Surface Damage After Multiple Dislocations of a 38-mm-Diameter, Metal-on-Metal Hip Prosthesis

• Published in: The Journal of arthroplasty Vol. 23; no. 7; pp. 1090 - 1096
• Main Authors: Bowsher, John G., PhD, Donaldson, Thomas K., MD, Williams, Paul A., MSc, Clarke, Ian C., PhD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.10.2008
• Subjects: Arthroplasty, Replacement, Hip - adverse effects; Co-Cr-Mo; dislocation; Hip Dislocation - etiology; Hip Dislocation - surgery; Hip Prosthesis - adverse effects; Humans; Male; malpositioning; metal-on-metal hip prosthesis; Middle Aged; Orthopedics; Prosthesis Failure; Reoperation; revision hip arthroplasty; metal-on-metal hip prosthesis; dislocation; malpositioning; revision hip arthroplasty; Co-Cr-Mo
• ISSN: 0883-5403; 1532-8406
• DOI: 10.1016/j.arth.2007.09.007

Abstract We present, for the first time, a detailed damage assessment of a large-diameter metal-on-metal (L-MOM) hip prosthesis to show the extent of surface damage that can occur in a patient after multiple dislocations. The patient was a man (51 years old) who dislocated 8 times and was finally revised at 27 months. Radiographically, the cup was malpositioned with 65° lateral opening and 15° retroversion. The retrieved cup was a 1-piece, 38-mm Co-Cr-Mo (M2a; Biomet, Warsaw, Ind) with a titanium-alloy backing. The retrieved components demonstrated all known modes of wear, including a polished wear scar, multidirectional scratching, “stripe” wear, surface contamination of titanium-alloy, front face wear, and backside wear. The clinical significance is that cup positioning remains critical regardless of whether a large diameter head is used or not.