Surface damage after multiple dislocations of a 38-mm-diameter, metal-on-metal hip prosthesis.
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 degrees lateral opening and 15 degrees 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.
Department of Orthopaedics, Loma Linda University Orthopaedic Research Center, Loma Linda, California 92354, USA.
John G
JG
Bowsher
Thomas K
TK
Donaldson
Paul A
PA
Williams
Ian C
IC
Clarke
D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D006617:Hip Dislocation / Q000209:etiology / Q000601:surgery*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure; D012086:Reoperation