(DOWNLOAD) "Total ankle arthroplasty today" by Michel Bonnin & Scott Jacob Ellis " eBook PDF Kindle ePub Free
eBook details
- Title: Total ankle arthroplasty today
- Author : Michel Bonnin & Scott Jacob Ellis
- Release Date : January 03, 2013
- Genre: Medical,Books,Professional & Technical,
- Pages : * pages
- Size : 30091 KB
Description
Attempts at ankle arthroplasty began in 1970 with the implantation of an inverted hip prosthesis into the tibia and a cemented acetabular cup in the calcaneus. As hip and knee arthroplasty gained popularity during this time, so did efforts to find an alternative to ankle fusion for end-stage arthritis of the ankle. However, high rates of osteolysis, bone loss, component loosening, and wound complications led to the abandonment of ankle replacement. Recent advancements in prosthesis design, combined with a better understanding of ligamentous balancing and component alignment have renewed interest in total ankle replacement as an alternative to ankle arthrodesis.
First generation total ankle replacements attempted to find a balance between highly conforming, constrained designs, and unconstrained, unstable designs. Conformity in a prosthesis is defined as the relationship between the radii of curvature of the two articulating surfaces. A highly conforming design maximizes contact area, thus decreasing contact pressure and theoretically improving wear resistance. In addition, a highly conforming prosthesis provides greater inherent constraint and relies less on the surrounding ligaments for stability. Most early implants, such as the Imperial College of London Hospital (ICLH) implant and the St. George/Bucholz were highly constrained prostheses. Fixation was achieved through cementation, analogous to techniques used in total hip and knee replacement at that time. These high constrained, cemented designs allowed for dorsiflexion and plantarflexion, yet dissipated forces in inversion, eversion, and axial rotation through the bone-cementprosthesis interface. This transfer of energy created high sheer stress at the point of fixation, which ultimately caused component loosening and prosthesis failure.
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