Ankle Joint Prosthesis Sarah Lovell- BME281 Presentation 1

Background  The ankle joint is made up of:  two bones in the leg  first bone in the foot, called the talus.  The ankle joint as a whole is named the tibiotalar joint.  Problems in the ankle joint are most commonly caused by:  post-traumatic degenerate disease  rheumatoid disease These diseases are rarely found in the ankle but commonly found in the knee and hip

Theories?  1 st theory: the magnitude of force is less on the ankle than on the knee and hip.  2 nd theory: the forces are comparably equal on the knee, hip and ankle joint but are more easily tolerated by the ankle joint because it is  more stable  has kinetic simplicity  has a larger surface area to bear the body’s weight  The ankle joint experiences forces exceeding two times the weight of the body when the person is walking Stauffer, Richard N., M.D., Edward Y.S. Chao, P.H.D., and Robert C. Brewster, M.D. "Force and Motion Analysis of the Normal, Diseased, and Prost... : Clinical Orthopaedics and Related Research." LWW. Wolters Kluwer Health, Inc., n.d. Web. 26 Sept

How do we fix this?  Arthroplasty : usually performed on patients suffering from arthritis  relieves pain  maintains motion in the ankle joint  Arthrodesis: performed on patients that need an ankle fusion.  relieves pain  eliminates the motion in the joint by permanently connecting the talus to the end of the leg bones, restricting the up and down movement of the talus  Ankle Replacement: prosthetic joint is put in the ankle and connects to a prosthetic foot and the amputated limb Molino, Joseph L., and Michael Rebarber. "Patent US Prosthetic Ankle Joint." Google Books. IFI CLAIMS Patent Services, 13 Feb Web. 26 Sept

Ankle Joint Replacement  Purpose: meant to allow the ankle to move between the dorsiflexed position and the plantarflexed positions, even if the movement is limited.  comprised of:  A base member  a bracket member  a collapsible and expandable linkage system.  The linkage system is assembled by:  a first recumbent bar  a first upright bar  a second upright bar  A second recumbent bar.

 1 upper housing  2 lower housing  3 axis  4 upper receptacle  5 motion member  15 tube clamp adapter  16 prosthetic foot  17 motion member attachment  6 chamber (anterior)  8 pylon

Risks  Risks are not known to occur often during there surgeries but patients are made aware of:  infection  injury to nerve and blood cells  fractures to the bone  bone’s failure to heal to ankle replacement  failure of the bones to heal together  wound problems  blood clots.

Post Surgery  The surgery can take up to 2 ½ hours  Required to stay in the hospital for 2-3 days after surgery, then out on crutches.  After 2 weeks of being on crutches, the patient will return to the hospital to get the sutures removed but will stay on crutches for another 4 weeks.  After 6 weeks the patient will get x-rays done to decide whether or not they should remain on crutches based on whether the joint can hold the body’s weight. "Total Ankle Replacement Surgery for Arthritis." Total Ankle Replacement Surgery for Arthritis. N.p., n.d. Web. 28 Sept

Results  Current studies predict a 90% patient satisfaction rate within the first 4 years after having the replacement surgery  Short term results are more promising than long term  Ankle replacements have been offered for 25 years and are still advancing in their technology and improving their functioning and movement abilities.  Most current ankle joint prosthetics available are heavy, bulky and limit the majority of motion but lighter and more movement friendly artificial ankle joints are being worked on and will hopefully be available soon "Total Ankle Replacement Surgery for Arthritis." Total Ankle Replacement Surgery for Arthritis. N.p., n.d. Web. 28 Sept

Questions?