Metalwork allergy rates in patients following scoliosis corrective surgery and posterior spinal instrumentation: a systematic review

Metal hypersensitivity following spinal instrumentation represents an uncommon but clinically significant complication that can lead to implant failure, persistent pain, and revision surgery. The prevalence and characteristics of metal allergies in scoliosis surgery patients remain poorly characterised. To systematically review the literature on rates of metalwork allergy in patients who have undergone scoliosis corrective surgery, with specific focus on severity, type, and duration from surgery to diagnosis, as well as treatment options, and need for reintervention. A systematic literature search was conducted following PRISMA 2020 guidelines across PubMed and Embase databases from inception to October 2025. Studies reporting metal hypersensitivity rates, types, severity, and time from presentation to diagnosis in scoliosis or posterior spinal fixation patients were included. Six studies met inclusion criteria, encompassing 806 participants. The confirmed metal allergy rate was 3.0% in paediatric populations. Nickel was the most common allergen, followed by cobalt and chromium. Most reactions were moderate severity (96.8%), with duration to diagnosis ranging from 1 month to 15 years post-surgery. Metal hypersensitivity after scoliosis surgery occurs in approximately 3–4% of patients, predominantly manifesting as moderate-severity local reactions to nickel-containing implants within 2–5 years post-operatively.