Late dissociation of the polyethylene liner from a modular acetabular metal shell after primary total hip arthroplasty--a report of five cases.
Modular designs of hip prostheses have become popular recently. Along with complications inherent in all hip arthroplasty systems, modular systems have the additional potential for dissociation of components. Five male patients underwent total hip arthroplasties, in which all of the acetabular components were Harris-Galante II porous acetabular cups. Many years after the operation, the polyethylene liners were dissociated without any previous trauma or dislocation of the femoral heads, these dissociations and dislodgements were managed with open reduction. This complication can be predicted from clinical symptoms and signs. Roentgenograms must be taken and carefully compared to previous roentgenograms. We postulated two causes for the dissociation. First, the polyethylene liner was not fixed securely within the acetabular metal shell at the time of operation. Second, the locking mechanism of the acetabular metal shell was not strong enough to firmly hold the polyethylene liner within the acetabular metal shell. It does warrant that certain precautions must be taken when implanting modular components. The locking mechanism of the harris-Galante II porous acetabular component is mechanically weak and fails easily, therefore its design must be improved in an attempt to prevent postoperative dissociation of the polyethylene liner.
Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea.
C D
CD
Han
W S
WS
Choe
J H
JH
Yoo
D000077:Acetabulum; D000328:Adult; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D011095:Polyethylenes; D011474:Prosthesis Design; D011475:Prosthesis Failure
D008670:Metals; D011095:Polyethylenes