Name: ______Date: ______
Biology Lab: Mr. Werner Period: ______
Virtual Hip Surgery
I. Background
When other therapies fail to provide relief from the pain of hip arthritis, hip replacement may be the answer. Hip replacement (a.k.a., hip arthroplasty) can relieve pain and give a person back the range of motion they need to go about their daily tasks.
Hip replacement is usually considered once other therapies, such as pain medications, have failed. Most people undergo hip replacement as a result of osteoarthritis of the hip joint. But one might also consider hip replacement if they experience severe pain, loss of motion or deformity of your hip joint. Hip replacement is also used in people with hip injuries, rheumatoid arthritis and other medical conditions, such as a bone tumor or bone loss due to insufficient blood supply (avascular necrosis).
Symptoms that might lead an individual to consider hip replacement include:
* Pain that keeps a person awake at night
* Little or no relief from pain medications
* Difficulty walking up or down stairs
* Trouble standing from a seated position
* Having to stop activities such as walking, because there is too much pain
Hip replacement previously was an option primarily for adults age 60 and above. But improved technology has made strong and longer lasting artificial joints that are feasible for more active people, including younger people. However, active people face the possibility of another surgery to replace worn out artificial hip joints after 15 or 20 years.
Hip replacement surgery involves replacing the femoral head — the "ball" of the thighbone — with a metal ball. The metal ball attaches to a metal stem that fits into the thighbone. A plastic and metal socket is implanted into the pelvic bone to replace the damaged socket. The prosthetic parts, which mimic the natural design of your hip, fit together and function like a normal hip joint.
Artificial hip joints come in many varieties. Generally the surgeon decides which hip joint is the best for the patent. Materials used in making the prostheses include a combination of durable, wear-resistant plastic and metals, including stainless steel and titanium. Implants are biocompatible — meaning they're designed to be accepted by the body — and they're made to resist corrosion, degradation and wear.
Hip replacement surgery usually takes two to three hours, during which time the patient will be under general or regional anesthesia. During the operation, the surgeon separates your thighbone from the socket. Working between the large hip muscles, the surgeon removes the diseased or damaged bone and tissue, leaving healthy bone and tissue intact. The artificial socket is pressed into place. The top end of the thighbone is hollowed out to allow insertion of the metal stem with the attached ball. The ball and the socket join to form the new hip joint.
After surgery the patient is moved to a recovery area for a few hours while the anesthesia wears off. Nurses or other anesthesia aides watch the patient’s blood pressure, pulse, alertness, pain or comfort level and your need for medications.
II. Virtual Hip Replacement, Part A.
(1) According to the x-ray, which side of the hip appears more damaged and why?
(2) According to the same x-ray, which stem size would be most appropriate for your patient?
(3) Now that a stem has been selected, which metal cup size would be most appropriate for your patient?
(4) Why is it critically important to protect the sciatic nerve throughout this procedure?
(5) When using the reamer, why should you try to ream more towards the top?
(6) Why does the plastic linter offer more coverage at the top, back part of the metal cup?
(7) Why has the patient developed osteophytes?
(8) Approximately how long will your patient remain in the hospital? Following discharge from the hospital, how many weeks of physical therapy will you recommend?
III. Virtual Hip Resurfacing, Part B.
(1) Why do you think it is important to preserve bone in younger patients?
(2) According to the x-ray, which metal cup size would be most appropriate for your patient?
(3) With the acetabulum at 60 mm, the femoral head will be 6 mm smaller. Which femoral head should you use?
(4) Why would it be good practice to measure the neck of the femur once again?
(5) Why is it necessary to ensure that the center of the femoral neck is located accurately?
(6) Why will a larger head diameter give the patient an advantage?
(7) Why is it necessary to make a small trough in the femoral head?
(8) Approximately how long will your patient remain in the hospital? Following discharge from the hospital, how many weeks of physical therapy will you recommend?
* Bonus: Why does a surgeon slice through the muscles in the direction the fibers run, instead of going across the fibers?