Cobalt toxicity after McKee hip arthroplasty

Area of Science:

• Orthopedic Surgery
• Toxicology
• Materials Science

Background:

• McKee hip arthroplasty is a medical procedure to replace a hip joint.
• Adverse reactions to prosthetic materials can lead to complications.

Purpose of the Study:

• To investigate the role of cobalt as a cause of symptoms in patients with problematic McKee hip arthroplasties.
• To evaluate the diagnostic utility of patch testing for cobalt sensitivity in this patient group.

Main Methods:

• Case series describing seven patients with unsatisfactory McKee hip arthroplasties.
• Patch testing for metal sensitivity (cobalt, nickel, chrome).
• Surgical exploration with macroscopic and histological examination of tissues.
• Measurement of cobalt concentrations in urine and tissues using atomic absorption spectrophotometry.

Main Results:

• Six of seven patients were cobalt-positive on patch testing.
• Necrosis of bone, muscle, and joint capsule observed in five explored hips.
• Symptoms included progressive pain, instability, and dislocation.
• Radiological findings showed acetabular fracture, bone resorption, and prosthesis loosening.
• Elevated cobalt levels detected in urine and tissues of affected patients.

Conclusions:

• Cobalt hypersensitivity is a significant factor in adverse outcomes following McKee hip arthroplasty.
• Patch testing is a valuable diagnostic tool for identifying cobalt sensitivity in patients with hip arthroplasty complications.
• Further investigation into metal sensitivity is warranted for patients experiencing persistent issues.