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Techniques and Applications of Scanning Acoustic Microscopy in Bone Remodeling Studies
Published in Cornelius Leondes, Musculoskeletal Models and Techniques, 2001
Mark C. Zimmerman, Robert D. Harten, Sheu-Jane Shieh, Alain Meunier, J. Lawrence Katz
Limb lengthening as the name implies, refers to the clinical practice of increasing the length of the long bones of the skeleton. In contemporary orthopedics, this is nearly synonymous with the process of distraction osteogenesis. This technique was first developed and practiced during the 1950s by Dr. Gavril Ilizarov in Sibera. Briefly, this process involves the steady and slow separation of two bone fragments after the surgical creation of a fracture. An external fixation device is used to provide stability, and a means for gradually increasing the distance between the bone ends via an adjustable mechanism. The actual process of distraction or lengthening ensues after a latency period of a few days to allow for initial healing and callus formation. The new tissue (or bone regenerate) formed in the created gap begins to mineralize from the original bone ends toward the center of the gap. Many factors affect the outcomes of these procedures, and for that reason distraction osteogenesis has become an active area of research in the orthopedic community.
Dealing with Problems of Biomedical and Regulatory Interest
Published in Guigen Zhang, Introduction to Integrative Engineering, 2017
External fixation is useful for the treatment of unstable fractures, limb lengthening, and congenital and pathological orthopedic deformities. The functionality of an external fixation device relies mainly on the use of tensioned wires to support bone fragments. One major problem with these wires is their yielding. Once the wires yield, the fracture healing process will be compromised. Computational models have been developed to examine the cause of the nonlinear behavior observed in these tensioned wires and illustrate how material yielding can be minimized to enhance the functionality of such a fixation device.
The application of nanogenerators and piezoelectricity in osteogenesis
Published in Science and Technology of Advanced Materials, 2019
Fu-Cheng Kao, Ping-Yeh Chiu, Tsung-Ting Tsai, Zong-Hong Lin
However, some fracture healings can not be treated with rigidly stable managements, as most fractures need to be treated with bracing that involves some degree of motion, including cast immobilization, intramedullary nails, bridge plating, and external fixation devices. Therefore, primary bone healing is rare, and the majority of fracture healing proceeds via secondary bone healing, or endochondral ossification, which occurs via a cartilage callus. There are four major phases of secondary bone healing, which include the inflammatory phase, early callus phase, mature callus phase, and remodeling phase. The inflammatory phase is characterized by an acute bone marrow response, post-damaged inflammation, and hematoma formation immediately following the fracture and up to 3–4 days after (Figure 2(a)). The damaged tissue releases proinflammatory mediators, such as interleukin 1 (IL-1), IL-6, and tumor necrosis factor alpha (TNF-α), to initiate the repair process [20]. The second stage is the early callus phase. This phase is predominated by soft cartilage callus formation, angiogenesis, and chondrogenesis at the fracture gap [21] (Figure 2(b)). Subsequently, the cartilaginous matrix is mineralized to begin the third phase, the mature callus phase. At this point, the chondrocytes undergo apoptosis and osteoblasts infiltrate the callus. The primary bone is laid down on these surfaces [22] (Figure 2(c)). In the last phase or remodeling phase, the newly formed woven bone is progressively replaced by mature lamellar bone, ultimately restoring the original cortical structure [23] (Figure 2(d)).
Management of clavicle shaft fractures with intramedullary devices: a narrative review
Published in Expert Review of Medical Devices, 2020
Paul Reginald King, Robert Patrick Lamberts
Operative treatment options consist of external fixation and internal fixation. External fixation can be achieved through monoplaner devices or ring fixators. Internal fixation comprises open reduction and internal fixation using locked or non-locked plates. Alternatively, open or closed reduction with internal fixation using intramedullary rods, wires or nails, can be used [1,24].
Single-step sinter-aging heat treatment of metastable-beta type Ti–Nb–Cu alloy
Published in Powder Metallurgy, 2021
Yao et al. [11] studied the precipitation of Ti2Cu particles in Ti–2.5Cu alloy subjected to different heat treatments. Ti2Cu were formed in two shapes. Spherical particles due to the decomposition of supersaturated alpha-Ti and acicular ones are produced by aging. Nanosized acicular Ti2Cu were nucleated in the interior of grains. Acicular particles made greater contributions to the strengthening. Cardoso et al. [12] studied the mechanical behaviour of precipitation hardened Ti–Cu alloys. Precipitation can be achieved by the decomposition of martensite. After homogenisation at a temperature in the beta field, samples were quenched and examined. Quenched Ti–Cu alloys present Ti2Cu precipitates. No evidence of beta phase stabilisation was found in the quenched samples. Luangvaranunt and Pripanapong [13] studied the precipitation hardened Ti–Cu alloys. Ti–2Cu and Ti–10Cu alloys were produced by powder metallurgy. Alloys were precipitation hardened to observe the effect of heat treatment. Hardness increased after solution treatment to 320 and 526 HV, and after aging to 441 and 612 HV. Lamellar morphology of alpha-Ti/Ti2Cu was favourable to the homogenised morphology of heat treated alloys. Shirai et al. [14] studied the prevention of pin track infection by Ti–Cu alloys. The most frequent complication in external fixation is pin infection. To reduce the incidence of infection, many reports have looked at preventing bacterial adhesion by treating the pin surface. Two Ti–Cu alloys were synthesised. One was Ti–1Cu and the other was Ti–5Cu. Reaction of pathogens to the alloys was compared with their reaction to stainless steel and pure Ti. Both Ti–Cu alloys inhibited colonisation by bacteria. Cytocompatibility studies were performed. Ti–1% Cu alloy showed no difference in the number of colonies. Ti–Cu alloy pins were evaluated in a rabbit model. Ti–1% Cu alloy inhibited inflammation and infection. Ti–Cu alloys have antimicrobial activity and reduce the incidence of pin infection. Ti–1% Cu alloy shows promise as a biomaterial. Kolli and Devaraj [15] reviewed the beta Ti alloys, which have found applications in aircrafts, and implants. Beta-phase is metastable at temperatures below the beta transus.