A Comparison of Tenosynovial and Transverse Carpal Ligament Biopsy for Amyloid Detection in Open Carpal Tunnel Release.

PURPOSE: Our purpose was to compare differences in the incidence of amyloid deposition in tenosynovium (TS) versus transverse carpal ligament (TCL) biopsies obtained during open carpal tunnel release. We hypothesized that the incidence of amyloid would be similar between TCL and TS when obtaining both specimens from the same patient. METHODS: All primary, elective open carpal tunnel release cases that underwent biopsy for amyloid between January 2022 and September 2023 were reviewed. Tenosynovial and TCL specimens were independently evaluated by a pathologist to assess for amyloid. Demographic data were collected, and incidence of amyloid deposition was compared between the two samples. Agreement statistics, sensitivity, and specificity were calculated for TCL, using TS as the reference standard. RESULTS: A total of 196 cases met either Tier 1 (n=180) or Tier 2 (n=16) biopsy criteria. Forty-eight cases were excluded for missed biopsies or laboratory processing errors, leaving 148 cases available for analysis. Amyloid deposition was present in 31 out of 148 (21%) TS specimens and 33 out of 148 (22%) TCL specimens. Overall, the results of the TS biopsy agreed with TCL biopsy in 138 out of 148 cases (93%). In the 10 cases for which the results of the TCL and TS biopsy differed, six cases had (+) TCL and (-) TS, and four cases had amyloid deposition in TS without evidence of deposition in the TCL. Sensitivity and specificity values for the TCL specimen were 87% and 95%, respectively. Positive and negative predictive values were 82% and 97%, respectively. CONCLUSIONS: For cases of open carpal tunnel release undergoing biopsy, amyloid deposition was noted in 21% of TS specimens and 22% of TCL specimens. Results of TS and TCL biopsies obtained from the same patient agreed in 93% of cases. Single-source biopsy for amyloid represents a reasonable diagnostic approach. Future cost analyses should be performed to determine whether the addition of two biopsy sources to improve diagnostic accuracy is justified. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

Prevalence of Cardiac Amyloidosis in Patients Undergoing Carpal Tunnel Release With Amyloid Deposition.

BACKGROUND: Carpal tunnel syndrome (CTS) is considered an early sign of cardiac amyloidosis (CA) because amyloid deposition is often confirmed in the tenosynovium removed during carpal tunnel release (CTR); however, the prevalence of concomitant CA is unclear.Methods and Results: We prospectively examined 700 patients who underwent CTR and evaluated amyloid deposition after tenosynovium removal. Amyloid deposition was observed in 261 (37%) patients, who were significantly older and predominantly male (P<0.05). Of them, 120 agreed to cardiac screening. We performed 99 mTc-labeled pyrophosphate (99 mTc-PYP) scintigraphy in 12 patients who met either of the following criteria: (1) interventricular septal diameter (IVSd) ≥14 mm or (2) 12 mm ≤ IVSd < 14 mm with above-normal limits in high-sensitivity cardiac troponin T (hs-cTnT). Six patients (50%) had positive findings on 99 mTc-PYP scintigraphy and were diagnosed with wild-type transthyretin CA. Concomitant CA was observed in 6/120 (5%) CTR patients with amyloid deposition and 50% (6/12) in patients with left ventricular hypertrophy (≥12 mm) with increased hs-cTnT levels. CONCLUSIONS: Amyloid deposition was frequently observed in the removed tenosynovium of elderly men with CTS. Cardiac screening may be useful for early diagnosis of CA in patients undergoing CTR with amyloid deposition.

Principles of Tendon Structure, Healing, and the Microenvironment.

Tendon is a strong viscoelastic tissue, responsible for conducting force from muscle to bone. In the hand, flexor tendons course through fibro-osseous sheaths, composed of an intricate tenosynovium and fibrocartilaginous pulley system. After flexor tendon laceration, changes occur in tendon force transduction as well as vascularity, affecting tendon healing on a tissue and cellular level. Tendon healing occurs through intrinsic and extrinsic mechanisms, which in combination with local anatomy, can predispose to adhesion formation. Understanding the relationship between microenvironmental cues and tendon healing on the cellular and tissue level will improve our knowledge and treatment of flexor tendon injuries.

Evidence for the presence of synovial sheaths surrounding the extensor tendons at the metacarpophalangeal joints: a microscopy study.

MRI-detected inflammation around the extensor tendons of metacarpophalangeal (MCP-) joints is prevalent in RA and poses a markedly increased risk of RA development when present in arthralgia patients. Such inflammation is called 'peritendinitis' since anatomy literature reports no presence of a tenosynovial sheath at these tendons. However, the presence or absence of tenosynovium at these extensor tendons has never been studied. Therefore, an anatomical and histological study of extensor tendons at the MCP-joints of three embalmed human hands was performed. Immunohistochemical staining showed the presence of markers for synovial macrophages and fibroblast-like synoviocytes bordering a natural dorsal space next to the extensor tendon, suggesting the presence of a synovial lining. This implies that contrast-enhancement on MRI around extensor tendons at MCP-joints observed in early RA and pre-RA likely represents tenosynovitis and that inflammation of this synovial tissue is an early feature of RA.

Prevalence and Subtypes of Tenosynovial Amyloid in Patients Undergoing Carpal Tunnel Release.

