The amyloidoses

1. Introduction & High-Yield Summary

The amyloidoses comprise a heterogeneous group of systemic and localized protein misfolding disorders characterized by the extracellular aggregation and deposition of insoluble, antiparallel beta-pleated sheet fibrils in tissues and organs. These amyloid deposits disrupt tissue architecture, impair microvascular perfusion, and alter cellular biomechanics, ultimately resulting in progressive organ dysfunction and structural tissue failure.

In orthopaedic surgery and musculoskeletal medicine, amyloidosis has emerged from a historical diagnostic obscurity into a major clinical priority. Musculoskeletal tissues—specifically the flexor tenosynovium of the wrist, the ligamentum flavum of the lumbar spine, and the rotator cuff and long head of the biceps tendons—serve as preferential seeding sites for amyloid deposition, particularly wild-type transthyretin (ATTRwt), mutant transthyretin (ATTRv), immunoglobulin light-chain (AL), and beta-2 microglobulin (Aβ2M) amyloidosis.

• Musculoskeletal Prodrome Precedes Organ Failure: Orthopaedic manifestations—predominantly bilateral carpal tunnel syndrome, lumbar spinal canal stenosis, atraumatic long head of the biceps tendon rupture (Popeye sign), and recalcitrant trigger digits—frequently represent the earliest clinical herald of systemic transthyretin amyloidosis, preceding fatal cardiac amyloidosis and heart failure by 5 to 10 years.
• High Pre-Test Prevalence in Orthopaedic Populations: Up to 10% to 15% of patients aged 50 and older undergoing carpal tunnel release, and up to 33% to 45% of elderly patients undergoing lumbar spinal decompression for spinal stenosis, demonstrate histologic amyloid deposition in resected soft tissues upon Congo red staining.
• The Orthopaedic Surgeon as Gatekeeper: The orthopaedic surgeon occupies a pivotal gatekeeper position. Identifying tenosynovial or ligamentous amyloid through intraoperative tissue biopsy allows early diagnosis of occult cardiac amyloidosis via Technetium-99m pyrophosphate (99mTc-PYP) bone scintigraphy and serum free light chain (sFLC) assays before irreversible restrictive cardiomyopathy occurs.
• Transformative Disease-Modifying Pharmacotherapies: The emergence of transthyretin tetramer stabilizers (tafamidis, acoramidis) and hepatic RNA-silencing gene therapies (vutrisiran, patisiran) has revolutionized management, reducing all-cause mortality by 30% and cardiovascular hospitalizations by 32% when instituted early in the disease course.
• Critical Contraindications in Musculoskeletal Care: Local corticosteroid injections into amyloid-infiltrated tendons and tenosynovium must be strictly avoided; corticosteroids accelerate collagen catabolism and trigger catastrophic spontaneous tendon ruptures in already compromised connective tissues.

2. Anatomy

Amyloid fibrils exhibit a profound structural tropism for dense, collagenous fibro-osseous compartments subject to repetitive mechanical load, hydrostatic pressure, and high extracellular matrix shear stress. Understanding the regional anatomy and surgical danger zones is essential for operative decompression, specimen harvesting, and preventing catastrophic neurovascular injury.

Carpal Tunnel and Flexor Compartment of the Wrist

The carpal tunnel is an inelastic fibro-osseous conduit bounded deeply and laterally by the carpal bones (scaphoid tuberosity, trapezium ridge, hook of hamate, and triquetrum) and roofed volarly by the transverse carpal ligament (flexor retinaculum). The tunnel transmits nine flexor tendons (four flexor digitorum superficialis, four flexor digitorum profundus, and the flexor pollicis longus) along with the median nerve. Amyloid deposition selectively infiltrates the synovial sheaths enveloping the flexor tendons, provoking massive tenosynovial hypertrophy. This volumetric expansion within an unyielding osteofibrous space elevates intracompartmental pressures from a physiological baseline of 2.5 mm Hg to sustained levels exceeding 30 to 50 mm Hg, inducing microvascular ischemia, axonal conduction block, and median nerve fiber demyelination.

