The inflammatory pseudotumor formed after metal-on-metal hip arthroplasty

Due to its advantages of low wear, high stability and flexibility, the new generation metal-on-metal hip prosthesis is favored by many patients with hip diseases, especially young patients. However, in recent years, several studies have indicated that adverse reactions to metal debris (ARMD) caused the formation of inflammatory pseudotumor, which ultimately led to a higher revision rate after metal-on-metal hip arthroplasty. This aroused the widespread concern from doctors and patients. Moreover, revision surgery for metal-on-metal hip arthroplasty in the setting of inflammatory pseudotumor is faced with a great risk of failure because of the large defects of bone and surrounding soft tissue and difficulty in removing the original prosthesis and the fixing of the modified prosthesis. Therefore, the use of such products is restricted with caution in their choice. We summarized the recent developments in the research in the risk factors, diagnosis and treatment of inflammatory pseudotumor after metal-on-metal hip arthroplasty. The risk factors for the formation of inflammatory pseudotumor around the hip prosthesis mainly include the increase of metal ion concentration, the position of prosthesis implantation and the patient's own factors. The diagnosis mainly depends on physical examination, imaging examination, laboratory examination, arthroscopy and histological examination. The treatment strategies for clinical symptomatic and asymptomatic patients are also varies. Through the detailed analysis, evaluation and summary of the above contents, we may provide guidance for the selection of hip prosthesis, and lay the foundation for further exploration of the mechanism of inflammatory pseudotumor caused by ARMD.