The role of expandable prostheses. Issue 6 (November 2017)

• Record Type: Journal Article
• Authors: Benevenia, Joseph; Steadman, Peter; Ippolito, Joseph
• Is Part Of: Current orthopaedic practice. Volume 28:Issue 6(2017)
• Publication Date: 2017-11
• Subjects: expandable prosthesis -- pediatric tumor; Orthopedics -- Periodicals; 616.7005
• DOI: 10.1097/BCO.0000000000000568
• Languages: English
• ISSNs: 1940-7041

Abstract

Abstract : In skeletally immature individuals who require wide tumor resection with removal of an active physis, an expandable prosthesis can be used for limb salvage. These prostheses first became available in the early 1980s for patients with primary oncologic disease; however, the early designs were plagued with mechanical failure. Later designs employed ball-bearing mechanisms and a C-collar mechanism for an interposition spacer. By the mid 1990s a minimally invasive expandable prosthesis became available in which expansion was achieved through a small incision. With each new innovation, a decrease in the complication rate was noted; however, problems still occurred with the surgical procedure that was required for each lengthening. By the early 2000s, noninvasive lengthening was innovated by the application of an external electromagnetic field, with the advantages being more frequent expansions in smaller increments, minimal patient discomfort, and no operations necessary. Although the complication rate for lengthening decreased, these designs reported a high mechanical failure rate. Nevertheless, these designs were improved upon, with mean MSTS scores of 82% to 85% and satisfactory functional outcomes. One of the notable problems with expandable prostheses has been infection, with the risk of infection increasing by 5% per lengthening. The utility of specific coatings, such as silver, has been investigated. Because expandable implants are designed for pediatric patients, their longevity is still a concern.