• Recurrent Motor Branch of the Median Nerve: Arises from the radial-volar aspect of the median nerve just distal to the transverse carpal ligament. Branching patterns include extraligamentous (50%), subligamentous (30%), and transligamentous (20%). Massive, rubbery amyloid tenosynovium obscuring the median nerve substantially increases the risk of iatrogenic transection during release unless the nerve is mobilized under direct visualization.
• Palmar Cutaneous Branch of the Median Nerve: Arises 4 to 7 cm proximal to the wrist crease, coursing between the flexor carpi radialis and palmaris longus tendons before crossing superficial to the transverse carpal ligament. Incisions placed too radially directly risk injury, leading to painful neuroma formation and intractable pillar pain.
• Berrettini Branch and Superficial Palmar Arch: Communicating sensory ramus between the median and ulnar digital nerves and the superficial vascular arch situated approximately 10 to 12 mm distal to the distal edge of the transverse carpal ligament (Kaplan’s cardinal line).

Spine and Ligamentum Flavum

The ligamentum flavum consists of bilateral paired elastic ligaments connecting the laminae of adjacent vertebrae from C2 down to S1. Unlike other spinal ligaments, healthy ligamentum flavum is composed of 80% elastic fibers and 20% collagen fibers, providing elasticity that prevents buckling into the spinal canal during extension. In amyloidosis, particularly wild-type ATTR, amyloid fibrils deposit within the interfibrillar matrix, inducing progressive elastolysis, loss of elastic compliance, fibroblast proliferation, and chondroid metaplasia. This pathological cascade produces marked ligamentous hypertrophy exceeding 4 to 6 mm in thickness (physiological thickness is 2 to 3 mm), driving circumferential mechanical constriction of the thecal sac, lateral recess compromise, and subarticular nerve root impingement.

• The Dural Adhesion Interface: Amyloid-infiltrated ligamentum flavum loses its natural cleavage plane against the dorsal thecal dura mater. The dura becomes thinned, friable, and densely adherent to the amyloid mass, sharply increasing the incidence of intraoperative dural tears during Kerrison rongeur resection.
• Traversing and Exiting Nerve Roots: Within the lateral recess, the traversing root passes medial to the pedicle and ventral to the hypertrophied superior articular process and thickened lateral margin of the ligamentum flavum, predisposing to compression radiculopathy.

Shoulder and Long Head of the Biceps Tendon

In the shoulder, amyloid deposits within the subacromial-subdeltoid bursa, the rotator cuff tendons (supraspinatus, infraspinatus, subscapularis), the glenohumeral synovium, and the long head of the biceps (LHB) tendon within the bicipital groove. Infiltration severely compromises the structural architecture of type I collagen bundles, predisposing to spontaneous, atraumatic tendon ruptures. A spontaneous rupture of the proximal long head of the biceps tendon without preceding trauma in an elderly male produces the pathognomonic “Popeye deformity,” which serves as an authoritative herald sign for underlying ATTR cardiomyopathy.

3. Pathogenesis

The core pathogenic mechanism underlying all amyloidoses is the abnormal conformational transition of soluble, natively functional globular proteins into insoluble, beta-sheet-rich fibrillar assemblies. Under physiological conditions, chaperone networks and the ubiquitin-proteasome system maintain protein folding fidelity. Aging, genetic mutations, high precursor concentrations, or altered local microenvironments trigger thermodynamic destabilization, causing precursor proteins to misfold, self-assemble into oligomeric intermediates, and coalesce into unbranched, rigid fibrils 7.5 to 10 nm in diameter. These fibrils are organized in a cross-beta conformation, where beta-strands run perpendicular to the long fibril axis, conferring extreme resistance to physiological proteolytic degradation.

Four primary amyloid fibril precursor proteins are of paramount relevance to orthopaedic surgery:

