Characterizing human subchondral bone properties using near-infrared (NIR) spectroscopy

Isaac O Afara,Juha Töyräs,Ismail A Olumegbon,Rami K Korhonen,Cristina Florea,Chibuzor T Eneh,Markus K H Malo

doi:10.1038/s41598-018-27786-3

Isaac O Afara, Juha Töyräs + Show 5 more

Open Access

https://doi.org/10.1038/s41598-018-27786-3

Copy DOI

Abstract

Degenerative joint conditions are often characterized by changes in articular cartilage and subchondral bone properties. These changes are often associated with subchondral plate thickness and trabecular bone morphology. Thus, evaluating subchondral bone integrity could provide essential insights for diagnosis of joint pathologies. This study investigates the potential of optical spectroscopy for characterizing human subchondral bone properties. Osteochondral samples (n = 50) were extracted from human cadaver knees (n = 13) at four anatomical locations and subjected to NIR spectroscopy. The samples were then imaged using micro-computed tomography to determine subchondral bone morphometric properties, including: plate thickness (Sb.Th), trabecular thickness (Tb.Th), volume fraction (BV/TV), and structure model index (SMI). The relationship between the subchondral bone properties and spectral data in the 1st (650–950 nm), 2nd (1100–1350 nm) and 3rd (1600–1870 nm) optical windows were investigated using partial least squares (PLS) regression multivariate technique. Significant correlations (p < 0.0001) and relatively low prediction errors were obtained between spectral data in the 1st optical window and Sb.Th (R2 = 92.3%, error = 7.1%), Tb.Th (R2 = 88.4%, error = 6.7%), BV/TV (R2 = 83%, error = 9.8%) and SMI (R2 = 79.7%, error = 10.8%). Thus, NIR spectroscopy in the 1st tissue optical window is capable of characterizing and estimating subchondral bone properties, and can potentially be adapted during arthroscopy.

Highlights

Osteoarthritis (OA) is a condition of synovial joints often associated with pain, cartilage erosion, immobility and general joint dysfunction
We assess for the first time the capacity of optical spectroscopy in specific near infrared (NIR) spectral regions for non-destructive evaluation of human subchondral bone properties
The results indicate that wavelength-dependent penetration of light into osteochondral samples plays a significant role in the relationship between the optical response and subchondral bone properties

Summary

Introduction

Osteoarthritis (OA) is a condition of synovial joints often associated with pain, cartilage erosion, immobility and general joint dysfunction. We investigate the potential of NIR spectral data in the three optical windows to assess human subchondral bone properties, based on the hypothesis that light in the different optical windows penetrate to different depths of osteochondral tissues and could provide diagnostic information related to the subchondral bone properties. To test this hypothesis, we investigate the relationship between the spectral response of human osteochondral samples in the different optical windows and their subchondral bone properties using partial least squares regression (PLSR) analytical technique, augmented with spectral pre-processing. The subchondral bone parameters, including subchondral bone plate thickness (Sb.Th), trabecular bone thickness (Tb.Th), bone volume fraction (BV/TV) and structure model index (SMI) were obtained using micro computed tomography (micro-CT)

Objectives

Methods

Results

Conclusion