Near infrared spectroscopic evaluation of biochemical and crimp properties of knee joint ligaments and patellar tendon.

Manabu Sakakibara,Jari Torniainen,Mithilesh Prakash,Jaakko K Sarin,Lauri Stenroth,Isaac O Afara,Aapo Ristaniemi,Juha Töyräs,Mikko A J Finnilä,Rami K Korhonen

doi:10.1371/journal.pone.0263280

Abstract

Knee ligaments and tendons play an important role in stabilizing and controlling the motions of the knee. Injuries to the ligaments can lead to abnormal mechanical loading of the other supporting tissues (e.g., cartilage and meniscus) and even osteoarthritis. While the condition of knee ligaments can be examined during arthroscopic repair procedures, the arthroscopic evaluation suffers from subjectivity and poor repeatability. Near infrared spectroscopy (NIRS) is capable of non-destructively quantifying the composition and structure of collagen-rich connective tissues, such as articular cartilage and meniscus. Despite the similarities, NIRS-based evaluation of ligament composition has not been previously attempted. In this study, ligaments and patellar tendon of ten bovine stifle joints were measured with NIRS, followed by chemical and histological reference analysis. The relationship between the reference properties of the tissue and NIR spectra was investigated using partial least squares regression. NIRS was found to be sensitive towards the water (R2CV = .65) and collagen (R2CV = .57) contents, while elastin, proteoglycans, and the internal crimp structure remained undetectable. As collagen largely determines the mechanical response of ligaments, we conclude that NIRS demonstrates potential for quantitative evaluation of knee ligaments.

Highlights

Knee ligaments are fibrous connective tissues that provide mechanical stability to the knee by preventing excessive translation and rotation of the joint
Analysis of the largest regression coefficients (Fig 6a) indicated that while the hydrogen-oxygen bonds of water clearly contribute to the model, it is affected by NIR absorption of some collagen constituents (i.e., CH-groups), resulting from hydroxyproline, glycine, or proline
Some properties of ligaments have been investigated in the past with Near infrared spectroscopy (NIRS), comprehensive study of all major chemical and structural properties of the five main knee ligaments has not been previously done

Summary

Introduction

Knee ligaments are fibrous connective tissues that provide mechanical stability to the knee by preventing excessive translation and rotation of the joint. The four main ligaments are anterior cruciate, posterior cruciate, lateral collateral, and medial collateral ligaments (i.e., ACL, PCL, LCL, and MCL, respectively). Patellar tendon (PT), connecting patella to tibia, is often considered to be one of the knee ligaments as well. NIRS evaluation of biochemical and crimp properties of knee joint ligaments and patellar tendon d894-4126-bad2-79fe47b3e2fa Ristaniemi, A., Torniainen, J., & Paakkonen, T. Biomechanical, biochemical, and near infrared spectral data of bovine knee ligaments and patellar tendon (Version 1).

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Discussion

Conclusion