Adverse Clinical Outcomes in a Primary Modular Neck/Stem System

We report our experience with 215 recalled neck modular stems due to corrosion. Among the 195 hips with 2 years follow-up, 56% had no clinical symptoms, 26% had groin pain (typical of corrosion), and 17% had other symptoms. Cobalt levels were comparable between asymptomatic (3.4 μg/L, range 0.7–7.3 μg/L) and symptomatic patients (4.0 μg/L range 0–13.2 μg/L). Abnormal imaging findings were seen in 46% of symptomatic and 11% of asymptomatic hips (P = 0.001). Twenty-six hips (13%) have either undergone revision surgery or have been scheduled. Evidence of corrosion was seen at revision surgery in all patients. Despite modest elevations in serum cobalt levels, abnormal imaging studies were seen in 36%, clinical symptoms were seen in 44%, and revision for corrosion was undertaken or scheduled in 13% of the hips.