Risk Stratification and Pain Outcomes Following Revision Total Hip Arthroplasty for Adverse Local Tissue Reactions.

BACKGROUND: Revision total hip arthroplasty (THA) for adverse local tissue reactions (ALTRs) secondary to head-neck taper corrosion is associated with a high complication rate. Diagnosis of ALTR is based on risk stratification using the patient's history and examination, implant risk, serum metal ion levels, and imaging. The purpose of this study was to determine if stratification using similar risk factors is predictive of outcomes following revision THA for metal-on-polyethylene (MoP) ALTR. METHODS: We performed a retrospective review on 141 patients revised for ALTR due to head-neck taper corrosion. Pain outcomes following surgery were analyzed using a generalized linear mixed model. Complications were defined as instability/dislocation, infection, fracture, nerve palsy, leg-length discrepancy, or reoperation. RESULTS: The overall complication rate was 17.7%. The odds of having pain decreased by 44% after revision surgery (Odds Ratio = 0.56, 95% Confidence Interval: 0.324 to 0.952). There was no significant difference in instability/dislocation based on either increased or decreased head-neck offset (P = .67) or magnetic resonance imaging findings of abductor loss, effusion size, and degree of ALTR (P = .73). Increased serum cobalt (P = .31) and chromium (P = .08) levels did not predict complications; however, a decreased cobalt-chromium ratio was associated with postoperative complications (2.8 versus 3.5; P = .002). CONCLUSION: These findings are the first to suggest that patients who have ALTR after MoP THA undergoing revision surgery demonstrated major pain relief. Increasing femoral head offset did not change rates of instability/dislocation. In clinical scenarios where preoperative cobalt-chromium femoral head offsets were greater than available ceramic head offsets, a mandatory decrease in femoral head offset did not increase rates of instability/dislocation.