AB165. SOH24AB_216. Matter of prosthetic hip-associated cobalt toxicity (PHACT)?—A clinical case report, and systematic review of cases of PHACT in patients with prosthetic hip ceramic head fractures subsequently revised to metal-on-polyethylene implants

Background: Prosthetic hip-associated cobalt toxicity (PHACT) remains a rare but serious complication, potentially leading to missed diagnoses and delayed treatment. This systematic review explores cases of PHACT associated with fractured ceramic head followed by revision surgery with metal-on-polyethylene implants. Notably, patients in this subgroup often exhibited earlier symptom onset and elevated cobalt ion levels. Through a systematic review, we aim to explore and summarise the most common symptoms and clinical outcomes associated with PHACT among this specific patient subgroup. Our focus is on identifying patterns of systemic symptoms and associated clinical outcomes.

Methods: Adhering to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, we conducted a structured search across PubMed, Medline, and Scopus databases. Inclusion criteria comprised published case reports or case series detailing PHACT cases after ceramic head fractures revised to metal-on-polyethylene bearings. Over 40 cases were identified, and their clinical presentations and outcomes were analysed.

Results: The majority of PHACT cases in this cohort manifested with neurological symptoms (visual impairment, sensorineural hearing loss, and cognitive impairment), cardiovascular manifestations (cardiomyopathy, cardiogenic shock, and heart failure), and endocrine dysfunction (thyroid dysfunction). Various atypical symptoms were also observed.

Conclusions: PHACT within this patient group presents insidiously with diverse, sometimes overlapping, systemic symptoms. The study highlights the potential for missed diagnoses due to the lack of apparent risk factors or related medical history. This review emphasises the need for proactive identification of at-risk patients, as well as the opportunity for follow-up assessment and cobalt level monitoring. This study may serve to inform further research and recommendations for managing prosthetic ceramic head fractures.

Keywords: Ceramic head fracture; cobalt toxicity; metal-on-polyethylene; revision surgery; total hip replacement