risk and why. Prevent, detect and manage each problem/condition. • Age related changes versus clinical problems • Delirium • Osteoporosis • Depression • Fluid & electrolyte imbalances • Malnutrition / anemia • Constipation • Falls (prevention), minimizing restraint use Skills Know why, when and how to competently perform psycho-motor skills Transition Planning Considerations Coordinate individualized transitions for complex patients. • Common needs of orthopaedic patients • Community resources • Transportation • Rehab/convalescent facilities • Team roles in transition planning Page 6 of 196 ANATOMY AND PHYSIOLOGY Bone Structure, Development, and Function There are 206 bones in the human body. Humans are born with nearly 300 bones, but many fuse together over time. Bones vary widely in size ranging from the tiny ear bones to the large (nearly 2 feet long) femur bone that is strong enough to withstand 30 times one’s body weight. There are two different types of bones: cortical bone and cancellous bone. Cortical bone, also known as compact bone, is a very dense type of bone. Around 80% of the skeleton is composed of cortical bone and its primary functions are to provide structural strength to the skeleton, and help maintain homeostasis through the release and reabsorption of calcium. Cancellous bone, also called trabecular bone or spongy bone, houses both red and yellow marrow. Red marrow is the site of blood cell production (hematopoiesis), where yellow marrow is mostly composed of fat cells. Most bones contain a combination of approximately 80% cortical and 20% cancellous bone (Bergeron, et al., 2018). Physiological and biomechanical differences of growing bones Bone Tissue and Bone Cells Bone is living and growing tissue with porous mineralized structure, comprised of cells, vessels, and crystals of calcium compounds. Bone cells are separated into two classifications: osteoblasts make bone, and osteoclasts resorb/dissolve bone (Schoenly, NAON, 2013). The osteoblasts become osteocytes, or mature bone cells, which are merged into compact bone. About 90% of all bone cells are osteocytes and their life span is decades long. Although they no longer build bone, osteocytes are important to bone maintenance and homeostasis. Osteoclasts, in comparison, remodel bone by breaking it down to release minerals and other materials into the body. Their activity is stimulated by the osteoblasts. Bone plays a vital role in storing and releasing minerals. Approximately 60% – 70% of bone matrix is composed of the minerals calcium and phosphate (Bergeron, et al., 2018). Dynamic state of the immature skeleton The osteoid density of a child’s bone is less than adults. Juvenile bone is more porous than adult bone because the Haversian canals occupy a much greater part of the bone. This explains why a child’s bone can bend more than adults. Page 7 of 196 Remodelling • Wolff’s Law of Remodeling states that bone will remodel itself over time to become stronger if loading on a particular bone increases. The outside cortical bone becomes thicker to better withstand a load. A bone will become weaker if the loading decreases. This is the rationale behind early weight bearing during bone healing. Body alignment Varus deformity: This condition gives a bow-legged appearance and may be inherited or could be the result of uneven degeneration of the knee joint articular cartilage (Bergeron, et al., 2018). Valgus deformity: Frequently the result of uneven degeneration of the knee joint articular cartilage, this condition gives the appearance of being knock-kneed (Bergeron, et al., 2018). Factors that influence bone mineral density • Genetics (ie: Caucasian race, having a parent who broke a hip) • Medications: (ie: long term use of corticosteroids (3+ months), medications that affect calcium and Vitamin D absorption (anticonvulsants, phosphate-binding antacids, tranquilizers, sedatives & muscle relaxants) • Smoking • Viral infection: (ie: HIV, Hep B & C) Page 8 of 196 • Diet: (ie: eating disorders (cause amenorrhea in women which leads to ↑bone loss caused by estrogen deficiency), frequent Caffeine use, regular alcohol consumption, diet low in calcium and Vitamin D) • Activity: (ie: