RT Journal
A1 Urban, Robert M.
A1 Goldberg, Steven H.
A1 Jacobs, Joshua J.
A1 King, Graham J.W.
A1 O'Driscoll, Shawn W.
A1 Cohen, Mark S.
T1 Modes of Wear After Semiconstrained Total Elbow Arthroplasty
JF The Journal of Bone & Joint Surgery
JO The Journal of Bone & Joint Surgery
YR 2009
FD February 1
VO 91
IS 2
SP 488
OP 489
DO 
UL http://dx.doi.org/
AB 
We agree with Dr. Morrey that cause and effect are difficult to establish in a retrospective, observational study of a subset of retrieved total elbow arthroplasty prostheses. A multicenter study involving the patients of several elbow arthroplasty surgeons was needed to generate a sufficient number of implants to allow us to make observations regarding modes of wear in total elbow arthroplasty. Rather than determining cause and effect, the primary purpose of the study was to demonstrate that osteolysis and aseptic loosening occur in patients with total elbow replacement, that these processes are similar to what has been more extensively described with total hip and knee replacements, and that osteolysis and aseptic loosening are related to particular modes of wear. Dr. Morrey asks: "Did bushing wear cause lysis that allowed the fracture or did the fracture produce metallic particles that accelerated bushing wear?" Our systematic review of serial radiographs, from the initial postoperative radiographs through the final radiographs prior to the revision arthroplasty that yielded the implants, has led us to believe that, in certain cases, bushing wear preceded and contributed to implant fracture. The typical pattern in cases of component fracture was one of periarticular osteolysis creating a stress riser between unsupported and well-fixed sections of the stem. For example, Implant 12, which exhibited a humeral fracture sixty-two months post-implantation, was associated with substantial periarticular osteolysis (Fig. 1), leaving a well-fixed proximal portion of the humeral stem and an unsupported distal portion of the humeral stem that predisposed the humeral stem to fracture due to cantilever bending forces (Fig. 2). The anteroposterior radiographs showed thinned bushings with wear of the prosthesis in valgus.