Prevalence of amyloid deposits in synovium and flexor retinaculum, risk factors and asymptomatic cardiac involvement in patients with carpal tunnel syndrome.

INTRODUCTION

Amyloid deposition in the tenosynovium and transverse carpal ligament, and particularly cardiac involvement, are rare in patients with carpal tunnel syndrome; however, the prevalence may be underreported. This prospective study assessed the prevalence of amyloid deposits in the synovium and transverse carpal ligament and whether dual-site sampling improved detection. Risk factors for a positive test and asymptomatic cardiac involvement were also investigated.

METHODS

In a prospective cohort of 100 consecutive patients undergoing carpal tunnel release, intraoperative biopsies were taken from the tenosynovium and the transverse carpal ligament and examined using Congo red and immunohistochemistry staining. Concordance between biopsy sites was assessed, and independent predictors for a positive test were evaluated by multivariable logistic regression. Amyloid-positive patients underwent cardiac assessments, including cardiac biomarkers and 99mTc-pyrophosphate scintigraphy.

RESULTS

Amyloid deposition was present in 62 patients. Concordance between biopsy sites was 91%. Older age, male sex, bilateral carpal tunnel syndrome, multiple trigger fingers, and spinal stenosis independently predicted tissue amyloid. Asymptomatic cardiac amyloid deposition was identified in eight patients: three fulfilled criteria for cardiac amyloidosis and five demonstrated scintigraphic uptake with preserved function.

CONCLUSION

Amyloid deposition in carpal tunnel syndrome was common in our study population, and subclinical cardiac involvement was not rare. Dual-site biopsy improved detection compared with the single-site sampling, and we recommend this routinely during carpal tunnel release. If not feasible, we recommend prioritizing older or male patients and those with bilateral carpal tunnel syndrome, multiple trigger fingers or spinal stenosis. Multiple trigger fingers may indicate a systemic process and high amyloid/cardiac risk.

LEVEL OF EVIDENCE: III.