Upper Extremity Neuromuscular Disorders
Medical caregivers of patients with upper extremity neuromuscular disorders should use a multidisciplinary approach in order to maximize their patients’ function and minimize related adverse events. Nonsurgical treatment options are often trialed initiall
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Kenneth R. Means, Christopher L. Forthman, W. Hugh Baugher, Ryan D. Katz, Raymond A. Wittstadt, and Keith A. Segalman
pper Extremity Basic Orthopedic U Principles Normal bone healing occurs not with scarring but rather through replacing the injured bone with new bone, making it a unique human tissue. Bone healing occurs via a gradual progression through four different stages. The same basic stages of bone healing occur following a fracture or a surgical trauma, such as an osteotomy or fusion procedure. The initial stage is the inflammatory stage when inflammatory cells migrate to and hematoma forms at the site of injury. The second stage is called the soft callus stage. Here, cartilage cells enter the injured area and create a cartilage matrix. This matrix is moderately stable mechanically but not yet calcified. The third stage is the hard callus stage, in which the matrix becomes calcified and is removed slowly while osteoblasts replace it with osteoid, or bone substance. At this stage definitive
K.R. Means, MD (*) • C.L. Forthman, MD W.H. Baugher, MD • R.D. Katz, MD R.A. Wittstadt, MD • K.A. Segalman, MD The Curtis National Hand Center, MedStar Union Memorial Hospital, 3333 N. Calvert St., JPB 2nd Floor, Johnston Professional Building # 200, Baltimore, MD 21218, USA e-mail: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
mechanical stability is established, and the fracture is clinically healed. The final stage is remodeling in which osteoclasts and osteoblasts work to remove and replace bone, respectively. This final stage can occur for several years and seeks to return the injured bone to its native shape and biomechanical characteristics as well as possible. Bone healing is sometimes also described as either primary or secondary. Secondary bone healing is the process that has just been described above and occurs for all bones that heal without rigid fixation. Clinical examples include healing in a splint, cast, or with surgical pinning or intramedullary rods. In these instances, the bone is said to have relative stability or fixation during the healing process. Primary bone healing has traditionally been thought to occur when bone fractures are fixed with plates and screws or interfragmentary compression screws. This type of stabilization is termed absolute, or rigid, fixation. Primary bone healing has classically been thought to occur without callous formation and instead via direct extension of “cutting cones” containing osteoclasts and followed by osteoblasts and other cells from one side of the fracture into the other side of the fracture. There is recent evidence to suggest that even rigid internal fixation of fractures leads to secondary bone healing but that the amount of callous formed is much smaller than that for less rigid methods of bone stabilization. Tendon healing occurs primarily via fibroblast proliferation and subsequent collagen synthesis
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