Project Two: Hip to be Square
Introduction to the Hip
The hip joint is a ball and socket synovial joint, where the head of the femur rotates in the acetabulum of the hip bone. When this motion becomes painful or the joint is otherwise unable to articulate, a total hip arthroplasty may be prescribed to a patient. the surgery is a treatment for a variety of medical conditions including rheumatoid and degenerative arthritis of the hip (which is usually coupled with aging), hip dysplasia, and trauma.
The use of orthopaedic implants to promote free and painless movement of various joints in the body is a critical application of biomaterials.
The artificial hip is designed to mimic the natural hip joint with a ball and socket design where a ball is attached to a stem and fitted into the demur. The choice of material used to create the orthopaedic implant is greatly influenced by its design. The ball and stem portion of the implant is usually under tensile stress from impulsive and erratic movements, meaning it should be manufactured using a material with substantial toughness and high strength under fatigue. the cup, however, is typically under compressive stress and therefore could be constructed out of another material. In either case, implants are designed to last; a lifetime of twenty years is customary. Orthopaedic implants can be made out of ceramics, metals, polymers, or some combination of the three depending on the circumstances at hand.
Hip Anatomy
Project Two Objectives
Jackie Chiles has struggled with hip pain for, what feels like, as long as he can remember. Beginning around the age of 10, Mr. Chiles' parents would notice him regularly walking with a limp, generally placing more weight on his right leg compare to his left. Although not one to complain, Mr. chiles' would eventually begin to complain of soreness in his left hip. Although the pain was generally mild, he found it to be pronounced by leg movement. Although not an especially active child, the pain was impacting his daily activities, causing an increase in his tendency to limp. On occasion, he would begin to experience pain in his right hip as well; pain in both hips would ultimately result in him being bed-ridden and missing time from school. Fortunately, after a few days of bed rest, pain in his right hip would subside, and he would be able to return to relatively normal activities, although the mild pain in his left hip would persist. After meeting with his family physician, Mr. Chiles was referred to a physiotherapist and began a physio regimen. Through his physio program, Mr. chiles would regularly work on improving his range of motion under non-load bearing exercises. He also began swimming regularly, which he found to be a welcoming activity that was not associated with the same level of pain he might experience during other physical activities.
Despite the positive results from the physiotherapy program, Mr. Chiles' family experienced some significant hardships during his early teenage years, and physio quickly became less of a priority for him. Throughout secondary school, Mr. Chiles' limp slowly became more pronounced over time, further limiting his range of motion. Despite continuing swimming, Mr. chiles only managed to get to the pool once or twice per month, compared to the 1-to-2 times per week he used to during his physio program. As Mr. Chiles' family situation negatively impacted his focus on this own well-being, he found the pain in his left hip become more pronounced over time, especially with activity. By the time Mr. Chiles graduated secondary school, his limping had become associated with frequent left hip pain, and he couldn't walk more than a few minutes without having to rest.
As an adult, Mr. Chiles learned to live with his condition. Working a desk job that generally required little activity. Mr. Chiles adapted his lifestyle so that his walking was kept to a minimum. although he generally felt relief while sitting, he was unable to walk without pain and began to use a cane to take the weight off his left hip. Now retired, Mr. Chiles continues to rely on a cane for getting around. but even then, relief from pain is only temporary, and he is unable to walk more than a few minutes before having to rest. Mr. Chiles has been prescribed various painkillers without relief. As his pain becomes ever-limiting, he is seeking potential treatment options.
The project requires that your team:
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Diagnose your patients' condition that warrants total hip arthroplasty
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It is required that you correctly diagnose your patients' condition
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Design a custom hip implant for your assigned patient
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Your custom implant is required to fit your patients' hip arthroplasty
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Strong emphasis will be placed on the creativity of your team's design
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Your team is required to identify a list of acceptable materials for your design
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Your team is required to select one material for each component of your design
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Your team is required to identify how your implant is to be fixated to bone
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The type of fixation you choose is required to be reflected in your design
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Analyze your selected design parameters
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Your team is required to design a computer program that serves to verify your selected design parameters
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Subprogram 1 should calculate the minimum allowable implant stem diameter under this loading scenario
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Subprogram 2 should calculate the fatigue life for your implant design
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Subprogram 3 should calculate the number of years before there is a risk of femoral fracture
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Justify why your design meets the needs of your patient
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Your team is required to justify the form, materials section, and surgical fixation fo your design
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