• Transthyretin (ATTR): Transthyretin is a 55 kDa homotetrameric transport protein synthesized predominantly in the liver (and choroid plexus) that transports thyroxine and retinol-binding protein. In wild-type ATTR (ATTRwt), senescence-associated homeostatic failure promotes spontaneous kinetic dissociation of the stable tetramer into unstable, misfolded monomers that polymerize into amyloid fibrils. In variant ATTR (ATTRv), hereditary point mutations in the TTR gene (such as Val30Met, Val122Ile, or Thr60Ala) thermodynamically destabilize the tetramer, accelerating dissociation and amyloid seeding at a younger age.
• Immunoglobulin Light Chain (AL): Arises from a clonal plasma cell proliferative disorder (monoclonal gammopathy of undetermined significance, smoldering myeloma, or multiple myeloma) producing excess monoclonal lambda or kappa light chains. These misfolded light chains exhibit direct cytotoxicity to tissues, provoking rapid systemic organ failure, peripheral neuropathy, and soft-tissue amyloid deposits.
• Beta-2 Microglobulin (Aβ2M): In patients with end-stage renal disease (ESRD) maintained on long-term hemodialysis (>5 to 10 years), standard low-flux dialyzer membranes cannot clear the 11.8 kDa beta-2 microglobulin protein. Serum concentrations elevate 10- to 60-fold, driving crystallization and deposition in periarticular bone and synovium, termed dialysis-related amyloidosis (DRA). Aβ2M deposits trigger osteoclastogenesis, bone resorption, and mechanical destruction of spinal and peripheral joints.
• Serum Amyloid A (AA): Formed during chronic systemic inflammation (rheumatoid arthritis, ankylosing spondylitis, osteomyelitis, inflammatory bowel disease) where elevated interleukin-1, interleukin-6, and TNF-alpha drive massive hepatic synthesis of acute-phase reactant SAA. Amyloid A primarily affects renal and gastrointestinal parenchyma, with secondary involvement of articular synovium.

4. Natural History & Epidemiology

The natural history of systemic amyloidosis is characterized by a silent or localized musculoskeletal prodromal phase that progresses inexorably over years into fatal multi-organ infiltrative failure unless interrupted by targeted disease-modifying therapy.

• Demographic Patterns: ATTRwt demonstrates a marked male predilection, with male-to-female ratios ranging from 4:1 to 10:1. The median age at diagnosis of ATTRwt cardiomyopathy is 72 to 78 years, but musculoskeletal symptoms manifest significantly earlier, typically between 55 and 70 years of age. Post-mortem autopsy series indicate that over 25% of individuals older than 80 years have microscopic wild-type ATTR deposits within myocardial tissue. In contrast, AL amyloidosis has an annual incidence of 10 to 12 cases per million, affects males and females equally, and has a median onset around 63 years.
• The Musculoskeletal Prodrome Timeline: Bilateral carpal tunnel syndrome is the most recognized musculoskeletal herald sign, developing 5 to 10 years prior to the clinical onset of heart failure in ATTRwt. Lumbar spinal canal stenosis requiring decompression typically precedes cardiac diagnosis by 2 to 5 years. Spontaneous long head of the biceps tendon rupture occurs up to 5 years prior. Consequently, orthopaedic interventions provide an early clinical diagnostic window to prevent cardiovascular morbidity.
• Untreated Prognosis: Historically, untreated AL amyloidosis with cardiac involvement portended a dismal median overall survival of 4 to 6 months from the onset of congestive heart failure. Untreated ATTRwt cardiac amyloidosis carried a median survival of 3.5 to 5 years from cardiac presentation. With the advent of contemporary transthyretin tetramer stabilizers and immunotherapies, 5-year survival in compliant patients exceeds 75% to 80% when therapy is initiated before end-stage cardiac remodeling occurs.

5. Clinical Presentation

Patients presenting to an orthopaedic surgeon often display isolated musculoskeletal complaints while harboring occult systemic involvement. A high index of suspicion and structured clinical evaluation are essential to distinguish amyloid-related musculoskeletal disease from common idiopathic degenerative conditions.

History & Systemic Review of Systems

The history must systematically probe both focal mechanical symptoms and systemic amyloid red flags:

• Upper Extremity Symptoms: Inquire regarding bilateral nocturnal paresthesias, waking up to shake the hands (“flick sign”), thenar numbness, loss of fine pinch coordination, and persistent locking or snapping of multiple digits (bilateral trigger fingers). A history of sudden, audible “pop” in the shoulder followed by painless distal arm bulging indicates spontaneous biceps tendon rupture.
• Spine Symptoms: Classic neurogenic claudication characterized by bilateral buttocks, thigh, and calf aching, heaviness, cramping, or paresthesias exacerbated by upright walking and spinal extension, and promptly relieved by sitting, forward flexion, or leaning on a shopping cart.
• Cardiovascular Red Flags: Unexplained exertional dyspnea, orthopnea, bilateral lower extremity pitting edema, lightheadedness, or syncopal episodes. A history of previously hypertension that has “spontaneously normalized,” or intolerance to standard antihypertensives (ACE inhibitors, beta-blockers) causing profound paradoxical hypotension, is a hallmark of autonomic neuropathy and cardiac amyloid infiltration.
• Autonomic and Peripheral Neuropathy: Orthostatic hypotension, persistent alternating constipation and diarrhea, early satiety, and progressive sensory loss in a “stocking-glove” distribution.
• Dermatologic and Mucocutaneous Clues: Periorbital ecchymosis or purpura (“raccoon eyes” or “panda eyes” resulting from vascular fragility in AL amyloidosis, often triggered by Valsalva), macroglossia (enlarged, scalloped tongue with lateral tooth indentations pathognomonic for AL), and prominent submandibular soft-tissue swelling.

