Outcomes and Survival of a Single Model of Modular Neck Primary Total Hip Arthroplasty at a Mean of Eight Years.

Abstract

We report the outcomes and survival of a recalled modular neck primary total hip arthroplasty (THA). This study's purpose was to describe the survival, complications, patient-reported outcome measures, and serum metal ion levels at a mean of 8 years. We identified 89 hips that received a modular neck THA between May 2010 and March 2012. Failure was defined as the removal of the femoral component for any reason, excluding infection. The patient-reported outcome measures, including the Western Ontario and McMaster Universities Arthritis Index, Harris Hip Score (HHS), and Veterans RAND 12 Physical and Mental Score, and serum metal ion levels were recorded and compared between unrevised and revised patients. The mean time to the most recent follow-up and revision surgery was 7.79 and 4.31 years, respectively. The mean survivorship was 10.0 years, with a survival of 51% at 13 years. There were 33 infection-free failures identified, with symptomatic adverse local tissue reaction or pseudotumor being the most common (62.5%). Of the patients who underwent revision surgery, six required repeat revisions. When comparing unrevised and revised cases, the unrevised group had significantly greater HHS function (P = 0.002), HHS total (P = 0.003), and Veterans RAND 12 Physical (P = 0.04) scores. Metal ion analysis showed that the mean serum Cobalt ion levels were significantly higher for the revised patients compared to the unrevised patients (P < 0.001). This study demonstrated that the taper corrosion-related failure continues to be an issue with this specific modular neck primary THA implant. Functional data demonstrated poorer outcomes in patients who required revision and a following revision surgery compared to patients who did not require a revision surgery. Patients who have received this implant should continue to be monitored on a routine basis, and care providers should have a low threshold to investigate symptoms. IV.