The histological and elemental characterisation of corrosion particles from taper junctions

Objectives: This study aimed to characterise and qualitatively grade the severity of the corrosion particles released into the hip joint following taper corrosion. 

Methods: The 26 cases examined were CoC/ABG Modular (n = 13) and ASR/SROM (n = 13). Blood serum metal ion levels were collected before and after revision surgery. The haematoxylin and eosin tissue sections were graded on the presence of fibrin exudates, necrosis, inflammatory cells and corrosion products. The corrosion products were identified based on visible observation and graded on abundance. Two independent observers blinded to the clinical patient findings scored all cases. Elemental analysis was performed on corrosion products within tissue sections. X-Ray diffraction was used to identify crystalline structures present in taper debris. 

Results: The CoC/ABG Modular patients had a mean age of 64.6 years (49.4 to 76.5) and ASR/SROM patients had a mean age of 58.2 years (33.3 to 85.6). The mean time in situ for CoC/ABG was 4.9 years (2 to 6.4) and ASR/SROM was 6.1 years (2.5 to 8.1). The blood serum metal ion concentrations reduced following revision surgery with the exception of Cr levels within CoC/ABG. The grading of tissue sections showed that the macrophage response and metal debris were significantly higher for the ASR/SROM patients (p <0.001). The brown/red particles were significantly higher for ASR/SROM (p <0.001). The taper debris contained traces of titanium oxide, chromium oxide and aluminium nitride. 

Conclusion: This study characterised and qualitatively graded the severity of the corrosion particles released into the hip joint from tapers that had corrosion damage.