Physical Examination & Provocative Maneuvers

Perform a thorough musculoskeletal, vascular, and neurological examination, incorporating validated provocative maneuvers:

• Durkan’s Carpal Compression Test: The examiner applies direct thumb pressure over the volar carpal tunnel between the thenar and hypothenar eminences for 30 seconds -> Positive finding: Reproduction or exacerbation of numbness and paresthesias in the median nerve distribution [Sensitivity 87–91%, Specificity 90–95%].
• Phalen’s Wrist Flexion Maneuver: The patient holds bilateral wrists in complete unforced flexion (90 degrees) with dorsal surfaces opposed for 60 seconds -> Positive finding: Tingling or numbness in the radial three-and-a-half digits [Sensitivity 68–88%, Specificity 73–90%].
• Tinel’s Percussion Sign: Light manual or reflex hammer percussion over the volar carpal tunnel -> Positive finding: Distal electrical tingling radiating into the thumb, index, long, and radial ring fingers [Sensitivity 50–60%, Specificity 67–87%].
• Kemp’s / Extension-Rotation Maneuver: Standing active lumbar extension with ipsilateral lateral bending and axial rotation -> Positive finding: Reproduction of radicular leg symptoms or sharp localized buttock pain due to neural foraminal and spinal canal narrowing [Sensitivity 65–75%, Specificity 60–70%].
• Ludington’s Maneuver & Popeye Sign Inspection: The patient clasps both hands behind the head with fingers interlocked and contracts the biceps -> Positive finding: Asymmetrical distal muscular bulge in the arm denoting loss of proximal anchor integrity from long head of the biceps tendon rupture [Sensitivity 90–95%, Specificity 95–98%].
• Thenar Muscular Atrophy: Inspection of the radial aspect of the hand reveals flattened thenar contour with weakness of the abductor pollicis brevis on resisted thumb palmar abduction, reflecting advanced motor axonopathy.

6. Imaging and Diagnostic Studies

The diagnostic pathway requires a multimodal approach combining conventional orthopaedic imaging, advanced cross-sectional MRI, definitive tissue histopathology with mass spectrometry subtyping, and reflexive systemic cardiological evaluation.

Radiographic and Advanced Imaging Features

• Plain Radiographs: Standard wrist and lumbar spine radiographs are typically unremarkable or show non-specific degenerative changes. In dialysis-related amyloidosis (Aβ2M), radiographs reveal classic juxta-articular subchondral radiolucent bone cysts (“amyloid geodes”) in the carpal bones, femoral head, and acetabulum without surrounding reactive osteosclerosis or marginal osteophytosis. Destructive spondyloarthropathy presents on spinal radiographs as severe disc space narrowing and endplate erosion mimicking pyogenic spondylodiscitis.
• Magnetic Resonance Imaging (MRI):
  • Wrist: Demonstrates substantial flexor tenosynovial thickening displaying intermediate-to-low signal intensity on both T1- and T2-weighted sequences due to dense fibril packing, contrasting with inflammatory synovial pannus (which is hyperintense on T2 and Avidly enhances). Median nerve swelling is prominent proximal to the transverse carpal ligament with flattening within the canal.
  • Spine: Demonstrates marked ligamentum flavum thickening (>4 to 6 mm) that remains hypointense or isointense on T1 and T2 images, producing severe central canal compression and “trefoil” deformity of the thecal sac.
  • Shoulder: Massive subacromial-subdeltoid bursal distension filled with low T2 signal mass (“shoulder pad sign”), accompanied by full-thickness rotator cuff tears, articular cartilage thinning, and extensive amyloid infiltration.

