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February 01, 2014
Contributors: Morteza Meftah, MD; Brian Dominues, BA; Stephen J Incavo, MD; Amgad M Haleem, MD; Amgad M Haleem, MD
Materials and Methods: This stem was recalled by the manufacturer because of corrosion of the modular neck. Sixteen patients (10 men and 6 women) with 18 total hip replacements were either symptomatic or had serumcobalt/chrome levels and/or MRI findings outside defined limits. All patients had findings of corrosion at the modular neck/body junction. The mean time until revision was 29.44 months, and mean follow-up was 9.5 months (range 3-24 months).
Results: At the time of revision surgery, only one stem was removed without a cortical window. Thirteen stems were removed with a cortical window, and four cases with a cortical window had a more serious trochanter fracture that required trochanteric plate fixation. Traditional primary stems were used for revision in all 18 cases. No cases required revision stems. There were no cases of subsidence after surgery. Serum cobalt levels improved from a mean of 5.4 +/- 5.7 µg/L (reference range [rr], 0.2-31 µg/L) before surgery to 3.2 +/- 4.7 µg/L (rr, 0.2-14.7 µg/L) after surgery in a mean follow-up period of 25 weeks + 6.6 weeks. Serum chromium levels changed from a mean of 2.1 +/- 1.5 µg/L (rr, 0.1-4.3 µg/L) before surgery to 2.1 +/- 0.9 µg/L (rr, 0-4 µg/L) after surgery during the same time interval.