Changes in viscoelastic properties of articular cartilage in early stage of osteoarthritis, as determined by optical coherence tomography-based strain rate tomography

Suguru Nakamura,Daisuke Furukawa,Yoshito Tsukahara,Kumi Orita,Hiroaki Nakamura,Mitsuhiko Ikebuchi,Nobuo Niimi,Souichi Saeki

doi:10.1186/s12891-019-2789-4

Abstract

BackgroundBiomechanical changes in articular cartilage are associated with the onset of osteoarthritis. We developed an optical coherence tomography-based strain rate tomography method: stress relaxation optical coherence straingraphy (SR-OCSA). The purpose of this study was to establish an approach for measuring mechanical properties of articular cartilage using SR-OCSA, and to investigate the distribution of viscoelastic properties of articular cartilage in early osteoarthritis.MethodsAnterior cruciate ligament transection surgery was performed on the left knees of 8–9-month-old New Zealand white rabbits. SR-OCSA was used to visualize and measure the viscoelastic properties of articular cartilage via attenuation coefficient of strain rate (ACSR). Using the same conditions as in the SR-OCSA test, an indentation test was conducted, and relaxation time was measured to evaluate the relationship between ACSR and relaxation time.ResultsSR-OCSA could nondestructively detect and visualize changes in the distribution of viscoelastic properties of articular cartilage in early osteoarthritis. SR-OCSA captured significant increases in ACSR in cartilage at 2 weeks after surgery, when a histologically slight osteoarthritis sign was present. As cartilage degeneration progressed, ACSR increased, whereas relaxation time decreased in a time-dependent manner. Moreover, ACSR negatively correlated with relaxation time. In particular, ACSR was elevated around the tidemark and the elevation tended to move as cartilage degeneration progressed.ConclusionsSR-OCSA could tomographically and nondestructively detect and visualize changes in the distribution of viscoelastic properties of articular cartilage in early osteoarthritis. The mechanical properties around the tidemark were degraded as cartilage degeneration progressed. Thus, SR-OCSA provides important data needed to understand the biomechanics of early osteoarthritis.

Highlights

Biomechanical changes in articular cartilage are associated with the onset of osteoarthritis
We have developed an Optical coherence tomography (OCT)-based strain rate tomography method: stress relaxation optical coherence straingraphy (SR-OCSA)
Our study showed that the SR-OCSA could nondestructively detect changes of viscoelastic properties in degenerative cartilage via tomographic distribution, Fig. 7 Representative optical coherence tomography (OCT) image of each group (a) and corresponding tomographic distribution of attenuation coefficient of strain rate (ACSR) in the same sample (b)

Summary

Introduction

Biomechanical changes in articular cartilage are associated with the onset of osteoarthritis. The purpose of this study was to establish an approach for measuring mechanical properties of articular cartilage using SR-OCSA, and to investigate the distribution of viscoelastic properties of articular cartilage in early osteoarthritis. While OA has a multifactorial etiology and involves the entire joint, its central pathological feature is the progressive loss of articular cartilage [1, 2]. OA has been diagnosed by determining characteristic radiographic changes in bone; these changes are only visible in the irreversible stage, with substantial cartilage loss and degeneration [4]. The establishment of a quantitative method for the early evaluation of cartilage degeneration is important to assess the efficacy of DMOADs and develop appropriate cartilage repair strategies

Objectives

Methods

Results

Discussion

Conclusion