Unexplained Pseudotumor Formation in Ceramic-on-ceramic Hip Bearings: A Case Report

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Rheumatology

Background:

• Adverse local tissue reactions (ALTRs) are a known complication following total hip arthroplasty (THA).
• While commonly associated with metal-on-metal joints, ALTRs, including pseudotumor formation, have been reported with ceramic-on-ceramic (CoC) THA.
• The inert nature of ceramic debris is being questioned due to these occurrences.

Observation:

• A 56-year-old male with ankylosing spondylitis developed hip pain and swelling 4 years after bilateral CoC THA.
• Imaging revealed extensive osteolysis and pseudotumor formation around the right hip.
• Histopathology confirmed pseudotumor composed of fibrin, fibroblasts, macrophages, and lymphocytes.

Findings:

• Pseudotumor formation in this CoC THA case occurred without component damage, malposition, impingement, or elevated metal ion levels.
• This case supports existing literature suggesting pseudotumor formation can occur with ceramic-on-ceramic articulations.
• The exact tribology and individual immune responses to ceramic wear debris require further investigation.

Implications:

• This case underscores the potential for pseudotumor formation even in seemingly uncomplicated ceramic-on-ceramic total hip arthroplasty.
• Further research is crucial to elucidate the mechanisms underlying ceramic debris-induced tissue reactions.
• Understanding these reactions may lead to improved implant design and patient management strategies for THA.