Impact of Preoperative Metal Patch Testing on Surgery Using Metal Implants.

Area of Science:

• Orthopedic Surgery
• Allergy Testing
• Biomaterials

Background:

• Preoperative metal patch testing (MPT) is performed for metal implant surgeries in some Japanese facilities.
• The clinical impact of MPT results on surgical plans and outcomes remains largely uninvestigated.

Purpose of the Study:

• To evaluate the utility and impact of preoperative MPT in patients undergoing joint replacement surgery.
• To determine the association between metal allergy, MPT results, and postoperative aseptic loosening.

Main Methods:

• Retrospective analysis of MPT results from orthopedic surgeons across four institutions (2014-2018).
• Review of medical records for patients undergoing total hip, knee, or shoulder arthroplasty (2014-2018) to assess MPT prevalence and surgical outcomes.

Main Results:

• Analysis 1: 72 patients underwent MPT with a 26.4% positivity rate; 4 cases led to altered treatment plans (alternative materials or cancellation).
• Analysis 2: Out of 1087 arthroplasty patients, only 16 underwent MPT. Aseptic loosening occurred in 0.3% of patients, none with allergy history or prior MPT.
• Metal allergy did not show a significant association with aseptic loosening in the studied cohort.

Conclusions:

• Preoperative MPT demonstrated limited utility in this patient cohort, with few cases altering surgical plans.
• Metal allergy does not appear to be a major factor in aseptic loosening after joint replacement.
• Further research is required to establish the necessity of MPT before joint replacement surgery.