JOA - 2026-05-13 - Journal Article
Amyloid in Primary Hip Arthroplasty Specimens: An Opportunity for Early Detection of Amyloidosis?
von Kaeppler E, Garcia R, Zhang Y, Bostrom M, Ramirez D
Topics
Key Takeaway
Systematic Congo red staining of primary THA specimens identified amyloid in 4.2% of contemporary cases versus 0.06% historically, with ATTR subtype confirmed in 11 of 29 mass-spectrometry-subtyped cases.
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Summary
This single-institution retrospective study assessed amyloid prevalence in primary THA specimens using Congo red staining with mass spectrometry subtyping, comparing a contemporary cohort (Jan–Mar 2025) to a historical cohort (2021–2023). Amyloid was detected in 73 of 1,744 contemporary cases (4.2%) versus 9 of 15,680 historical cases (0.06%), a 70-fold difference attributable to systematic application of recently recognized histologic deposition patterns. Of 29 subtyped cases, 11 were ATTR, the cardiac-associated subtype now targetable with tafamidis and other disease-modifying agents.
Key Limitation
The 70-fold prevalence increase between cohorts is driven entirely by a protocol change in histologic screening criteria, not a true incidence comparison, so the 4.2% figure cannot be generalized without prospective validation of the screening algorithm.
Original Abstract
BACKGROUND
Recent advances in pharmacologic therapies to treat amyloidosis demand renewed focus on early identification of patients who will benefit from these therapies. Incidental detection of amyloid in orthopaedic specimens has been previously described, but the clinical significance of these findings remains unclear. Modern techniques for amyloid detection and subtyping may identify clinically relevant amyloid in routine orthopaedic specimens. The purpose of this study was to assess the prevalence of amyloid in a unique contemporary cohort of total hip arthroplasty (THA) specimens using recently recognized histologic patterns of amyloid deposition.
METHODS
A retrospective study was performed of specimens from all primary THAs from January to March 2025 at a single institution. The prevalence of amyloid was assessed using Congo red staining in cases with suspected amyloid deposition on hematoxylin- and eosin-stained tissues, and amyloid subtyping was performed by mass spectrometry in a subset of samples. This was compared with the historical prevalence of amyloid in THA specimens from January 2021 to December 2023 at the same institution. There were 1,744 THA specimens included in the contemporary cohort and 15,680 in the historical cohort.
RESULTS
The prevalence of amyloid was higher in the contemporary than the historical cohort, with 73 (4.2%) cases of amyloid deposition identified in the contemporary cohort and nine (0.06%) in the historical cohort. There were 29 cases subtyped with mass spectrometry, identifying 11 cases of the cardiac-associated transthyretin (ATTR) subtype.
CONCLUSION
Historically, making the pathological diagnosis of amyloidosis was of little clinical value, as there were no treatment options. As novel, life-saving therapeutics evolve for the treatment of amyloidosis, routine THA specimens represent an opportunity for early identification of patients who would benefit from these therapies. Further study is warranted to develop a clinical pathway from orthopaedic tissue diagnosis to treatment of amyloidosis.