supply, biomechanical instability, immunosuppression, and smoking. By understanding the different mechanisms of bone healing and the factors that affect them, we may have a better understanding of the underlying principles of bony fixation and thereby improve patient care.

Thoracic Cord Compression

The majority of extradural spinal tumors are metastatic. Magnetic resonance imaging (MRI) and computed tomography (CT) imaging are both useful for evaluation of epidural cord compression and biomechanical instability. For the patient with an extradural thoracic tumor, goals of therapy may include recovery or preservation of neurologic status, local oncologic control, recovery or maintenance of mechanical stability, and improvement of quality of life. This chapter discusses the key therapeutic decision-making criteria and surgical considerations in the management of patients with epidural cord compression due to an extradural thoracic tumor.

Reslip of a Previously Fixed Slipped Upper Femoral Epiphysis with an Associated Vitamin D Deficiency

Slipped upper femoral epiphysis (SUFE) is a relatively common adolescent hip disorder that represents a biomechanical instability of the proximal femoral growth plate. A link between vitamin D deficiency and SUFE has emerged in recent years; however, we present a unique case of a 10-year-old girl who presented with a reslip of a previously fixed SUFE with an associated vitamin D deficiency.

Reverse torque values in indexed abutments

Mechanical stability of implant-abutment set is fundamentally important for the success in implant supported rehabilitation. For this, the knowledge about torque removal values is essential. In this way, the objective of this work was to evaluate the torque reverse values in indexed abutments of Morse Taper system. Five Morse taper implants with their respective abutments were tested (n=5). Each abutment received a sequence of two consecutive torques in insertion (15Ncm) with an interval of ten minutes, and one reverse torque, all measured by digital torque wrench. The t-student test with 5% significance was used to evaluate the data. The analysis of results showed there is statistical significant difference in reverse torque values between the insertion torque value and reverse torque value intra-group, the indexed abutments presented an average percentage of torque loosing of 15% (P=0.002). It is possible to conclude that the use of indexed abutments of Morse taper system presented statistical significant reduction of reverse torque values, which in turns increase the risk of no biomechanical instability.