PURPOSE: The purpose of this study was to determine the prevalence and subtypes of amyloid in tenosynovial biopsies of patients undergoing carpal tunnel release (CTR). METHODS: A retrospective review was performed involving patients who underwent CTR from June 2020 to July 2021. Prior to this period, a protocol had been established to obtain routine intraoperative tenosynovial biopsies. Tenosynovium was preserved in formalin and stained with Congo red for amyloid. Positive specimens were sent to an external laboratory for confirmation and subtyping by mass spectrometry. Men 50 years or older and women 60 or older were included for analysis. Acute, traumatic, and revision cases were excluded. RESULTS: Of 185 patients who underwent CTR with tenosynovial biopsy, 54 (29%) demonstrated positive Congo red stain, confirmed by the external laboratory. A subtype analysis revealed wild-type transthyretin (TTR) in 44 patients (80%), mixed wild-type TTR with κ light chains in 1 patient, and hereditary TTR in 1 patient. Patients with positive specimens were significantly older than those who tested negative (77 vs 68 years, respectively), and positivity increased by decade for both sexes. Male sex, atrial fibrillation, and spinal stenosis were significantly more prevalent among positive cases. There were no complications from the biopsies. CONCLUSIONS: We confirmed evidence of amyloidosis in the tenosynovium of 29% of men 50 years or older and women 60 or older who underwent CTR. The majority demonstrated wild-type TTR. As these patients are at risk of developing cardiomyopathy, there is an opportunity for early detection, monitoring, and interventions known to improve outcomes. Considering the low cost of Congo red staining and the potential value of subtyping with regard to treatment of cardiomyopathy, our findings support routine tenosynovial biopsy during CTR in patients who meet the age criteria. TYPE OF STUDY/LEVEL OF EVIDENCE: Differential diagnosis or symptom prevalence study II.

Preclinical diagnosis of wild-type transthyretin amyloid cardiomyopathy in a patient undergoing carpal tunnel release.

Wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM) has received increased attention because of its novel treatment options. Carpal tunnel syndrome (CTS) is known as early symptoms in transthyretin amyloidosis (ATTR) preceding cardiac involvement and one of the "red flags" for ATTR-CM. A 64-year-old man underwent carpal tunnel release for carpal tunnel syndrome at 62 years. He was diagnosed with wild-type ATTR due to deposition of transthyretin (TTR) amyloid in flexor tenosynovium specimens and no TTR gene mutation. Examination for detection of cardiac involvement was performed after the operation, and there were no definitive findings of ATTR-CM; however, an early stage of ATTR-CM remained a possibility. Serial image evaluation and biomarker analysis revealed positive findings for ATTR-CM, and we performed an endomyocardial biopsy, resulting in the detection of amyloid deposition. He was diagnosed with ATTRwt-CM 2 years after the operation, and even then, he had no heart failure symptoms. Early diagnosis and treatment are important for the improvement of clinical outcomes in patients with ATTRwt-CM. TTR deposition in the ligaments or tendons is often observed in patients with CTS and should be considered at high risk of future ATTR-CM. Serial follow-up of these patients may enable the diagnosis of preclinical ATTR-CM. .

Tendinopathy of the long head of the biceps tendon: histopathologic analysis of the extra-articular biceps tendon and tenosynovium.

BACKGROUND: Bicipital tendinitis is a common cause of anterior shoulder pain, but there is no evidence that acute inflammation of the extra-articular long head of the biceps (LHB) tendon is the root cause of this condition. We evaluated the histologic findings of the extra-articular portion of the LHB tendon and synovial sheath in order to compare those findings to known histologic changes seen in other tendinopathies. METHODS: Twenty-six consecutive patients (mean age 45.4±13.7 years) underwent an open subpectoral biceps tenodesis for anterior shoulder pain localized to the bicipital groove. Excised tendons were sent for histologic analysis. Specimens were graded using a semiquantitative scoring system to evaluate tenocyte morphology, the presence of ground substance, collagen bundle characteristics, and vascular changes. RESULTS: Chronic inflammation was noted in only two of 26 specimens, and no specimen demonstrated acute inflammation. Tenocyte enlargement and proliferation, characterized by increased roundness and size of the cell and nucleus with proteoglycan matrix expansion and myxoid degenerative changes, was found in all 26 specimens. Abundant ground substance, collagen bundle changes, and increased vascularization were visualized in all samples. CONCLUSION: Anterior shoulder pain attributed to the biceps tendon does not appear to be due to an inflammatory process in most cases. The histologic findings of the extra-articular portion of the LHB tendon and synovial sheath are similar to the pathologic findings in de Quervain tenosynovitis at the wrist, and may be due to a chronic degenerative process similar to this and other tendinopathies of the body.

Histopathology of tenosynovium in trigger fingers.

Stenosing flexor tenosynovitis, trigger finger, is a common clinical disorder causing painful locking or contracture of the involved digits, and most instances are idiopathic. This problem is generally caused by a size mismatch between the swollen flexor tendon and the thickened first annular pulley. Although hypertrophic pulleys have been histologically and ultrasonographically detected, little is known about the histopathology of the tenosynovium covering the tendons of trigger fingers. We identified chondrocytoid cells that produced hyaluronic acid in 23 (61%) fingers and hypocellular collagen matrix in 32 (84%) fingers around the tenosynovium among 38 specimens of tenosynovium from patients with trigger fingers. These chondrocytoid cells expressed the synovial B cell marker CD44, but not the chondrocyte marker S-100 protein. The incidence of these findings was much higher than that of conventional findings of synovitis, such as inflammatory infiltrate (37%), increased vascularity (37%), hyperplasia of synovial lining cells (21%), or fibrin exudation (5%). We discovered the following distinctive histopathological features of trigger finger: hyaluronic acid-producing chondrocytoid cells originated from fibroblastic synovial B cells, and a hypocellular collagen matrix surrounding the tenosynovium. Thus, an edematous extracellular matrix with active hyaluronic acid synthesis might increase pressure under the pulley and contribute to the progression of stenosis.