Non-neoplastic Orthopedic Pathology Updates: Common Problems and Pitfalls and How to Avoid Them.

Area of Science:

• Orthopedic Pathology
• Surgical Pathology
• Diagnostic Histopathology

Background:

• Primary bone neoplasms receive disproportionate literature attention compared to non-neoplastic orthopedic pathology.
• Practicing pathologists and clinicians require updated expertise in non-neoplastic orthopedic diseases due to increasing consult volumes.
• Recent literature addresses arthroplasty, diagnostic clarification for avascular necrosis vs. osteoarthritis, and infectious vs. degenerative joint disease.

Purpose of the Study:

• To summarize recent developments in non-neoplastic orthopedic surgical pathology.
• To provide updated diagnostic criteria and highlight pitfalls in interpreting orthopedic pathology specimens.
• To discuss the clinical impact of accurate pathologic examination in non-neoplastic orthopedic conditions.

Main Methods:

• Review of recent literature on non-neoplastic orthopedic pathology.
• Analysis of diagnostic criteria for conditions including periprosthetic joint infection, calcium pyrophosphate dihydrate (CPPD) deposition disease, and transthyretin (TR) cardiac amyloidosis.
• Emphasis on histopathologic evaluation, including frozen section analysis for joint infections and Congo red staining for amyloidosis.

Main Results:

• Accurate neutrophil counts are crucial for diagnosing periprosthetic joint infection, distinguishing it from aseptic loosening.
• Calcium pyrophosphate dihydrate (CPPD) deposition disease, often diagnosed histologically, affects large joints and can mimic osteoarthritis.
• Early detection of transthyretin (TR) cardiac amyloidosis via tenosynovium evaluation and subsequent treatment improves clinical outcomes.

Conclusions:

• Accurate histopathologic diagnosis of non-neoplastic orthopedic conditions is critical for patient management and treatment.
• Updated diagnostic criteria and awareness of pitfalls are essential for pathologists interpreting orthopedic specimens.
• Advances in diagnosing conditions like periprosthetic joint infection and TR cardiac amyloidosis have significant clinical implications.