[Histopathological diagnostics of arthrofibrosis].

Area of Science:

• Orthopedic Surgery
• Pathology
• Cellular Biology

Context:

• Joint surgery, particularly total knee arthroplasty and anterior cruciate ligament repair, faces complications like arthrofibrosis.
• Arthrofibrosis involves significant fibrosis and cellular changes within the joint.

Purpose:

• To present the cellular and molecular pathogenesis of arthrofibrosis.
• To outline histopathological diagnostic criteria and differential diagnoses.
• To propose a classification system for arthrofibrosis, distinguishing between joint endoprosthesis-associated and non-joint endoprosthesis-associated types.

Summary:

• Histopathological diagnosis relies on standardized tissue processing and formalin fixation.
• Synovia-like interface membrane (SLIM) classification aids in diagnosing endoprosthesis-associated arthrofibrosis.
• Key indicators include fibrosis, high fibroblast cellularity, and cytoplasmic beta-catenin expression (threshold of 20 positive fibroblasts/HPF for endoprosthesis-associated cases).
• Non-endoprosthesis-associated arthrofibrosis is classified via joint pathology algorithms into diffuse or localized (cyclops-like) forms.

Impact:

• Establishes a framework for diagnosing arthrofibrosis based on histopathology and cellular markers.
• Highlights the importance of interdisciplinary collaboration (clinical, surgical, radiological, etc.) for accurate diagnosis.
• Provides a basis for understanding and potentially managing arthrofibrosis complications in joint replacement and ligament surgeries.