Diagnostic Hierarchy and Systematic Evaluation Matrix

When an orthopaedic surgeon suspects amyloidosis, the following standardized diagnostic hierarchy dictates workup and referral:

7. Classification

Modern classification frameworks integrate biochemical fibril composition, anatomical distribution, and validated systemic risk stratification systems.

Biochemical Classification of Musculoskeletal Amyloidosis

Validated Prognostic Staging Systems

Once systemic cardiac involvement is diagnosed, validated staging systems dictate prognosis and eligibility for disease-modifying therapies:

8. Treatment

Managing musculoskeletal amyloidosis requires an integrated multidisciplinary paradigm combining targeted surgical decompression with systemic disease-modifying pharmacotherapy.

Medical & Systemic Disease-Modifying Pharmacotherapies

Historically, management of amyloidosis was limited to palliative fluid control and heart failure therapy. Over the past decade, molecular targeted agents have transformed systemic outcomes:

Operative Management & Surgical Principles

Surgical intervention targets immediate mechanical neural decompression and accurate tissue diagnosis:

• Open Carpal Tunnel Release (OCTR) vs. Endoscopic (ECTR): Open carpal tunnel release is the procedure of choice in suspected amyloidosis. Direct exposure enables careful inspection of the thickened flexor tenosynovium, safe identification and preservation of the recurrent motor branch amidst bulky tissue, partial tenosynovial debridement to reduce bulk, and harvesting of an adequate 1 x 1 cm tenosynovial biopsy for Congo red and mass spectrometry analysis. Endoscopic release does not allow tenosynovial inspection or tissue harvesting and risks incomplete release due to bulky soft tissue obscuring the blade assembly.
• Lumbar Spinal Decompression: Laminectomy and bilateral medial facetectomy with resection of the thickened ligamentum flavum. Resection must proceed cautiously from normal cranial dura toward the compromised level. The use of a fine Woodson elevator to gently mobilize the adherent dorsal dura from the amyloid-laden ligament prevents dural tears. All resected ligamentum flavum in patients aged 65 and older should be routinely sent in formalin for histologic evaluation.
• Shoulder & Tendon Procedures: In patients with full-thickness rotator cuff tears and confirmed ATTR, primary rotator cuff repair exhibits high structural failure rates (>50%) due to severe tendon friability and poor anchor purchase in osteopenic, amyloid-infiltrated bone. Reverse total shoulder arthroplasty (rTSA) yields superior functional outcomes in advanced cuff tear arthropathy. For symptomatic biceps pathology, subpectoral biceps tenodesis or simple tenotomy provides reliable pain relief; tenotomy avoids hardware pullout through degenerated tendon tissue.

Indications & Contraindications

9. Outcome

Surgical decompression delivers substantial relief of mechanical compressive symptoms, although neurological recovery may be modulated by underlying amyloid neuropathy:

• Carpal Tunnel Release Functional Outcomes: Patients achieve significant improvements in Boston Carpal Tunnel Questionnaire (BCTQ) symptom severity and functional status scores, as well as QuickDASH metrics. However, sensory normalization (static two-point discrimination) and thenar motor power recover more slowly and less completely than in non-amyloid carpal tunnel cohorts due to pre-existing microvascular and endoneurial amyloid infiltration.
• Spine Decompression Outcomes: Lumbar decompression yields durable improvements in Oswestry Disability Index (ODI) scores, visual analog scale (VAS) back and leg pain, and Zurich Claudication Questionnaire scores. Long-term structural revision rates for recurrent stenosis or adjacent segment degeneration are comparable to age-matched non-amyloid degenerative stenosis cohorts.
• Cardiovascular Survival Transformation: The most profound outcome of orthopaedic detection is survival. When patients with ATTRwt are identified through orthopaedic tenosynovial or ligamentum flavum biopsy and initiated on tafamidis before developing overt NYHA Class III/IV heart failure, all-cause mortality is reduced by 30%, cardiovascular hospitalizations decrease by 32%, and functional decline on the 6-minute walk test is significantly arrested.

