The Particulars: Previous research has found that joint replacements can sometimes end in implant failure that is due to factors other than infection or apparent biomechanical issues. It is possible that pain persisting after an apparently successful joint replacement may be due to an allergic reaction to components of the implant, but few studies have explored this possibility.

Data Breakdown: In a small study, researchers assessed patients who experienced persistent pain after undergoing hip, knee, or shoulder replacement surgery and were scheduled for a revision implant. Overall, 58% of patients who were tested for allergies had a positive test relating to their joint replacement. Those with preoperative allergic reactions mostly had reactions to metals, whereas as those who tested for allergies postoperatively mostly reacted to bone cement. Of 15 patients with a revision implant that was chosen based on allergy testing, 14 reported that their condition improved moderately or “a lot.” This compared favorably to the three patients out of 20 whose revision implant was not chosen based on allergy testing. The authors pointed out, however, that their study had a significant loss to follow-up, no placebo-control arm, and a small number of subjects overall.

Take Home Pearls: Choosing revision joint replacement implants based on allergy testing appears to decrease patient complaints of persistent postoperative pain. Additional, larger outcome studies are needed to confirm these results.