Allergic reaction and metal hypersensitivity after shoulder joint replacement

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Allergy and Immunology

Background:

• Metal ion release from orthopedic implants can lead to local and systemic effects, including hypersensitivity reactions.
• Assessing the correlation between implant-related hypersensitivity and patient symptoms is crucial for understanding adverse outcomes.

Purpose of the Study:

• To determine if hypersensitivity in shoulder arthroplasty correlates with patient symptoms.
• To evaluate the prevalence of hypersensitivity and allergies in patients undergoing shoulder arthroplasty.

Main Methods:

• A cohort of 40 patients with shoulder replacements (2015-2017) were followed for at least 2 years.
• Evaluations included radiographic and clinical assessments (Constant-Murley Score), patch testing for 22 haptens, serum/urine metal ion analysis, and occupational medicine interviews.
• Patients with prior metal implants were excluded.

Main Results:

• No clinical complications or radiographic loosening were observed at an average follow-up of 45 months.
• Positive patch tests (nickel sulfate, benzoyl peroxide, potassium dichromate) were found in a small percentage of patients, but all remained asymptomatic.
• Elevated serum and urinary levels of aluminum and chromium were detected, indicating metal ion release over time, irrespective of patient demographics or implant type.

Conclusions:

• Shoulder arthroplasty is a confirmed source of metal ion release, potentially acting as a sensitizing exposure.
• Patch test positivity did not correlate with hypersensitivity symptoms or diminished clinical outcomes in this patient group.
• Consistent, low-level metal ion release was observed regardless of implant characteristics or patient factors.