10. Complications

Complications associated with amyloidosis span immediate intraoperative mechanical events to long-term systemic deterioration:

11. Pearls and Pitfalls

12. Controversy

Several major controversies persist in the orthopaedic management and systemic screening of musculoskeletal amyloidosis:

• Universal vs. Risk-Stratified Biopsy in Carpal Tunnel Surgery: Proponents of universal biopsy advocate that all patients aged 50 and older undergoing carpal tunnel release should have routine tenosynovial biopsy, noting that tenosynovial amyloid is identified in 10% to 15% of this demographic and provides an irreplaceable window for early ATTR diagnosis. Opponents highlight substantial laboratory costs, administrative burden, potential false negatives from sampling error, and variable pathology proficiency with Congo red staining. Current consensus favors risk-stratified screening: targeting males ≥50 and females ≥60 with bilateral disease, trigger digits, lumbar spinal stenosis, or cardiac symptoms.
• Cost-Effectiveness and Global Accessibility of TTR Stabilizers: The annual wholesale acquisition cost of tafamidis exceeds $225,000 USD, and novel RNA-silencing therapies cost between $300,000 and $450,000 USD annually. Health economic models debate the cost-effectiveness threshold of widespread screening, creating profound ethical and clinical dilemmas regarding equitable patient access and healthcare system sustainability.
• Optimal Management of Massive Rotator Cuff Tears in ATTR Patients: Whether to perform arthroscopic repair versus joint-preserving debridement or early reverse total shoulder arthroplasty (rTSA) remains intensely debated. Primary tendon repair in ATTR patients exhibits structural retear rates exceeding 50% to 70% due to diffuse amyloid infiltrative tendinopathy. Proponents of early rTSA argue that it reliably restores elevation and eliminates pain without relying on friable tendon healing.

13. Evidence-Based Synthesis

Modern clinical decision-making is grounded in high-quality randomized controlled trials and prospective registry analyses, corroborated by seminal biomechanical and anatomical descriptions.

14. References

• Moore ZJ, Rizkalla JM, Weiner J et al. Transthyretin amyloidosis in spinal canal stenosis: A systematic review. J Orthop. 2024. doi:10.1016/j.jor.2024.02.047 [Level I: Systematic Review / Meta-Analysis]
• Maurer MS, Schwartz JH, Gundapaneni B et al. Tafamidis Treatment for Patients with Transthyretin Amyloid Cardiomyopathy. N Engl J Med. 2018. doi:10.1056/NEJMoa1805689 [Level I: Randomized Controlled Trial (ATTR-ACT)]
• Sperry BW, Reyes BA, Ikram A et al. Tenosynovial and Cardiac Amyloidosis in Patients Undergoing Carpal Tunnel Release. J Am Coll Cardiol. 2018. doi:10.1016/j.jacc.2018.07.092 [Level II: Prospective Diagnostic Cohort Study]
• Donnelly JP, Hanna M, Sperry BW et al. Carpal Tunnel Syndrome: A Potential Early, Red-Flag Sign of Amyloidosis. J Hand Surg Am. 2019. doi:10.1016/j.jhsa.2019.06.016 [Level IV: Clinical Practice Review / Cohort Analysis]
• Jeanneteau J, Bigorre N. Screening for Transthyretin Amyloidosis During Carpal Tunnel Release: An Opportunity for Early Diagnosis. Am J Cardiol. 2026. doi:10.1016/j.amjcard.2026.07.007 [Level IV: Prospective Screening Cohort]

15. Master Class Pro-Tip

When performing open carpal tunnel release in an older adult, observe the quality of the flexor tenosynovium upon incising the transverse carpal ligament. Amyloid infiltration appears not as the hyperemic, boggy, or villous tissue typical of rheumatoid tenosynovitis, but rather as a dull, pale-yellow, or salmon-pink rubbery mass that firmly encases the flexor digitorum superficialis tendons. When this appearance is encountered, immediately resect a clean 1 x 1 cm specimen from the superficial tenosynovium, place it in standard formalin, and explicitly order ‘Congo red staining with polarized light microscopy’ on the surgical pathology requisition. Concurrently initiate an immediate clinical reflex: place a cardiology consult and order serum free light chains (sFLC) with immunofixation and a Technetium-99m pyrophosphate (99mTc-PYP) bone scintigraphy scan. Identifying amyloid in the palm before it manifests as intractable congestive heart failure is one of the rare opportunities in elective hand surgery to directly save a patient’s life.

Master Class Surgical Pearl: Intraoperative Recognition & Reflex Biopsy for Tenosynovial Amyloidosis