Radiographic signs of osseointegration in porous-coated acetabular components.
There currently is no direct method to radiographically determine osseointegration of an uncemented, porous-coated acetabular component. We defined five radiographic signs for detecting acetabular osseointegration: (1) absence of radiolucent lines; (2) presence of a superolateral buttress; (3) medial stress-shielding; (4) radial trabeculae; and (5) an inferomedial buttress. We assessed their ability to predict acetabular osseointegration by reviewing the postprimary and prerevision radiographs from a series of 119 total hip arthroplasties that had revision surgery. Each sign had a high positive predictive value for the presence of bone ingrowth (range, 92.2-96.3%). The absence of radiolucent lines, presence of superolateral buttresses, and presence of medial stress-shielding were the most sensitive signs for indicating bone ingrowth. Ninety-seven percent of the cups with three to five signs were bone ingrown, whereas 83% of the cups with one or no signs were unstable. When three or more signs were present, the positive predictive value of the radio-graphic test was 96.9%, the sensitivity was 89.6%, and the specificity was 76.9%. The five signs of acetabular osseointegration reliably predicted osseointegration, especially when used in combination. They can be used as a tool for radio-graphically assessing the status of patients with porous-coated uncemented cups.


METHODS
Diagnostic study, Level III (Study of nonconsecutive patients; without consistently applied reference "gold" standard). See the Guidelines for Authors for a complete description of levels of evidence.
Moore
Milan S
MS
Cascade Orthopaedics, Auburn, Washington, USA.
McAuley
James P
JP
Young
Anthony M
AM
Engh
Charles A
CA
D000077:Acetabulum / Q000000981:diagnostic imaging*; D019644:Arthroplasty, Replacement, Hip; D002146:Bony Callus / Q000000981:diagnostic imaging; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D016348:Osseointegration; D016062:Porosity; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D011859:Radiography; D012086:Reoperation; D013997:Time Factors; D016896:Treatment Outcome