Near Infrared Spectroscopy Enables Differentiation of Mechanically and Enzymatically Induced Cartilage Injuries

Abstract

This study evaluates the feasibility of near infrared (NIR) spectroscopy to distinguish between different cartilage injury types associated with post-traumatic osteoarthritis and idiopathic osteoarthritis (OA) induced by mechanical and enzymatic damages. Bovine osteochondral samples (n = 72) were subjected to mechanical (n = 24) and enzymatic (n = 36) damage; NIR spectral measurements were acquired from each sample before and after damage, and from a separate control group (n = 12). Biomechanical measurements were then conducted to determine the functional integrity of the samples. NIR spectral variations resulting from different damage types were investigated and the samples classified using partial least squares discriminant analysis (PLS-DA). Partial least squares regression (PLSR) was then employed to investigate the relationship between the NIR spectra and biomechanical properties of the samples. Results of the study demonstrate that substantial spectral changes occur in the region of 1700-2200 nm due to tissue damages, while differences between enzymatically and mechanically induced damages can be observed mainly in the region of 1780-1810 nm. We conclude that NIR spectroscopy, combined with multivariate analysis, is capable of discriminating between cartilage injuries that mimic idiopathic OA and traumatic injuries based on specific spectral features. This information could be useful in determining the optimal treatment strategy during cartilage repair in arthroscopy.

Near-infrared spectroscopy for structural bone assessment

“…[62][63][64] An instrument that can assess bone health and guide a tailored intervention technique could significantly reduce this burden. 65,66 As these findings are consistent with bone and cartilage studies for other locations, [24][25][26][27][46][47][48][49] it is plausible that this technology could be extended to other orthopaedic or jointrelated interventions.…”

“…39 This study describes the first of many emerging clinical uses of NIRS, which include cancer, 40,41 serum markers, 24,41,42 heart disease, 43 transplant rejection, 44 and fibrosis. 45 In analyzing fresh human bone, our study marks a progression from studies where NIRS has been used to analyze animal and cadaveric human connective tissues, [24][25][26][27][46][47][48][49] or confined to prediction of bone water content. [30][31][32] While many of these studies are based on benchtop spectrophotometers, our report is one of the first to use portable and miniaturized handheld instrumentation to monitor disease using commercially available low-cost instruments in a non-destructive manner.…”

“… 23 , 24 Existing studies have demonstrated the ability of NIRS scans to assess animal 24 and cadaveric human 25 connective tissues, and to predict the integrity of articular cartilage. 26 , 27 However, no study has adapted miniaturized NIRS scans for assessment of fresh human bone, which is an important need/requirement for intraoperative use. In this proof-of-principle study, we examined the capacity of NIRS scans for non-destructive, rapid characterization and prediction of human sternal bone structural properties, assessed and cross-validated via the gold-standard Micro-CT scans.…”

Applications of Vibrational Spectroscopy for Analysis of Connective Tissues

“…Another study used PLS modelling techniques to predict the thickness of the healthy and injured cartilage [ 124 , 125 ], and biomechanical, histological and biochemical properties of articular cartilage [ 125 ]. PLS-discriminant analysis (PLSDA) based on NIR spectra was also used to investigate mechanical properties of bovine articular cartilage samples [ 126 ]. Most recently, the optical properties (absorption and scattering coefficients) of articular cartilage tissue in the visible -NIR region (600 to 2500 nm) were assessed and found to be associated with proteoglycan content and equilibrium moduli in the superficial zone (absorption coefficient), and proteoglycan content and instantaneous and dynamic moduli in the middle and deep zones (scattering coefficient) [ 127 ].…”

Visible and Near-Infrared Spectroscopy Enables Differentiation of Normal and Early Osteoarthritic Human Knee Joint Articular Cartilage

“…Studies on NIRS of cartilage have focused on animal models [ 3 , 29 , 38 ] and on differentiating normal from advanced OA [ 29 ] tissue where clinical intervention has minimal impact. In a clinical setting, identifying normal from early OA would be more beneficial, as early diagnosis would enable earlier intervention that could substantially delay or halt disease progression.…”